'CD
f \ !-:
DEPARTMENT OF AGRICULTURE
VITICULTURAL STATION, RUTHERGLEN, VICTORIA.
WINE-MAKING IN HOT CLIMATES,
L . R O O S ,
Director of the (Enological Station of the Htrault.
Translated by
RAYMOND DUBOIS, B.Sc. (Paris),
Diplome de I'Ecole d* Agriculture de Montpellier, Director of the
Viticultural Station, Victoria ;
AND
W. PERCY WILKINSON,
Private Assistant to the Government Analyst, Consulting Analyst to the
M. and M. Board of Works.
ROBT. S. BRAIN, GOVERNMENT PRINTER, MELBOURNE.
19OO.
10649.
TRANSLATORS' PREFACE.
Iii presenting this translation of U Industrie Vinicole
Meridionale* by Professor L. Roos, to Australian wine-
makers, the sole aim of the translators has been to render
a thoroughly modern work on wine-making available,
of a type of which the necessity has been obvious, and
frequently commented on for some years.
The selection of the present work for translation was
guided principally by the fact f that the climate, and
conditions of wine-making, in the South of France, for
which the book was expressly written, are practically
identical with those of Australia. The new methods and
innovations in viuification adopted there (as also in
California) should be applied here without hesitation, if
we are to keep abreast of recent advances, or rather, of
our competitors in the export wine trade with Great
Britain, on which the future expansion and success of our
viticultural industry largely depends.
\Ve feel convinced, from an intimate knowledge of the
actual local conditions of wine-making, that the general
and immediate adoption throughout Victoria of the
improved methods of vinification so ably advocated by
Professor Roos, and already extensively applied in practice
in the South of France, Algiers, and California, will
prove of the utmost advantage to our wine industry :
* Roos, L., L' Industrie Vinicole Meridionale, pp. vi. 326. 8vo. Montpellier
and Paris. 1898.
t One of us (R. Dubois) studied for several years under Professor Roos
at Montpellier.
and should result in greatly diminishing the quantity ot
wine annually passed through the still, and in increasing
the production of sound dry wine of good keeping qualities,
which will be of higher average market value than hitherto.
Our earnest hope is that Australian wine-makers will
accord Professor Roos' book the serious attention and
consideration it merits, as recording the latest definite
advances iii wine-making in hot climates.
RAYMOND DUBOIS.
W. PERCY WILKINSON.
Viticultural Station,
Rutherglen, 15th February, 1900.
WINE-MAKING IN HOT CLIMATES.
CHAPTER I.
FERMENTATION.
Etymologically, the word fermentation (derived from the
L&tiD.tfervere9 to boil) marks the phenomenon by which the
transformation of a part of the substances constituting a
given liquid takes place, the phenomenon being accompanied
by movements similar to those produced by the boiling of
a liquid.
The term fermentation seems therefore only applicable to
cases where chemical transformations are accompanied by
a kind of boiling.
As long as the causes of these chemical transformations,
of which the bubbling is only the corollary, were not known,
the above definition sufficed ; but since the cause is known,
since we know that many other chemical transformations
although not accompanied by bubbling are similar to those
which gave rise to the word fermentation, it became neces-
sary to designate phenomena of the same order by different
words, or, as has been done, apply to all, despite its etymo-
logical inexactitude, a word which would have a conven-
tional signification.
It is scarcely necessary to speak of Pasteur, as his
numerous works on this question are universally known.
It was he who demonstrated, after the unfruitful researches
of most eminent scientists, that fermentations were the work
of infinitely small organisms called microbes.
All fermentations have a point in common, which is that
a very small weight of organized matter is sufficient to
transform relatively considerable quantities of material.
Thus, a few pounds of beer yeast may produce thousands
of gallons of that liquid, and a few grains of acetic ferment
are sufficient to transform a cask of excellent wine into
A 2
4 WINE-MAKING IN HOT CLIMATES.
Non-organized, often very soluble bodies, are known,
acting in the same way. For instance, pepsine may trans-
form a considerable weight of insoluble fibrin into soluble
peptone.
Fermentations and transformations of this class are some-
what similar, and, therefore, the general term of fermenta-
tion has also been applied to transformations brought about
by soluble ferments. However, to distinguish the two
phenomena, the fermentation brought about by organised
ferments has been called true fermentation, while that
brought about by the soluble ferments or diastases has been
named pseudo- -fermentation or diastasic-fermentation.
The microbes or agents of true fermentations exist in
infinite variety, they are subdivided into several species,
the principal being moulds, yeasts, mycoderma, micrococci,
bacteria, bacilli, and vibrios. With regard to the diastases
they are also in great variety, and bear different names in-
dicating either their origin or behaviour. That known as
pancreatine (a mixture of soluble ferments) normally exist-
ing in the pancreas, plays a very important part in digestion ;
that called amylase renders the starches soluble.
As a general principle, all fermentation induces in the
liquid the disappearance of one or several substances, and
vice versa, the appearance of one or several new products.
The most important of all is the alcoholic fermentation.
ALCOHOLIC FERMENTATION.
This is a true fermentation, and is, in the great majority
of cases the work of organised microscopical plants, known
as yeasts (levures).
It is the transformation of several substances of an
analogous chemical constitution (glucose and other sugars)
into alcohol as the principal product, carbonic acid, glycerine,
succinic acid, and a few other substances, some of which are
not yet completely known.
We say intentionally glucose and other sugars, although
it is well known that alcohol may be obtained from many
other substances, starch for example, but these substances
are not capable of being directly transformed into alcohol
and secondary products. They must first be transformed
into glucose or fermentable sugar.
FEBMENTATION. 5
There are, it is true, a few rare exceptions to this rule,
and though of very great scientific interest, they remain
unimportant in practice.
The transformation into glucose, of substances forming
alcohol, may be brought about by chemical means, or more
often by diastasic fermentations preceding the alcoholic
fermentation.
Sometimes, as happens in the case of a large number of
yeasts, the- alcoholic ferment secretes a diastase, bringing
about the transformation into fermentable sugar. Cam-
siurar, for instance, only gives alcohol after having been
submitted to a diastasic fermentation, which is indirectly
the work of the yeast itself, for it is by the aid of a soluble
ferment, invertine, secreted by it, that the preliminary pre-
paration is accomplished.
Starting from glucose, the production of alcohol is the
result of true fermentation ; starting from cane sugar, it is
the result of a double fermentation, one diastasic, the other
true.
The most searching analyses, made on many different
cepayes, have not revealed in grapes, at maturity, the
presence of cane sugar in noticeable quantities.
Grape must only contains glucoses, as directly fermentable
constituents, the two most important being dextrose and
levulose, existing in about equal proportions at maturity.
Therefore, the vinous fermentation can only be regarded as
a true fermentation.
Alcoholic fermentations are numerous ; the best known in
our regions are those furnishing wine, ale, or beer, cider, and
perry. But the alcoholic beverages used in different
countries, and prepared from very dissimilar substances —
milk, juice of certain roots — are also the result of fermenta-
tions analogous to those already mentioned.
They are all produced by related organisms, but yet not
identical. The characteristic of their common work is the
production of alcohol, but they differ individually with
respect to the weight of alcohol produced in relation to the
weight of sugar consumed, and by the nature and quantity
of secondary products formed.
These secondary products are of two kinds : first, those
depending on the variety of the t'«-rnicnt effecting the trans-
formation.
6 WINE-MAKING IN HOT CLIMATES.
The products of fermentation, principal and secondary, are
eliminated by the organisms as the result of their work.
The researches of Pasteur, justly considered unattackable
from a scientific stand-point, brought about the conceptions
we have just briefly described.
The alcoholic ferment is a plant cell, nourishing and re-
producing itself in a suitable liquid, and, as a result of its
nutrition, producing new substances utilized by it in turn.
The agents of alcoholic fermentations are called yeasts,
and belong to the order Saccharomyces.
The first studied and best known is the Saccharomyces
Cerevisicz, or beer yeast.
The Saccharomyces Cerevisice is composed of cells, which
appear under the microscope in a lenticular more or less
globular shape, often elliptic, and sometimes circular. They
measure, on the average, five or six thousandths of a milli-
metre in diameter, and are surrounded by a thin membrane,
the composition of which is approximately that of cellulose.
The yeast cells, according to their age, have varied aspects;
when young they appear turgid, full of non-granular highly
refractive protoplasm ; when old they seem almost empty,
shrivelled, wrinkled, with the protoplasm full of pigment,
and more or less opaque.
The reproduction of these micro-organisms occurs in two
different ways, but only one is of interest to the fermentation
industry, the reproduction by budding.
It consists in the cell swelling at one point of its surface.
The swelling is full of protoplasm, and, at the beginning,
is not differentiated from the protoplasm of the mother cell.
The swelling is at first very wide at the base, but contracts
gradually until it forms a true ramification on the mother
cell. Under ordinary circumstances these ramifications very
soon become detached. The cells, in groups of two or three,
become separated, and, isolated or not, become new mother
cells, ready to reproduce by the same process.
It goes without saying that to vegetate and reproduce
normally, the yeasts must find in the liquid they live in,
besides special physical and chemical conditions, elements
which are necessary to the constitution of their tissues.
These elements are of two classes, organic and inorganic,
as has been proved by numerous analyses of yeasts.
FERMENTATION. 7
The thin membranous envelope covering the protoplasm
seems to consist of a substance analogous, if not identical,
with cellulose. The following analysis, due to Schlossberger,
shows this striking analogy : —
Envelope of the Yeast. Cellulose.
Carbon ... 45-50 ... 44-:>n
Hydrogen ... 6-90 ... 6-20
Oxygen ... 47-60 ... 49-30
100-00 100-00
The envelope represents one-fifth to one-sixth of the tot si 1
weight of the yeast in a dry state. The protoplasm h;is n
much more complex organic and inorganic composition.
The greater part is formed of nitrogenous matter, similar to
albumen ; but contains also fatty substances.
The inorganic matters represent about 6 per cent, of the
total weight of the dry yeast, they number about one dozen,
their respective importance is rather varied.
Phosphoric acid and potash predominate, the phosphoric,
acid represents over 50 per cent, of the weight of the ash,
the potash about 40 per cent.
To conclude, the liquid must offer to the yeast, carbon,
nitrogen, oxygen, hydrogen, phosphoric acid, potash, and
traces of other mineral matters, to insure its development.
In the must or juices used by different fermentation
industries, the sugars furnish carbon, hydrogen, and oxyirm.
As for the other matters, they exist in various more or less
complex forms in the liquid itself. The nitrogen in the
form of albumenoid or even ammoniacal compounds. The
inorganic matters are constituents of the parts of the plants
which furnish the must.
The characteristic of the yeast is that it consumes con-
siderable quantities of carbohydrates (sugars), retaining only
a very small proportion (TVth) for the constitution of its <>\\ n
substance. All the rest is transformed into alcohol and
other secondary products already mentioned.
The work of the yeast is too complex to be expressed by
a chemical equation.
8 WINE-MAKING IN HOT CLIKATES.
The following simple table will show what becomes of 100
grammes of glucose under the action of beer yeast, in a
liquid suitably constituted : —
Alcohol ... ... ... 46-56
Carbonic acid ... ... ... 48' 36
Glycerine ... ... ... 3-25
Succinic acid ... ... ... 0*61
Glucose used by the yeast for its
constitution, and in the formation
of not clearly defined products ... 1*26
100-00
VINOUS FERMENTATION.
The vinous fermentation is that by which the must of
fresh grapes is transformed into wine.
Under ordinary conditions, it is a spontaneous fermen-
tation. The must does not require to be sown with yeast, as
is often done in the manufacture of other fermented drinks.
At maturity, the grape is covered with micro-organisms,
which induce the fermentation of the must.
This fact was clearly established by Pasteur ; and it is
only at the time of maturity that the exterior of the grape is
covered with yeast-spores.*
Grapes protected against outside dust by proper devices,
furnish musts incapable of spontaneous fermentation, if
they are prepared with the precautions necessary to preserve
them from contamination.
The particles of dust are fixed on the grapes and stalks,
and even on any other of the vine organs, by a kind of waxy
matter. This forms the grape-bloom.
Most diverse matters are found side by side, mineral
particles, spores of common mildew, germs of wine yeasts,
and in still greater number, the germs of a yeast, common
to all sweet fruits, but, as we shall see, of no great import-
ance in vinification, this is the apiculate yeast.
The principal factor in vinous fermentation is the elliptic
yeast (Saccharomyces ellipsoideus).
* Ib was believed for a loner time that the ferment or yeast existed in the
pulp of the grape. This erroneous opinion is even now quoted by certain
authors.
PLATE I.
Wine Yeast (Young).
Wine Yeast (Old).
Apiculntus YeuM •
FERMENTATION. 0
In spite of its name it is almost circular, of lenticular
shape, transparent, like the yeast of beer, and fall of re-
fractive liquid when young and active ; more or less full <>f
pigment, opaque, and shrivelled when old or living in an
unfavorable liquid.
The dimensions of the elliptic yeast are about five thou-
sandths of a millimetre each way. Its mode of n-prn-
duction is the same as that of the beer yeast, but the
ramified form is less frequent in the Saccharomyces t'.llij>-
soideus than in the Sacckaromyces cerevisite.
However, if in reality the elliptic yeast is the principal
agent of vinous fermentation, it is not so exclusively. The;
apiculate yeast (Saccharomyces apiculatus) is one of the
most widely distributed in nature. Pasteur was the first
to indicate its existence on acid and sweet fruits generally,
and grapes in particular. Reitsch and Martinand * also
indicated the predominance of apiculate yeast on the
surface of ripe grapes.
They have shown, further, that it exists in abundance at
the beginning of any spontaneous vinous fermentation.
Its action, however, is only partial, for it cannot live in
must containing more than 3 to 4 per cent, of alcohol.
Reitsch and Herselin established this fact by a series of
conclusive laboratory experiments.!
The elliptic yeast, on the contrary, is able to work in a
much more alcoholic liquid. It commonly gives up to 16
per cent, (by volume) of alcohol, J but it really starts work-
ing in ordinary cases, that is, in unsterilized musts, only
when the fermentation has been commenced by the apicu-
late yeasts.
For vinous fermentation to take place under good con-
ditions, and for a must to give not only the maximum
yield in alcohol, but also that harmony of qualities which
assures its value, the fermentable liquid should realize
certain chemical and physical conditions, some of which
arc still obscure, but others very distinctly established.
Later on, when discussing the vintage, and vinification. we
will study the influence of the chemical and physical con-
ditions of the must, on the quality of the wine. We desire
* Comptes Rendus de 1'Acad. des Sciences, 6 April, 1891. Des inicro-
organismes des raisins raurs.
t Reitsch and Herselin. Proyrcs agricolc et viticcle, 1895.
t 28 per cent, of proof ppirit.
10 WINE-MAKING IN HOT CLIMATES.
to draw attention here to the relative inferiority in prac-
tice, now long known, of the wine-making industry as
compared with other fermentation industries.
Defects in qualities of wines are of two kinds. Those
known as organic, depending on the grape, the cepage, its
state of maturity, the atmospheric influences which it was
submitted to, alterations caused by diseases it may have
been subject to, &c.
Against some of these defects nothing very effective can
be done ; against others, resulting from vine diseases, for
instance, continual care and efficacious treatment are gene-
rally sufficient to annihilate them.
The other qualities or defects, which may be termed
accidental, are the result of different manipulations to
which the grapes were submitted during their transforma-
tion into wine, and of the conditions under which the
transformation was effected. Theoretically, the transfor-
mation ought to take place under the exclusive influence of
the yeasts we have just mentioned, but practically it is not
so.
The vinous fermentation generally remains the principal
result, but side by side there are effected a number of other
fermentations, which are known as secondary fermentations,
because they usually have less influence on the nature of the
product. Their action, however, is never nil in practice,
and the further the must is from its normal state, the
greater their importance becomes.
In all the industries of fermentation of sweet musts, what-
ever the origin of that must is (brewing, distillation, for
example), manufacturers do not go groping like blind people ;
the conditions of these fermentations, on^ the contrary, are
carefully studied, and care is always taken to realize the
most favorable conditions.
In the wine-making industry this is not done, perhaps
because it is the most important of all. This seems to every-
body, however, to be a very poor reason. We are more
inclined to think that it is because the wine-grower does
not know, and will not take the trouble to frankly regard
himself as a manufacturer during the vintage time.
We know what objections will be raised against this
argument. The grape harvest is only made once a year,
whereas, the operations of other industries are repeated
every day. W e agree that this is a difficulty, but also think
FEKMENTAT10N. 1 1
that it does not justify either a complete lack of observation
or disregard ; it seems, on the contrary, that the necessity of
observing the conditions is so much more necessary as the
occasions are more rare.
Are there many vignerons who are able to recall the
behaviour of particular vatfuls of the preceding year, the
diverse phases of their fermentation, or who possess such
a stock of observations as to enable them to deduce the
best conditions for the vinous fermentations ? They are
rarce aves.
The characteristic failing of vine-growers is to act without
method, and the result is an exceedingly great diversity of
processes used in working the raw material, which, after all,
does not vary much in composition.
12 WINE-MAKING IN HOT CLIMATES.
CHAPTER II.
STUDY OF THE GRAPES.
MATURATION.
The phenomenon of the maturation of fruits has been the
object of numerous studies. Many eminent scientists have
tried to solve this captivating problem, but we cannot yet
state that complete light has been thrown on the subject.
We shall refer here to a study, dating from the last few
years only, which is interesting from two points of view —
first, because it summarizes the principal works on the
subject ; secondly, because it is applied to a very important
cepage of the southern region of France.
That cepage is the Aramon, and the Aramon grafted on
American vines in extensive culture.
The researches mentioned date from 1891. In that year
the vine which furnished the samples was not submitted to
any particular care. In the preceding year it had received
an ordinary fertilizing with farm manure composed of
arachide shells litter.
The plot of ground, situated in the commune of Ville-
veyrac (Herault), is flat, constituted of clay-limestone soil,
limited to the west by a departmental road and by private
roads on the other sides.
The vineyard, planted with Jacquez in 1884, was grafted
with Aramon in 1886.
The samples were taken every fortnight, from the 1st of
May to the 21st of September, 1891. The vintage took
place on the 28th September.
The first sample taken on the 1st May represents the
whole of the buds ; but, from the 1 5th of May, it was pos-
sible to separate the three principal aerial organs — the
grape, leaf, and branch — and to analyze each separately.
In this study we will consider more particularly the for-
mation of sugar in the grape.
STUDY OF THE GRAPES. 13
FORMATION OF SUGARS IX THE GHAL'E.*
"Although these experiments were not carried out with
the exclusive object of throwing light on the controversy a>
to the origin of sugars, we shall see that the results may In-
valued, in presence of the principal hypothesis actually
existing on the genesis of the sugars in grapes. As happened
with Fortes and Ruyssen, we found ourselves confronted with
three theories to explain the essential phenomena of mat ura-
tion — diminution of acids and augmentation of saccharine
matters — for, as we have seen, these two phenomena occur
at the same time.
" 1st. The theory which regards tannin as the generator
of sugar.
" 2nd. The theory which considers starch as the principal
source of almost all the organic principles.
" 3rd. The theory which accords to the acids the part
played by starch in the above theory.
" We have not followed the tannin in the various phases
of vegetation, and cannot therefore express an opinion on
the first of these theories. It has been, however, almost
completely abandoned,
" With regard to the second, we searched for starch in the
different organs and succeeded in detecting it under the
microscope, in small spherical granules, greenish, but not
coloured blue by iodine, and not luminous in polarized light
with the Nicols crossed. Only a few granules of an
irregular shape were coloured blue by iodine.
" The starch with these two characteristics was only found
in the seeds of the grape. The granules, however, were
smaller than those of ordinary starch — comparable in dimen-
sions to those of rice starch.
"We cannot conclude from these succinct results that
starch only exists in small quantity, or not at all, in the
different organs of the vine. Sachs, Cuboni, Sehimper, with
less rudimentary methods, consisting of eliminating the
chlorophyll by a preliminary treatment, have detected and
even estimated the starch in vine leaves ; we have no wish
to depreciate the results obtained by these observers, without
previously obtaining the support of more convincing experi-
ments.
* L. Roos & E. Thomas. Contribution a 1'etude de la vegetation de la
vigne. (Ann. Agronomiques.)
14 WINE-MAKING IN HOT CLIMATES.
" Starch seems, therefore, to exist in the leaves, and, in a
general way, in all the green parts of the plant ; it may
therefore be considered as the source of the more or less
numerous organic products, particularly the saccharine
matters.
" But this hypothesis has been contradicted by Buignet,
who, to begin with, contests the presence of starch in acid
fruit.
" In admitting its presence in the plant, he adds that its
transformation could not in any case furnish the sugar of
the fruits, as this sugar is laevogyre, while the glucose
derived from starch is dextrose, with a rotation of + 53°.
This is an argument which seems to dispose of the opinion
of Alessandri and Pollacci,* who assert that the sugar is the
result of the saccharin" cation of the starch in the pips or
seeds ; and that of Leon Brasse,| who studied the trans-
formation of starch in a great number of different leaves,
amongst which, it is true, the vine leaf does not figure, and
demonstrated that a soluble ferment, amylase, existed in
all leaves, capable of saccharifying not only the soluble
starch, but also crude starch.
" This appears convincing, but to be really so it would be
necessary to know if the vine starch exists only in one
modification, and if that modification is that furnishing
dextrose by saccharification.
" We know that the sugar resulting from saccharification
of inuline is laevogyre, and it is not proved that inuline does
not exist in the vine.
" Previous observations due to Deherain established that
the rotation of fruit sugars, though at first decidedly positive,
diminishes progressively and passes to minus. Later on,
Prof. Bouffard, of the School of Agriculture, Montpellier,
arrived at similar results while studying Aramon must.
Our results entirely confirm those of the two above authors,
and allow us to affirm that grape-sugar is composed of an
admixture of glucoses in which dextrose predominates before
maturity.
" Buignet asserts that the sugar of fruits is at first in the
state of cane sugar, which, later on, by inversion yields
glucoses. But the argument he advances against the
* Botanische Zcitung, 1883.
t Dissolution de 1'aiuidon dans les feuilles. Ann. Agronom., t. xii.
STUDY OF THE GRAPES. 15
amylaceous origin may be turned against him, for if it is
true that grape-sugar has about the same composition as
inverted sugar in the fruit at maturity, this is not true it'
it is considered before that epoch, and the inversion giving a
mixture in equal parts, laevogyre, of dextrose and levulose,
could not at any moment produce a sugar of positive
rotation.
" To conclude this matter, Boehm has proved that the
leaves form starch with the aid of sugar, and that, by sub-
mitting plants normally exempt from starch to the action
of, -i saccharine solution, one can, after a while, distinctly
detect the formation of starch.
" Schimper, arguing from his own experiments and those
of Boehm, concludes that the appearance of starch in the
leaves being always posterior to that of glucose, this
cannot have an amylaceous origin, at least in the leaves ;
its accumulation in the fruit would therefore be the result of
a direct migration in the shape of glucose, or an indirect
migration of the glucose transformed previously into ordi-
nary starch, and further into soluble starch, which would
pass into the berry to become saccharified.
"Arnylase operates, no doubt, in rendering the starch
soluble, and subsequently in saccharifying it.
" It is also to that ferment that the disappearance of
cane sugar should be attributed.
" However, it is possible to admit that the inversion of
the crystallizable sugar furnishes a part of tbe glucoses
detected in the fruit, that a part of those glucoses emanates
from the starch, the dextrose being furnished by the
ordinary starch, the levulose by a kind of inuline, or, as
we will see later on, might have a different origin.
u Let us now examine our results, in comparison with
the theory which sees in the transformation of the acids
the genesis of the sugars.
"From the weights of the grapes, leaves, bram-hrs, and
the number of branches gathered for .each experiment,
we intend to establish the composition of an average
branch, starting from the 28th June, the date at which
the blooming is completely achieved ; and place in
juxtaposition the absolute quantities of acids expressed as
sulphuric acid, of saccharine matter as glucose, and of the
ashes contained in the different organs.
1C,
WINE-MAKING IN HOT CLIMATES.
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STUDY OF THE GRAPES.
17
" To enable these results to be readily grasped, we have
expressed them by a graphic curve indicating the elements
in absolute value at different epochs.
ABSOLUTE QUANTITIES- OF SACCHARINE MATTER (AS
GLUCOSE), OF ACIDITY (AS SULPHURIC ACID), AND ASH
CONTAINED IN AN AVERAGE CANE.
Sugar.
1--X--
Ash.
Acids.
28'June | 12 July | 26. July | 9 Aug. | 23 Aug. | 6 Sept. | 21 Sept.
" We have seen previously that the percentage strength of
the sugar in grapes increases at the precise moment that
the production of acidity diminishes. If we consider the
absolute value of the grape, and the average branch, it is not
so any more ; the acidity constantly increases in absolute
value up to the 23rd August, and the formation of sugar is
observed at the same time.
" The augmentation of the sugar is even enormous, from the
Oth to the 23rd August, for it is during that period 25 times
greater than that observed previously for equal intervals.
"The variations of the acidity and saccharine matter
therefore seem independent of each other — at least up to the
23rd August. From that date the saccharine uiattrr
increases considerably up to maturity, but we observe at the
same time, a great diminution in the quantity of the acid.
10649. B
18 WINE-MAKING IN HOT CLIMATES.
It seems impossible to admit that the total sugar is derived
from the acids, for we notice that the absolute quantity of
each increases simultaneously. At the same time, we cannot
say that the acids do not furnish their contingent of sac-
charine matter.
" Fremy noticed that the acid reaction of fruits
diminishes with ripening, but he also notes that in a great
many cases the acids of the fruit do not disappear, but
become neutralized by combining with the bases circulating
in the plant. If that reaction really occurs in the vine
there should be an increase in the weight of the ashes at the
precise moment that the free acids disappear.
" In fact, we notice between the 23rd August and the 6th
of September a marked increase in the weight of the ash
—we cannot say that the totality of the acids disappeared, or
have become combined with the bases. For in the preced-
ing intervals the weight of the ash was increasing together
with the acids. To fix with certainty the destiny of the
acids, we ought to be able to measure the whole of the acid
produced during a given time. In other words, to know
and measure all the acids, at first free, and afterwards
combined.
"It seems to us that a part of them at least is utilized
in the formation of organic salts, the bases of which are
found in the ashes.
" What becomes of the remainder ?
" Although we cannot state that the acidity decreases in
absolute value when the saccharine matter is augmenting,
we may at least notice that when the acidity decreases, the
sugar, composed in greater part of dextrose, changes its
composition.
" This change is very distinctly shown by the polarimetric
deviation, which from slightly plus or nil passes to minus,
and increases in that direction up to maturity.
" It will be easily conceived that the necessity for perfect
washing, and of diluting the matter in a large volume of
water, prevented us from making precise polarimetric obser-
vations. We noticed slight plus deviations up to the
23rd of August, and at that date the must, which contained
5' 3 per cent, of glucose, showed no deviation whatever ; on
the 6th September the must contained 9 per cent, of glucose,
and the observed deviation in a 20-centimetre tube was
-12°.
STUDY OF THE GRAPES. 19
" The augmentation of sugar may, therefore, be attributed
for the greater part, to the formation of levulose during that
period.
" Prof. Bouffard, already mentioned, concludes in the same
way. according to experiments made by him on Aramon
cepage, that the dextrose is first formed, and that the
levulose appears later on.
" As the result of our observations, it appears that the
'diminution in absolute value for the acidity, is always accom-
panied by an augmentation of levulose in the fruit, and one
is led to think, that if the acids contribute to the fermentation
of sugar, it is the levulose that originates from them.
" We certainly do not want to generalize this hypothesis,
or even to apply it to the Aramon cepage in an absolute
manner. Our experiments, only conducted during one year,
and under given conditions as to soil and climate, ought
to be confirmed by new studies or experiments made under
different conditions as to soil and climate.
" We may add that on the 10th August, the acidity of the
grapes was constituted by more than 50 per cent, of free
tartaric acid, which progressively diminished, and on the
21st of September was not detectable."
COMPOSITION OF RIPE GRAPES OF DIFFERENT CEPAGES IN
THE SOUTH OF FRANCE.
The succinct study of the phenomena of ripening which
we have just considered, is only of theoretical interest to the
wine-making industry.
The knowledge of the immediate composition of grapes at
vintage time is of much more direct interest.
Until recently no complete study of the subject had been
made. Girard and Lindet have filled this gap, and we will
borrow from their very conscientious and complete work, a few
general ideas on the composition of the different parts of the
fruit, and figures relating to the principal ccpages of the
South of France.*
With regard to its apparent structure, the grape is divided
into two parts.
The stalk, that is to say, the ligneous and herbaceous purrs:
and, secondly, the berries borne by it.
* A. Girard and L. Lindet. Composition des raisins des principaux
cepages de France. Bulletin du Ministere de I1 Agriculture, Paris, 1895.
B 2
20 WINE-MAKING IN HOT CLIMATES.
The berry comprises three principal organs : the skin or
pellicle (outside envelope); the pulp, mass of cells filled
with juice ; the pips or seeds, reproductive organs, generally
disposed symmetrically around the centre of the berry.
Each of the four parts composing the fruit — the support,
pellicle, pulp, and seed — has a special composition. Each
brings to the vat special substances exerting a favorable or
unfavorable influence on the wine, proportional to the abso-
lute quantity of active substances they may contain.
As far as vinification is concerned, the grape consists of a
liquid part — the must, and a solid part — the marc.
The must alone contains all the substances necessary to
the fermentation of white wine, sometimes even of a reddish
wine, and contains all the substances necessary to the life of
the vinous yeast.
These are, placed in their order of importance (water
excepted) : —
Glucoses : dextrose and levulose.
Organic compounds, acid or not.
Salts of organic acids (bitartrate of potash).
Mineral or inorganic salts, phosphates, sulphates, traces of
chlorides, &c.
The mixture of dextrose and levulose is the most important
part of the must, these sugars constitute its value, deter-
mining the future alcoholic strength, and give to the wine its
vinosity through the three principal bodies formed as the
result of their transformation, alcohol, glycerine, and succinic
acid.
The organic acids and the acid salts of the must are of
secondary importance, but of such relative importance that
every vine-grower ought to be able to determine the exact
amount of acidity in must.
It is this acidity which renders the must more favorable
to the alcoholic than any other fermentation, when its per-
centage is sufficient. It may therefore be necessary to in-
crease in practice the amount of the acidity. This operation
is often done ; although very frequently in a rather empirical
manner, sometimes by acidifying musts which would do much
better without it, and not acidifying musts enough which
really need the addition.
We shall refer again later on to this operation, as the
only one we consider useful for the improvement of certain
defective vintages.
STUDY OF THE GRAPES. 21
The other substances contained in the must contribute to
the formation of extractive and mineral matters, after having
served to nourish the yeast.
The must extracted from the interior of a berry without
coming in contact with the outside of the fruit is sterile, and
will not ferment. It is through the crashing of the grapes,
and washing of the skins by the must, that the sowing with
yeast occurs.
The marc, constituting the solid part of the grape, includes
the stalks, skins, ligneous part of the pulp, and seeds.
The fermentation of red wine takes place in the presence
of all these organs, unless submitted to special treatment,
such as stemming or removal of seeds ; each of these may
impart to the wine defects or qualities which it is well to
know. Stemming, and removal of the seeds, are opera-
tions, especially the latter, rarely used in the manufacture of
common wines.
The stalks contain a number of substances studied by the
Italian Professor Comboni. It would not serve any useful
purpose to describe these in detail, it will suffice to indicate
the principal eifect of the stalks.
They contain tannin which is dissolved by the wine. This
is beneficial, but we must not confuse the true tannin exist-
ing in small amount in the stalks with certain substances of
a disagreeable, bitter, and astringent taste which may pass
into the wine.
These substances, which may all be summed up under the
heading, organic acids and salts, are detrimental to the
finesse of the wine, as well as to its preservation and im-
provement. It is this particular astringent taste of wines
fermented on the stalks which resulted in erroneously
attributing to them an excessive richness in tannin. This
was a mistake ; for Coste-Floret, who advocates with firm
conviction the operation of stemming, has proved that the
difference of richness in tannin was very slight between a
stemmed and non-stemmed vintage.
On the contrary, Prof. Bouflard asserts that stemming
sensibly diminishes the richness in tannin in the proportion
of 1*15 to 1*60 for the Aramon.
We are, therefore, confronted with two conflicting state-
ments.
In reality, the stalks of ripe grapes contain only a small
amount of tannin, and even if they did not furnish any to the
22 WINE-MAKING IN HOT CLIMATES.
wine, their presence would play a useful part, that of sub-
dividing the marc and facilitating the penetration of the
surrounding liquid.
They may prove inconvenient on account of the detri-
mental substances already mentioned, and this will certainly
be so if the proportion of stalks is too great. This is very
rarely the case for the cepages in the South of France, if the
length or duration of the maceration is not too prolonged,
and if the temperature of fermentation does not become too
high.
Under the influence of excessive temperature and pro-
longed contact with the liquid, the cells of the stalks are
softened and disintegrated, and the matters or bodies they
contain are directly exposed to the solvent action of the
surrounding liquid, helped to a great extent by the elevated
temperature. This inconvenience is considerably diminished,
or even stopped, if the duration of maceration is reduced and
the temperature maintained between recognised limits. As
the stalks introduce into the wine elements which assist in
the formation of a good foundation, and their presence being
mechanically useful, we are inclined to think that preliminary
stemming should not be employed in the case of wines for
ordinary consumption. We do not find in this practice
marked economical advantages, especially if we reduce the
noxious influence of the stalks by well-conducted fermen-
tation.
Later on, when discussing stemming, we will go into the
question more fully, and give precise opinions about this
practice.
The pellicle or skin constitutes the most important solid
organ of the grape in the vinification of red wine. It brings
with it the colour, most of the tannin, a notable proportion
of extractive and mineral matter, and the greater part of
the germs of yeast.
Armand Gautier* has carried out important researches
on the colouring matter of the grape, and more successfully
than previous investigators. From the study of this sub-
ject he was enabled to establish the formation in the leaf
of coloured matters, derived from colourless substances
producing ampelochroic acids, which, migrating from the
leaf towards the fruit, constitute in the pellicle different
colouring matters now known as cenolic acids.
* Comptes rendus, vols. 84 and 114.
STUDY OF THE GEAPES. 23
These oenolic acids are all red, but of various shades,
according to the cepage. They give the colour to the skin
of the grape, and exist in great variety, their chemical
composition, although not exactly identical, is close enough
to allow it to be practically considered so.
These colouring bodies are distributed in the cells \\\ tin-
periphery of the grape under the. epidermis, in the majority
of cepages.
Quite characteristic is their insolubility in \\.-iter, except,
however, in cepages teinturiers, or varieties derived from
them, such as Bouschet hybrids.
They are slightly soluble in strong, but not in weak acids.
This explains the possibility of making white wine from red
grapes (a great number of cepages at least) as the colouring-
matter does not find in the must before fermentation a
proper solvent.*
The oenolic acids form a chemical group, the propertie>
of which closely resemble those of the tannins, as has been
established by Louis Hugounenq.t We, therefore, see at
once the importance of the pellicle, for through its oanolic
acids and pure tannins it furnishes the wine with useful
tannin-like substances.
The action of the tannins is very favorable, they are good
antiseptics and powerful preservatives against the possible
future deterioration of the wine. On, the other hand, they
communicate to the wine that special flavour called by wine
tasters charnu, mdche, grain.
The pellicle also contains an important odoriferous sub-
stance which has been carefully studied by Girard and Lindet.
" One of 'the most interesting facts, noticed by us during
the analytic study of the different parts of a grape, is the
localization in the cellular tissue of the skin of an odorifer-
ous substance which gives to the wine of each cepage an
essential and peculiar character — this substance is totally
distinct from the bouquet, which is only formed gradually
as the wine becomes matured.
* According to recent experiments made by Rosensthie), this opinion may
be disputed, at least as far as the fruit sugars are concerned, if not the water.
Rosensthiel proved that, when out of contact with air, the colouring matter of
fruits is dissolved in their juice by prolonged contact, and especially at an
elevated temperature ; this, it is understood, without interference of fermenta-
tion, in other words, in absence of alcohol. He goes so far as to state that we
may preserve the must with the colour, flavour, and perfume of the fresh fruit.
A very easily conducted experiment shows that the colouring matter of the
grape is not soluble in water. It suffices to dilute with water a concentrated
alcoholic solution of the colouring matter to precipitate it as a powder.
t Jtecherches nouvellcs sur le vins. Imp. A. Storck, Lyon.
24. WINMfAKING IN HOT CLIMATES.
" All oenologists know that every wine resulting from the
fermentation of a particular cepage has, especially while the
wine is yonng, a characteristic flavour. The wines made
from Aramon and Carignane, for instance, from the South
of France, and those from Pinot and Gamay, from the Bour-
gogne cepages, differ entirely from each other.
"Expert tasters can differentiate these odours, which
must not be confused, as is often done, with the so-called
earthy taste. It is not the climate nor soil which determines
it, they are peculiar to each cepage, and are often sufficient
to characterize it. The influence of climate and soil only
modifies them.
" The origin of these odours has not been indicated up to
the present. Our researches enable us to state that they
must be sought for in the cellular tissue of the skin, where,
ready formed, this odorous matter, which imparts the
character to the wine, exists side by side with the colouring
matter, which determines the robe of the wine.
u Vergnette-Lamothe had, it is true, so far back as 1867,*
originated the idea that certain essential odoriferous oils
existed in grape skins, but the part played by them, and their
nature, had not been ascertained so far.
"It is only in studying the weak alcoholic solutions from
macerated skins for the estimation of the colouring matter
and tannin, that we recognise the importance of this obser-
vation.
" Each of these solutions after a few days was impregnated
with a strong odour reminding us of the flavour of young
wine, and were easily differentiated from one another even
by non-expert observers."
The seeds contain a fatty oil which is fairly abundant, and
a number of substances some of which would be detrimental
to the wine, if they were dissolved.
Fortunately, the most useful substance the seeds may yield
to the wine, tannin, is placed near the periphery in such a
way that it enters into solution before any of the others are
appreciably affected. The increase in tannin due to the
presence of the seeds is not positively proved, although some
authorities believe that that substance is completely and
quickly dissolved.
According to Girard and Lindet, " the seed also contains
a resinous matter, the formation of which seems to be in direct
Le Vin, by Vergnette-Lamothe, p. 335.
STUDY OF THE GKAPES. '„'.'>
proportion to that of the tannin ; volatile acids are also con-
tained, which apparently belong to the fatty series. They
result from the saponification and oxidation of the neutral
oil contained in the nucleus of the seed.
" The resinous matter is easily soluble in alcohol, slightly
soluble in boiling water, and almost insoluble in cold water.
a By evaporation of these solutions it is deposited in the
form of a light-brown powder, which tastes harsh when
recently prepared but gradually becomes sweetish.
" It may be dissolved in alkaline liquids and precipitated
from the combination so formed by the addition of an acid.
It is easily oxidizable, especially in the presence of alkalies,
and through oxidation loses the above-mentioned properties.
"To summarize, it is analogous to ordinary resins, but
more rapidly alterable, and may be placed provisionally on a
level with the product extracted from the bark of certain
trees by Hoffstetter and Stahelein, and named by them
Phlobaphenes.
" Amongst the properties mentioned above, one of them
cannot fail to attract the attention of oanologists, namely,
that the harsh taste is progressively attenuated by time —
that attenuation enables us to account for certain long-
known changes in the taste of maturing wines.
" But the presence of volatile acids detected in the seeds
is still more important — they probably play an important
part in the production of the bouquet."
We are inclined to think that Girard and Lindet place an
exaggerated importance on the substances contained in the
seeds. The analogy of the action of time on those substances,
compared with its action on wine itself, does not seem to
be sufficient to credit them with such importance. The
harshness of young wines is generally recognised ; it exists
in stemmed red wine, and even red wines fermented without
the seeds ; and even in white wines, fermented without
contact with either skins or seeds.
However, if the seeds are not crushed — and they never
should be—their presence is harmless. The epidermis is
impermeable enough to prevent the solution of the substances
contained in them, which might exercise a detrimental in-
fluence on the wine. Besides, they are contained in the
centre cells, and their solution is not to be feared, provided
that the epidermis is not softened by too prolonged macera-
tion.
26 WINE-MAKING IN HOT CLIMATES.
In short, in the South of France, all the solid parts of the
fruit may remain in contact with the must during fermenta-
tion, in the manufacture of red wine. Their presence pre-
sents some advantages and very few inconveniences.
COMPOSITION OF GRAPES OF THE PRINCIPAL
"CEPAGES" OF THE SOUTH OF FRANCE.
AKAMON "CEPAGE."
Constitution of the bunch.
1893. 1894.
Stalks ... ... ... 4-07 ... 3'65
Berries 95-93 96-35
100-00 100-00
Constitution of a berry of average weight 3-69 gr.
Pulp ... ... ... ... 88-81
Skin ... ... ... ... 9-45
Seeds 1-74
100-00
The 88*81 per cent, of pulp represented 83*4 litres of
juice per 100 kilos, of berries.
Chemical composition of the pulp representing SS'8l per cent,
of the weight of berries.
1893. 1894.
Density of juice ... ... 1-064... 1-056
Water ... ... ... 82-46 ...
Fermentable sugar... ... 14-09 ... 11-48
Bitartrate of potassium ... 0-62 ... 0-51
Free tartaric acid )* n ,>Q TO- 12
Malic and other acids ] \ 0-68
Nitrogenous matter ... 0-27 ...
Matters not estimated ... 1*61
Mineral mattersf ... ... 0-13 ...
Ligneous insoluble ... 0-43 ...
100-00
* Expressed as malic acid. The figure for 1893 appears very small and is
met with quite rarely. — L. R.
t The potash in combination with tartaric acid deducted.
STUDY OF THE GBAPES. 27
Chemical composition of the skin = 9-45 per cent, of ////•
weight of the berry.
1893. 1894.
Water ... ... ... 76-80 ... —
Tannin ... ... ... J-27 ...
Bitartrate of potash ... — ... 0-88
Free acids* ... ... ... n-r.'.t
Ligneous... ... ... 20-10 ...
Mineral matters ... 1-83
100-00
Chemical composition of the seeds = 1-74 per cent, of tl»>
weight of the berry.
1893.
Water ... ... ... ... 34-82
Oil ... ... ... ... 6-92
Volatile acidsf ... ... ... 0-57
Tannin ... ... ... ... 2-56
.Resinous matters ... ... ... 4-45
Ligneous ... . ... ... ... 48-82
Mineral matters 1-86
100-00
Chemical composition of the stalks = 3'85 per cent,
(average) of the grapes.
1893. ' 1894.
Water ... ... ... 79*66 ... 78-91
Tannin ... ... ... 1'23 ... 2-52
Resinous matters ... ... 1*07 ... 0'87
Bitartrate of potash ... ... 0-92
Free acids | ... ... ... 0-33
Ligneous ... ... 15*71 ... 14*49
Mineral matters ... ... 2-33 ... 1'96§
100-00
* Expressed as tartaric acid.
t Expressed as sulphuric acid.
+ Expressed as tartaric acid.
§ The potash in combination with tartaric acid deducted.
28 WINE-MAKING IN HOT CLIMATES.
CARIGNAN CEP AGE.
Constitution of the bunch.
1893. 1894.
Stalks ... ... ... 3-00 ... 2-91
Berries 97-00 97-09
100-00 . 100-00
Constitution of a berry weighing 2-58 grammes.
1893.
Pulp ... ... ... ... 89-40
Skin ... ... ... ... 7-60
Seeds ... ... ... ... 3-00
100-00
The 89*40 per cent, of pulp represented 83 litres of must
per 100 kilos, of berries.
Composition of the pulp=89'4Q per cent, of the weight
of berries.
1893. 1894.
.Density of juice ... ... 1-076 ...
Water ... 77-85 ...
Fermentable sugar ... 16-12 ... 12-64
Bitartrate of potash ... 0'62 ...
Free tartaric acid ... ... ) ^./-g \*§±
Malic and other acids ... /
Soluble nitrogenous matters... 0*18
Matters not estimated ... 3-80 ... —
Mineral matters ... ... 0-17 ... —
Ligneous insoluble ... 0-68 ... —
100-00
STUDY OF THE GRAPES. 29
Chemical composition of the skins=!'§ti per cent, of the
berry.
1893. 1894.
Water 73-76 ...
Tannin ... ... ... 1-61 ...
Bitartrate of potash ... — ... 1'07
Free acid ... ... ... 0-70
Ligneous and not estimated ... 22*73 ...
Mineral matters ... ... 1*90 ....
100-00
Chemical composition of the seeds=3 per cent, of the weight
of the berry.
Water 33*28
Oil ... ... ... ... 7-81
Volatile acids ... ... ... 0-81
Tannin ... ... ... ... 0-31
Resinous matters ... ... ... 1*30
Ligneous and not estimated ... ... 54*66
Mineral matters ... ... ... 1*78
100-00
Chemical composition of the stalks = 2-41 per cent, of the
weight of the bunch.
1894.
W-iter ... ... ... 69*50 ... 72'0€
Tannin ... ... ... 1*01 ...
Resinous matters ... ... 0*85 ... 1-J1
Bitartrate of potash ... ... 1*1"
Free acids ... ... ... ()*4*
Ligneous and not estimated ... 2-V96 ... 22'0'.»
Mineral matters ... ... 2-68 ... 'J'l"
100-00
30 WINE-MAKING IN HOT CLIMATES.
PETIT-BO USCHET CEP AGE.
Constitution oj the bunch.
1893. 1894.
Stalks ... ... ... 4-40 3'82
Berries ... ... ... 95-60 96-18
100-00 100-00
Constitution of a berry weighing 1-95 grammes.
1893.
Pulp ... ... ... ... 85-80
Skin ... ... ... ... 11-36
Seeds 2-84
100-00
The 85-80 per cent represented 80-8 litres of must per 100
kilos, of berries.
Chemical composition of the pulp =85- 80 per cent, of th(
weight of berries.
1893. 1894.
Density of juice ... ... 1-061 ...
Water ... ... ... 82-11 ... —
Fermentable sugar ... 15*74 ... 15*80
Bitartrate of potash ... 0-66 ...
Free tartaric acid ) (H8 _
Malic and other acids (
Soluble nitrogenous matters ... 0-22 ...
Matters not estimated ... 0*68 ... —
Mineral matters ... ... 0-08 ...
Ligneous insoluble... ... 0-33 ...
100-00
STUDY OF THE GKAPES. 31
Chemical composition of the skin-=l\'%$ per cent, of the
weight of the berry.
1893. 1894.
Water ... ... ... 77-94 ...
Tannin ... ... ... 1*06 ...
Bitartrate of pot;i s 1 1 ... ... 1 .03
Free acids ... ... — ... 0-43
Ligneous ... ... 19-95 ...
Mineral matters 1-05 ... —
100-00
Chemical composition of the seeds=2'S4 per cent, of the
weight of the berry.
1893.
Water 38-02
Oil 4-48
Volatile acids
Tannin ... ... ... ... 2'26
Resinous matters -... ... ... 4-07
Ligneous and not estimated ... ... 49-41
Mineral matters ... ... 1'76
100-00
Chemical composition of the stalks — 3-82 per cent, of tin-
weight of the bunch.
1893. 1894.
Water ... ... ... 80-30 ... 76-52
Tannin ... ... ... 0-89 ... 1-05
Resinous matters ... ... 1*01 ... 1-24
Bitartrate of potash ... ... 1*20
Free acids ... ... ... ()*26
Ligneous and not estimated .... 15-40 ... 17-r>:t
Mineral matters ... ... 2-4n ... -,N)4
iniMJO 100-00
Stalks
Berries
WINE-MAKING IN HOT CLIMATES.
PICQUEPOUL BLANC CEP AGE.
Constitution of the bunch.
1893.
... 4-15 .
95-85
100-00
1894.
3-04
96-96
100-00
Constitution of a berry weighing 2*62 grammes.
Pulp
Skin
Seeds
1893.
91-90
5-63
2-47
100-00
The 91-90 per cent of pulp represented
per 100 kilos, of berries.
•6 litres of must
Composition of pulp = 91-90/>£r cent, of the weight of the
berries.
Density of juice
Water ... .
Fermentable sugar
Bitartrate of potash
Free tartaric acid
Malic and other acids
Nitrogenous matters
Matters not estimated
Mineral matters
Ligneous insoluble . . .
1893.
1894.
1-060
80-67
—
15-88
... 16-68
0-53
—
0-66
... 0-81
0-21
1-42
... —
0-30
—
0-33
—
100-00
STUDY OF THE GRAPES. 33
Chemical composition of the skin = 5-63 per cent, of tin-
weight of the ben-*/.
' 1893. 1894.
Water ... ... ... 73-52 ...
Tannin ... ... ... O50 ...
Bitartrate of potash ... ... 0-80
Free acid ... ... — ... 0*49
Ligneous and not estimated ... 24-29 ...
Mineral matters 1-69
100-00
Composition of the seeds = 2-47 per cent, of the weight of
the berry.
Water ... ... ... ... 31-31
Oil ... ... ... ... 8-81
Volatile acids ... ... ... (j-64
Tannin ... ... ... ... 0*81
Resinous matters ... ... ... 1-40
Ligneous and not estimated ... ... 55-66
Mineral matters 1-33
•96
Chemical composition of the stalks = 3*50 per cent, (average)
of the bunch.
1893. 1894.
Water ... ... ... 75-48 ... 72"J4
Tannin ... ... ... 1-30 ... 2'33
Resinous matters ... ... 0-81 ... 1-40
Bitartrate of potash ... ... 1-15
Free acids ... ... ... 0-35
Ligneous and not estimated ... 2<>-50 ... 21-14
Mineral matters 1-82 1'38
100-00 99-99
The grapes used for the manufacture of red wine bring
to the vat soluble and insoluble matters, which co-npt-rate
in the- formation of the wine. The former are submitted to
a chemical transformation or are simply dissolved in the
liquid ; the latter play a mechanical part, which cannot In-
disregarded.
10649. C
34
WINE-MAKING IN HOT CLIMATES.
The soluble matters are far the most important ; in the
manufacture of white wine they are limited to those con-
tained in the pulp, the white wines being fermented without
contact with stalks, skins, or seeds.
This amply explains the difference in richness of extractive
matter observed between red and white wine, even in white
wine made from red grapes.
However, the substances contained in the must alone are
sufficient to insure largely the healthy life of the vinous
ferment whose function it is to transform it into wine.
We shall see later on in what degree it is useful to modify
the composition of the must.
MATTERS BROUGHT TO THE VAT BY 100 KILOS. OF VINTAGE.
We have already stated that each of the four constituent
parts of the complete fruit — stem, skins, pulp, and seeds-
bring to the vat special products influencing the wine, either
favorably or otherwise, proportionally to the absolute
quantity of active substances they contain.
We have just been studying the percentage composition of
each of the four parts of the fruit ; we are now going to
show in the following tables, borrowed from Girard and
Lindet's work, what is in absolute value the quantity of
active or inactive substances brought to the vat by 100 kilos,
of Aramon, Carignan, and Petit-Bouschet cepages, that is
to say, the three red cepages most widely cultivated in the
South of France.
100 kilos, of Entire Bunches bring
to the Vat—
Name of Product.
Total.
Pulp.
Skins.
Seeds. Stems.
kil. gr.
kil. gr.
kil. gr. kil. gr.
kil. gr.
Aramon cipage.
Fermentable sugar
Bitartrate of potash ...
11-910
0-434
0;079
...
0-030
11-910
0-543
Free tartaric acid
Malic and other acids
0-102:
0-579
j- 0-062
...
0-013
0-756
Tannin
0114
0-043
0-097
0-254
Resinous matters
...
0-074
0-032
0-106
Soluble nitrogenous matters
Oil ...
0-230
...
0-115
0-230
0115
Volatile acids *
0-009
0-009
Mineral matters t
0110
0-136
0-OH1
0-075
0-352
NOTE.— For references (*), (t), and (J) see footnotes to next page.
STUDY OF THE GKAPES.
35
Name of Product.
100 kilos, of Entire Bunches bring
to the Vat-
Total.
Pulp.
Skins.
Seeds.
Stem*
kil. gr.
kil. gr.
kil. gr.
kil. gr. ; kil. gr.
Carignan cepage.
Fermentable sugar
Bitartrate of potash ...
Free tartaric acid
Malic and other acids ...
Tannin
13-980
0-537
}- 0-502
0-079
0-052
0-118
Resinous matter
Soluble nitrogenous matters ...
0156
Volatile acids*
Mineral matters f
0147
0110
...
13-980
0-079
0-032
0-648
0-052
0-017
0-571
0-118
0'009
0-029
0156
0-039
0-034
0-073
0156
0-227
...
0-227
.
0-023
0-023
o'-iio
0-052
0-061
0-370
Petit-Bouschet cepaye.
Fermentable sugar
12-960
12-960
Bitartrate of potash ...
0-543
0112
...
0-040
0-695
Free tartaric acid
Malic and other acids ..
} 0147§
0-047
0011
0-205
Tannin
...
0115
0-061
0-042
0-218
Resinous matters
0110
0-050
0-160
Soluble nitrogenous matters
0181
0181
Oil
0124
0-124
Volatile acids*
...
... |
not esti-
mated
}I
Mineral matters t
0-065
0-073
0-048
0-081
0-267
* Expressed as sulphuric acid.
t The potash in combination with tartaric acid deducted.
£ At complete maturity, we have not noticed free tartaric acid in the
Aramon grapes, nor in several other cdpagcs.
§ The figure given is very small.
C 2
36 WINE-MAKING IN HOT CLIMATES.
CHAPTER III.
VINTAGE.
The word vintage has a very wide signification ; it means
the gathering of the grapes, the result of the gathering, and
the general cellar operations connected with it. In the fol-
lowing pages we will mean by the vintage the gathering of
the grapes and the produce of that operation.
The choice of the time for the vintage is an important
question to the vine-grower.
In the South of France^ in the few days preceding perfect
maturity, the transformation of the berry is so rapid, and the
crop exposed to so many dangers, that we may easily con-
ceive the haste with which the vine-grower endeavours to
place in safety, sheltered against the inclemency of the
weather, the fruit of the year's hard labour and uninterrupted
care.
Logically, for the manufacture of table wine, the vintage
must be made when the grapes have acquired their maxi-
mum of saccharine richness and maximum weight. It is
well, therefore, to know some of the processes enabling us to
fix the precise moment at which the grapes cannot gain any-
thing by remaining longer on the vine.
These processes are of three kinds, empirical, physical,
and chemical. The first, based on the exterior alterations and
appearance of the grapes — the browning at the base of the
stem, the increased transparency of the skin, the way in
which the pedicel can be detached from the berry, with a
portion of the pulp remaining attached to it, and, above all,
the Pollacci process, relying on the close observation of the
phenomena of ripening.
Pollacci noticed that ripening always commences from the
outside and works gradually towards the centre of the grape ;
it suffices, according to him, to taste the pulp in contact with
the seed, and compare it with the pulp in contact with the
skin. Complete maturity is indicated at the moment that no
difference in taste is detected.
The physical and chemical means, necessitating special
though fortunately simple apparatus, are preferable and more
accurate.
VINTAGE. 37
DETERMINATION OF SUGAR.
The method most employed in determining the saccharine
richness is, according to the density of tin- must, determined
by means of . a densimetre, known ;ils<> us glucometre,
mastimetre, gluco-cenometre, &c.
If accurately graduated, or even if not, provided that the
correction is known, they give reliable indications. They
(liffcr slightly from one another, in some cases the graduations
read on the instruments can only be transformed into sugar
by calculation. In other cases the graduation indicates
directly the quantity of sugar present.
They all depend on the well-known law of Archimedes —
"All bodies plunged into a liquid are submitted from top to
bottom to a pressure equal to the volume of //<////>/ <//*-
placed"
It is clear, therefore, that if an instrument capable of
floating is plunged into the must, the heavier the must, that
is to say, the more sugar it contains, the less it will sink.
The density of a liquid containing a substance in solution
is submitted to variations almost proportional to the quantity
of the substance dissolved. Grape must, it is true, contains
besides sugar a fair proportion of other substances, but their
total weight compared with the sugar is negligible.
The glucometre devised by Dr. Guyot, and constructed by
the Salleron firm, is, we think, the most convenient of tlioc
instruments. It consists of a thin glass tube, widened in
cylindrical shape for one-third of its length, and provided
at its base with a small bulb.
The instrument so constructed is adjusted by placing
mercury or shot in the bulb, in such a way that when plunged
into pure water at a fixed temperature it sinks almost to the
top of the tube — at that point the zero is marked.
If now we allow the instrument to float in a saccharine
liquid of which the strength is known, it will sink less, and
level with the liquid a figure corresponding with the known
strength is marked.
To complete the graduating, it suffices to divide into pro-
portional intervals the space between the zero and the }K)int
determined by the experiment.
The graduation of these instruments is usually ready
printed on a piece of paper, fixed inside the tube at the
required height.
WINE-MAKING IN HOT CLIMATES.
r-« -s =:
--H
The graduation of the Guyot glucometre,
shown in the drawing, presents the advantage
of enabling us to read under three different
forms from one observation, giving the richness
in sugar expressed as kilogrammes per hecto-
litre, the degree Baume", also called liquor
degree, and the quantity of alcohol expressed in
volume per cent., which will result from the
fermentation of the must, if it is done under
favorable conditions, and completely.*
The Salleron mustimetre only indicates the
density of the must, and by means of a special
table sold with the instrument we can ascertain
from one observation : —
First. The corresponding degree Banine".
Second. The weight of sugar in grammes
per litre of must.
Third. The alcoholic strength of the wine
after fermentation.
Fourth. The weight of crystallized sugar
to be added to one litre of must
for the wine to contain 10 per
cent, of alcohol by volume.
Fifth. The density of the resulting wine;
and therefore the weight of
one hectolitre — the results
enabling us to gauge a cask
without measuring the liquid.
The very complete indications obtained from
a single observation, followed by the reading
of the table, make it a very handy and useful
instrument.
The glucoroenometre simply gives the -degree
Baurn6.
The shape of all these instruments is similar,
they are simply areometres of constant weight
and variable volume, which means that the
volume submerged varies with the density of
the liquid.
* A correction, however, must be made. The Guyot scale always indicating
for the determined sugar the weight and alcoholic volume a little in excess,
namely, 0'8. This, no doubt, is the result of this scale being calculated on the
basis of the theoretical chemical equation.
VINTAGE. 30
The different indications given by these areoinetres directly
or indirectly are useful, but not indispensable. It is neces-
sary in order to determine the moment of perfect maturity
to rapidly test for the stationary state of tin- saccharine
weight. For this purpose any densimetre, correct or not.
may be used, provided the same instrument is used for each
trial.
The chemical processes for determining sugar are very
exact, but are too complicated to be usefully recommen<le<l
to vine-growers.
We only attach secondary importance to the exact
knowledge of the sugar content of the must. If it is neces-
sary to operate with precision in scientific researches, it is
not so when we have to deal with wine-making on a
large scale, and densimetrical observations are sufficiently
accurate.
DETERMINATION OF ACIDITY.
This is of great importance, and gives a very good indica-
tion of the state of maturity.
The acidity of the grapes decreases from the change of
colour of the berry till maturity, remaining at that time
almost stationary, and then increases when the grapes arc
drying.
The increase after maturity is only apparent, and does not
affect the percentage weigl 1 1 .
If we measure the absolute quantity of acid in a ripe
berry, and in a berry of equal size taken at the same
moment, but left attached to the stalk to dry, we do not
find a notable diminution in the acids.
In practice, however, it is easy to detect the above-
mentioned stationary state.
We have often mentioned in previous publications and
lectures the necessity for the wine-maker to be able to
determine exactly the acidity of the musts, for it is an
important factor in the future quality of the wine.
We will explain later on the reasons which lead us to
attach such importance to the acidity.
In a laboratory, no doubt, and to anyone used to chemical
manipulations, the determination of acidity is a very simple
operation. The necessary apparatus for it always e\i>t-
even in the most elementary laboratories. In the vineyard
40
WINE-MAKING IN HOT CLIMATES.
it is complicated to any one unacquainted with the exact
measurements made on small masses, and with the necessary
calculations to bring the result to concrete figures.
The acidimetric apparatus consists essentially of an instru-
ment measuring a known volume of the liquid to be
examined, a graduated tube or burette for delivering the
alkaline solution accurately, and an alkaline solution of
previously determined strength as compared with a known
weight of acid.
The neutral point is rendered easily detectable by the use
of colouring matters, called in chemistry indicators, which
have the property of changing colour in the presence of acids
or alkalies. It suffices to have an extremely slight excess of
either acidity or alkalinity for these changes of colour to be
manifested.
The natural colouring matter of the grape is itself a good
indicator, red in acid solution, changing to green with
alkalies.
For white musts, phenolphthalein dissolved in alcohol is a
very convenient indicator. It remains colourless in acid
solutions, and becomes purple red in presence of an infini-
tesimal quantity of alkali. Acidimetres are numerous and
varied in arrangement. They do not all render the measure-
ment of acidity easy of performance by the vine-grower.
One of these, constructed by Dujardin,*
called Acidimetric tube is the smallest and most
simple. It consists of a cylindrical glass tube,
closed at its lower end, and bearing graduated
marks on the central part. The first division
from the bottom indicates the volume of wine
or must to be used ; the divisions over it serve
to measure the quantity of alkaline liquid ne-
cessary to obtain the reaction marking the end
of the operation.
The modus operandi is simple.
Pour the must or wine into the tube up to A,
adjust the liquid to the level of the division by
means of a pipette, and add, if operating on
white musts, two or three drops of phenolph-
thalein solution.
Pour in carefully, and in small quantity,
the titrated alkaline solution, a rosy tint
* J. Dujardin, successeur de Salleron, Paris.
Fig.
Acidimetric Tube,
Dujardin.
VINTAGE. 41
appears, which, however, disappears on shaking. Add the
alkaline solution in successive small portions till the last
drop colours the solution a permanent rose tint.*
The acid strength expressed as tartaric acid per litre is
given by the figure opposite the level of the liquid in the
tube.
It is a very simple operation, but perhaps less simple in
practice than it seems through reading the description.
The drawback of most acidimetres is that they are operated
with small quantities of liquid, and therefore any error in
measurement becomes greatly increased when calculated to
One litre.
When the must is measured by me ins of a pipette it gives
good results, but is rather difficult to an inexperienced per-
son. The operation seems easier when the measurement is
made in a tube, as in the above acidimetre, but the slightest
error in agreement between the level of the liquid and the
division leads to a considerable error. As for the reading
of the volume of alkaline solution, in a burette or tube it
always remains uncertain, and leads to errors, and falsifies
the result, varying more or less the smaller the quantity of
liquid that is operated upon.
We must, therefore, if we want the vigneron to get into
the habit of measuring the acidity of the grape must, devise
a simple apparatus, facilitating the operation and working*
on a sufficiently large volume of liquid to render the errors of
reading the divisions negligable ; and giving the acid
strength of the must per litre from one observation only.
We may easily make such an acidimetre with the following
pieces of apparatus : Fig. 4. First, a burette, or cylindrical
tube, 1 centimetre in diameter, and divided into -^ths from
0 to 20 cubic centimetres, B. Second, a graduated flask
'with a narrow neck cut off exactly at 100 c.c.m. to allow the
measurement of the must to be made simply by filling it, I.
A large glass beaker holding 400 cubic centimetres, D. A
titrated alkaline solution (potash or caustic soda), E.
A solution of phenolphthalein, F, of which two or three
drops are placed in the must before the operation, and by
turning red indicate the end of the operation.
The acidity of the wine is usually expressed in terms of
sulphuric acid per litre. This is a conventional arrangement
* In the case of red must a greenish colour marks the completion of the
reaction.
42
WINE-MAKING IN HOT CLIMATES.
not calling for criticism, but when we have to deal with
musts it is preferable to express the acidity as tartaric acid,
as it is the only acid used to correct the vintage. It would
suffice to titrate the alkaline solution in such a way that one
cubic centimetre would neutralize exactly 10 centigrammes
of tartaric acid, so that the figure read on the burette would
represent the weight of tartaric acid per litre.
Fig. 4.— Portable Acidimetre.
But, however simple the use of an acidimetre of this kind
may be, we must draw the attention of the vine-grower to
a few details as to the method of operating in order to
obtain exact results.
MODE OF OPERATING.
Crush with the hands, about 500 grammes of grapes, and
squeeze the juice through a cloth.
VINTAGE. 43
Fill the flask with the must thus obtained until it
overflows.
Pour the contents of the flask into the 400 cubic centi-
metre beaker ; rinse the flask with an equal quantity of
water (rain water or distilled, if possible) ;md a<M it t<> tin-
must.
Add to it 4 or 5 drops of phenolphthalein solution.
Fill the burette to the zero point with the alkaline solu-
tion ; deliver the alkaline solution gradually from the
burette into the must until the reddish coloration appears
permanently.
When that result is obtained, read on the burette the
graduation level with the surface of the alkaline solution.
Let us assume, for the sake of argument, that it is 9-7 ; this
means that the must contains 9'70 grammes of tartaric acid
per litre, or 970 grammes per hectolitre. In this case it
would be unnecessary to add any acid to the must.
Under these circumstances, even if placed in unskilful
hands, this apparatus will give sufficiently exact results,
especially if care be taken to make previously a rapid trial
giving the approximate acid strength.
To do so one operates as above described, adding the
alkaline solution in fractions of 1 cubic centimetre each.
At 8 cubic centimetres, for instance, the liquid has not
yet become red ; at 9 cubic centimetres it is completely
red, this meaning that the result is between 8 and 9
grammes per litre. It will, therefore, suffice to commence
the operation again, adding at once up to 8 cubic centi-
metres of the alkaline solution, and continuing drop by
drop till the appearance of the permanent rose tint.
A little before obtaining the final tint the liquid becomes
slightly brownish. This renders the determination of the end
of the reaction rather difficult for beginners. This colour-
ing occurs with all musts, even when there is no indicator
added, and should not be taken into account. It is in on In-
to diminish it that the must is diluted with water.
As long as the colour remains brown it need not he
further considered than as a precursory sign of the end of
the operation ; an additional two drops (^.th cubic, centi-
metre) of alkaline solution added to the must will cause the
colour to turn from brown to red quite decidedly.
A final experiment on the range of colours as above will
render this quite clear.
44 WINE-MAKING IN HOT CLIMATES.
The pieces of apparatus required are easily procured from
commercial houses. With regard to the alkaline solution,
any scientific pharmacy can supply it to order. The wine-
maker may, however, rectify the alkaline solution by dis-
solving a known weight of tartaric acid in an accurately
measured litre of distilled water (8 grammes, for instance),
and using that solution in place of the must it should show
on the burette the figure 8, if the titrated liquid furnished
by the pharmacist is exact.
The tartaric acid of commerce is . sufficiently pure to be
used for the trial, and any pharmacist will weigh it
accurately.
All non-coloured or slightly reddish musts may be tested
in the manner above described, but for coloured musts, such
as those of the Bouschet hybrids, the end reaction is not so
distinct. It is preferable, in this case, to work on must
diluted with twice its volume of water, and without an indi-
cator. The modus operandi would then be as follows : —
Fill the 100 cubic centimetre flask with must, and pour
the contents into the 400 cubic centimetre beaker ; rinse the
flask twice with water, filling it each time, and add the
rinsings to the must.
Run in, with constant shaking, the alkaline solution from
the burette.
The diluted must will pass through the following range
of colours : —Red, violet red, violet, brown, and suddenly
become deep green. This indicates the end of the reaction.
The green colour must not be observed by transmitted
light, the liquid being too deep in colour to allow a clear
perception of the transition tint, but by rotating the beaker
it is easy to detect it in the thin film of liquid wetting the
sides of the beaker.
The wine-maker, therefore, has at command two means
quite sufficient to enable him to ascertain the maturity of his
crop. First, the glucometre shows when the grapes are
not increasing in sugar content ; second, the acidimetre
shows when they are not diminishing in acidity.
It is desirable for the vintage to be made at that precise
moment, for then only can the maximum of alcoholic
strength be obtained, and therefore the maximum of
pecuniary value, considering, as goes without saying, the
common wines of the South of France. The correction of
VINTAGE. 45
the acidity, which one is very often obliged to increase,
is a simple and economical operation considering the .uain
of alcohol it brings about.
However, that desideratum is not always easy to realize in
practice, as the wine-maker is not always ;il>]<- to wait till
the opportune moment.
Many circumstances, amongst which we will note- the
necessity of assuring the indispensable labour, restrid tin-
desired objects of the large growers; the small grower alone
remains master of his vintage.
In the South of France there is a very marked tendency to
vintage sooner than is necessary. We know there are inanv
good reasons to justify this tendency, but we have still better
reasons to combat it.
INFLUENCE OF THE TIME OF VINTAGE ON THE QUALITY
OF WINES.
General observations have shown that early vintages
ferment well, and that the resulting wines are judged more
favorably by expert tasters.
We will endeavour to explain why this is so.
For fermentation to take place under favorable condi-
tions, it is necessary for the yeast, which has to transform
the sugar into alcohol and secondary products, not to be
retarded by the composition of the must or its temperature
during fermentation. We know that the yeast cannot with-
stand a high temperature, nor too large a proportion of
alcohol. Moreover, the higher the temperature the smaller
the quantity of alcohol the yeast can withstand.
If, in the fermentation of an early vintage, we do not notice
a slackening in the activity of the ferment, although the
temperature is often very high, it simply means that the
alcoholic strength is low.
In a late vintage, on the contrary, the alcohol being in
greater abundance, adds its detrimental effect to that of the
temperature, and the result of the two actions is^to paralyze
the ferment, preventing it from transforming the remaining
sugar into alcohol.
The complete disappearance of the sugar will, it is true,
in many eases, take place through a slow fermentation, but. at
the same time, other organisms will l>e at work communicat-
ing to the wine characteristics which will have the effect <>1
diminishing its organolejrfic value.
46 WINE-MAKING IN HOT CLIMATES.
Even iii admitting a complete and rapid fermentation
(which is often obtained with a late vintage notwithstand-
ing the unfavorable conditions of temperature, if the wine
is not to contain more than 10 or 11 percent, of alcohol when
completely fermented), the wines resulting are more often
than not less appreciated by expert tasters.
The tasting is very complex, and exceedingly difficult to
analyze, especially when we have to judge the pecuniary
value of a wine. We must apply for the tasting trial to
wine merchants, who always have a tendency to judge
more favorably types of wine adapted to their own particular
trade. All wine merchants have not the same requirements ;
a wine adapted to an export wine merchant's trade would
command a higher price than another wine which would
have been paid for at the same rate by a merchant selling
locally.
There is, in this instinctive tendency of the wine taster to
judge the value of a wine from his own personal stand-point,
something disconcerting for scientific researches.
However, these divergences of appreciation are not very
considerable, and if we sometimes find many wine tasters
agreeing with each other, to award the same number of marks
to a wine submitted to their judgment, they often indicate by
different terms the qualities distinguished by them. It is
therefore very difficult to determine to what element the
wine owes its quality or value, and chemists cannot fail to
recognise that an analysis of wine, however complete it may
be, cannot give its real organoleptic value
By comparing these two methods of examination, chemical
analysis and tasting, we may endeavour to discover if some
of the results of the analysis, are constant- for a comparative
tasting appreciation, and therefore if we cannot deduce a
rule from the great number of cases observed and see if that
rule is absolute and shows no exceptions.
Indeed, a rule may be deduced from the numerous
analyses of natural wines of different regions, and to that
effect we have studied the analyses published : —
By Professors Gayon, Blarez, and Dubourg, of the wines
of the Gironde, for two successive years (1887 and 1888).
By Prof. Margottet, Director of the Agronomic Station
of the Cote-d'Or, of the wines of Bourgogne.
By Giraud, David, and myself, of the wines of the He'rault
vintages of 1889 and 1890.
VINTAGE. 47
The wines of the Gironde and Bourgogne are unques-
tionably superior, owing to their origin ; their average
acidity is 5-21 for the former, and 5-98 for the latter,* acidity
expressed in terms of sulphuric acid per litre.
The analyses of the wines of the Herault furnish us
with still more suggestive results ; the acidity of the wines
for the 1889 vintage averaged 5*15, for the 1890 vintage
4*80 ; and everybody knows that the quality of the wines of
the 1889 vintage was unquestionably superior to that of the
wines produced the following year.
To sum up, the conditions under which the samples of the
1890 crop were taken enable us to deduce conclusive results
from the analyses made.
A jury of wine tasters was asked to express their opinion
of the wines ; before analysis the bottles were specially
marked, to enable them to be identified later on. The wines
judged to be the best were those in which the average acidity
was highest. The average result of the analysis gave 5.44,
being 0-64 above the average acidity of the other wines of
the same year, analyzed at the same time. The opinions of
the expert tasters, therefore, very fortunately corroborate
what we have been saying respecting the acidity of the must ;
and this is not a blind judgment, for the appreciation is
constant with regard to natural acidity. The judgment is
quite different with regard to artificial acidity ; if we take a
wine of medium quality with an acidity of 4'OU for instance,
and if that acidity is brought to 5 or 5-5 by the addition of
tartaric acid, it will still be declared to be of medium quality
by the expert wine taster, for the impression perceived by
his palate will be totally different to that resulting from a
wine naturally containing 5- 5 acidity.
All wines favorably judged by skilful tasters possess a
relatively high acidity, which is never below 4' 50 grammes,
expressed in terms of sulphuric acid per litre.
It does not follow that all acid wines are good. It only
means that wine cannot be good if deficient in acid.
We cannot hope, therefore, to make a good wine if the
average total acidity does not reach 4-50 per litre.f And in
^Figures given by P. Paul in his work on Vindication, already mentioned.
t This amount, however, is only sufficient in the case of a wine of high
alcoholic strength. It is too low, for wines containing 8 per cent, of alcohol.
To calculate the acidity as tartaric acid, the figures expressing it, as sulphuric
acid must be multiplied by 1'53.
48 WINE-MAKING IN HOT CLIMATES.
southern regions with our ccpages, a well-ripened vintage
does ifot reach that indispensable acidity, but contains it
only in under-ripened vintages.
For these two reasons ; difficult fermentation and lack of
acidity, the wines of late vintages are often classified as
inferior when compared with the wines of an early vintage.
We have tried to discover if by properly correcting the
acidity of the vintage it is possible to obtain wine of equally
good flavour, but richer in alcohol, by retarding the time of
gathering. With this object two lawful means may be used ;
the addition of tartaric acid extracted directly from the grape,
seems most simple and practical, on account of the facility
of estimating it, and its small market price.
There are also cases where the second crop may be used
with advantage,* as advocated by eminent oenologists, such
as Prof. A. Gautier.
Both of these means lead to the same result, for, as we
have said in another work,f the acidity of the second green
crop is mainly due to tartaric acid.
During two successive years we made laboratory tests,
the results of which have always been excellent, the tem-
perature of fermentation being easily regulated in the
laboratory. In cellars this is not possible, at least, not yet,
therefore we cannot expect on the commercial scale such
satisfactory results, but we have made large scale experi-
ments, amongst which we quote the two following :—
1st. At Frontignan (Herault).
Vineyard well sheltered against cryptogamic diseases
(heavier yield than previous year)|. On the 6th September
a small vat of 15 hectolitres, was rilled with Ararnon and
Carignan, in the proportion of three to one ; the first racking
took place four days afterwards.
On the 21st September the same vat was filled in, exactly
the same way, with the only difference that 60 grammes of
tartaric acid per hectolitre were added. The racking again
took place four days later.
* In the Revue de Viticulture, dated 7th September, 1895, an article
appeared on this subject. Owing: to its importance for local wine-makers, it was
translated by one of us (W. P. W.). See the Australian Vigneron. Dec., 1895.
And applied by us at the last vintage at the Yiticultural College, Rutherglen
(R. D.).
f Roos and Thomas. Contribution a 1'etude de la vegetation de la vigne.
— Ann- Agronomiques.
t The trials were made in 1895, when mildew was very prevalent.
VINTAGE. 49
From September to February the two wines were kept in
25 litre casks, without any special care, or racking or filling
up, which allows conclusions to be drawn, as to their
respective power of conservation under unfavorable con-
ditions.
The following are the results obtained by the analysis of
these two wines : —
Early Vintage T.ate Vintage
(Frontignuti). (Fruntlgnau).
Alcohol (by volume) ... 8 '6 per cent. 10 '5 per cent.
Dry extract ... ... 16*0 grammes 18 '90 grammes
per litre per litre
Reducing matters (sugars) traces traces
Acidity (total) ... ... 5 '75 grammes 6'01 grammes
per litre per litre
The wine of the late vintage is of richer colour than tlmt
of the earlier vintage ; the latter did not keep well, it turned
and became cloudy. The wine of the late vintage kept in a
much more satisfactory manner.
2nd. In the environs of Thuir (Pyrenees Orientales).
Vineyard well protected against cryptogamic diseases.
On the 12th September, a TO hectolitre vat was completely
rilled with Carignan gathered in equal parts from two plots
of the same soil, one being manured, the other not ; the
racking took place five days later.
On the 28th September the same vat was filled with
Carignan, .gathered in the same proportion from t lie same
plots, but 70 grammes of tartarie acid per hectolitre were
added.
The racking took place five days later, and the two wines
were afterwards submitted to the same treatment. Here are
the results of the chemical analysis : —
Karly Vintage Late Vintnge
(Thuir). (Thuir).
Alcohol (by volume) ... 10*50 per cent. 11 '60 per cent.
Dry extract ... ... 18 '50 grammes 25*00 grammes
per litre per litre
Reducing matters (sugars) traces 1'25 grammes
per litre
Acidity (total)... ... 5*10 grammes 5*90 grammes
per litre per litre
The wine of the late vintage is richer in colour. It is.
therefore, perfectly certain that the time of vintage has a
very great influence on the composition of the wine. The
figures expressing the alcohol and dry extract are notably
higher for the late vintage wine.
10649. D
50
WINE-MAKING IN HOT CLIMATES.
But are those wines really better, or will they simply
bring a higher price when placed on the market ? *
Personally, we think they are better, if the fermentations
were not too poor, and if the wines have a sufficient quantity
of acid. If, in other words, the vintage has been corrected
in such a manner as to obtain wines of an average acidity of
4-50 or over, per litre. It is also to be noticed that the
detrimental influence of high temperatures is diminished by
high acidity.
Therefore, this reason alone should be sufficient to induce
us to increase the acidity of the must before fermentation.
The temperature appears of greater importance when we
examine the phenomena accompanying the use of tartaric
acid in the vintage.
If the acidity of wine is an important factor for its quality,
the ratio of acidity is not alone sufficient to constitute that
factor. It is necessary that the acidity should be due
exclusively to the acids existing normally in the vintage,
even if not quite ripe. Amongst these acids the tartaric acid
alone is of importance. We have frequently tried to increase
the acidity of a wine deficient in acid (otherwise well consti-
tuted, but of medium quality only) by adding tartaric acid ;
and to submit it to the judgment of skilful tasters. In most
cases the wine was improved, but never enough to be con-
sidered a good wine.
The acidity of the wine should never be due to free
tartaric acid in notable proportion ; the tartaric acid dis-
appears in the grape as maturity advances, and does not
exist at all a few days before complete' maturity.
This is a phenomenon noticed by different authorities, one
of them being Prof. Bouffard.
From researches undertaken in collaboration with Eugene
Thomas, in 1891, f it appears that on the lUth of August the
acidity of the grape, expressed as 19-90 of sulphuric acid per
litre, was half of it due to free tartaric acid, whereas on the
21st September the acidity had fallen to 5-60, which was
exclusively due to fixation of the other acids of the grape.
* These four wines were presented to the Central Agricultural Society and to
the Departmental Society for the Advancement of Agriculture of the Herault.
The wine tasters of the former society called to express an opini n, concluded
in favour of the early vintage wines from Thuir, and in favour of the late
vintage wines from Frontignan. The wine taster of the latter society found in
both cases that the late vintage wines were superior.
t L. Roos and E. Thomas. Contribution a 1'etude de la vegetation de la.
vigne. — Ann. Agron., 1892.
VINTAGE. 51
The above figures show the percentage proportion. The
analysis made on that occasion enable us to establish the
mil disappearance of the tartaric acid, so far as free tartaric
acid is concerned, but they do not yet show the diminution
of the acid in actual value.
This disappearance, however, is certain, as the following
absolute values drawn from the same researches go to prove.
On the 10th August, 343'60 grammes of grapes contained
a total amount of acids equivalent to 6'83 grammes, expressed
as sulphuric acid, whereas on the 21st of September the same
grapes weighing 753 grammes contained only 4'21 grammes
of total acidity. This disappearance aifects, so far as free
acids are concerned, the tartaric and other acids of the fruit,
and it is quite probable! that it is simply the result of the
plant absorbing chemical bases from the soil, converting them
into neutral salts through combination with the acids.
There was, in fact, in the 343*60 grammes of grapes on the
10th August, 1*27 grammes of mineral matters, of which
O55 grammes were potash. At the same time, in the 753
grammes of grapes gathered on the 21st September, there
were 2*86 grammes of mineral matters, of which 1*20 were
potash in presence of 4'21 grammes of acidity.
Complete maturity has, therefore, the effect of fixing as
saline compounds, especially potassic, a part of the acids
forming the normal acidity of the grape, in such a way that
if the vintage does not possess at maturity the required
acidity, it is not that it does not contain the required acids
for that purpose, but that the excessive amount of potash
partially neutralizes their properties.
The addition of tartaric acid to the vintage has the effect
of immediately entering into combination with the potash,
and has, therefore, the secondary effect of increasing the
acidity, by causing the re-appearance in the liquid in a free
state of the acids pre-existing in neutral combinations. This
effect is so true, that not only do we fail to find any free tar-
taric acid in the wines resulting from an acidified viuta.nv.
but, further, we can by laboratory experiment find the total
tartaric acid added in the form of a surplus of bitartrate of
potash.
This fact has been verified by us frequently, as well as by
Prof. Bouffard, who established it a few years ago in the
course of experiments on the vindication of Jacquez.
D ^
52 WINE-MAKING IN HOT CLIMATES.
These considerations explain why the addition of tartaric
acid to the vintage produces much more favorable eifects
than the addition of tartaric acid to the wine.
In the latter case, unless we deal with very small quan-
tities, a part of the added tartaric acid remains free, and
imparts to the wine that harsh taste, setting the teeth on
edge, and contracting the muscles of the mouth in a dis-
agreeable manner, which is so characteristic of tartaric acid.
The experiments we have just been considering are no
doubt incomplete. We should also have made trials on late
vintage wines non-acidified in order to judge them com-
paratively. This did not occur to us at that time, but we
intend to complete these experiments at an early date.
A most remarkable fact noticed during the above experi-
ments is that, although we tried to bring the acidity of all
the late vintage wines up to the same standard of acidity
as those of the early vintage, the late vintage wines remain
more acid than those of the early vintage. We expected a
diminution of the acidity, as the increase of the alcoholic
strength checks the solvent action of the liquid on the bitar-
trate of potash. The only possible cause we can see to
explain the increase of the acid is an increase of succinic
acid.
There is another plausible explanation. It is a fact that
the wines resulting from the above experiments varied con-
siderably in intensity of colour, the late wines being much
richer in colour. The colouring matters which play the part
of acid in the wine are not measured in the must, and it is
to the increase of colouring matter that the unforeseen
increase of the acidity may be due. But this yet remains to
be cleared up.
The results obtained are, however, of a nature to cause
new experiments to be made in cellars, in correcting the
vintage, firstly by acidification, and secondly by regulating
the temperature.
We feel convinced that if these two conditions are realized,
wine of a much higher class will be obtained by vintaging
later than is usually done.
M. Coste, Departmental Professor of Agriculture of the
Herault, informed us recently that in any vineyard, small
enough to allow the vintage to be made rapidly, the date of
vintaging should be postponed as much as possible and the
musts corrected subsequently.
VINTAGE. 53
It is not within the scope of this work to discuss the viri-
cultural reasons that may interfere with this practice. But
if the economical advantages of late vintages were well
established, means might be found to reduce the danger
there is of leaving grapes too long on the vine.
\Ve have only aimed at showing by comparative tri.-ils
that it is possible to obtain wines of very different composi-
tion, taste, and value, according to the time the vintage is
made.
IMPROVEMENT OF CERTAIN VINTAGES.
We have already seen* the quantities of soluble matters
brought to the vat by 100 kilos, of different &' pages. In
the great majority of cases the vintage does not require to
be modified in composition, in order to furnish wines of clean
taste and good keeping quality.
There are cases, however, where improvement of the
vintage is necessary.
The defects most frequently met with are: —
Ait imperfect bloom on the berries, caused by heavy
rains, which also soil the grapes with earth.
.1 deficiency in saccharine strength, due either to an
invasion of cryptogamic diseases or of unfavorable
climatic conditions.
.1 lack of acidity, always noted during hot and damp
seasons.
In the first case the use of cultivated yeasts is indicated.
Selected pure yeasts may now be obtained in commerce, or
they may be cultivated by vine-growers, carefully choosing
only healthy grapes to start with.
We have had occasion to point outf that some vim
resulting from flooded vines, which had yielded under ordi-
nary conditions a turbid muddy liquid, deserving any name
except n'ine, had given, by the use of cultivated yeasts, wines
of clean taste and excellent keeping qualities.
It is, therefore, to cultivated yeasts that recourse should !>«•
had. whenever the skins of the grapes, from whatever cause,
are deficient in yeast germs, as is often the case in some
regions of France.
* < Jirard and Lindet, loc. cit.
t Vinif. et lev cultivees. Proyris agrlcole et viticoie.
54
WINE-MAKING IN HOT CLIMATES.
The addition of sugar to the must is the remedy for
deficiency of sugar in the grapes.*
DEFICIENT ACIDITY.
This is very frequently noticed in the South of France.
It is a true defect, for the quantity of acid in the must
has a very great influence on the development of the yeast.
We may lay down as a general principle that the more
acid a vintage is, the greater difficulty ferments other
than alcoholic will find in developing.
The standards of required acidity for a few important
cepages are : —
8 grammes of tartaric acid per litre for musts of
Aramon, Carignan, and other varieties used for
making ordinary wines.
10 grammes of tartaric acid for Bouschet hybrids.
12 grammes of tartaric acid for Jacquez.
Whenever the acid strength is below these standards, it
should be brought up to them in order to obtain the maxi-
mum quality.
The acidification of the vintage with tartaric acid is a
lawful operation, for it does not add anything to the result-
ing wine, if the addition to the must be properly made.
The acidified vintage, as we have just pointed out, does
not furnish a harsh wine, as in the case of wine acidified
after fermentation.
The acidification of the vintage is a common practice in
the South of France. Very often it is badly conducted, and
frequently done when not necessary. The explanation
offered by some vine-growers is that a neighbour did it the
previous year and made a fairly good wine.
The measurement of the acidity of the must is not an
impossible operation for vine-growers. Commerce places at
their disposal a cheap apparatus reducing the operation to-
its simplest expression. They are thus enabled to know
when it is necessary to add tartaric acid to the vintage, and
the figures we have given will enable them to know in
what proportion the addition of acid should be made.
* We have omitted the details of this practice as it is rarely necessary in
Victoria. (Trans.)
VINTAGE. 55
When the quantity to be added to a given vat has been
calculated, the acid is distributed by 1m ml, over the grapes
in the crusher, as they are passing through.
We may operate in another way by filling a bucket with
the crystals of tartaric acid, and washing with ;i snvsnu of
must from the vat, by means of a .pump, until completely
dissolved.
It may sometimes happen, as was frequently observed in
1896, that, although resulting from well-matured gnipcs.
the must shows a percentage of acid higher than the tigmv>
above mentioned as desirable. This is generally the result
in dry and warm seasons. L. Mathieu, in a study UH the
improvement of acid wines,* does not advise any special
process.
It does not appear that a superabundance of acid is an
inconvenience. Wines resulting from rather acid vintages,
but well ripened, are always good. In these not very
frequent cases, it is to a superabundance of bitartrate of
potash that the excessive acidity is due. It simply results
in the lees being richer in cream of tartar.
It is not so, however, if we consider a badly-ripened
vintage, as is too often the case in the Centre and East
of France.
We have only addressed ourselves to the hot climates in
what we have said so far, where complete maturity can
always be obtained.
* L. Mathieu. Amelioration des viris verts. Iteoue dc Viitculturt.
56
WINE-MAKING IN HOT CLIMATES.
CHAPTER IV.
VILIFICATION.
We will not describe here the details relating to the
gathering, or the various methods used to convey the grapes
to the cellar, but will only study the fermentation proper.
VINIFI CATION OF RED WINE.
The first manipulation the grapes are subjected to is
the crushing.
Crushing, with very few exceptions, is recommended by
all osnologists and practised by all vine-growers. It consists
in disintegrating the grapes in such a way that the juice
and pulp are expelled from the skin without the stalk or
seeds being crushed. The machines used for this purpose
are called crushers.
CRUSHERS.
The most old-fashioned form, still used in a few small
vineyards, is a kind of kneading trough, with the opening
placed above the fermenting vat, in which the grapes are
squashed by the rosy feet of young farm girls.
This is an excellent means of crushing, the stalks and
seeds remaining intact, while the vintage is submitted to
prolonged contact with the air, for the surface being
incessantly agitated insures perfect aeration of the must.
Crushing by the feet is, however, a tedious and expensive
operation, and can only be used by small proprietors. It
presents a repugnant feature, however, no matter what
cleanliness be attributed to the crushers. This reason alone
amply justifies the progressive abandonment of the old-
fashioned kneading trough, to the advantage of mechanical
crushers.
VINIFICATJON. 57
M. Paul, civil engineer, in his work l)c In rinijicatiori*
classifies crushers into four groups : —
Simple crushers, operating by compression <>r pro-
jection.
Stemmer and crusher combined.
Extracting crushers, also called continuous pfettes.
Extractor and dassilier crushers.
This last group does not seem to us applicable t«> true
crushers, but rather to a. series of apparatus performing a
number of operations, which arc not all indispensable.
The .best-known mechanical crusher is that constructed
with two cylinders. This is the oldest and must used. It
acts by compression (like a rolling mill), the grapes being
forced to pass through a limited space, too narrow to allow
the berry to escape being crushed.
I'i-. "..-Cylinder Crusher fixed above the Vat.
It is composed of two cylinders. (Fig. 5.) One with
grooves running parallel to the axis, the other with helicoidal
grooves. The distance apart of the cylinders is carefully
regulated. If too close, only a limited amount of the
work is utilized, and if too far apart the crushing is
insufficient. The cylinders are rotated at different speeds, in
the ratio of 1 to 3, the cylinder with helicoidal grooves
revolving fastest.
They are worked by hand or mechanical power, the work
j KM- formed corresponding to the regularity of feeding.
* Paris. J. Fritseh, IMU.
58
WINE-MAKING IN HOT CLIMATES.
Those worked by hand are usually mounted on wheels and.
placed ahove the opening of the vat ; under these conditions
the aeration of the vintage is imperfect, the cpntact with
air being almost nil.
This is, fortunately, a defect which may easily be remedied,
as we shall show when discussing aeration.
One of the greatest inconveniences of the cylinder
crushers is that the accidental introduction of a hard body
(a stone, for instance) may break the cylinders and stop the
work. Attempts have been made to minimize this defect,
but so far unsuccessfully.
The working of such a crusher is laborious. The men
must often be relieved, but this only becomes an incon-
venience in the case of large cellars. In small cellars, on
the other hand, this does not apply, the work being inter-
mittent, on account of the loads of grapes arriving at the
cellar at intervals.
A crusher constantly fed and worked by four men,
relieving each other at intervals, cannot crush more than"
3,000 kilos. (6,600 Ibs.) of vintage per hour. The yield of
juice for a given cepage is poor with this type of crusher.
This is only a defect in the case of white wine, especially
when made from red grapes.
If the vintage is crushed by means of a double crusher
(with four cylinders) the yield of juice is notably increased.
Finally, this type of crusher is good, and will long remain
the most practical, for small and medium sized cellars.
The depth of the grooves is of importance ; if too shallow
the rolls cannot draw the grapes through, and they form
ti vault over the cylinders or slide over them.
If too deep they cannot do good work, if the cylinders
are too far apart ; or crush both stalk and seeds if the
rolls are too close together. rlhis is an objection raised by
P. Paul against large grooves.
In a report on cellar appliances read before the Inter-
national Viticultural Congress held at Montpellier, in 1893,
Paul states that grooves geared into one another do not give
good results.
This criticism does not seem to be fully justified.
If we consider the case of grooves sufficiently large to
allow the grapes by their elasticity to become adapted to the
shape of the grooves, without being torn to pieces, we may
hope for satisfactory crushing, without the seeds or stalks
being ground.
VERIFICATION.
This is exactly
what M. Blaquiere,
of Beziers, tries t<»
realize with \\\*jtuted
i/rupe com-
whicli con-
>ists of two cylinders
witli six large longi-
tudinal flutes, G G,
geared without
touching, in such a
way that all the sur-
f sires during rotation
are at a constant dis-
tance apart, and are
revolved in opposite
directions by means
of outside cog-wheels
worked by hand,
whim (horse), or
steam power.
Fig. 6. — Blaquiere's Crusher (side elevation).— G G, crushing
cylinders ; T, hopper ; V, crank wheel.
V
The fluted
cylinders of the
hand model are
75 cm. (30 inches)
long, witli an ex-
terior diameter
of 29 cm. (11£
inches). They are
mounted parallel
to one another on
steel shafts, and
revolved in unison
by two equal
pinions. At the
extremity of one
of the shafi
Fig. 8. — Blaquu'iv's ( 'ru-lier (front view).— G, crushing rvlindtr- :
T, h. .}•]>«•!• ; \ \ . .Tank \vhc-t K.
60
WINK-MAKING IN HOT CLIMATES.
another large cog-wheel, revolved by means of a pinion
keyed on the same shaft as the crank.
The ratio between the large cog-wheel and the pinion is
_ or - — , which means that one complete revolution of
1^0 1
the fluted cylinders corresponds to 8J revolutions of the
mink. The movement is slow enough, and the depth of the
flutes sufficient to prevent the vintage sliding on the surface
without being drawn down.
Fig. . — Blaquiere's Crusher (top view). - G G, crushing cylinders ;
V V, crank wheels.
A crusher of this kind performs more work than one with
ordinary cylinders.
The crushing which results is satisfactory ; all the grapes
get squashed, the other parts remaining uninjured.
Blaquiere's crusher is comparatively novel, and has not
yet been, to our knowledge, described in detail. We con-
sider it an excellent machine, but it has the defect common
to all compression crushers, that of liability to damage
through the accidental introduction of any hard body
(stones, &c.).
This, however, rarely happens, as the hard body generally
crushes with the rest, but an accident during vintage time
leads to so many grievous consequences that its occurrence
should be rendered almost impossible.
Later on this matter will be considered when studying
stemmers, as the stemmer attached to this crusher presents
some interesting details of construction.
VINDICATION.
61
n
n
A new, very inn-resting,
Mini original crusher, luix-.l
on a principle which has
never been applied heioiv In
grape crushing, has heeii
invented hy T. Paid. c:illcil
the . (ero-crusking-titrbine.
Althonii'li only lour or five
ye;irs old, the innchine h;is
been moditied in seveml
details by the inventor.
Fig. 9.— Aero-crushing-turbine.— P. Paul (diagnmi).
Fig. 9 shows the outline of the machine, and Fig. 10 its
elevation.
10. - Aero-e-rushinsr-turbine, P. Paul, provided with an elrvutcr fi-i-iHiiir stemmer and drainer.
62
WINE-MAKING IN HOT CLIMATES.
In the report of the International Viticultural Congress,
held at Montpellier,* the following simple and clear descrip-
tion of this machine is given :—
" P. Paul, constructing engineer of Cette, is the first
to have applied centrifugal force to the crushing of grapes.
His system has been described by so many viticultural
authorities in various reviews, that it will suffice to state that
the squashing of the berry and liberation of the must is
obtained by projecting the grapes against the vertical walls of
the fixed cylinder of the turbine. With the speed of rotation
properly controlled we are certain to squash all the berries
without crushing either the seeds or the stalks, points of
great practical importance.
tl To break the tissue of the seeds or stalks the speed of
rotation requires to be infinitely greater ; and in this lies the
original and important point, the perfect selection between
the matters to be crushed, and those the crushing of which
would prove useless, or even detrimental.
" M. Paul's turbine is a crusher, not a compressor. It
liberates the jmVe from the berry, and delivers both marc
and juice together ; to effect their separation various devices
are required, according to the nature of the wine to be made.
"The prize (vermeil medal) awarded was the only one
placed by the Congress at the disposal of the jury to be
granted for grape crushers.
u M. Paul exhibited two types of turbine : — one worked by
hand, the other by steam power. The first was tried by the
jury at the domaine des Gausses (vineyard owned by Prosper
Gervais). The grape passed through, was Aramon. Out of
1,150 kilos. (2,530 Ibs.) of vintage, 708 kilos. (1,557 Ibs.)
of white must were extracted in twenty minutes.
"The yield given by the machine was therefore 61*5 per
cent. It was worked by four men, two to operate each
crank.
" Later on, apart from official trials, it was tried at the
Chateau de Villeroi (Compagnie des Salins du Midi) with a
dynamo-metric crank, with the following results :—
" With Terret-Bourrets the force required to crush one
kilo, of vintage was 27*20 kilogram-metres, of which 3'504
kilogram-metres was expended in rotating the apparatus.
Etienne Gervaise. Congres International Viticole de Montpellier.
VINDICATION. 63
u With Aramori the force required was 23*10 kilogram-
metres.
" Therefore two men are not sufficient to work the
machine, as they cannot develop more than 12 kilogram-
metres (Claudel. Formnles, &c., p. 14.)
" It would be interesting lor the constructor to try and
manufacture a machine capable of being worked by two men.
It is easy to see from what has been said flint such ;i machine,
might crush 2W,0<)0 kilos. (44,000 Ibs.) of vintage per day,
which is all that is required by the medium proprietor.
" The Aero-crushing-turbine worked by steam power, was
seen by the jury working in the don mine du M6le, near
d'Aiguesmortes, with the vintage in full swing.
" It was fed by an elevator (Burton system), at the same
time the must was elevated by a rotary pump, the whole
being worked by a ."> h.p. engine.
" The yield of must was rather difficult to determine, for
marc and juice fell together into a tank, from which it was
conducted to the press. The following are the results
obtained, taking as liberated must that which flowed naturally
after the press was charged :—
"From 2,879 kilos. (6,333 Ibs.) of vintage (Aramon) ],37(.>
kilos. (3,033 Ibs.) of white must were extracted. The yield
in must was therefore 47*8 per cent. But it should be
remembered that the marc still remaining in the press con-
tained a large quantity of must, liberated from the pulp,
which further drainage would have removed.
" The machine is of very simple construction, and we can-
not see a priori any possibility of its getting out of order.
We may mention that at the cellar of Villeroi (Compagnie
des Saliris du Midi), after being used last year on trial, the
machine was installed permanently this year, and tlmt it
has worked without a breakdown, and crushed from 180 to
200 tons per day. Dynamo-metrical tests have not been
made on this turbine, but it is supposed that it requires a
motive force of from 4 to 5 h.p.
" At Villeroi, as well as at Mole, the turbine is fed by two
elevators. This is a very important item for the success-
ful working of the machine. But the turbine is not the
only machine requiring regular feeding, this being a sine
i/t/'f »nn condition for the proper working of all continuous
machines.
WINK-MAKING IN HOT CLIMATES.
" Finally, another important advantage of the turbine is
that the marc is much easier to press, the cellular tissue
of the berry being completely destroyed, and with it the
elasticity which is such a great obstacle in the pressing of
the fresh vintngr."
Such is the judgment of the Commission of 'the Inter-
national Viticulturnl Congress. It is favorable to the
machine worked by steam, but perhaps rather vague with
regard to the turbine worked by hand.
The report of the Commission ends up with " The Aero-
crushing-turbine gives excellent results where mechanical
power is available," but adds it u has not yet received the
sanction of general usage.?
However, the turbine working on a large scale has been
installed in a number of cellars long enough to enable us
to appreciate it. In conclusion, it is an excellent machine
for large cellars.
We must add to the advantages expressed in the above
report the perfect aeration of the vintage. The must
coming out of the turbine is, so to speak, an emulsion of
air and must.
We have not measured the amount of air emulsionized,
but according to various reports published by the inventor,
it is 5 per cent, in volume.
These are, as we shall see later on, very favorable condi-
tions for a good start in the fermentation.
The various advantages of this highly original crushing
machine justify the as yet uncontradicted success which
welcomed it from its first appearance.
As we have already stated, the regularity of the feeding ol
crushers has a great bearing on the perfection of their work.
The mode of feeding will vary greatly according to local
conditions, and the various means by which the elevation of
the vintage to the crusher are obtained.
In most cases the arrival of the drays to the level of the
top of the vats by means of a gradient is recommendable ;
in that case the feeding takes place by pouring the contents
of the tubs directly into the crusher.
Chain and cup elevators are good, and comply with various
required conditions. They are recommendable for large
cellars, but may also be arranged and worked by hand in
small places.
VINDICATION. 65
These elevators may be used with cither fixed or movable
crushers. In the first case, it is necessary to hnvc menus of
conveying the must from the crusher TO tin- vats (in many
cases simply by a wooden shute) ; in the latter, the elevator
being fixed on a truck running on mils. may l.«- mo\< d
alongside tlic cellar : when established in this manner, even
if outside the cellar, the elevator may fill two parallel rows
of vats with a simple shute conveying the crushed vintage
from the top of the elevator to the fermenting vat. The
crusher in this case is moved on another truck parallel to
the elevators.
We must add that a few vine-growers (though quite
exceptionally) consider crushing useless, regarding the result
of the different manipulations the grapes are subjected to,
before being placed in the vat, as quite sufficient.
Whether the vintage is elevated by a cup elevator, or
thrown into the vat by means of shovels, it acts certainly
as a partial crushing; but the use of crushers is preferable
and indispensable when making white wine.
( Yushing is praised by the majority of oenologists. and is
an excellent practice, as it enables the fermentation to get a
good start, and facilitates the drainage of the marc.
In uncruslied or badly-crushed vintages, we alway* rind
grapes remaining attached to their pedicle, intact, and HI led
with miiermented must. "When pressed these grapes burst
and contaminate the wine with fermentable substances,
which only have at their disposal old yeast, living with
difficulty in a liquid almost completely fermented. Tin-
work done by the ferment in this case is very slight,
frequently the sweetish wine resulting becomes the prey of
noxious ferments, which, except in the case of sterilized
must, always exist in the wine, awaiting favorable conditions
to multiply.
The presence of unfermented . sugar fills one of these
conditions.
STEMMING.
This operation, which consists in separating the grape
from the stalk, has been known from ancient times, and
is a necessary practice in some viticultural regions, such
as Bordeaux.
In the South and South-west of France, however, it is
only occasionally practised.
10649. E
66
WINE-MAKING IN HOT CLIMATES.
In former times it was performed by means of a kind of
rake, with teeth fixed far enough apart to allow the grapes
to pass between, but placed close enough to retain the stalks,
the -operation being done over a screen ; it is an expensive
method and gives very imperfect results.
STEMMERS.
Only mechanical stemming is employed nowadays. It is
done by means of special machines called stemmers, gene-
rally attached to the crusher, and performing the sorting as
the crushing is going on.
The stemmer consists of a horizontal perforated cylinder
or cylindrical envelope, in the axis of which a shaft revolves
bearing helicoidally mounted boards (Fig. 11) or spikes.
Fig. 11. - Stemmer fixed above the Vat.
VINDICATION.
The shaft, studded with spikes, or carrying boards, is
revolved rather rapidly together with the crasher.
The crushed vintage falls into the stemming cylinder. It
is then energetically beaten by the spikes, separating the
grapes from the stalks. The former, together with flit-
juice, fall through the perforations into the collecting trough ;
the latter gradually work their way to the extremity of the
cylinder, arid are then expelled.
Blaquiere, the constructor of the crusher previously
described, has also invented a stemrner, which differs in
many respects from the ordinary appliance.
It consists of a per-
forated cylinder revolving
round an axle. This
cylinder is provided inside
with from three to six
pieces of wood, projecting
a few centimetres, and
placed parallel to the axis.
The cylinder is inclined
horizontally and revolves
slowly.
The crushed vintage
falls into the raised end of
the stemmer, and is then
caught by the projecting
pieces of wood and carried
onwards to the lower end
by its own weight.
The shocks resulting
from the successive falls
of the bunches completely
detach the grapes from
the stalks, the grapes
falling throngh the per-
forations. The forwarc
movement of the stalks
results from the inclina-
tion of the cylinder, every
fall carries the stalks
towards the outlet, and
E 2
OB WINE-MAKING IN HOT CLIMATES.
with a machine of this kind it is only after a considerable
number of falls that the stalks are finally expelled.
Fig. 13. — Blaquiere's Combined Crusher, Drainer, and Stemmer (front view).
ADVANTAGES OF STEMMING.
Stemming is not much practised in the southern regions
of France, and does not seem to be generally called for in the
manufacture of red wine. It is, however, advocated by many
authorities, such as Coste-Floret, who has used it for more
than ten years on his extensive vineyard*, and recommends
the practice strongly.
Stemmed wines, according to Coste-Floret, have more
finesse, are more alcoholic, and have better keeping qualities,
than wines from the same vintage made without stemming.
He admits that wines made from stemmed grapes will have
to force their way, as the public taste has been always culti-
vated for wines from unstemmed grapes.
" The difficulty that the stemmed wines have to encounter is
due, according to Coste-Floret, to the depraved taste of a
certain class of consumers who formerly drank our common
wines from non-stemmed grapes, but who appear to have now
abandoned us. We must create a new market if we do not
wish to see our wines discarded and used as raw material for
* Saint Adrien, near Beziers.
VINDICATION. 69
manipulations which do not deserve to be encouraged, and we
must make wines of good quality, able to be sold directly as
MJI rural pure wines."
Indeed, it is truly desirable that our wines should n<»r In-
discarded, and they should certainly be consumed without
sophistication, but is it not excessive to think, as ('u-tr-
Floret appears to, that an important class of consumers no
longer drink our wine, and that it should be necessary t<>
stem the grapes to induce them to return to this custom.
We are not of the same opinion. Wines made from
stemmed grapes have more finesse and are slightly more
alcoholic than wines from unstemmed grapes, but, contrary
to Coste-Floret's opinion, they have poorer keeping qualities,
and contain less dry extract.
The greater richness in dry extract of wines from un-
stemmed grapes is a well-known fact, and we shall presently
quote some figures to prove this ; but is the excess in dry
extract due to the stalks ? We do not think so.
We have previously seen how small the proportion of
stalks is in our southern regions, and how small also the
percentage of soluble matters contained in the stalks. It
is only by grammes that we express the soluble matters
brought to the vat by 100 kilos, of vintage of Aramon, for
instance, and, even then, the greater proportion consist> of
tartar and tannin.
The great richness of wine from unstemmed grapes in dry
extract cannot therefore be attributed to the stalks, but
simply to the mechanical part played by them in dividing
the marc and facilitating the penetration of the sin-rounding
liquid, and therefore its solvent action. We must reject any
idea of unfavorable influence of the stalks, on account of their
small proportion in all our southern cepages, and of the
small quantity of soluble matter they contain, provided they
have not been bruised by the crusher, and that the fermen-
tation has been well conducted.
We do hot deny the usefulness of stemming in some
special eases, in that of damaged vintages for instance, but if
its efficacious action is evident in such a case, it must not be
attributed to the fermentation of the grapes afrer separation
from the stalks, but rather to the more or less perfect
rejection of damaged from undamaged vintage, which is
the result of the stemming, owing to all the rotten ami
dried grapes being separated with the stalks. In the case
70 WINE- MAKING IN HOT CLIMATES.
of a healthy vintage, and of cepages where the proportion
between the stalk and the grape is not greater than in our
cepages in the South of France, we do not see the necessity
of advocating the general adoption of this operation.
In any case, the action of the stemming is only secondary,
not direct. The properties distinguishing stemmed from
non-stemmed wine, are only the result of bad fermentations
due to unfavorable temperature, or of remaining too long on
the marc. The, defect in the case of wine from non-stemmed
grapes is not to be imputed to the stalks, but to an increased
maceration of the other parts of the marc, to which the pene-
tration of the wine is facilitated by the presence of the
stalks.
M. Vincens, Professor in the School of Agriculture at
Ondes, starting from the idea that the market value of
wine depends on four principal factors — the alcoholic
strength, dry extract, acidity, and coloration — studied
methodically the influence of stemming on these four
factors.
The trials were carried out for three cepages — Negrette,
Aramon, Petit-Bouschet — an equal quantity of wine being-
made from each, with and without stemming.
We will quote his results.* Noting that the stemming
was done by hand.
Composition of Experimental Wines.
Coloration
Intensity.
3rd violet red 175
200
4th — 440
445
3rd — 80
— 65
" The above trials were made with the usual instruments
found in trade— Salleron's ebulliometre ; Houdart, ceno-
barometre, and Salleron's colorimetre.
The acidity was determined with a normal potash solution.
" The observations of temperature, which we consider
useless for this table, show that in all cases the maximum
temperature was 1° higher, and took place one day earlier,
in the non-stemmed than in the stemmed vintages. These
* Revue Internationale de viticulture ct d'cenologie t. I., No. 4.
Alcohol
Acidity as
per cent, by
volume.
JJry
Extract.
H3S04
per litre.
Negrette, stemmed 8 9
16-5
3-66
,, not stemmed 8 '7
17-5
3-80
Aramon, stemmed 8 '8
19-5
5-58
,, not stemmed 8 '75
20-4
5-11
Petit-Bouschet, stemmed 8 '9
19-4
4-37
,, not stemmed 8 '9
21-3
4-46
VINDICATION. 71
results confirm the well-known fact, that the presence of
stalks in the vat accelerates the fermentation.
" When examining the composition of the wines, we see
that the increase in alcoholic strength due to stemming is
very slight. It is nil for Petit-Bouschet, insignificant for
Aramon, and reaches two-tenths of a degree for Negrette.
This difference is evidently due to the fact that during the
submersion of the marc, which was only done in the case of
Negrette, the stalks absorbed a greater quantity of alcohol.
" The differences between the figures for dry extract is
much more noticeable. It varies from (>8 to 1*9 grammes
per litre, and constitutes a disadvantage for the non-stemmed
wines* which contain less. We noticed, in estimating
the astringent matters according to the process of Aime"
Girard, that the difference was almost entirely due, with
the exception of Aramon, to the oeno-tannin, an excellent
agent in the preservation of wine.
" Except for the Aramon, which has a very peculiar com-
position, the acidity is higher in non-stemmed wine ; although
the difference is very slight, we must take into consideration,
in the case of our southern wines, which are generally flat, a
lack of fresh, cool, acid taste.
" If we now examine the colour, the figures representing
its intensity being in inverse proportion, we see that the dif-
ferences in favour of non-stemmed wines are nil for Aramon,
one-eighth for Negrette, one-fifth for Petit-Bouschet.t
" To the taste the stemmed wines were less harsh or rough
than the non-stemmed, but these were morefruttes, corses,
and they would unquestionably be preferred by wine mer-
chants.
" As the stalks always absorb a certain quantity of wine,
an increase iu yield of 2 per cent, is due to the stemming,
but this augmentation not covering the cost of extra mani-
pulation we need not take it into consideration.
"To sum up, in our experiments stemming has always
furnished inferior wines, less rich in dry extract and
colouring matter, and only slightly different in alcoholic
strength.
* We quote exactly, although it is easy to observe on examining the above
table that it is stemmed wine that should be read in place of non-stemmed.
t There is a contradiction between this conclusion and the figures of the
table, but it is without importance, the result being in both cases very slightly
different.
72 WINE-MAKING IN HOT CLIMATES.
" As the advantage resulting from the aeration of the
vintage, and the expulsion of foreign matters and germs of
noxious fermentation, may be realized without stemming, we
may conclude that for wine made from heavy-bearing kinds
of the south-west, of which the three experimented upon
are the most important, that this practice is useless, if not
actually injurious."
We concur entirely with the views expressed by Vinccns,
taking exception however to those referring to altered (in-
jured) vintage, and for special vinifi cations, such, for in-
stance, as the vinification of red wine with grapes partly
drained for white wine.
Later on we will discuss these exceptional cases when
describing the manufacture of white wine from red grapes.
THE VATT1NG.
The squashed vintage delivered from the crushers is fer-
mented in vats. For the fermentation to take place in a
satisfactory manner, so that the resulting wine will possess
the maximum qualities compatible with the nature of the
vintage, it is necessary : —
First — That the vinous ferment which causes the pheno-
mena be the only one at work in the must.
The presence of healthy, vigorous, and abundant yeast is
indispensable to attain this object.
The aeration of the crushed vintage is an important factor
in the multiplication of the ferment.
Second — That the transformation be effected as rapidly as
possible. The rapidity of the work depends on the life of the
ferment, which will only furnish its maximum yield if the
chemical and physical conditions of the liquid are suitable.
Third — That the solid parts of the grape be sufficiently
in contact with the liquid part to enable it to dissolve the
necessary substances. This is obtained by various methods
and special manipulations.
AERATION OF THE VINTAGE.
Let us assume the grapes to be introduced into the vat
without being crushed, and the air in the vat replaced by an
inert gas, such as nitrogen. If we then prevent the access
of any air and crush the grapes in situ., it would be noticed
that the phenomena following the crushing were not at all
VINDICATION. 73
comparable to what takes place under ordinary circum-
stances. The fermentation would be very difficult to start.
and if it started at all would have no energy and probably
be the seat of a great many alterations. If this be so it
incans that the germs of the. ferments existing on the sur-
face of the grape have only had at their disposal the small
quantity of oxygen remaining in the grape, and thai ir is
indispensable for the yeasts to have at their disposal a
quantity of air sufficient for their normal development. It
is not so for all the micro-organisms existing on the surface
of the grape, for a number of these find the conditions con-
genial, and succeed in changing the must into a liquid
having nothing in common with wine.
Let us suppose again a vintage crushed in contact with
the air, but with a limited aeration, such as would result
from crushing grapes in a bottle almost full, and closed
before crushing so as to prevent the access of any additional
air. The fermentation would start and become rather active.
The activity may be measured by the amount of carbonic
acid produced in a given time. If we study this fermenta-
tion we will see that it diminishes rapidly, although there is
a great quantity of sugar left, showing that the ferment still
has food left, and that the cells of the ferment require after
their first work a certain quantity of air to restore them to
activity and enable them to multiply.
This statement made by Duclaux, and deduced from
Pasteur's classical experiments, is easy to verify.
If the above must is racked in contact with air it will be
seen that disengagement of gas increases at once. Aeration,
we therefore maintain, is not only useful but absolutely
indispensable to enable the germs on the grape skin to
develop, and it is necessary to restore the ferment while the
fermentation is proceeding, to enable the complete conversion
of the sugar to take place.
The first aeration takes place during the crushing, and it
is the imperfect aeration in cylinder crushers which causes
the inferiority so often noticed in wines so made, as compared
with those from crushing by the feet. In the latter case the
vintage remains longer in contact with the air. consequently
the aeration is more perfect.
In some districts (Bordeaux) they even go further. The
vintage is thrown up in the air with shovels, before being
placed in the vat.
74 WINE-MAKING IN HOT CLIMATES.
Does this mean that we must place the mechanical
crushers aside and return to ancient methods ?
Certainly not. Sufficient aeration may be obtained with
machines. Some machines, such as the aero-crusher, effect
the aeration during the crushing, in other cases, especially
if the grapes have to travel in a long and open shute, it
produces the same result. The paddles of the stemmers also
have an aerating effect. We may also, immediately after
the crushing, pump the must over the head (marc floating
in the vat), being careful to spread it all over. This practice
is quite sufficient to introduce into the must the quantity of
oxygen necessary for a good start. The pumping over of
the must may be repeated if necessary, and will prolong the
fermentation until the sugar has entirely disappeared.
Stemming, as we have seen, has not got a very direct
influence on the quality of the wine, but it acts indirectly
through the intense aeration it furnishes, and many think it
is the only benefit we can get from the adoption of this
practice in the South of France.
We cannot do better than support our views by those of
Pasteur. The following is his opinion, built on the irrefut-
able experimental methods everybody grants to that scientist,
taken from his Etudes des Vim:—
" I have noticed that when musts are exposed to contact
with the air in a shallow vessel for many hours and stirred
that fermentation is much more active than with non-aerated
musts. The fact that aeration produces such apparent
effects even during fermentation, while the liquid is already
charged with carbonic acid and alcoholic ferments, is worthy
of attention."
Pasteur describes experiments which leave no doubt on
that subject, and which show conclusively that non-aerated
must produces more acid wines than those aerated.
To- any one who reads between the lines, abnormal increase
of acidity is not a good sign, but rather a sign of defective
fermentation, for the increase of acidity is generally due to
the formation of volatile acids so characteristic of diseased
wines.
Apart from this, the aeration of the vat has a very bene-
ficial influence on the ultimate preservation of the wine.
We have no experiments to support this fact, as convincing
as those of Pasteur, but it seems logical, and many authori-
ties admit it.
VINDICATION. < .)
Ott, an American scientist, lavs down the principle that
the more abundant the oxygen in the must, the more albu-
minoid matters the ferment will absorb, and flint the wines
resulting will keep better — the presence of albuminoid
matters in excess in the wine being conducive to diseases.
Ott's opinion is, we believe, annually confirmed in the
vineyards of California, where aeration is a common practice.
It consists in forcing air .by means of a pump to the
bottom of the vat, ami discharging it in a fine stream through
a perforated rose. This operation is repeated each day for
ten minutes. The forcing of air through the fermenting
must is no doubt a good thing, and tends to the preservation
of the resulting wine ; but it has a decided inconvenience in
the case of wine required in commerce to be brilliant arid
According to Ott, aeration matures the wine quickly, and
gives it that tawny colour so characteristic of old wines.
We may obtain certain advantages by well-conducted
aeration, but it must be well conducted, for it may become
injurious if practised to excess and under bad conditions.
Aeration before the fermentation starts, can never be too
thorough or complete.
When once fermentation has started, we must act with
caution, for given with circumspection, the oxygen maintains
the life of the various ferment and enables it to work with
proper activity. It slightly oxidizes the colouring matter,
and gives it .a greater facility of dissolution, without modify-
ing its tint. If the oxidation is excessive the colouring matter
alters and becomes brownish, and loses its fixity in solution.
This applies specially to fermentation in the South of France
and Algeria, where very often the temperature is so high that
the ferment dies.- Excessive aeration under these circum-
stances acts on the colouring matter in a disastrous way.
Notwithstanding this great inconvenience aeration must not
be rejected, for it still has a marked utility. It ;illo\vs the
complete conversion of the sugar, which is indispensable if we
wish to avoid making wine which will certainly be of doubt-
ful keeping qualities.
Rietsch and Herselin* pointed out these advantages in a
series of laboratory experiments bearing on apiculatus and
ellipsoideus yeasts.
oyrvs Ayricolc ct Viticole* 1895
<b WINE-MAKING IN HOT CLIMATES.
They were able to obtain in all the fermentations at high
temperatures at 36° C. (97° F.) a more rapid and complete
decomposition of the sugar when aeration was used.
The vine-grower, therefore, is confronted with an unpleasant
situation if the temperature of the vat is allowed to rise too
high. Without aeration he will obtain wine of uncertain
keeping quality, with aeration better keeping wine but less
fine will result.
The maintenance of the temperature of the vat between
proper limits is the only way of avoiding this embarrassing
situation.
The process has also many other advantages. We have
had an opportunity of making a series of experiments in
Algerian cellars on this subject, and these have since been
continued in our laboratory in conjunction with F. Chabert,
as studies on the different actions of high temperature on
alcoholic fermentation. These studies are not yet completed,
but allow us to clear up certain obscure points in the above
observations.
We will reproduce, in extenso, these studies, and hope they
will prove the absolute necessity for controlling the tempera-
ture during fermentation.
CONTRIBUTION TO THE STUDY OF VINOUS
FERMENTATIONS.
INFLUENCE OF TEMPERATURE.
(By L. Roos and F. Chabert.)
The temperature of fermentation plays a part in vinification
which recent studies have shown to be so important, that
it is to-day a subject of thought for every renologist.
The flavour and keeping qualities of wines, depend to a great
part on the temperature at which the transformation of the
must is made. If it is too low the fermentation does not
start, or starts too slowly, for the ellipsoideus yeast does not
develop well, and bacterial actions take place which alter
the value of the product. If it is too high the wine retains
untransformed sugar, which forms a suitable medium for and
favours the development of bacteria, which may so alter the
VINDICATION. 77
nature of the liquid as to render it unfit for consumption. The
natural consequence of tin's doable observation le,-id> u> t<i ln-.-it
our musts in cold climates, a very old practice justified by ex-
perience, and to keep the temperature between given limits
in hot regions.
The study of the various processes of heating or refriger-
ating musts, does not come within the scope of this paper.
We have simply tried to discover the temperature preferred by
the wine yeasts, that is to say. the temperature at which
they perform a maximum of work in a minimum time.
High temperature during fermentation has an unfavorable
influence on the resulting wine. It reduces its alcoholic
strength, alters its taste, and diminishes its keeping <piality.
The consecutive alterations of fermentations at high tem-
peratures are well established, but ha ve according to us. been
too generally attributed to the development of micro-
organisms, called parasitic, to distinguish them from those
which transform the sugar into alcohol.
Our experiments tend to show that, together with the
bacterial action (an indirect result of the excessive tempera-
ture) there is another action of the same class, but perhap>
less important, attributable to the yeast itself, the evolutions
of which, and its conditions of work, are profoundly modified.
Our experiments were made on raisin must, during the
year, and with fresh grape musts during the vintage of IMMi.
We did not use yeasts ofa special character, but simply took
them from the wine lees of the district, making sure, how-
ever, that the wine yeasts were self-eulti va fed. The colonies
were obtained in solid gelatine and multiplied in sterilized
must. The lees from which we extracted the yeasts came
from the environs of Mndaison (Herault) and Saint Laurent
d'Aigouze (Gard).
We tried to keep ;is far as possible within general viti-
cultural conditions, but do not pretend not to recognise the
difference there is between laboratory practice and cellar
operations. This simply means that we cannot give our
results as the exact expression of what takes place in a cellar,
but that they are simply land-marks placed on the path of
this very complex study.
Before giving our results, and describing the apparatn-
used by us, we will briefly summarize the previoii> work on
this subject.
78 WINE-MAKING IN HOT CLIMATES.
OPINIONS OF VARIOUS AUTHORITIES AS TO THE
BEST TEMPERATURE FOR FERMENTATION.
Chaptal * states that the most favorable temperature is
15° R. (66° F.) It languishes below that temperature,
becomes too tumultuous above it, and if the temperature is
too high or too low does not take place at all.
According to A. Gautier f the most favorable temperature
is between 28° and 32° C. In no case should it fall below
18° C. or exceed 36° C. Once that extreme maximum is
reached the glucose riot only forms alcohol, but also other
products, and the rapid disengagement of carbonic acid
carries away a notable quantity of alcohol .J
Gautier points out already the formation of " other pro-
ducts " is a result of fermentation at high temperature. Our
experiments verify this opinion, for they show in the ferment-
ing liquid the existence of products, not yet well defined, but
exerting a distinct action.
Prof. Bouffard § fixes 25° C. as the temperature required
for a good fermentation. " The temperature of 20° C. which
sometimes cannot be exceeded in Bourgogne and that of
35° C. always reached in Algiers are unfavorable. Wines
made between 20° and 32° C. have more suavity in perfume
and taste. Those obtained between 30° and 35° C. are flat,
less perfumed, and possess foreign tastes due to the develop-
ment of parasitic ferments."
L. Rougier,|| in his Manuel Pratique, also studies the
influence of temperature. Below 8° or 10° C. fermentation
is impossible. The activity of the ferment increases little by
little as the temperature rises to 25° or 30° C., above 40° or
45° C. the fermentation tends to stop before the sugar is
completely transformed. When the temperature gets over
30° C. the carbonic acid carries away a certain quantity of
alcohol and volatile principles constituting the bouquet.11"
* L'Art de f»ire le Vin, p. 94, by Count Chaptal. 1819. We must draw
attention to the correspondence between the Centigrade and Reaumur — 15°
Reaumur, 18'7£° Centigrade.
t Ijictionntiire de Chemie de Wurtz. Art. Vin.
J We will see that if a notable quantity of alcohol is carried away it is to be
attributed to the elevation of the temperature, and not to the rapidity of the
evolution of gases, which, on the contrary, become slower.
§ Role de la Chaleur et du Froid dans la Vinification. Progres Agricole et
Viticole. 1891.
|| Manuel Pratique de la Vinification. L. Rougier, p. 25. 3rd Ed. 1895.
IF This remark corroborates Prof. Bouffard's opinion above given, that wine*
made at high temperatures are deficient in perfume.
VINDICATION. 79
Dr. Frederic Cazalis* quotes the experiments of Miiller-
Thm-gaii. These experiments show that " the fermentation
of a must between 9° and 36° C. proceeds so much the more
rapidly, and with more bubbling, as the temperat HIT is higher,
but past that point, it stops the more rapidly, leaving a part
of tne sugar unconverted, as the temperature is higher."
('a/alis notes afterwards the considerable influence the tem-
perature has on the yield in alcohol, quoting the following
figures : —
Fermentation at 9° 0. ... 1 7 -29°/0 alcohol by volume
18°C. ... 15-09,,
27° C. ... 12-23,, „
36° ('. ... 8-96,,
These results, exact no doubt under the conditions of the
experiments of Miiller-Thurgau, cannot be generalized. The
factor time, is missing from the table, and it is one of the most
important. If we may admit the accuracy of the results with
the Rhine yeasts, when treated in laboratories, it is easy to
oppose against their generalization the fact well known to the
vignerons of the South of France that we may easily obtain
up to 10 or 11 per cent, of alcohol at temperatures over 36 C.
Dr. Fred. Cazalis concludes that the temperature for a good
fermentation lies between 15° and 25° C. Prof. Miiller-
Thurgau noticed that fermentation ceases between 25° and
36° C. before all the sugar is transformed into alcohol, because
" the alcohol at such a high temperature acts upon the fer-
ment, and even small amounts can arrest its activity." t We
admit this action of the alcohol but only as one of the factors
causing the stoppage of fermentation.
We will show by experiments that the presence of alcohol
is not the only cause retarding the work of the ferment.
If it were possible, it would be sufficient to bring the liquid
back to a proper temperature to see the yeast regain its
former activity, but this does not happen. The fermentation
only proceeds slowly, and is not even sensibly increased by the
addition of fresh yeast taken from another vat in full activity.
U. Gayont gives as a limit 27° to 38° C., which should not
be exceeded in any case if we do not wish to see the must
* Traite Pratique de VArt de faire le Vin. Dr. Frederic Cazalis, p. 144.
Montpellier. 1890.
t This is only true for quantities of alcohol varying between 8 and 10 per
cent., and for temperatures exceeding 36° C. (R"os and Chabert.)
£ U. Gayon, Rapport sur la Vinification dans les Anntes Chaudcs. Bordeaux,
1895.
80 WINE-MAKING IN HOT CLIMATES.
attacked by disease ferments, and especially by the mannitic
ferment.* It is the toxic action of the alcohol, the absence
of oxygen, and the high temperature of 40° C. which para-
lyzes the ferments.
Miiutz and Rousseaux f define the " critical point " as the
temperature the yeast cannot support without suffering ; if
that temperature is exceeded by a slight degree, its influence
on the course of the fermentation has an important influence.
This critical point is characterized by the fact that the yc;i>t.
still living if that point is just reached, dies directly it is ex-
ceeded. We can enable the ferment, therefore, to recover by
refrigeration, provided that the critical point is not exceeded.
Should it be exceeded and the yeast destroyed, nothing can
be done. These authors give an instance, the critical point
being supposed to be between 38° and 40° C.
We admit with Miintz and Rousseaux a morbid state of the
yeast at high temperature, increasing as the temperature
exceeds 35° C., we admit also a kind of critical point : — 38° to
40° C., which should not be exceeded if we wish to bring the
ferments back to activity by refrigerating ; but we think
that 38° to 40° C. conduces only to a more accentuated morbid
state, and not to the death of the ferment, as this only occurs
at a high temperature, for when sown in fresh must these
yeasts start fermenting regularly again.
H. Dessoliers,^ in a study on vinification in hot countries,
explains at length the influence of temperature on fer-
mentation. " The temperature is a dominant and essential
element in fermentation. The duration of fermentation will
be so much the greater that the must has been the longer-
exposed to a high temperature (40° to 42° C.). The duration
of the action of the high temperature must be taken
into consideration more than the temperature itself." Des-
soliers shows that high temperature produces sweetish wines
liable to alterations, and quotes an observation due to
Maerker, who asserts that yeasts do not multiply at tempera-
tures over 28° C. This statement cannot be accepted without
reserve. At 35° or 40° C. the yeasts multiply, not under
favorable conditions perhaps, but nevertheless they multiply.
* Gay on points out that the mannitic ferment starts during the true fermen-
tation. We have shown that this disease easily develops in a sweet wine at 40°
C. L. Roos, Journal de Pharmacie ct de Chimie, 1892.
t Miintz and Rousseaux. Etudes sur la Vinification dans le Roussillon,
faites aux Vendaiiges de 1894. Bulletin du Ministere de I * Agriculture. 1895,
p. 1208.
£ H. Dessoliers, Vinification en Pays Chauds. Alger. 1894.
I
VINDICATION. 81
Dessoliers states that yeast cannot germinate if it has
been submitted to too high a temperature. We have,
however, shown above that it can germinate normally if
placed in new must.
One of us, taking into consideration numerous experi-
ments made on yeasts from many different countries, fixed
the maximum vitality of the vinous ferment, wlmtr.ver species
it may belong to, at between 28° and 32° C. At 20° 0. the
activity is very slow. At 40° C. it is nil. At 45° C. it dies,
or is of no further use.* " The very best temperature is
30° C., and the must cannot go much above or below this limit
without becoming liable to bacterial diseases^ those made at
the higher temperature becoming most liable. The vinous
yeast may be killed at temperatures insufficient to kill other
ferments. At high temperatures the yeasts eliminate
products detrimental to the wine, which may even render the
must sterile, although still containing sugar, and the other
conditions apparently seeming favorable ; or the yeast in
full activity develops badly, or perhaps not at all."f
To summarize, different authorities agree that in high
temperature lies the most important cause of the defects of
wines made in hot regions. The sugar they often contain,
through the fermentation not being completed, is a favorable
ground for the development of bacterial diseases.
The numerous applications of refrigeration to musts
confirm this opinion of scientific authorities.
METHODS AND APPARATUS EMPLOYED.
Exact estimations of acidity calculated as sulphuric acid
were made for all the musts experimented upon.
Reducing Sugar. — We used, for the estimation of this, the
ordinary cupro-potassic solution, but substituting the elec-
trolytic determination of the precipitated copper for the
volumetric method, relying on the disappearance of colour.
The musts, although diluted, were rich enough for the
slightest divergency in measurement of the volume of liquid
in the burette, corresponding to the end of the reaction to
* L. Roos. Principle generaux de la vinification en rouge, froyres agricoie
et viticole, 1894.
t L. Roos. Etudes sur la vinification en pays chauds. Revue de Viticulture,
1894.
10649. *'
82
WINE-MAKING IN HOT CLIMATES.
result in notable errors. The musts were examined in
Laurent's polarimetre. We used Salleron's mustimetre to-
obtain approximate indications.
Acidity. — Determined by titrated lime water. The wines
resulting were more closely examined. We determined :—
Reducing Matters, always expressed as glucose, estimated
by the ordinary method, that is, decoloration of a cupro-
potassic solution by the wine previously treated with sub-
acetate of lead.
Alcohol in Volume, per cent, determined by distillation, and
density by pyknometer, this being the most accurate method.
Acidity is expressed as sulphuric acid per litre.
Total Nitrogen (with the exception of nitrogen existing
in the shape of pyridine compounds) was estimated by the
Kjeldahl process.
By the way, we draw attention to an experimental point.
It is often difficult to obtain a complete decomposition
without loss, when examining wine rich in sugar. By evapo-
rating on a water bath from 50 to 100 c. c. of wine in a small
flask of 200 to 300 c.c.,
and adding to the residue
a few drops of concen-
trated sulphuric acid, a
spongy carbonaceous
mass is formed well
adapted to complete
decomposition, without
producing the violent
frothing so liable to oc-
casion trouble or loss.
The fermentations
were conducted at four
different temperatures,
including the maximum
and minimum generally
observed in our regions,
25°, 30°, 35°, and 40° 0.
These temperatures
were maintained constant
by meansof the apparatus
Fig. 14. -Flask submerged by a lead ring, con- shownin Tig. 14. The
taining the must — C, circular gas burner; L, rpppTitarlp contains wafpr
Liebig bulbs, containing sulphuric acid; R,
thermo-regulator ; S, tripod ; T, thermometer.
VINDICATION.
83
1
in which the thermo-regulator is placed. The regulator is
influenced to a certain extent by the pressure of the ga*
supply. We were, therefore, obliged to interpose between it
and the gas supply a Moitessier pressure regulator.
A flask, B, of two litres capacity, containing l-f> litres of
must, kept submerged by a lead ring, supported in the tank
on a wood-lead ring, and closed with a doubly periomt. -I
cork. Through one hole a thermometer, T, passed, through
the other an exit tube, connected with a LieMg's absorption
apparatus, L, where the alcohol and the water vapour
escaping were caught.
The quantities of gas disengaged were measured either by
the balance, orthe self-registering gas disengagement machine
of Houdaille.* In either case the temperature of the must
inside the flask and of the surrounding water were recorded
every other hour.
In the first case the
weighings were
made at even inter-
vals. In the second
case the carbonic
acid was measured
by the Houdaille
self-registering ap-
paratus, of which
we will now give a
short description,
Fig. 15.
It consists of a kind of gasometer, G, with two compart-
ments, C and C, plunged in water, oscillating on a horizontal
axis in such a way that, moving round the pivot under the
pressure of the gas, one of the compartments may empty
itself while the other is filling. Each oscillation, by means
of a very simple system of levers, prints a point on the
cylinder moved by clock-work.
The cylinder may move normally in the direction of the
lever; in front of it is a groove, I), and as it revolves once
in twelve hours, it suffices for a small lateral displacement
of the cylinder, to avoid the overlapping or super-position of
the points, and therefore allows the continuous observation
* Houdaille. Snr un appareil enregistreur des fermentations alcooliques.
Annnlts dt VEcole d1 Agriculture dt Mont/tellier, 1887-
F 2
Fig1. 1*.— G G1, compartments of the gasometer, G; D,
groove ; I, cylinder ; P Pl, counterpoise ; R, trough
containing the water; T, tuhe leading gas to register.
84
WINE-MAKING IN HOT CLIMATES.
of a few days' fermentation. We used a four-compartment
register, one being applied to each fermentation.
This apparatus works very accurately in the case of a gas
insoluble in water, but is not so satisfactory with carbonic
acid. The solubility of carbonic acid in water is an obstacle
to its perfect action. This might be avoided in using a liquid
in which carbonic acid is insoluble.
It is very difficult to find such a liquid ; glycerine is the
only one not exerting a solvent action, but it has the dis-
advantage of being too viscous, and diminishing the mobile
action of the compartment.
"We endeavoured to render the solution of the carbonic acid
almost nil, by maintaining the water in the trough constantly
saturated with carbonic acid, by interposing an atmosphere
of that gas between the water and the atmosphere.
With this object each of the com-
partments received a slow current
of carbonic acid, obtained by a
regular flow of alkaline carbonate
into dilute sulphuric acid, the two
bottles being placed one above the
other, F F, fitted with a Mariotte
tube, Fig. 16.
A board, in which is bored a hole
to allow the movement of the rod
connected with the compartments,
shelters the surface of the water
againstdraughts which might sweep
awa>: ,the liberated gas. This slight
modification enabled us to obtain
with the Houdaille apparatus results quite comparable with
those obtained by weighing.
We will, later on, describe the device by which we tried
to measure the quantities of alcohol carried over mechani-
cally by the carbonic acid.
hydride.
STUDY OF FERMENTATIONS.
At 25° C. the start is very slow, the froth only appears on
the fourth day, although the disengagement of gas shows
the fermentation to be already well established. The liquid
is rendered turbid by the yeasts, and the sulphuric acid in
the Liebig bulbs is coloured brown by the gas.
VERIFICATION. 85
At 30° C. very rapid start, very regular course, slacking
down before the sugar is completely transformed, the liquid
is very turbid, and the sulphuric acid in the bullis is coloured
more intensely brown than before.
At 35° C. the start is also very nipid, and the activity is
very regularly maintained as long as the alcoholic strength
is below a certain limit. It slacks oft' sum MM- than the fer-
mentation at 30° C. and leaves more sugar uutnuisfuniu-d.
The liquid is very turbid at the beginning, and becomes clear
after the yeast diminishes its activity, the sulphuric acid in
the bulbs becoming very intensely coloured.
At 40° C. the start is not very noticeable, and the fermenta-
tion is always very slow. The liquid did not get very turbid.
although there was an abundant deposit of yeast at the
bottom of the flask. A great part of the sugar remained
undecomposed. The sulphuric acid in the bulbs becomes
only slightly coloured.
The fermentations which are most active at the beginning
are, in order of rapidity 35°, 30° V.-, sometimes, however, that
at 30° C. takes the lead, but in most cases the fermentation
at 35° C. overtakes it ; this only happens at the commence-
ment and for a short time, after which they keep at the same
rate.
The fermentations Ut 25° and 40° C. start with more diffi-
culty, the latter being always slower and less active.
Between the fermentations at 25° and 30° C., the difference
of the rate of activity can only be observed at the beginning.
The start is more difficult at 25° C., but when once the fer-
mentation has commenced it proceeds very regularly with
much greater loss of weight than that of the fermentation at
30° C. In such a way that by prolonging the experiment
\ve arrive at the decomposition of the sugar quite equally in
both flasks. While by that time the flasks at 35° and 40° C.
have already stopped fermentation.
A constant and remarkable fact noticed in our experiments
is that, with the same must,, the higher the temperature rises
the deeper the colour becomes. We can evidently nor put
this down to oxidation of the colouring matter of the must,
for it is isolated from contact with the air by the Liebig
bulbs. In the cases where we tried the action of the air
during fermentation, we observed this modification of colour
before the introduction of air, and did not observe any
influence of this kind due to the air in that operation.
86
WINE-MAKING IN HOT CLIMATES.
The sulphuric acid in the Liebig hulb becomes differently
coloured, the density of the brown colouring being deeper for
the fermentation at 35° G., a little less for the fermentation
at 30° C. This coloration seems to depend on two factors,
the temperature and the rapidity of the evolution of gas, and
this explains the coloration of the acid corresponding to the
flasks fermenting at 40° C., for if in this case the tempera-
ture is higher, there is only a very slight quantity of car-
bonic acid passing through the sulphuric acid bulbs.
The brown coloration turns to a very fine pink on the
addition of water to the sulphuric acid. We thought that
the turning to pink was peculiar to dry grape musts (raisin
must), but fresh grape musts gave the same results.
INFLUENCE OF TEMPERATURE ON THE YIELD OF
ALCOHOL.
Two cases will be considered, the absolute yield of alcohol
independently of the quantity of sugar decomposed, and. the
relative yield — that is to say, the ratio between the alcohol
obtained and the sugar which has disappeared.
In both cases the yield in alcohol is less as the tempera-
ture is higher. In absolute yield this result only holds if we
consider fermentations lasting more than ten days ; below
this limit the fermentations at 25° C. furnished less alcohol
than that at 30° C., but the relative yield always remains
greater.
In short, lor a normal duration of eight days the fermenta-
tion at 30° C. is the best, then follow in order 25°, 35°, 40°
C., the latter always taking much longer than the others.
If we allow the fermentation at 40° C. to remain undisturbed,
it continues to gain in alcohol, but very slowly, and then only
under the influence of a fermentation, the exterior characters
of which are very different from those of an ordinary fer-
mentation. Two of our experiments (on must from fresh
grapes), which did not contain: — One, 4 per cent, of alcohol on
the seventh day, and the other, 6 per cent, on the tenth day,
showed for the first 9*5 per cent, two months after, and the
other 6-4 per cent, after eighteen months.
We have never obtained 47 per cent, of alcohol per 100 of
sugar decomposed, considered as a practical yield, although
we have closely approached it.
VINDICATION. 87
This might be because our temperatures were too high,
even that of 25° C.
The yield of 47 per cent, which can be obtained in cold
regions is never obtained to our knowledge in warm regions,
and we think that the measurement of the sugar, based on
the transformation of that body by fermentation, must be
done in order to be exact, when the operation is effected at a
very low temperature, and during a long time.
The following tables summarize the analytic results
obtained on some of our wines, and give the differences
observed in relative and absolute value : —
RAISIN MUST, No. 1.
Reducing matters ... ... 174 grammes per litre.
Mustimetre ... ... 170 „ „
Polarimetric deviation ... — 22° (sugar degree)
25° C. 30' C. 35° C. 40° C.
Alcohol in volume, per cent. ... 10-1 9-7 9"£ 2'1
Alcohol in weight, per litre .,. 80-8 77'6 736 16'8
Sugar remaining ... ... 2*0 2*5 4*5
. Sugar transformed ... ... 172- 1 l7l'6 169*6
Ratio of alcohol to sugar trans-
formed ... ... ... 46-94 45-22 43'39
Difference from the practical
yield of 47 per cent. ... O06 178 3*61
Difference from the theoretical
yield of 48-5 per cent. ... 1-56 3'28 5-11
Quantities of alcohol condens-
able bypothetically, in abso-
lute volume ... ... T57 3'17 4*70
Quantities of alcohol condensable
hypothetically, in weight, per
litre ... ... ... 1-42 2-54 3'76 —
RAISIN MUST, No. 5.
Reducing matters ... ... 1 74*5 grammes
Mustimetre ...
Polarimetric deviation
... 167-0
... — 32'4° (sugar degree)
25° C.
30° C.
35° C.
40° C.
Alcohol in volume, per cent.
9-9
9-7
9-1
7-3
Alcohol in weight, per litre
79-2
77-6
72-8
,58-40
Sugar remaining
3-0
3-0
100
41-0
* An accident prevented the determinations being made for the fermenta-
tion at 40° C.
88
WINE-MAKING IN HOT CLIMATES.
RAISIN MUST, No. 5 — continued.
25° C. 30° C.
35° C. 40° C
sugar
Sugar transformed
Ratio of alcohol to
transformed
Difference from the practical
yield of 47 per cent.
Difference from the theoretical
yield of 48*5 per cent.
Quantities of alcohol con-
densable, hypolhetically, in
absolute volume
Quantities of alcohol con-
densable, hypothetically, in
weight, per litre
171-5 171-5 164-5
46-17
0-83
2-43
2-40
45-25
1-65
3-25
44-25
2-65
4-25
133-5
42-24
4-66
6-26
3-27 3-86 4-57
1-92 2-62 3-10
3-65
RAJSIN MUST, No. 6.
Reducing matters
Mustimetre ...
Polarimetric deviation . . .
Alcohol in volume, per cent.
Alcohol in weight, per litre
Sugar remaining
Sugar transformed
Ratio of alcohol to sugar
transformed
Difference from the practical
yield ...
Difference from the theoretical
yield ...
Quantities of alcohol con-
densable, hypothetically, in
absolute volume
Quantities of alcohol con-
densable, hypothetically, in
weight, per litre
247 grammes
247 ' .,
— 28-2° (sugar degree)
25° C.
30° C.
35° C. 40° C.
11-1
10-6
9-3 *
88-8
84-N
74-1
56-8
63-2
83-3
190-2
183-8
163-7
46-68
46-13
45-44 -—
0-32
0-87
1-56
1-82
2-37
3-06 —
2-02
1-62
2-51
2-01
2-84
2-28 —
After eight days, even when the flask had returned to
the temperature of the surrounding air, the fermentation
did not start, which leads us to think that the temperature
of 40° C. had killed the yeast. We only noticed this in one
instance.
* The fermentation at 40° C. did not move appreciably. This was due, no
doubt, to the great saccharine richness of the must.
VINDICATION.
89
FRESH GRAPE MUST (TERBET-BouRRET AND PICQUKPOUL),
No. 8.
Reducing matters ... 190 grammes.
Mustimetre ... ... 190 „
Polarimetric deviation
Alcohol in volume per cent.*
Alcohol in weight, per litre ...
Sugar remaining ...
Sugar transformed
Ratio of alcohol to sugar
transformed
Difference from the practical
yield ...
Difference from the theoretical
yield ...
Quantities of alcohol con-
densable, hypothetically, in
absolute volume
Quantities of alcohol con-
densable, hypothetically, in
weight, per litre
— 40° (sugar degree).
25° C. 30° C. 35° C. 40° C.
10-9 10-9 9-6 9-3
87-20 87-20 76-80 74-4
2-50 2-00 22-90 27'0
187-50 188-00 167-10 163'0
46-5 46-38 45-96 45'64
0-50 0-62 1-08 1-36
2-00 2-12 2-58 2'86
2-18 2-31 2-48 2-66
1-04 1-85 1-98
FRESH GRAPE MDST (ARAMON), No. 11.
203-40 grammes.
2-1
Reducing matters
Mustimetre
Polarimetric deviation
Alcohol in volume, per cent.
Alcohol in weight, per litre ...
Sugar remaining ...
Sugar transformed ...
Ratio of alcohol to sugar
transformed
Difference from the practical
yield ...
Difference from the theoretical
yield ...
Quantities of alcohol con-
densable, hypothetically, in
absolute volume
Quantities of alcohol con-
densable, hypothetically, in
weight, per litre
200-00
— 37° (sugar degree).
25° C. 30° C. 35° C. 40° C.
9-6 7-2 6-1
76-80 57-60 51'2
39-15 76-90 86-9
164-25 126-50 110-5
46-75 45-50
0-25 1-50
1-75 3-00
43-9
3-1
4-6
1-68 2-15 2-94
1-34 1-72 2-35
* The analyses of these wines were made three months after the start of the
fermentation.
90
WINE-MAKING IN HOT CLIMATES.
In this trial the experiment at 25° 0. was not made, the
analyses were only made one month and a half after the
start.
We see that fermentation left for a few days at a high
temperature can only be completed after a long time — four
months at least, for fermentations that have been submitted
to a temperature of 40° C. during ten days. This excessive
duration of slow fermentation, seems to depend on the time
during which the flask has been submitted to the high
temperature ; however, we repeat, one may obtain complete
fermentations, giving sound wines, but that result can only
be obtained in the laboratory, that is to say, in must
previously sterilized and sown with pure yeast.
INFLUENCE OF THE TEMPERATURE ON THE WORK OF
DIFFERENT YEASTS.
High temperatures, therefore, have a retarding action
on the yeasts of the Herault, which were used in these
experiments.
We tried to ascertain if, as suggested by Marchand,
Director of the Experimental Cellar at Mascara, in Algeria,
the yeasts suffer more or less at high temperatures, accord-
ing to the cold or hot regions they originate from.
Marchand having studied the working of two yeasts taken
from the same cepage, but from different regions, and work-
ing in the same musts, noticed that these yeasts could stand
very different temperatures, the one originating from the hot
district suffering less than the other.
This observation led us to think that the most favorable
temperature found by us for the yeasts of the Herault
(30° C.) might be high for yeasts originating from cold
climates, and low for those from hot climates.
To verify this idea, we have made a series of experiments
with yeasts from the Rhine, Burgogne, and Herault. But
we only obtained the divergent results given in the following
table : —
25° C.
10520
95-40
130-98
not seem
Mudaison yeast
Bourgogne yeast
Wolbrath yeast
These figures do
Marchand's theory, for the Rhine and Burgogne yeasts we
30° C.
164-00
140-00
112-00
sufficient
35° C. 40° C.
109-00 85-20
131-20 106-50
112-90 90-00
for rejecting
VINDICATION.
91
used had been reproduced man}7 times in the laboratory, at
somewhat high temperatures, which may have enabled them
to acquire special resistance.
If this were so, we may foresee the possibility of (-renting
a race of yeasts capable of withstanding without difficulty
the temperature of the South of France, but this is only an
hypothesis.
INFLUENCE OF TEMPERATURE ON THE LOSS OF ALCOHOL.
We used, to collect the alcohol, the
following device, Fig. 17 : — The exit
tube, the Liebig bulbs having hem
removed, leads to a bottle, F, containing
a small quantity of water ; the vapours
not caught by this, pass through a con-
denser surrounded by ice.
The results obtained by this menus
are not accurate, and not comp:ir;iUe.
for there is a condensation of alcohol
taking place on the portion of the llask
Fig. 17.-F, bottle containing projecting above the water bath, and
the water; R, condenser; 7i p i j mi i • i ii
s, worm ; T, tube carrying therefore cold. Ihe higher the tem-
meentation°lvc " perature of the liquid, the greater tin-
condensation.
The quantity of alcohol carried over is subordinate to the
rapidity of the disengagement of gas, and the gaseous dis-
engagement being equal, is so much the greater ;is the
temperature is higher, for the tension of the vapour of
alcohol increases rapidly with the temperature.
In all our experiments the disengagement of carbonic
acid did not differ much between the 25°, 30°, and 35
fermentations, but was very slow at 40° C. As the strengths
of alcohol are always greater in the three first fermentations
than in the last, we should expect to find more alcohol
carried away from the fermentations at 'jr>°, 30°, and 3.")° ('.
than that at 40° C., even considering the high tension of
alcohol at 40° C. The following figures calculated for one
litre confirm our expectations :—
25° C. 30° C. 35° C. 40° C.
Raisin must
Fresh grape must...
c.c.
1-3
1-8
c.c.
2-0
2-1
c.c.
2-1
2-85
c.c.
traces
1-5
9 WINE-MAKING IN HOT CLIMATES.
These figures are quite sufficient to show that there is a
loss of alcohol through mechanical means. We do not
think, however, that this loss is the only canse of the diminu-
tion of the yield, but, on the contrary, that the most important
cause resides in the incomplete utilization of the sugar.
INFLUENCE OF TEMPERATURE ON THE TOTAL ACIDITY
OF WINE.
The temperature has a marked influence on the total acidity
of wine. Experiments have shown us that the acidity always
increases with the temperature. Here are several of our
results :—
Raisin Raisin Terret-Bourret .
must. must. Picquepoul. '
25° C. ... 25 23 3-8
30° C. ... 2-6 2-4 3-8 4-1
35° C. ... 27 28 4-1 4-8
40° C. ... 2-8 3-0 4-9 5'1
We cannot blame for this increase of acidity, parasitic
fermentations which are the cause of it in ordinary wines,
as our experiments were made with sterilized must, sown
with pure yeast ; the only reason we can see, therefore, is that
the yeast modifies its work with the temperature, and pro-
duces acid substances, as the precipitation of a part of the
bitartrate of potash, always greater at low temperature, is
insufficient to explain the differences observed.
ACTION OF TEMPERATURE ON THE YEAST.
One of us has already shown that it is possible to recog-
nise, by microscopical observation, if the yeast has worked
at a proper temperature.*
The morphological differences of yeasts worked at different
temperatures are very noticeable. The yeast at 25° C. is
turgid, with hyaline and homogeneous protoplasm, and
spherical. That at 40° C. is elongated, less regular shaped,
and coloured, its membrane seems thick, generally wrinkled,
sometimes star-like, a few cells only remaining refractive.
In a chemically neutral liquid (distilled water), for in-
stance, the deformations are still more marked, the wrinkles
distorted and pigmented, an appearance common with yeast
* L. Roos. Vinification en pays chauds.
PLATE II.
Wine Yeast of the Herault working at 25° C.
Wine Yeast of the Herault working at 40° C.
YINIFICATION. 93
fermented at 40° C. If after being washed, the yeast is
placed in distilled water, after having been submitted for
eight days to a temperature of 40° or even 25° C., there is also,
apart from the special action of the temperature, that of the
complete lack of nutritive substances in the liquid ; the yeast
produces endogenous spores (Rees spores) at both 25° and
40° C.
Therefore, the temperature has an action on the shape of
the yeast in the must, sufficient to be detected under the
microscope. It is rational to think that these morphological
appearances are the exterior manifestations of a morbid
state, the limit of which causes the death of the yeast.
Riestch and Herselin state that in two series of experi-
ments made with Musigny yeast, the yeast, died, after nine
days' fermentation, at 36° C.
Miintz, who we have already quoted, asserts that the
morbid state is at 37*5° C., which he calls the critical point.
Our experiments lead us to a different opinion. Our
yeasts did not die at 40° C., even after remaining ten days in
the must at that temperature. Some have even been kept
at 42° C. without dying.
It is evident that if we consider as the death of the
ferment, the fact that the must brought down to a proper
temperature cannot start fermentation again, we agree
with the above authorities, for it is a fact that over-
heated fermentations brought down to lower temperatures
will not start again. This is not due to the death of
the ferment, but to the impossibility of developing in the
liquid in which it is.
To strengthen this opinion, we may mention that we have
always obtained active yeast cultures by sowing them in
new must, even after they had reached the temperature ot
40° C. It does not seem possible to us to fix a limit t > the
temperature at which yeast is killed, for the composition of
the liquid itself is an important factor advancing or
retarding this limit.
INFLUENCE OF THE TEMPERATURE ON THE QUANTITY OF
NITROGEN.
Under ordinary circumstances fermentation does not take
place without the yeast, which absorbs from the liquid the
nitrogenous principles necessary to its constitution, elimi-
nating nitrogenous products. It is a general observation of
94
WINE-MAKING IN HOT CLIMATES.
Schutzenberger that the elimination of nitrogenous matters
increases when the yeast is under unfavorable conditions.
It appeared to us that the influence of high temperature,
which determines the morbidity of the yeast, might also
determine a greater elimination of nitrogen, for we noticed
in our fermentations that, generally speaking, starting from
the same must, the wine obtained is so much the richer in
nitrogen as it has been fermented at a higher temperature.
Nitrogen, per Litre
Raisiu must- ...
Terret-Bourret and Pic-
quepoul
Aramon
Carignan
25° C.
30° C.
35° C.
40° C.
...
0-265
0-322
0-490
0-115
0-187
0-115
0-112
0-120
0-193
"
0-135
0-183
0-205
Experiments made by Miintz on this subject have attracted
scientists' attention. He noticed that wines obtained at 40° C.
contain more ammoniacal salts than those made at tempera-
tures below 37° C. But there is this great difference between
the experiments made by Miintz and ours, that his bear only
on ammoniacal salts, and ours on more complex compounds ;
and, what is more, he attributes the increase of ammoniacal
salts to the destruction of the nitrogenous molecules by
the yeast, and that the yeasts themselves can become the
prey of micro-organisms.
In our experiments nothing of the kind could happen,
for, we repeat, we used must sown with pure yeast ; the
yeast, far from producing ammonia, would, on the contrary,
have used all the ammonia that might have been in the
must.
We have found traces of ammonia only in wine fermented
at high temperatures, while Miintz found it in wines ferment-
ing at a normal temperature.
It is therefore a fact, not before stated, that high
temperatures produce wines rich in complex soluble nitro-
genous compounds.
What is the nature of this nitrogenous matter ? We can
only offer a suggestion. We think that the sterility
VINDICATION. 95
acquired by the must ought to be attributed, partially at
least, to these nitrogenous bodies.
The result of practical observations made in Algeria
shows that fermentations, languishing at 40° and 42° C.,
completely stop and cannot start again, when brought back
to a low temperature.
Two explanations may be advanced — first, the death of
the yeast ; second, the liquid has become toxic, and there-
fore either unfermentable or only fermentable with difficulty.
We have already seen that at 40° C. the yeast was still
living. We have sown new must, previously sterilized, with
yeast that 'had remained ten days at 40° C., the fermentation
having stopped. This yeast became prolific.
This experiment has been repeated often, and has always
given concordant results.
Our laboratory experiments confirm the second hypothesis,
which is supported by H. Dessolier's practical observations
in Algeria.
From a filled arid fermenting vat, six hogsheads of wine
were racked when the temperature reached 25° C., then
successively six others, each at temperatures of 30°, 35°, 40°,
and 42° C., the rest of the vatful was refrigerated, and fresh
hogsheads taken from it when the temperatures were falling,
passing 35°, 30°, and 25° C. The following table shows the
number of days required to completely transform the sugar
in each of these series : —
Time required
Hogsheads. for complete
fermentation.
25° 0 ... ... ... ... 10 days
30° C ... ... ... ... 10 „
35° 0 ... ... ... ... 10 „
40° C ... ... ... 20
42° C more than ... ... 225
35° C ... ... ... ... 80
30° C ... ... ... ... 50
25° C ... ... ... ... 36
The maximum temperature reached only lasted a few
hours ; its influence, however, was sufficient to more than
treble the normal duration of fermentation.
Our results are still more definite, but we prolonged the
action of the temperature from eight to ten days, and thus
observed fermentation not completed after four months, in
the flask, at 40° C. brought down to 25° (.'.
96 WINE-MAKING IN HOT CLIMATES.
To verify the toxicity towards the yeast, of a liquid fer-
mented at 40° C., we tried it by adding a certain proportion
of fresh must, and sowing the mixture with active yeast.
With this object, eight volumes of wine at 25° C. and eight
volumes of wine at 40° C. were respectively mixed with two
volumes of fresh must. The quantity of sugar and alcohol
was rendered uniform in the two mixtures by additions of
alcohol and pure glucose. They were both sown with yeast
from the same culture, and both kept at a temperature of
28° C.
Regular weighings showed that the course of fermentation
was much more satisfactory in the flask containing the initial
wine at 25° G. than in that at 40° C. The loss of sugar was
twice as great in the first mixture, and was complete in nine
days, while in the mixture of the wine at 40° C., the fer-
mentation proceeded slowly, and a month after the start
the liquid still contained 16 grammes of sugar per litre.
Our experiments show, therefore, that a liquid previously
sterilized, and sown with pure yeast, may become unferment-
able under the sole action of a high and prolonged tempera-
ture. We must put aside the hypothesis of the toxicity
brought about by secondary fermentation, and only attribute
it to the action of the products eliminated by the yeast. We
do not deny the intervention of parasitic fermentation in
that sense. We simply desire to point out that the same
phenomena take place without it.
We intend to try and show that it is, without doubt, due
to the presence of albuminoid matters eliminated by the
yeasts.
The yeast eliminates volatile acids, mainly acetic and
propionic acids, but these exist in any fermentation, even
normal, and do not seem to have any action on the work of
the yeast, provided that they do not exceed a limit above
that normally given by the yeast.
Kayser has observed that the temperature of fermentation
has no influence on the quantity of volatile acids produced.
Volatile Acids calculated as Acetic Acid.
25° C. 35° C.
Yeast 2 ... ... 0-979 ... 0-780
„ 8 ... ... M12 ... 1-504
9 0-862 0-828
I
VINDICATION. 97
U. Crayon has recently pointed out* that whenever the
proportion of volatile acids increased, that phenomenon
coincided with the presence of micro-organisms other than
yeasts, which is in accord with the observations of Kayser.
As regards the production of higher alcohols and the
alkaloids which accompany them, it is very smjill. :md these
substances have not a very energetic action on the yeasts.
The same may be said of substances such as Iciicinc and
tyrosine, whicli are produced in such small (jiiantitics. that it
is necessary to operate on large volumes of liquid to detect
them. As also for pyridine and collidine, noticed by
Ordonneau, and proteine matters as yet undetermined whicli
we merely mention, and classify with the toxalbumens,
according to Roussy, who observed them in beer yeast.
To ascertain if these substances have an analogy with those
observed by Roussy, we injected rabbits with liquids obtained
by macerating wine yeast previously washed for eight < lay-
in distilled water at 25° and 40° 0. We noticed rises of
temperature, in the animals which were given a few centi-
metres of the solution from the maceration at 40° C. after
•filtration through a Chamberland candle.
The infusion at 25° C. does not give any apparent results.
but the injection of an equal volume of a yeast culture, that
had not been submitted to an abnormal temperature, also
produced hyperthermy. As the filtrate from the maceration
at 25° C. does not produce any effect, we may infer that the
active substances liable to be developed by the yeast are
elaborated in the organs of the animal, the temperature of
which is too high for the yeast.
It is therefore to these albumenoid substances, which we
consider analogous to those of Roussy, that we attribute the
sterility acquired by must, when left for a few days at a too
elevated temperature.
This sterility, however, is not permanent. According to
our experiments we cannot say that fresh yeast will not
develop at all in the liquid. It works there, but very slowly
at the commencement, and, what is very remarkable, more
actively later on, although the contrary would have been
expected, the activity of the yeast diminishing as the
alcoholic strength increases. If such a result takes place.
* U. Gayon. Sur les ucides contenus dans des vina. Jttoue de Viticulture,
April 24, 1889.
10649. G
93
WINE-MAKING IN HOT CLIMATES.
it is due, no doubt, as Schutzenberger observed, to diastases,
amongst which are classified the toxalbumens, the diastase
being submitted to a progressive alteration, the effect of
which is the diminution, 'and even the complete loss, of the
specific power of the yeasts.
CONCLUSIONS.
First. —For indigenous yeasts (South of France) the most
suitable temperature for fermentation is 30° C. (86° F.). We
think wtnemakers will with advantage keep their vats about
that temperature.
Second. — The rise of temperature above 35° C. causes a
noticeable diminution in the final alcoholic strength.
Third. — The qualities of a wine, its organoleptic, and
perhaps pecuniary value, are in inverse proportion to the
temperature at which it fermented.
Fourth. — The difficulty noticed in completely fermenting
a wine remaining sweet on account of excessive temperature,
is due to the liquid containing substances eliminated by the
yeast, and exerting a toxic action on it.
Fifth. — Fermentations at high temperature give wines
richer in albuminoids, than those fermented at normal tem-
peratures.
Sixth. — In our experiments, the greater amount of nitrogen
yielded cannot be attributed to parasitic ferments, for we
experimented with sterilized musts.
INFLUENCE OF THE TEMPERATURE OF
FERMENTATION ON THE YIELD IN ALCOHOL.
A fact which has attracted the attention of a few oenolo-
gists for some time, and which we have often observed, is the
enormous disproportion between the alcoholic strength and
the initial sugar contents of Algerian wines. The musts are
very rich in sugar, but the wines from them relatively
deficient in alcohol. This is so frequent that an incorrect
opinion is held by many Algerian vignerons. They consider
the mustirnetre as an inaccurate instrument, always giving
exaggerated results. In many cases the differences are
even much greater than they think.
The observations with the mustimetre are generally made
without taking the temperature into account, and without
making any correction, and as in Algeria the temperature is
VINDICATION. 99
always above 15° C., this faulty method of observation always
gives results below the normal. On the other hand, it is the
rule in Algeria to put into the fermenting vat grapes dried by
the hot winds blowing from the desert (the Great Sahara).
These grapes are rich in sugar, and increase the percentage
of sugar in the vintage without its being shown by the musti-
metre, as the sugar only dissolves slowly from the mass.
It is inadmissible that an instrument giving accurate in-
dications in France should give inaccurate indications in
Algeria. We must therefore acknowledge a loss, and we
have ascertained that the loss is considerable. We tried to
measure it in fermentations resulting from leaving the must
to itself after crushing, as is generally done in Algeria.
After having, as far as possible, rendered the must homo-
geneous in a vat of 250 hectolitres (5,500 gallons), samples
were drawn at different depths, and carefully tried with the
innstimetre, applying corrections for temperature. The in-
dications obtained from the samples were concordant. They
were also checked by determination of the sugar with
Fehling's solution. The differences found were inconsider-
able. The must tried contained 243 grammes of sugar per
litre. According to Pasteur's experiments, inverted sugar
(identical with grape sugar) gives after fermentation 48*5
per cent, of its weight in alcohol ; in practice, however, this
yield is not reached. A yield of 47 per cent, may be con-
sidered as normal, corresponding to 1 per cent, of alcohol in
volume for 17 grammes of sugar transformed. The above-
mentioned must should therefore have furnished —
243
j— = 14*3 per cent, alcohol.
Here are, in its main lines, the course of the fermen-
tation :—
It started eight hours after filling the vat, which was
filled on the 3rd of September. During the whole day
on the 4th and first half of the 5th September the fermen-
tation remained very active. On the 5th of September, at
two p.m., there were only 83 grammes of sugar left
untransfornied, but the fermentation was visibly slackening ;
the temperature taken at that moment in the vat was—
At 50 centimetres below the head, 38° C.
„ 1 metre „ „ 40°.
, the bottom of the vat 39'5°.
G Z
100
WINE-MAKING IN HOT CLIMATES.
On the same day, at six p.m., the maximum temperature
was 41'5° 0., and the fermentation seemed to 1m vc
stopped, a determination of the sugar gave 78 grammes.
Twenty hours after the sugar strength had not varied, the
fermentation had stuck.
Racking was advised and took place the day after. The
wine tested after racking, contained 7-9 per cent, in volume
of alcohol, and 78 grammes per litre of untransformed
sugar. A few days afterwards the fermentation started
again, and continued at a low temperature (25° to 28° ('.)
outside, in casks of 550 to 600 litres (130 gallons). The
wine, when completely finished, showed 12*5 per cent, alcohol,
and only traces of sugar.*
There has been, therefore, 14-3-12-5 = 1'8 per cent, of
alcohol less than the amount calculated. The yield in this
case has only been 87*3 per cent, of the normal, that is to
say, a net loss of 12*7 per cent.
This observation is not exceptional, it has been given with
details, because it was followed up with concordant results,
but we consider it as expressing the minimum loss that takes
place, as the fermentations last year in Algiers took place
under most favorable circumstances.
With regard to the vat studied, the temperature of the
grapes was not excessive, 22° C. The hot winds (Sirocco), it
is true, had blown during the night of the 1st and 2nd Sep-
tember, but the temperature had fallen on the evening of the
2nd, and remained relatively low during the remaining
period of fermentation.
There are, therefore, in this particular case, favorable cir-
cumstances, tending to render it comparable with our fer-
mentations in the South of France. What can we expect,
then, when fermentation takes place under less favorable
conditions, such as those, for instance, the result of which we
have seen at Relizane, and which took place at temperatures
varying from 40° to 44° C. in the shade ?
From information gathered from several vine-growers, the
difference between the indications of the mustimetre and the
final alcoholic strength reached in some cases the extreme
figure of 3°.
* We must draw attention to the fact that the sugar remaining after the
principal fermentation, was ultimately transformed, furnishing the normal
yield of alcohol.
VINDICATION. 101
We can only see one cause, for these small yields, having
a direct action of a physical nature, and, perhaps, also
of a physiological order. This cause is the excessive
elevation of temperature. This we may easily ascertain,
and we have done so; the presence of notable quantities
of alcohol in the gases evolved during fermentation when
the temperature exceeds 36° C. being readily detected.
The alcohol may also be carried away mechanically ;it
lower temperatures, but in much smaller amount, and to
measure it, we need to use more effective means than
those employed above. It is, probably, to the alcohol
carried away, that the difference between the theoretical
yield obtained in the laboratory (48*5 per cent, of the weight
of sugar), and that which we may call normal (47 per cent.
which results from wine-making practice in France), is due.
There is therefore always a loss which seems inevitable,
but we must try- not to increase it.
To estimate the alcohol in the gases from the fermentation
we used Miintz's accurate process, which consists in trans-
forming the alcohol into iodoform, by means of iodine and
carbonate of soda, at moderate temperatures. If we plunge
into the gases escaping a cold body, such as the carefully
eleaued outside of a cold bottle, it will become immediately
covered with a condensed film, in which alcohol exists in
considerable proportion. It suffices, in order to 'detect it, to
wipe it with a brush into a test tube, and to apply to the
liquid thus obtained Mlintz's test. One generally perceives
the odour of iodoform. If the test is made when the tem-
perature of the vat is approaching 40° C., not only does the
odour appear stronger, but the liquid contains numerous
crystals, which, when shaken, appear to the eye to have a
silky appearance, and deposit in a mass varying in size as
the experiment is continued longer, and as the surface of
condensation is colder, or as the temperature of the vat is
high.
If we rack into a recipient some of the wine while at a
high temperature, the presence of alcohol is still more
accentuated, the odour being easily noticed.
In the experiments we were able to make, the surface of
eondensation was about 4° or 5° C. above zero, as there was
alcohol condensed at that temperature, the tension of the
alcoholic vapours in the gaseous mass must at least have
him equal to that corresponding to the temperature of the
102 WINE-MAKING IN HOT CLIMATES.
condensing surface. The tension at 4° or 5° C. is represented
by about 18mm. of mercury, and we may easily conceive
that the loss of alcohol through being mechanically carried
away may be considerable, if we consider the enormous
volume of gas resulting from the phenomena of fermentation.
The quantitative determination of the loss under given
circumstances could only be experimentally determined, but
we feel sure that it is very considerable in Algeria, far more
so than is generally thought to be the case, and this is ex-
plained by the comparison of the tension of vapour of al-
cohol at the average temperatures of 30° C. in France and
40° C. in Algeria.
The tensions in mm. of mercury are 78* at 30° C. and 1 34*
at 40° C.
In what has been said so far, we mean by yield the
amount of alcohol obtained, as compared with the sugar
transformed, and not in relation to the total amount of
sugar. For it would be a very different thing if we meant by
yield the alcohol obtained, without taking into account the
quantity of untransformed sugar. Another important action
of the temperature is to completely arrest the fermentation
at 40° C.; if the liquid remains in that state, the natural de-
crease of temperature is not complete or rapid enough to
allow the yeast to recover its activity, and a part of the
sugar remains untransformed, which contributes to the
diminution of the yield in alcohol, and constitutes a cause of
future alterations.
If the temperature of the fermenting must is carefully
maintained below 32° C., in Algeria or anywhere else, the
resulting wine shows a normal yield of 47 per cent, of
alcohol per 100 of sugar transformed in weight, and the
whole of the sugar is transformed, even in the case of wine
of high alcoholic strength. We have been able to verify
this fact in the most positive manner, in a cellar, where two
fermentations only differed in their temperatures.
By applying to the fermenting must a slight refrigeration,
the losses are simply diminished, and we obtain a medium
yield.
If we represent the normal yield as 100, the yield of a vat
allowed to rise to 40° C. would be 87*3, that of the same vat
refrigerated would be 92, and that of the vat not allowed to
exceed 32° C. would be 100.
VINDICATION. 103
To sum up, we consider that any elevation of tempera-
ture above 30° C. is an important cause in the diminution
of the alcoholic strength, and that the installation of re-
frigerating plant is necessary in every cellar exposed to
high temperatures.
Whatever expense is incurred by this improvement of the
process of vinijication will be amply repaid by the superior
value of the wines made by this method. They will he more
alcoholic, brighter, and, above all, possess better keeping
qualities than wines made in the ordinary way.
INFLUENCE OF THE TEMPERATURE OF VINOTS FERMENTA-
TION ON THE QUALITIES OF WINE.
As has been already said, the excessive temperature in-
fluences the yield of alcohol in two ways — one physical the
other physiological. It is necessary to study the physio-
logical or indirect influence, for it results, not only in the
diminution of the alcoholic yield, but also constitutes the
principal cause of the poor quality of wines.
The activity of the wine ferment is considerably slackened
down when the temperature gets over a certain limit. The
curve described above allows us to see easily the slackening
of the fermentation, and the stoppage of its action. The
functions of the alcoholic ferment are destroyed. Mini in
many cases noxious ferments take its place, <JOtisnmmg the
sugar without producing alcohol, and introducing into the
wine new products altering its organoleptic properti
This is not the only alteration. The alcoholic ferment
is not dead, for sown again in new must, and under favor-
able conditions, it will regain its activity ; but it is mor-
bid, and shows morphological differences, detectable by the
microscope, so definitely, that by simply observing it under
the instrument we are able to say if the temperature has
risen above 36° C.
We are inclined to think that the products of elimination
of a living organism sufficiently diseased, for its shape to In-
altered, must differ from those eliminated normally. In
confirmation of this opinion, we have, by means of the
microscope, classified many wines made from the same
cepaqes under similar conditions, containing foreign hacteria
in notable numbers. At M. Debonno'a well-known vine-
yard at Bouf'arick we were able to control this classification
with the microscope, assisted by two expert wine-tasters—
MM. Aury and Yielle, of Algiers.
104 WINE-MAKING IN HOT CLIMATES.
•Among the wines tasted were four samples of white wine,
racked a few days previously, and still cloudy but quite
dry, that is to say, containing only traces of sugar. The
absence of sugar was a sign that the temperature had not
risen enough to completely paralyze the ferment. The
microscopical examination disclosed that all the fermenta-
tions had not taken place at equal temperatures, as some of
the yeasts appeared, to have suffered. Methodical refrigera-
tion is used in M. Debonno's cellar, but the instalment is
insufficient to refrigerate effectively the huge quantities of
vintage manipulated each day. By microscopical observa-
tion the wines numbered 1, 2, 3, and 4 were classified
according to their value, 1, 3, 4, 2. MM. Aury and Vielle,
simply by tasting, classified them in exactly the same way.
This test has been repeated frequently, and always with
success, and with wines completely turbid, in which condition
it was not possible to make any conjecture as to their future
quality.
The same observations were carried out on two white
wines made from the Cinsaut cepctge, the grapes having
been gathered the same day, and fermented, some in a
metallic vat (Toutee system), and some in a wooden vat of
125 hectolitres capacity; the temperature did not exceed
29° in the metallic vat and was 38-5° C. in the wooden one.
The fermentations started on the 15th September, and they
were both almost finished on the 18th.
Microscopical observation showed that the wine made
in the metallic vat contained only vigorous turgid yeasts,
highly refractive ; in the wine from the wooden vat, the yeasts
were unhealthy, shrivelled, and wrinkled ; they did not in
either case contain bacteria, but to the taste the wine made
in the metallic vat was much superior.
These facts certainly support the opinion we have already
given — the wine yeast eliminates at high temperatures pro-
ducts injurious to the wine. The elimination of abnormal
products, by the ferment in a visibly morbid state, is one of
the principal reasons of the inferior yield of alcohol, in wine
fermented at a high temperature. But we are far from
denying the analogous action of foreign injurious bacteria —
often developing at a temperature detrimental to the alco-
holic yeast itself.
These foreign fermentations happen very frequently. Des-
soliers, in a very thorough study on " Vinification in Hot
Climates," published in the Algerie Agricole, mentions this,
VINDICATION. 105
but we maintain that the predominant effect is due tot he
wine yeast itself. In the wines just mentioned there were no
foreign organisms in appreciable quantity, the ,-i Iteration of
the organoleptic qualities cannot therefore be attributed to
the secondary fermentation, but to defective \ i is fermenta-
tion.
'When the fermentation rises to a temperature high eunuch
to prevent the transformation of the sug;ir. the d;mi;i
still more serious, especially if it remains for some time at
this temperature.
We think, without being able to positively assert it. tlmt
the yeast accumulates morbid products in the must in suffi-
cient quantity to render the must sterile. It is from thi>
sterility that the sweetish acid taste of incompletely fermented
wine arises. The must is then invaded with a host of
organisms, amongst which may be found germs of nil the wine
diseases, which develop with extreme rapidity, living no
doubt at the expense of the sugar, and converting the wine
into an undrinkable liquid, only fit for the still, which even
then only produces spirit of inferior quality.
We have observed a great number of these wines in the
Chelif plain, when travelling from Oran to Algiers, where
the conditions for the vintage were not found this year
to be as favorable as in other viticultural centres in Algm'ii.
Several days after the first racking, and even on the mare,
these wines contained a great quantity of sugar, and only a
few wrinkled yeast cells could be detected under the micro-
scope. On the other hand, they were real breeding grounds
for a great variety of bacteria. We only found exceptions
to this fact in cellars where wine was fermented in small
quantities, and therefore. could not reach a high temperature.
The excessive temperature acts in a third manner in
diminishing the value of wine. White wines, fermented
without contact with the marc, are not submitted to this
action in the same way, or to the same extent, as red wines
fermented on the mare. Wine tasters are unanimous in
recognising the relative inferiority of red wines wliieh have
fermented at a high temperature. They find that they taste
of the mare, and that they terroitcnt. to use the rxpre»ion
employed locally. We are, therefore, led to suppose that the
products dissolved by the wine from the mare, at least at
different temperatures, are not the same quantitatively.
Chemical analysis does not reveal positive ditler^uces. We
106 WINE-MAKING IN HOT CLIMATES.
can only note as a constant fact that the reduced dry extract
of wine, made at a high -temperature, is in excess of normal
wines made from the same cepage. In fact, if we examine
the marcs from fermentations made at 30° and 40° C., the
tissues of the latter are found to be much more disorganized.
To conclude, roe consider that the elevation of the temperature
above a certain limit (32° C.) diminishes the quality of the
resulting wines. It is therefore necessary, in order to improve
our wines, to check elevation of temperature by the use of 0
refrigerating appliances.
INFLUENCE OF THE TEMPERATURE OF FERMENTATION ON
THE KEEPING QUALITIES OF WINE.
After what has been, said about the influence of the tem-
perature of fermentation on the quality of wine, it is almost
superfluous to speak of its action on the keeping quality of
wine, for the two terms quality and keeping quality are
almost synonymous when applied to wines having the same
origin. However, we consider it advisable to dwell a little
longer on this subject, to show the detrimental effects of high
temperatures.
Wine is a liquid composed of different parts, which can be
divided into two groups. The first includes alterable sub-
stances such as albumenoid matters, sugar, acid-tartrate of
potash, &c.; the other comprises antiseptic matters pro-
tecting the first group against possible alterations. These
are alcohol, glycerine, tannin, and various acids. In the
manufacture of wine, therefore, we should try and diminish
the quantity of alterable matters, and increase the quantity
of natural antiseptic substances.
In fermentations made at 30° C. the quantities of these
various substances seem to exist in proper proportion ;
experience has proved that wines obtained at that tem-
perature, even if only submitted to summary care subse-
quently, are able to keep well.
Experience has also proved that fermentations made above
that temperature, which we will call the optima for the yeast,
yield wines much more liable to alteration, this liability to
change varying in proportion as the temperature rises or
falls from that optima, and being greater for high tempera-
tures. It is to this that Algerian wines owe their reputation
for bad keeping qualities. An opportunity occurred in 189^:
of noticing* a disease in Algeria which seemed peculiar to
VINDICATION. 107
Algerian wines, but which has since been found more gem-mi :
this is known as mannitic fermentation. We were able to
show in 1892,* from experiments made in the laboratory,
and in Algeria during the vintage, that the disease was due
to bacteria, and that it was simply the result of the extreme
temperature, which had killed the yeast without killing the
bacteria, which always exist in great quantities even in
healthy vintages. Gayonand Dubourghave recently isolated
the mannitic ferment, and confirmed these observations, and
proved, as a result of their study, that the mannitic fermenta-
tion can only take place after an incomplete alcoholic
fermentation. This disease is very frequent in wines made
at a high temperature, for there iindecomposed sugsir is
always left, but if the temperature of the fermenting wine i>
brought down it will not occur. There will be no sugar
left, and consequently no fermentation is possible.
Other wine diseases, it is true, may develop even in com-
pletely fermented wines, but their development is infinitely
more frequent if the fermentation has been defective.
High temperature is therefore injurious to the keeping
quality of wine. It leaves in the wine a large proportion
of alterable substances, and is the cause of the diminution
in the alcohol as also of the glycerine, both of ivhich are
excellent preservative substances.
REFRIGERATION OF MUSTS DURING FERMENTATION.
The refrigeration of musts during fermentation has not
yet obtained the sanction of being an old practice, but trials
made since 1892 in our Africanf colony, and coiisidemhly
increasing every year in various parts of Algeria, have shown
decisively that the solution of the problem of wine inn king in
hot countries depends entirely on this operation.
* Journ. de Pharm. et de Chimie, 1893.
t In connexion with the recent extensive application of the system of
refrigerating musts during fermentation, in the South of France and Algeria,
it is interesting to refer to an Australian work by Dr. A. C. Kelly, The Vine
in Australia, pp. IX., 215, published in 1861, Melbourne and Sydney. In this
work Dr. Kelly described a simple system of refrigerating must during
fermentation. His remarks and experiments on this subject are very conclu-
sive and convincing, but were greatly in advance of the times, for, although
written some 40 years since for the immediate benefit of Australian wine-
makers, it is well-known that they are even now only tardily availing them-
selves of the advantages to be derived from fermenting their musts under proper
conditions.
The paragraphs of Dr. Kelly's work dealing with the importance of the
temperature during fermentation are, on account of their present interest,
reproduced completely in the Appendix to this work. (Trans.)
108
WINE-MAKING IN HOT CLIMATES.
In the South of France, the difficulties met with in Algeria
exist to a lesser extent, and if refrigeration there is not
indispensable it is nevertheless so useful that results obtained
in different vineyards during the last two or three years
enable us to predict the general adoption of this system at
an early date.
How should the fermentation be conducted ?
' Two systems have been proposed : the first consists in
cooling the must in the vat, the second in cooling it
outside.
The first system may be applied in two ways : one as used
at Jaffa, by Ermens, consists in a long pipe (coiled spirally)
fixed in the vat itself, and through which cold water circulates
during the fermentation. (Fig. 18.) The application of
B
Scale.
Fig-, is — Ermens arrangement for refrigerating inside the Vat.
VINDICATION. 109
this system is so very expensive, and according to the
inventor necessitates the use of such large quantities of cool
water to give good results, that it cannot be advocated.
The second method of refrigeration of the must inside tin-
vat is more tempting, because it is more simple. It con-
sists in facilitating the exterior radiation of the heat of the
must, by the use of vats made of material of great Con-
ductivity. These are the metallic vats of Touted.
We had an opportunity of watching two fermentations,
one in a wooden vat of 125 hectolitres capacity, the other
in a metallic vat of the same size. The maximum tem-
perature in the wooden vat was reached at 38-5°, and in
the metallic vat at 29°, a difference in favour of the
metallic vat of 9-5° C.
This decrease of temperature was ample, but we must
take into account that it was white grape must, in which
the homogeneity of the temperature is greater than in
red must. In the latter the head, or mass of marc, is a
danger zone, and ought to be refrigerated first. It forms
a compact felted block, which does not partake much
of the diminution of the temperature produced by
the conductivity of the walls of the vat. It would
be necessary in order to obtain in the fermentation of
red musts a result equivalent to those of white must fermen-
tations, to establish continuous circulation of the liquid
pumped from the bottom of the vat to the top of the head.
This manipulation already used to a great extent with any
system of fermentation would not be very complicated, the
only question to be considered is the monetary outlay, the
adoption of the Toute"e system meaning the integral renewal
of all the vats.
Refrigeration of the must by circulation outside the vat may
be effected in two different ways, sometimes it is spread in
contact with the air over a great surface. This leads to eva p< »-
ration and therefore refrigeration, increased if necessary by
a strong air blast, or else the must circulates in a closed
space refrigerated outside by a current of cool water, hy
damp cloths, or sometimes by the air itself, for it is only a
question of surface. This latter system, we consider, should
lie preferred.
The refrigeration of musts in contact with the air creates
energetic oxidation of the wine.
110 WINE-MAKING IN HOT CLIMATES.
The oxidation is an advantage, if done before the start
of the fermentation, but it is not so in the case of wine
partly or completely fermented. When the fermentation is
started the aeration may be useful, but it should be sparing if
we desire to protect the wine against the disadvantages
which it leads to.
Fermenting wine, if kept too long in contact with the air,
becomes flat and insipid.
It is therefore better to adopt the system of refrigeration
without contact with the air, and aerate afterwards if judged
necessary.
-It is by no means difficult to obtain simple and very
effective cooling apparatus. It is not necessary, as in the
case of a brewery, to reduce the temperature very low, but
simply to keep the fermentation about 30° C.
Water and air are the only two refrigerators that can
be used economically.
The air at vintage time in the South of France is
generally below 30° G., and is always at the disposal of the
vine-grower in unlimited quantity, and might be used.
Water, unfortunately existing in too limited supply, is
much more convenient, as it is generally at a lower tem-
perature than the air, and even if it were at the same tem-
perature, it produces an equal cooling effect from a smaller
surface of contact.
Water therefore should always be the refrigerating means,
whenever suiiciently plentiful.
A simple tube, more or less long, wetted outside by a current
of water, constitutes the machine, and is connected with
the bottom and top of the vat. Tinned copper tubes are
all that is required to make a wine refrigerator when water
is at disposal. The pipes may be joined by pieces of rubber
hose and placed in a suitable trough, in one length or in
a tank zigzaging, divided by partitions to regulate the
circulation of the water. This form presents the advantage
of being easily pulled to pieces and used afterwards as
ordinary conducting pipes.
The decrease of the temperature of the wine induces a con-
siderable deposit of tartar, which necessitates the use of
tubes of large diameter, easily dismantled for cleaning.
An apparatus of this kind may be fixed without much
expense in a cellar having water available, and can if neces-
sary, even be placed outside the cellar.
VINDICATION. Ill
If only a limited supply of water is available this device
can still be adapted, if the water is collected to be used
over again when its temperature has decreased, or, prefer-
ably, another system may be used utilizing more completely
the cooling power of the water, with or without the inter-
vention of air.
The cooling effect of the air may take place directly, sim j >1 y
by exchange of temperature, the surrounding air being
generally cooler than the wine, or indirectly by evaporation
of part of the water used for refrigerating. This physical
phenomenon being always accompanied by a decrease of
temperature. In the latter case it is not indispensable for
the air to be colder than the wine.
The metallic vats of Toutee only utilize, when bare, the
refrigerating effect of the air, but if covered with cloth kept
wet they utilize the refrigerating effect of the evaporation
also. It goes without saying that in this case the cooling
effect is greater.
We have seen by the figures quoted relative to fermenta-
tion in metallic vats, that these are quite sufficiently effective
for white and red wines, if in the case of the latter the must
is pumped over the head.
The adoption of the Toute*e system is therefore indicated
for a cellar with limited water supply, but it would be too
expensive to establish in a cellar already furnished with
vats.
When the water supply is limited, we must try to use the
same water again, or develop surfaces large enough to act
with air alone, or adopt a mixed system in which air and
water act together, as in the Toute*e vat covered with cloth.
Whatever be the ingenuity of apparatus utilizing water
alone, its consumption will always be large, more than halt'
the volume of wine cooled, but if the water supply is suffi-
cient for one day's operation, the night cooling will be ample.
With arrangements easily devised we may bring back the
water to a suitable temperature, ready to be used again the
next day.
But there are cases where the cooling of the water must
be done at the same time as it is employed.
Dessoliers proposed to rapidly reduce the temperature of
the heated water with a kind of refrigerator, submitting it
to a great surface for evaporation, aided with a strong Mast.
and devised for that purpose an apparatus called ckeminee
112
WINK-MAKING IN HOT CLIMATES.
climagene (Fig. 19), which consists of a chimney more or
less high, according to the quantity of water to be treated, in
Fig. 19.--Climagene chimney of Dessoliers —A, Distributing tank for the hot
water; B, cellular bricks ; C, receiving tank for the cooled water ; d, pump; b, ven-
tilating fan ; a, e, level indicator.
the centre of which cellular
bricks are piled up to the
top, overlapping each other.
The water poured on the top
descends to the bottom,
spreading completely over
the surfaces of the bricks
(Fig. 20). A strong venti-
lating fan sends an air blast
from bottom to top, creating
active evaporation, with
consequent cooling of the
water.
Fig. 20. — Olirnagene Chimney of Dessoliers—
Arangement of the cellular bricks.
VILIFICATION. 113
With the chetninee climagene, the results are excellent, but
the same result can be reached without going to the expense
of such a building.
There are different materials easily procurable every-
where, such as coke, already employed for similar purposes
by other industries, which present a larger surface than
cellular bricks. We feel certain that a cylinder made <>i
double hogsheads, with the bottoms knocked out, and filled
with coke, would afford a better solution of the problem
than Dessolier's chimney.
Jt is rational to utilize evaporation, as it is so active in
hot climates, but apparatus based on that principle only.
that is to say, in which the outside surface is just maintained
moist, cannot have a constant refrigerating action.
The refrigeration in this case depends on the hygromct re-
state of the air, and on the rapidity of the air current.
Theoretically, the cooling produced by evaporation is pro-
portional to the difference existing between the maximum
tension of water vapour at the temperature at which tin-
work is being done, and the tension existing in the air at the
same moment.
If we suppose the air to be completely dry the refrigerating
power seems unlimited, for if the air is constantly renewed
it will continuously vapourize the water, and therefore reduce
the temperature. In reality, equilibrium takes place at the
moment that the heat lost by the water by radiation and
evaporation becomes exactly equal to that received from the
surrounding air.
These states of equilibrium were experimentally deter-
mined by Gay-Lussac, who determined them for temperatures
between 0° and 25° C. by the figures indicating the maximum
decrease of temperature that can be obtained. The figures
interesting to us are those corresponding to the temperatures
of 15°, 20°, 25° 0., and they are respectively 10*8, 12-7,
and 14*7.
These experiments were repeated by Regnault, a nd appeared
to him to be incomplete, as the influence of the rapidity of
the current of air on the decrease of temperature was not
studied. This decrease increases with the rate of movement
of the air current, when it is higher than 8 metres per
second, which corresponds to a strong wind, but is easily
obtainable with a ventilating fan.
10649. H
114 WINE-MAKING IN HOT CLIMATES.
All the results apply to dry air, if the air is damp they
will be lower, although remaining in the same proportion,
and become nil if the air is saturated with moisture.
There are therefore in the utilization of evaporation two
factors, one of which can be modified — the speed of the
current of air ; the other, which is not controllable, being
the hygrometric state of the atmosphere ; but the action of
the latter is so pronounced that it would be imprudent to
depend on a system based on evaporation alone, in certain
regions where the hygrometric state is very variable.
The effect with such a machine would, however, never be
nil, notwithstanding what has been said ; even if working
in a saturated atmosphere the effect will always be greater
than we could have expected from the exact measurement of
the quantity of water evaporated.
It seems at first sight that the decrease of temperature
obtained can only be constituted by the sum of the calories
given to the water, and that necessary to evaporate the
weight of water which disappears during the experiment.
If we represent by A the first of these numbers, by B
the second, and by C the number of calories lost by the
wine, it should be possible to write A + B = C. In practice
this is not so. Not only is A + B less than C, but
experience proves that often A + B is only half of C.
The heat lost cannot be equal to the heat gained, we must,
therefore, conclude that there are undetermined elements in
the calculation, which intervene to a large extent, and which
cannot be measured directly. They are the exchanges with
the surrounding air. These are so much the greater as the
temperature of the wine varies from the surrounding air,
assuming that the surface of evaporation is of constant
conductivity.
We have experimented on a cooler constructed purposely
with a view of utilizing the evaporation effect only. It
gave insufficient results under rather good atmospheric con-
ditions. The surface of evaporation acted upon was rather
small, it is true. The apparatus consisted of six very flat
lenses made of tinned copper, mounted horizontally on a
vertical tube, and of a diameter of 40 centimetres. The
decrease of temperature observed in wine at 38° to 40° C.
was from 3'5° to 5*5° C., varying according to the strength of
the current of air, the surrounding temperature, the hygro-
metric state of the air, and the rate of flow of the wine,
VINDICATION. 115
which was between twelve and fifteen hectolitres per hour.
Although not perfectly satisfactory, an improvement in the
yield of alcohol resulted, which reached 4-7 per cent, more
tliiui that of the non-refrigerated wine (92 against 87'3, 100
being the normal yield).
No doubt larger decreases of temperature could be
obtained by using larger surfaces, but there will always be
an uncertainty of success in countries where the hygrometric
state varies, as it does in the South of France, during the
vintage time.
The problem of refrigerating musts is not very complex.
There are no insurmountable difficulties, for it is riot
necessary to get a very low temperature as in the case of
beer ; but only to reduce to 27° or 28° C. a vatful which has
overreached 32° C.
It is advisable to go slowly and maintain an average
temperature in the vat rather than to cool suddenly, for we
imagine that a sudden large decrease of temperature can
only be injurious to an organized plant such as yeast. If,
on the second day after the start, the fermentation has not
exceeded 28° C. we can without fear let it go on naturally.
The temperature will not become excessive, for by that time
the reaction producing the heat is almost all over.
STUDY OF VARIOUS MUST REFRIGERATORS.
The expense of refrigeration of the vintage consists of the
sum representing the sinking fund of the machine — 10 per
cent, of its value — the labour necessary for pumping the
water, which varies with local conditions, and the labour for
pumping the wine.
The labour is, of course, proportional to the volume
treated. It can, therefore, be expressed by a fixed sum per
hectolitre. This is very small, but the sinking fund for the
machine is so much the greater as the volume of wine
treated is smaller.
Suppose, for instance, a cooler costing 1,500 francs
(£62 10s.) applied to a vintage of 1,000 hectolitres (22,000
gallons) the operation will be over-estimated from the sinking
fund by 15 centimes per hectolitre, while if the instrument
is applied to a vintage of 10,000 hectolitres (220,000 gallons)
the over-estimation will diminish to H centimes per hecto-
litre.
H 2
116
WINE-MAKING IN HOT CLIMATES.
Iii no case, however, will the expense reach the increased
value acquired by the refrigerated wine. But it would
always be better in dealing with small vintages to buy
smaller machines, as these are less complicated and less
expensive.
The apparatus of Miintz and Kousseaux is an excellent
modification, for vinification, of a device used in other indus-
tries, and is actually adopted in many important cellars.*
It is composed
of two parallel
series of nineteen
tubes superposed.
Fig. 21. Each
tube is open at
both ends and
fixed to a vertical
plate. A water-
tight obturator is
fixed on each plate
in such a way as to
be easily detach-
able. Communi-
cation is estab-
lished between the
tubes in such a
manner that the
liquid introduced
at the bottom
passes succes-
sively through all
the tubes before
reaching the top.
A tube joins the top of one series to the bottom of the other.
A trough with a row of small holes spreads water over the
tubes, which are covered with canvas, the water drips over
the tubes and falls to the bottom trough.
This apparatus successfully utilizes the cooling effect of
the water, as the wine is exposed to a large surface before
Fig. 21.— Miintz and Rousseaux Refrigerating Apparatus.
* An important work by Miintz and Rousseaux, Etudes sur la Vinification
et sur la Refrigeration des Moitts, appeared in 1896, and was translated and dis-
tributed in pamphlet form amongst Victorian vine-growers in the same year
byoneof us.-(W.P.W.)
VINDICATION.
117
returning to the vat. Each tube measures 4 metres (13 feet)
in length and has a diameter of 40 millimetres (1 £ inches).
It is an expensive machine, which does not seem to be
altogether suitable for small growers, but it is in its proper
phi re in large cellars.
\\V nmdc- some experiments on other coolers which
seem simpler in construction, and of more reasonable price,
for the use of small and medium cellars. It goes without
saying that we only considered machines capable of being
easily cleaned, owing to their shape, and the facility with
which they could be taken to pieces.
We tried three systems — one constructed by P. Paul on
ideas we exchanged together ; one invented by Rouviere-
Huc, and described in the Proyres Agricole ; and the
third simply composed of concentric communicating vessels,
invented by P. Andrieu.
The machine designed by Paul and Roos is composed essen-
tially of two concentric tubes, 4 metres in length, of 2 or 3
centimetres in diameter, plunging into a trough of small
capacity. Each sheaf of concentric tubes forming an element
of the system, the number of the elements varying according
to requirements. Fig. 22.
Fig. 22.— P. Paul's Refrigerating Apparatus.— Forecarriage, B, exit of the cold wine.
The wine circulates in the annular space between the
inside surface of the outer tube and the outside surface of
the inner tube. The water travels in an opposite direction
118
WINE-MAKING IN HOT CLIMATES.
to the wine, first of all passing in the inside tube, acting
through the inside surface of the annular space, then in the
trough continuing its action on the outside surface.
In a machine composed of several divisions the wine rises
from one division to another, while the water 'descends from
one trough to another to be emptied at the last one.
The interior tubes are fixed to the extremities of the
exterior tubes by screened discs, fixed in the same way as an
ordinary pipe coupling. Tightening the screws at one end
of the tubes makes the whole system watertight by com-
pression on rubber rings. The dismantling of the machine
for cleaning purposes is simple, and the cleansing is very
easily done, as the tubes are straight.
The annular spaces of the two divisions are joined together
with flexible rubber hose and fixed by means of a coupling.
Finally, with the view of utilizing ice, which can now be
obtained at very small cost, low enough to permit its use,
the system has a box attached to the top to contain the ice,
over which the heated water is spread and .cooled before
being used. Fig. 23 and Fig. 24.
Fig. 23. — P. Paul's Refrigerating Apparatus. - A, entrance of wine to be treated ;
C, annular space in which the wine circulates ; D, water supply ; E, entrance of cold
water ; F, exit of warm water.
VILIFICATION.
119
.5
Fig. 24. — Paul's Refrigerating Apparatus.— Section view.
The first tests were made at the petroleum refinery. ;it
Balaruc-les-Bains, and we owe to the kindness of M. Durrand,
Director of this important establishment, the opportunity
given to make these tests under the most desirable
conditions.
The tanks used for the condensation of the petroleum con-
sumed daily 1,000 cubicmetres of water, which, entering
cold, flowed out at a temperature of about 50° C. If the
water is carefully collected at various distances descending
from the surface, we obtain all the temperatures com-
prised between the entering and exit temperatures of the
water.
The tanks are of considerable dimensions, and receive' the
vapours from enormous boilers. It is possible therefore
when distillation is in full swing to remove 20 or 25 hecto-
litres of water per hour during many hours without the
temperature varying 0*5° C., if it is drawn from a constant
depth.
These are very favorable conditions tor a test of this
kind.
120 WINE-MAKING IN HOT CLIMATES.
The cooler we have just described gave, with water trials,
the following results :—
EXPERIMENTS MADE ON THE 22ND AUGUST, 1896.
1. Quantity of wine (represented by-
warm water) ... ... 20-5 hectolitres per hour
Quantity of cold water... ... 15*0 „ „
Temperature of wine at entrance (warm water) 35'9° C.
Temperature of wine at exit „ „ 28° C.
Temperature of water at entrance ... ... 19° C.
Temperature of water at exit ... ... 27° C.
2. Quantity of wine (represented by
warm water) ... ... 20 hectolitres per hour
Quantity of cold water... ... 14'50 „ „
Temperature of wine at entrance (warm water) 31-75° C.
Temperature of wine at exit ,, ,, 26'3° C.
Temperature of water at entrance ... ... 19'0° C.
Temperature of water at exit ... ... 25'6° C.
(Results obtained after two hours' work.)
A trial was made the following day, starting (as an
experiment) with a higher temperature for the wine
entering.
The quantity delivered was in one case 20-50 hectolitres
for the wine and 1 4*50 hectolitres for the water.
1. Temperature of wine at entrance (warm water) 35to° C.
Temperature of wine at exit ... ... 28*0° 0.
Temperature of water at entrance ... ... 18 -2° C.
Temperature of water at exit ... ... 28-2° C.
2. Temperature of wine at entrance (warm water) 39-5° C.
Temperature of wine at exit ... ... 31 '0° C.
Temperature of water at entrance ... ... 18-5° C.
Temperature of water at exit ... ... 31'0C C.
(Results obtained after two hours' work.)
In all these trials the quantity of warm water used,
representing the wine, was measured with great exactitude.
The machine was fed from a tank the level of which was
constant. The syphon supplying the refrigerator yielded
less than the tank received.
VINDICATION. 121
It was, unfortunately, not possible to measure so exactly
the water used for refrigerating, as it was drawn from a tap
branching from a pipe feeding other taps at the same time,
so that although the tap was maintained at a constant
aperture, fluctuations in the delivery of water may have
occurred, small, no doubt, but sufficient however to pre-
vent us from trying to estimate the refrigerating action
attributable to the air.
The measurements for water given in the above tables
were made at the maximum, that is to say, when the pipe
only fed the tap used.
When tried in a cellar with the vintage fermenting in
wooden vats, this refrigerator gave similar results. We
must draw attention, however, to a special feature of this
machine.
On account of the thickness of the layer of wine circulating
in the annular space being very small there is great danger
of obstruction.
The refrigerator or cooler used had tubes, whose radius
differed only by one centimetre. Although the machine
worked well for a few hours we consider this difference is too
small and should be doubled.
It is necessary to introduce into the cooler must free from
solid suspended matters, such as skins, &c.
It should be used as follows : —
The must coming from the vat to be refrigerated, falls
into a tub divided into two compartments by a vertical
partition of wire gauze.
In the compartment opposite to that receiving the must
from the vat, a tube is plunged connected with the bottom
of the refrigerator, the suction tube of the pump being con-
nected with the exit at the top of the refrigerator forcing
the cool must into the vat again. Worked in this way no
obstruction can take place, and the machine may work from
250 to 300 hectolitres of must without being cleaned.
The work done by this cooler is naturally a function of
the number of divisions of which it consists. Six divisions
will suffice for a delivery of 40 hectolitres per hour, with
a decrease of temperature similar to that observed in the
above experiments.
122
WINE-MAKING IN HOT CLIMATES.
The second cooler experimented with is due to Rouviere
Hue, a well-known vine-grower of the environs of Mont-
pellier. It is especially suitable for small growers, is cheap,
and may be constructed by any plumber. These are ap-
preciable advantages.
Apparatus opened out.
Fig. 25. — Rouviere-Huc's Refrigerating Apparatus.
The refrigeration is effected by forcing the wine through
an annular space, limited by the metallic walls of two con-
centric cylinders. The whole system is immersed in a tank,
traversed by a constantly circulating current of cold water.
The annular space is partitioned by projecting metallic
plates, alternately overlapping, and forcing the wine to
travel alternately from the top to the bottom of the
machine.
The model tried at Balaruc-les-Bains did not give good
results, the installation was defective, and did not allow
VINDICATION. 123
an equitable judgment; however, the trial enabled us to
point out a few weak points of the machine which enabled
Rouviere-Huc to make additional improvements before the
vintage. These, although imperfect, permitted him to carry
on further trials in 1896.
He has been kind enough to communicate the figures
obtained, which are very satisfactory.
/Temperature of wine entering ... 32-0° C.
(Temperature of wine at exit ... 25-0° C.
| Temperature of wine entering ... 30'5°C.
' | Temperature of wine at exit ... 25-0° C.
j Temperature of wine entering ... 29-5° C.
{ Temperature of wine at exit ... 24 • 5° C.
, ,- j Temperature of wine entering ... 28*5° C.
{ Temperature of wine at exit ... 24-0° C.
These are for deliveries of wine and water respectively
of 18 and 8 hectolitres only, operating on a fermenting vat
of 150 hectolitres.
During the fifth hour, the must at entry being below
28° C., the operation was stopped.
The water pumped from a deep well, had a temperature
of 15'5° C. at entrance, and an average of 24° C. at the
exit.
Thirty-two hectolitres of water were used during the four
hours, and absorbed about 27,000 calories from the wine
in the vat.
The wine in the vat was reduced after the four hours'
circulation to 28° C., which is a most satisfactory tem-
perature.
These are very good results, and no doubt Rouviere's
cooler will become a practical machine, when a few addi-
tional improvements in its construction render its working
more convenient.
In spite of the results observed one should use the water
in a more systematic way, as the working of the machine
could only be improved thereby.
The third cooler experimented upon is due to Andrieu.
The principle it is based on differs from the above in this,
that it utilizes the refrigerating power of both air and \\-aivr.
124
WINE-MAKING IN HOT CLIMATES.
The machine has a surface of action much more consider-
able than the preceding. The wine circulates, as shown in
.Fig. 26, in an annular space, limited by two vertical
cylindrical metallic walls, one in contact with water the
other in contact with air.
A
Fig. 26. — Andrieux Refrigerating Apparatus. — A, entrance of wine to be treated ;
B, exit of cold wine ; D, entrance of cold water ; C, exit of warm water ; E, annular
space in which the wine circulates.
It is composed of concentric vats similar to the Toute'e
metallic vats, the inside vat containing water, and that on
the outside the wine to be cooled. The circulation of the
liquids is in opposite directions both from bottom to top.
In this particular instance the outside vats were made
of sheet iron covered inside with a varnish unaffected by
the wine. They measured 1*18 metres in height and O82
metres in diameter ; the inside tank was made of tin, 1*20
metre high and 0'63 metre diameter.
The inside vessel is arranged in such a way that its
surface is at a constant distance of 9J centimetres from
that of the outside vessel, both at the sides and bottom.
It is evident that this machine has a very large surface
for action, for each division has about 3J square metres of
available cooling surface, or 16J square metres for the three
divisions, while "the three divisions of Paul's cooler have
only 3J square metres. Again, one should add, to Andrieu's
machine, the surfaces at the bottom which also bring their
contingent of cooling effect.
The results obtained with this device were very satis-
factory. The decreases of temperature observed were con-
fined between 4° and 10° C., according to the initial
temperature of the wine entering (between 28° and 37° C.)
for deliveries of wine and water comparable to those of
Paul's cooler, that is to say, 1^ hectolitres of water for 2
hectolitres of wine.
VILIFICATION. 125
Here are the figures relating to the two experiments —
1. Quantity of wine ... ... 16-6 hectolitres per hour.
Quantity of water ... 13*6 „ „
Temperature of wine at ^
entrance ... ... 28'2° C. | Temperature of
Temperature of wine at exit 23'7° C. [ the air during
Temperature of water at j the experi-
entranoe ... ... 18-2° C. j raent, 20° C.
Temperature of water at exit 22 0° C.J
2. Quantity of wine ... ... 13'5 hectolitres per hour.
Quantity of water ... 8'64 „ „
Temperature of wine at ~]
entrance .... ... 38-8° C. ! Temperature of
Temperature of wine at exit 28tO° C. I the air during
Temperature, of water at j the experi-
entrance ... ... 18'5° C'. \ ment, 20° C.
Temperature of water at exit 28*5° C. J
(Results obtained after two hours' work.)
Considering the dimensions of the machine the delivery is
small. We would have preferred making experiments with
larger quantities, but this was not possible, as the section of
the exit tubes did not allow a delivery exceeding 16 or 1?
hectolitres.
The results are excellent, the only drawback being that
the machine is cumbersome.
It has the advantage of not being liable to become
obstructed, and the divisions or tanks may be used when
the vintage is over in various useful ways — storage of
wine, &c.
The outside vessels hold about 600 litres, the inside ones
about 360 litres.
Vine-growers, therefore, are only embarrassed in choosing
a cooler, for apart from those we have described, rather at
length, there are a great many others in existence which
might prove useful in a number of special cases. Vine-
growers should convince themselves of the fact, uncontrorer-
tible at present, that the maintenance of fermentation at a
temperature near 30° C. is a powerful factor in improving
the quality of the resulting wines, and they must, therefore,
make every effort to attain that desirable result.
126 WINE-MAKING IN HOT CLIMATES.
METHOD OF TAKING THE TEMPERATURE OF A
FERMENTING VAT.
With or without refrigeration, it is always of great interest
to the wine-maker, to know the temperature of the vats
during fermentation, even if only to follow it and make the
wine systematically. This is done by the use of ther-
mometers, arranged in a more or less convenient manner.
It is well to know, to start with, that the temperature
varies in different parts of the vat when it is full of vintage
in fermentation. It is generally low at the bottom and
high at the top, the average temperature being found
towards the middle of the liquid zone, below the head or
mass of floating marc. It is, therefore, at that point that
the temperature should be taken if we desire to know the
average.
The simplest way is to use an ordinary hand thermometer,
graduated on the stem, placed in a groove made at the end
of a piece of wood pointed at the end. The piece of wood
with the attached thermometer is pushed below the marc to
the required depth, and kept submerged in the liquid for a
length of time sufficient to allow the thermometer to reach
the temperature of the surrounding liquid.
This method is simple, but the observations are difficult,
and not very exact. When an ordinary thermometer,
arranged as described above, is used, and the thermometer
is drawn out, it passes through cooler surroundings, which
reduce the reading on the thermometer too quickly to allow
an accurate reading being obtained.
It is preferable, when an ordinary thermometer is used,
to choose one not too sensitive, that is to say, with a large
bulb and large bore. It will be necessary to leave it for
some time in contact with the liquid to attain its tem-
perature, but it will keep that temperature longer after
removal and facilitate the reading.
Alcohol thermometers are, all things being equal, better
than mercurial thermometers for this operation.
Maximum thermometers, that is to say, those recording
the indication of the highest temperature to which they
have been submitted, are preferable. Very accurate and
sensitive thermometers of this kind are made of the same
shape as an ordinary thermometer.
A process much in vogue, allowing the use of any ther-
mometer, consists in drawing from the vat a bucketful of
VILIFICATION.
127
the must to be examined ; the temperature remains constant
long enough to allow an accurate reading to be taken.
This would be an excellent method if the liquid was taken
from the centre of the vat, but being drawn from the bottom,
it more often than not indicates too low a temperature.
Thermometers with stems -
bent at right angles may
be found in commerce ; the
bulb is introduced into the
the vat or cask at the re-
quired height, the stem
standing vertically against
the outside wall. Fig. 27.
The indications are good in
this case if the bulb pene-
trates far enough into the
vat. Unfortunately, the
bulb does not generally
protrude very far into the
vat, so as to provide against
breakage, likely to occur
through the mass of marc
moving suddenly under
the influence of the liber- Fig. 27.
a ted carbonic acid gas.
However, the taking of the temperature in any case is a
very delicate operation, and for this reason Houdaille and
myself have invented an instrument which is easy to use,
and automatically registers the results.
Self-registering Thermometer of Houdaille and Roos. —
In devising, in conjunction with Houdaille, the self-
registering thermometer, which we will now describe, we
aimed at placing in the hands of wine-makers an instrument
for observation and control, which dispenses with the taking
of temperatures, and gives for each fermentation a record,
the importance of which will soon be appreciated.
The object is to have an instrument recording automati-
cally, at any hour of the day or night, exact indications in
a convenient form for observation. It should be of suffi-
ciently strong construction to be handled by workmen in
the cellar without danger of breaking, and capable of being
introduced or removed from the vat without difficulty ; of
128
WINE-MAKING IN HOT CLIMATES.
simple manipulation, and requiring no special knowledge ;
not inconveniencing the operations connected with wine-
making ; and, finally, not too costly.
To our knowledge, no thermometers answering all these
conditions were "in existence previously, arid we think that
our invention will give satisfaction in each of these respects.
Our self-registering thermometer consists essentially of
a metallic reservoir filled with alcohol and communicating
by a capillary tube with an elastic reservoir filled also with
alcohol, altering in shape under the influence of the change
in the volume of alcohol, according to the temperature it is
submitted to. These deformations are amplified by a lever
with a pen attached to one end, used for registering the
temperatures.
It consists of a projecting cylindrical tube, with a conical
base of strong tinned copper, of a diameter of 30 m.m.,
and a length varying from 1^ to 2 metres, according to the
depth of the vat.*
This protecting tube can
be dismounted in two parts,
joined by a coupling to facili-
tate cleaning ; it contains
the bulb and capillary tube
joining it to the receiver
(Fig. 28), fixed on a solid
wooden support. The re-
ceiver is composed of two
discs with concentric un-
dulations, soldered on their
outside edge, slightly
dished, and communicating
with the thermometer bulb
through the capillary tube.
The whole system is
filled with alcohol, air or
gas being carefully ex-
Fig. 28.— Self-registering Thermometer of i T^J
Houdaille and Roos. Clllded.
The discs, on account of their elasticity, swell under the
influence of the increase in the volume of alcohol when the
* It is desirable that the length of the thermometer be such as to allow the
bulb to go underneath the head (of marc), that is to say, about half the depth
of the vat.
VINDICATION. 129
temperature rises, and contract when the temperature falls,
on account of their own elasticity as well as the atmospheric
pressure.
The cylindrical thermometer bulb is made of thin copper,
and contains about 200 cubic centimetres of alcohol. Its
length is 6'0 centimetres ; it presents, therefore, a sufficient ly
large surface for exchange of temperature, to insure sen>i-
tiveness.
The sine qua non of effectiveness consists in the perfect
filling of the instrument, as the slightest bubble of air <,r
g;is would falsify the indications.
Near the receiver a support for the lever is fixed, con-
nected by one end to the discs, and provided at the other
\\irh a pen for registering and amplifying the expansions or
contractions of the discs.
The registration is made on a sheet ad hoc, which is dis-
placed before the pen by clock-work.
Contrary to what is generally adopted in self-registering
instruments, we have preferred to register the indications of
the instrument on a plane, instead of a cylindrical surface.
This arrangement allows the reading of the complete
record to be made at a glance, and facilitates the changing
of the recording sheets. We have simply transformed the
circular movement of a pinion to a rectilinear movement, by
engaging it with a toothed rack, instead of a cog-wheel.
This toothed rack is fixed in the front part of the brass
plate supporting the recording sheet.
The clock-work is sufficient for one week's continuous
record, and insures, therefore, the working of the apparatus
during the whole time of an ordinary fermentation. The
anchor, or cylindrical escapement, allows its working in anv
position, and does not necessitate the apparatus being fixed
vertically.
The instrument, as above described, is easily handled, and
transportable. It has been carried great distances without
special care, and without damage. It may be carried on the
shoulder (like a gun), but weighs much less.
We have no doubt that this instrument will render great
service to those who desire to follow or supervise their
fermentations, and keep them between recognised limit>.
The form of the curve will show at a glance if the tem-
perature rises too quickly, and if it is necessary to
refrigerate. The reading of the curve recorded during the
10649. I
130
WINE-MAKING IN HOT CLIMATES.
hours when direct supervising might have been defective,
will give the course of fermentation during that time, and
the proprietor may readily control with it the execution of
his orders, and by ultimately comparing the records of each
vat, and the wines resulting from them, get valuable docu-
ments on the influence of temperature on fermentations and
qualities of wines.
This self-registering thermometer, although very recently
invented, has been improved in many details, rendering it
stronger and more symmetrical.
FERMENTING HOUSE.
The vintage coming from the crusher reaches directly,
after travelling a variable distance, the vessels where
fermentation is to be effected.
The building in which the fermentation is effected is called
the fermenting house. There is nowadays a great tendency
to isolate the fermenting house from the storage or maturing
cellar. This arrangement exists in all newly-built cellars,
but is not an indispensable condition for success.
Contrary to general opinion, the fermenting house
must be very well ventilated, open freely to all winds, and
constantly swept by draughts.
Many think that it is better to use underground cellars for
fermenting because they are always cool during hot days.
This is an error pointed out by Toute"e, the inventor of
the metallic vat, in the following humorous story—
" I saw the cellar of a large grower, in a hot climate, in
course of construction. This grower desired to neglect
nothing in order to make it a success, addressing an architect
in the following way : — ' I want to make wine in -
where the temperature is rather troublesome, how can I
protect the vats from that temperature ?' ' Very simply,'-
answered the architect ; ' begin by sheltering the ground
against the solar rays by means of a shed, then excavate
the shaded ground, and cover the excavation with masonry
vaults, one metre thick, throw over the arches Iwo metres
thick of soil, arid I guarantee the interior will remain
unaffected by exterior temperatures. My charge is so much
per square metre excavation, and so much per cubic metre
masonry.' ':
VINDICATION. 131
" The question is put in the same terms and solved in quite
as smart a way by the vat maker, who says — 'To shelter
your musts against the sun and hot wind, isolate them in a
non-conducting envelope.'
" Walls of oak (heart wood) 7 to 9 centimetres thick,
that is how I make vats, they are sold by weight.
" Premises and vessels cost the bagatelle of £50,000.
u Well, imagine the stupefaction of our friend, when, enter-
ing his cellar with me, he noticed that the average tempera-
ture in Algeria being 29° C. on the 1st of September the
thermometer showed 41 ° C. in his cellar.
" And I say in his cellar, for his musts were at a much
higher temperature. When the poor man made up his mind
to take the temperature of his musts by an original method,
he found the testing glass in the laboratory recorded 49° (.'.
after ten minutes waiting and various trans versations which
had made it lose some 4° or 5°.
" It is that the source of the greater heat is not at the
exterior of the cellar, but rather in the interior of the vats,
and he had obtained a result all the more worthy of compas-
sion, inasmuch as he had taken every precaution to prevent
all exchange of temperature between the interior and the
exterior. Thanks to the £50,000 spent, the must was keeping
all the heat developed by the fermentation."
Under this pleasant form the above account shows per-
fectly the inconvenience and dangers of a badly ventilated
fermenting house. We advise, therefore, especially small
growers, having cellars in town or village, too frequently
poorly ventilated, to give up fermenting in cellars. Let the
musts ferment outside under a tree or shed, just sufficient to
protect the vat from the direct rays of the sun. Let them
try only, and the results obtained will convince them better
than any argument of the benefit they will gain by adopting
this modification.
FERMENTING VESSELS.
The vinous fermentation, already briefly described in the
first part of this work, is a complex phenomenon capable of
being influenced by numerous causes. Some even assert that
* Hipp. Lecq. De la Fermentation des mouts de Vin A Temperature basse
[><!>• r/-:>n/>/»i des Cuves Metalliques. Alger. Imprimerie Orientale, Pierre
Fontana et Cie, 29 rue d'Orleans, 1894.
I 2
132 WINE-MAKING IN HOT CLIMATES.
it is influenced by the shape of the vessel or the nature of the
materials the vessels are made of.
In fact, this influence as well as that of the mass is rather
indirect. There are a number of conditions to be realized for
fermentation to start well and continue in a ' satisfactory
manner, guarded against alterations liable to occur from
parasitic fermentations ; but, those conditions once realized, it
is unimportant whether it takes place in wood, stone, brick,
cement, wrought or cast iron.
The vessels usually used for fermenting are —
Wooden vats, conic frustrum shape, open or not at the top.
Stone vats, generally cubic in shape, open or not, coated or
otherwise, with varnish or glazed tiles.
Brick vats, generally cylindrical in shape, much used in
Algeria under the name of amphorae.
The vats recently devised, but already much used, of sidero-
cement ; that is to say, built of a network of interlacing round
iron, about £ inch in diameter, with a mesh of about 2 inches,
sunk into a thickness of 2 or 3 inches of cement. They vary
greatly in shape.
Toutee strongly advocates the use of iron vats, usually
cylindrical, for hot regions.
Finally, ordinary casks used generally in all viticultural
regions for storage.
The capacity of the fermenting vessels varies considerably.
Whatever their shape is, and whatever material they are
made of, the vat will suit for fermenting purposes, provided
its interior surface be inert, or incapable of producing altera-
tions in the taste or chemical composition of the must.
The vats of masonry or sidero-cement cannot be used
without preliminary preparation, but must be purified, with
the object of preventing the possibility of their acting on the
must.
The various lime compounds, which always exist in mortar
or cement, have an unfavorable influence on wine, and must
^therefore be eliminated.
This result is easily attained by washing the inside walls
with a solution of sulphuric acid, followed by a coating of
silicate of potash, which,* when once dry, is quite unattacked
by wine, and has the advantage also of renclering the walls
impermeable.
* Sulphuric acid of 10 per cent, strength and two coatings of a 25 or 30 per
cent, solution of silicate of potash.
VILIFICATION. 133
The iron, too, remaining in contact with the wine would
give it a styptic very disagreeable taste, and even modify the
wine so much as to render its conservation impossible. It
is ahsolutely necessary that the whole of the internal surface
of the vats should be covered with an impervious coating
without action on the wine.
FERMENTATION.
If we assume that the physical and chemical conditions of
the vintage are suitable, those remaining to be fulfilled for
fermentation to take place under good conditions and for the
wine to possess its maximum of quality are :—
First— Management of the vintage so that the marc be not
submitted to alterations through contact with the air.
Second — The drainage of the solid parts of the berry and
the marc, obtained by special distribution of the marc in the
midst of the liquid or by 'its lixiviation.
If fermentation is left to itself without preliminary pre-
cautions, the stalks and skins forming the marc, although
at first sunk in the midst of the liquid, agglomerate little by
little, and being lifted by the carbonic acid gas rise to the
surface.
It is this agglomeration of the solid parts of the grapes
which constitutes the head, and a fermentation is said to
have a floating head, when no special arrangement is made
to maintain the marc below the surface, and is said to have a
submerged head in the opposite case. They are called mul-
tiple submerged heads when the marc is subdivided into
several parts.
Generally speaking, the floating head is inferior to the
submerged head method, the reasons for the superiority of
tin- hitter are of two kinds — the marc of submerged head
fermentations is always perfectly protected from contact with
the atmosphere, and by its arrangement becomes thoroughly
extracted by the liquid, while that of a floating head fer-
mentation is, so to speak, completely in contact with the air
in open vats, and is only partly exhausted by the liquid.
The action of air on the marc is injurious, even if a quantity
of carbonic acid is present. In fermentations where the
marc is not at all in contact with the air, volatile acids,
especially acetic acid, which characterize defective fermenta-
tion, are never produced, while they are always found in the
opposite case.
134
WINE-MAKING IN HOT CLIMATES.
Pollacci determined these facts by experiments, which
consisted in following day by day, and hour by hour, two fer-
mentations conducted side by side, according to each method.
To strengthen what has been already said we will quote the
results of Pollacci's experiments.
POLLACCI'S EXPERIMENTS.
Fermentations made in glass cylindrical vessels, closed by
means of a glass plate, slightly lifted by a cardboard band
supported on the edge of the vessels.
Fermentation with floating
head.
Fermentation
merged head.
with sub-
Second Day — Evening.
Fermentation has begun,
the space above the head
still contains air, for a candle
burns in it. The head shows
a few moulds, and smell of
acetic acid is noticeable.
Third Day
Lighted candle still burns.
More moulds, and acetic
acid smell more pronounced.
Third Day
Lighted candle ex-
tinguished.
Moulds still increasing.
Acetic acid can be detected
by analysis in the liquid
surrounding the marc. The
head was rammed down.
Fermentation in full ac-
tivity.
No trace of moulds or
acetic acid.
-Morning.
A lighted candle extin-
guished when placed in space
above head.
No moulds, no acetic acid.
-Evening.
Candle still becomes ex-
tinguished.
No moulds, no acetic acid.
Fourth Day.
Same as last. The liquid
still contains 140 grammes
of sugar per litre. Acetic
acid smell not noticed after
ramming the head.
Same as last. The liquid
contains only 40
of sugar per litre.
VINIFICATIOX.
135
Fifth Day.
Same as last. Head
rammed.
Fermentation continues
active.
Sixth Day.
Same as last. Fermentation diminish-
I ing-
Same as last.
Day.
Fermentation almost
finished.
Eighth Day.
Fermentation continues.
The liquid still contains 35
grammes of sugar per litre.
Fermentation ended. The
liquid is clear, cold, and only
contains 0*80 grammes of
sugar per litre.
As has been already mentioned, the opening at the top of
the glass vessel was very small. It was, however, sufficient
to allow the access of air in such proportion as to permit
the development of germs, such as my coder ma aceti.
With the method of keeping the marc out of direct contact
with the air, the fermentation is healthier, quicker, and more
complete. With a submerged head, even with the must in
contact with the air, the moulds and mycoderma aceti germs
do not develop, as they do not find a suitable resting place,
or because the movements of the liquid constantly wet
them, and prevent the direct action of the air.
Is there not an evident benefit in submerging the he;i<l ?
For, as has been already said, the suppression of secondary
fermentation corresponds to the improvement of the vinous
fermentation.
The interference of the air is not always injurious, being
sometimes very useful ; but, as far as the marc is concerned,
it is always dangerous, except, however, before the start of
the fermentation after crushing.
136
WINE-MAKING IN HOT CLIMATES.
Fig. 29. — Fermentation with Submerged H ead.
The distinction is
therefore well estab-
lished in favour
of fermentations in
which the marc is
completely ont of
contact with the air.
The immersion, or
submersion of the
marc, in single or
multiple heads is ob-
tained by simple de-
vices, the following
(Figs. 29 and 30)
show plainly how the
problem can be solved.
The arrangement of
multiple heads as pro-
posed by Michel Per-
ret dispenses with the
racking of the must
for the establishment
of the false head, but
the results given are
not better than those
obtained with a single
head. The applica-
tion of the Ferret
method is very
tedious. It is neces-
sary to place several
false heads in posi-
tion, and the waste of
time is greater than
the simple racking as
in the previous case.
We will quote as
an ingenious modifi-
cation of the sub-
merged head system
that devised by Coste-
Floret, which con-
Fig. 3J.— Fermentation with Multiple Submerged Heads. Sists of tWO Vertical
VINIFICATIOX.
13:
partitions dividing the v;it.
Fig. 31 very clearly and
intelligibly shows it, and
dispenses with a detailed
description.
With the Coste-Floret
method important a < Ivan-
tages are evident, but we
also notice some slight de-
fects— the marc will always
rise up a little and float, and
will always be, though on a
very small surface, in con-
tact with the air. This is a
defect, but it may easily be
remedied by fixing a small
false head horizontally of
the same size as the marc
chamber, preventing the
marc from rising above the
liquid.
\Ye do not agree with
Coste-Floret, that lixivia-
tion of the marc results from
forcing the must to pass
through from one compart-
ment to the other.
In fact, even if the marc
can be prevented from rising,
it is not possible to prevent
a certain free space forming
between the marc; and the bottom of the vat. Therefore ,
when the must is made to pass from one side to the other,
the liquid will naturally travel along the line of le;ist
resistance, and consequently pass below the marc without
percolating through it.
We do not see the necessity for lixiviation in the case of
submerged fermentation, and a fortiori in the Coste-Floret
system. In both cases the surfaces of contact of the must
and marc are quite sufficient to allow the latter to give to
the wine all the useful principles it contains.
Fig. 31. — Coste-Floret's arrangement.
138
WINE-MAKING IN HOT CLIMATES,
The advantages of submerged head fermentation lie
mainly in the suppression of the injurious action of the air,
and the fuller utilization of the solid parts of the grape.
If we manage to place the marc (although floating) out
of contact with the air, and lixiviate it with the must
several times, the results will be quite as good, and will dis-
pense with the tedious manipulations connected with the
immersion of the marc, and we will always be able to stop the
extracting action of the must when necessary, by shortening
or prolonging the lixiviation.
In this respect the use of large casks is preferable to any
other vessel, on account of their special shape, narrower on
the top, preventing the excessive rising of the marc, so that
the greater part is kept submerged.
By taking the precaution of covering the top opening
with a board, all access of air is prevented, and the marc
surrounded with carbonic acid gas is not liable to the
alterations observed in open vats.
The lixiviation is obtained by pumping the must from the
bottom part of the cask or vat to the top, spreading it over
the head.
This distribution of the must over the whole surface of the
head is very important. If it is not done carefully a small
part of the marc is too strongly extracted, while the rest
remains unutilized.
With a strong jet falling on the head always in the same
place, a kind of channel is formed in the marc, through
which the must reaches the bottom of the head without
distributing through it, and therefore without exerting a
solvent action in its passage.
The proper distribution of the must is easily effected by
the use of several little devices, amongst which may be
mentioned the hydraulic swivel, and the break jet, which are
now used by many wine-makers.
The hydraulic swivel consists of a box around which tubes
are arranged horizontally like the spokes of a wheel, and
bent almost to right angles in the same direction. The box
revolves on a pivot when filled with liquid, on account of
the hydrostatic thrust exerted by the jets of liquid. The
VINDICATION.
139
adaption of the swivel to the distribution of the must pre-
sented several difficulties. These have been successfully
overcome by P. Paul.
Much more simple is the break jet, which we have in-
vented for use with a machine automatically distributing the
must over the head, and which will be described later on ;
although simple, it works perfectly, without inconveniences
of any kind.
The principle consists in placing under the jet, normally
to it, and at a small distance from the opening of the tap a
disc (Fig. 32) on which the jet breaks, and is transformed
into a circle of a diameter varying according to the form of
the jet.
Fig. 32.— Break Jet.
The jet from a pump is not quite continuous, or does not
possess the same force constantly, whatever pump is used.
The result is, that the breaking of the vertical jet on the
horizontal disc will spread in a very large rose while the
pump is forcing, and in a small one when the pump is suck-
ing, and therefore the whole of the marc will be sprayed.
The operation of spreading the must over the head is
generally done with a pump — any pump may be used-
coupled on the valve of the cask, if it is not desired to
aerate at the same time. If it is considered necessary to
140
WINE-MAKING IN HOT CLIMATES.
aerate the must before pumping it over the head, it is neces-
sary to allow it to fall into a tub placed under the vat, so
that it comes in contact with the air.
To facilitate the aeration Trabut invented a tap (Fig. 33)
by which air is introduced into the liquid jet in any quantity
required.
Fig'. 33.— Trabut's Tap for Aeration of the Must,
a. — Tube to regulate admission of air.
Trabut's tap works very satisfactorily, and may be used as
an ordinary tap, for the air tube can be completely closed.
The frequent necessity of pumping the must up for lixivia-
tion and aeration, induced several persons to try and obtain
the ascension of the must automatically, using the pressure
of the carbonic acid gas disengaged during the fermentation
for the motive power. The first to try and put the idea into
practice was Victor Cambon. The machine he devised has
been described in the Progres Agricole* from which we
take the following extract :—
" The machine invented avoids the inconveniences • • of
floating head fermentation. ^u^ A,
" It may be arranged in various ways, but the vat requires
to be hermetically closed.
" In the top a manhole is placed for the introduction of
the vintage, which should be easily closed hermetically. *~*
Progres Agricolc et Viticole- • 2nd August, 1891.
VERIFICATION.
141
u This being arranged, the following is one of the methods
that may be adopted : —
"On the top of ^—^
the vat (Fig. 34) -R // \\
is placed a small
wooden tank R
of a capacity of
about one-twen-
tieth that of the
vat. A tube T
is placed in the
bottom of the
tank, communi-
cating with the
top of the vat,
and closed by a
vjilve S,the stem
of which is con-
nected with a
lever oscillating
round a point 0,
and bearing a
floater F at the
other extremity.
A long tube U
Starting from the Fi*' **-<»***>"•* Arrangement.
bung-hole at the bottom of the vat throws the liquid into
the tank R, a sieve P prevents any skins, &c., getting into
the tube U, the vat being filled with the vintage through the
manhole H. It is then closed, and fermentation starts, the
carbonic acid gas not being able to escape compresses upmi
the must and marc and forces it upwards through the tube
V into the tank 11. When the liquid reaches the height of
the floater F the floater lifts the valve S, the must in the
tank falls into the vat, and the carbonic acid gas escapes
and bubbles through it. At the same time the tube U
ceases to run, the floater sinks and closes the valve, and the
same operation goes on again."
Cumbon obtained good results with this apparatus, hut
it lias several defects which we have tried to overcome and
will now point out.
In such a machine the orifice through which the uas is
liberated should be independent of that through which the
142
WINE-MAKING IN HOT CLIMATES.
liquid enters the vat. We must also determine a sudden
and complete opening of the two orifices, which should be
effected by the movement of the liquid in the tank, but which,
when once started, must continue, without the liquid inter-
fering. It should happen in the same way for the closing
of the valve.
There are other machines aiming at the same object, but
they do not realize the above conditions, and present the
same drawbacks as that of Cambon.
We have tried to solve the problem by means of a simple
and strong machine, which has been named fermentation
auto-regulator, arranged as shown in Fig. 35. It consists of
a brass cylinder tinned inside, on the top of which rest two
angle-irons, supporting the whole mechanism.
Fig. 35.— Fermentation Auto-regulator.
This simple mechanism consists of —
First — A straight lever A B, which is called the principal
lever, revolving round a horizontal axis A.
VINDICATION.
143
Second — A lever bent at a right angle CD E, revolving
round a horizontal axle D and having two notches, on the
vertical arm D E, we will call this piece double catch.
Third — A small straight lever F G revolving round a hori-
zontal axis A which we will call auxiliary lever. Three
tubes open into the cylinder, one H is constantly open. It
starts from the bottom of the vat and opens into the top of
the cylinder. This tube may have any shape — that of a worm
surrounded with cold water, or of any other system of cooler
if it is desired to refrigerate at the same time.
The other two tubes provided with taps start one I I1 from
the top of the cylinder, the other J J1 from the bottom. To
reach one directly, the other after forming an elbow, the
opening of the vat U. They are adjusted in the wooden
door, tightly fitting the opening of the vat.
Fig. 36 shows the
jiiTHiigement of the
three tubes and the
machine on the plat-
form above the vat.
The tube H being too
long has been passed
around a hogshead.
A glance at the two
figures will enable us
t < > see readily the work-
ing of the machine.
The principal lever
is connected at its ex-
tremity A, by means
of chains to the taps K,
and a weight P, suffi-
cient to overcome the
resistance of the open-
ing. At the other
B Of the
Flg' 36-— Arran^ement of Auto-regulator on the Vat.
lever, is a counterpoise P, calculated to overcome at the right
moment double the resistance of the weight suspended to the
taps, and the friction. All the different parts of the machine
$ire worked at definite intervals by the displacement of a
floater L, along a vertical rod, in the following manner : —
The machine being placed over a vat, as shown in Fig. 35,
and the vat being hermetically closed, except at the bottom
144
WINE-MAKING IN HOT CLIMATES.
tap, which is always kept open, the pressure of the carbonic
acid gas forces the must through the tube into the cylinder.
The result of this effusion of must is to raise the floater L. As
follows from Fig. 34, when the floater reaches the weight P it
will stop a moment, and as it has an upward pressure greater
than the weight P the floater continues to rise until equili-
brium is established, releasing the principal lever from the
weight P.
However, the lever will not move for it is kept in position
by the lower notch of the double lever C D E.
The ascent of the floater and the weight P continues till
the release R touches the horizontal bar C D of the double
lever, displacing it around its axis D, freeing the principal
lever, which rocks and is drawn down by the weight P sus-
pended to the taps.
The result of this rocking is the complete and simultaneous
opening of the two taps, the pressure in the vat is imme-
diately reduced to zero, the delivery of liquid into the
cylinder ceases at once, and the tube returning the liquid to
the vat starts working as a syphon J J1, while the gas con-
tinues to be liberated through the tube I I1.
Let us now study the descending movement of the floater.
The floater with the weight P descends from the moment
the tubes are open till the chain to which the weight P is
suspended is taut, then the principal lever is in an inverse
position to that shown in Fig. 34, and would be drawn
down by the weight P if it were not held up by the upper
notch of the double lever 0 D E, on which its extremity B
rests. The weight P is, therefore, only suspended to the
principal lever while the floater descends. It is only when
the latter, reaching its lowest limit, acts by its weight on the
chain of the auxiliary lever, that the notch will move from
its position, releasing the principal lever, which is then drawn
down, the weight P assumes its original position and closes
the taps. We have returned to the starting point, and the
movement will continue regularly as above described until
the end of the fermentation.
We may add, to complete this description, that the special
break-jet which spreads the must in a circular sheet at the
end of the return tube may also, if rendered movable, act
as a valve, preventing the carbonic acid gas from escaping
through the return tube when the taps are open, as the escape
of carbonic acid gas bubbling through the must might cause
a loss of liquid.
VILIFICATION. 145
The circulation resulting from the use of this machine
renders the mass homogeneous in temperature and composi-
tion. It allows the use of refrigeration by interposing a
cooler between the vat and the auto-regulator. As for
aeration, it may be done by spreading the must delivered
in the cylinder, and may be easily suppressed by simply
covering the cylinder. The carbonic acid gas remains in it
on account of its density.
The fermentation auto-regulator works very satisfactorily.
It is excellent if used for cement vats, but we do not advise
its use with wooden vats without previously ascertaining the
resistance of the vat to the pressure required.
The increase of pressure brought about is not very great,
depending on the height of the auto-regulator above the
level of the liquid in the must. But wooden vats often do
not stand even that slight increase in pressure. When well
built of solid wood, they may support double or treble the
pressure required, but it is better to test them previously.
Masonry, or sidero-cement vats, are always strong enough
to allow the use of the auto-regulator without danger of
bursting.
DURATION OF VATTIXG.
This means the time during which the must remains in
contact with the marc in the fermenting vats.
It is impossible, a priori, to fix a stated time for this, as
it varies according to the nature of the wine it is proposed
to make, to the cepage used, to the method of fermentation
adopted, the temperature of the vat, and the manipulations
the must undergoes during fermentation.
If fermentation is studied, three distinct phases will be
observed, corresponding to the activity of the ferments.
The first phase, without external manifestation, corresponds
to the multiplication of the ferments. During this period,
which is always very short, the sugar is only slightly de-
composed, and the production of carbonic acid gas is so
small that it remains in solution in the liquid. The second
phase, called tumultuous fermentation, corresponds to the
maximum activity of the ferments. The decomposition of
the sugar is rapid, and the disengagement of carbonic acid
gas gives rise to violent bubbling of the liquid.
The elevation of temperature, which is a function of the
quantity of sugar transformed in a unit of time, takes
place suddenly, alcohol accumulates rapidly in the liquid,
10649. K
146 WINE-MAKING IN HOT CLIMATES.
which gradually becomes less favorable to the work of the
yeast. This brings about the third phase characterized by
still active but relatively quiet fermentation.
Each of these phases is of greater or less duration,
according to the state in which the grapes arrive at the
cellar, and the perfection of the crushing and aeration of the
vintage before being placed in the vat.
As a general principle, the must should be racked and
separated from the marc, when the total sugar has been
transformed into alcohol. This corresponds approximately
to the zero degree of the mustinietre. It is then only that
the wine has extracted from the marc all the useful mat-
ters, and acquired its maximum quality. This is only true,
if all the conditions of fermentation, and especially that of
temperature are suitable.
We may lay down, as a rule, that the higher the tem-
perature is the shorter should be the time in the vat.
Up to 35° C., and for wines of an alcoholic strength
not exceeding 10 per cent, by volume, the fermentation
starts quickly and is soon finished. If the temperature
exceeds 35° C., or even if it does not exceed 35° in the case
of wines containing 12 per cent, and over of alcohol, the
fermentation becomes retarded, and even stops altogether
if the temperature exceeds 35° C. Under these circum-
stances, if the means are not at hand for reducing the
temperature of the fermentation to 30°, it is necessary to
rack, whatever degree is indicated by the mustinietre or
sweetness remains in the wine.
Fermentations between 32° and 35° C. are only possible
in the case of light wines. These are the only kinds that
are not much damaged, because the fermentation goes
quickly for two or three days at most, and during the
short maceration, the marc cannot affect the surrounding
liquid prejudicially.
In any case, directly the fermentation exceeds 35° C., if
refrigeration cannot be effected, the wine must be racked.
No doubt poor wines result from the latter procedure.
They are superior, however, to those obtained by leaving
them longer in contact with the marc. They will yield as
much alcohol, and have the same freshness and finesse, and
will, after all, command a higher price than the heavy
astringent wines of abnormal taste always resulting from
prolonged contact with the marc at a high temperature.
VINDICATION. 147
The wines called maceration wines ;ire only made
successfully in cold countries. The wine may acquire
by prolonged contact with the nuire at a normal tempera-
ture certain qualities demanded hy the trade, but at high
temperatures it only acquires detects. In the South of
France the duration of vatting is generally three or four
days, hut lasts eight days when the temperature does not
exceed :ju° ('. In the latter case the wine is coarser, the
dry extract is higher, and the wine produced is richer in
colour. The qualities of the colour remain good, without
any leaden yellow, depressed, undefinable shades of colour,
which always create a bad impression when examined in
the /,/x.sr.* (Fig. 38.) An eight days'
vatting, if well conducted gives with
Aramon (even if grown on flat land)
a w i ne which many expert tasters would
not believe to have been made from
Fig. 3s.-Tasse. Aramou exclusively.
We will not deal at length with the wines called one-night
wine. By this expression is meant wines of very short
vatting. They have generally mme finesse, and are richer in
alcohol than the longer fermented wines, but are after all
only intermediate between red and white.
VARIOUS ADDITIONS TO THE VAT.
ACIDIFICATION.
AVe have seen (page 47) the importance attached to the
acidity of the vintage, and have shown the amount desirable
— completed if necessary by means of tartaric acid — in order
to obtain tine solid wines of good robe (colour, &c.)
The necessary or useful quantity of tartaric acid to add is
calculated from a few determinations of the acidity of the
must, and it is placed witli the grapes in the crusher, or
spread over the vat while it is being filled. Tartaric acid is
the only acid that can be recommended for practical use. as
it is the only acid capable of fixing the excess of potash as
an insoluble combination and liberating the normal acids of
the grape neutralized by the potash.
* A shallow silver or electro-plate cup, the interior bossed in opposite direc-
tions, always used by wine judges in examining the colour of wine. — See Fig. 38.
K 2
148 WINE-MAKING IN HOT CLIMATES.
PLASTERING
Is an indirect means of acidifying the vintage, and consists
in spreading over the grapes in the crusher ordinary plaster
of Paris (calcium sulphate). This is a very unreliable means
of increasing the acidity. The plaster acts on the bitartrate
of potash in the must, liberating half the tartaric . acid in
combination ; but generally the plaster is calcareous, that is
to say, containing frequently a large amount of calcium car-
bonate which partly, if not entirely, neutralizes the excess of
acid resulting from the reaction.
The reactions of plaster in wine are rather complex. .A\V
have shown, in conjunction with Eug. Thomas, that in pre-
sence of bitartrate of potash, the plaster (calcium sulphate)
forms calcium tartrate and acid sulphate of potash, and that,
contrary to what is generally admitted, the acid sulphate of
potash does not remain as such in the wine. In turn it
reacts on the different organo-potassic compounds which
always exist in wine side by side with the bitartrate of
potash, and transforms them into neutral sulphates,
liberating a part of the acids previously combined as
organo-potassic compounds.
Plastering hastens the clearing of wine, and increases its
brightness and keeping qualities ; but unfortunately this does
•not take place without the liquid acquiring a special rough-
ness due to the presence of sulphate of potash in solution.
For plastering to be efficacious it should be done freely.
The maximum limit allowed by law (in France), 2 grammes
of sulphate of potash per litre, is not sufficient to enable the
method to give decided advantages ; it is extremely difficult
to fix a priori the quantity of plaster to be used for the
resulting wine to conform to the legal limits.
It is better to completely reject this method condemned by
law, and all the more reasonably, as in commerce plastered
wine is regarded unfavorably.
PHOSPHATING.
This practice, due to Hugounenq, is free from, some of the
adverse criticisms applied to plastering.
No law prohibits its use. It is recommended by many
cenologists, and, as a matter of fact, does not destroy the
finesse of the wine.
Phosphating consists in adding to the vintage pure di-basic
calcium phosphate.
VILIFICATION. 149
The chemical reactions taking place after phosphating are
of the same class as those occurring in the case of plastering.
Tartrate of calcium is formed by the action of the phosphate
of calcium on the acid tartrate of potash contained in the
must, but it is not yet known which phosphate of potash
remains in solution ; however, it cannot be injurious, and the
phosphoric acid it contains cannot but have a favorable action
on the fermentation.
The effects of phosphating are the same as those of plaster-
ing, with the difference already noted that phosphated wines
retain their finesse, and the phosphate of potash in solution
does not affect the taste of the wine to the same extent as
sulphate of potash.
The colour, however, does not seem to be influenced to the
same extent in phosphating as in plastering.
SELECTED YEASTS.
The addition to the vat of selected yeasts, that is to say,
yeasts taken from the lees from grand crus, is nowadays
practised by a large number of wine-makers.
The technical science of micro-biology enables us now to
take a single cell of good yeast, to cultivate it, guarded from
all possible means of contamination, and by using culture
mediums specially adapted to their development, to get in
a very small volume a number of active cells, infinitely
greater than are contained in a large bulk of vintage.
The object is to insure the rapid predominance of a x/yrr/V//
vinous fermentation, which will more or less check the work
of the ferments natural to the vintage.
It is the substitution of the work of a special yeast in
place of that of the natural yeast.
The advocates of selected yeasts have greatly exaggerated
the advantages resulting from their use, still their use
presents some real advantages.
In fact, well-conducted fermentation with selected yeasts
generally gives a slightly superior wine to that obtained
from, a spontaneous fermentation with the same grapes con-
ducted under the same conditions. This is generally admitted,
and is certainly important.
This superiority, however, is only observed in the case of
a well-conducted fermentation, especially as far as tempera-
ture is concerned.
In short, a more regular and rapid fermentation is
ol'tained. a ((iiicker clearing of the wine, and more highly
150 WINE-MAKING IN HOT CLIMATES.
developed qualities of preservation. These are results granted
by observers to follow from the use of well-selected ye;i>t-.
But there is another point, their influence on the bouquet of
the wine, which is much debated.
Many authors, who have studied the question of the use of
selected yeasts, have pointed out the action on the bouquet,
which is regarded by them as the principal effect. It is
presumably even so real, and so developed, that one of them
has not been afraid to assert that wort fermented with
Chablis yeast had been taken by wine judges for true
Chablis.
We need not point out the evident exaggeration of such a
statement.
The aroma or bouquet of wine must be regarded as the
product of numerous factors of two classes.
The first cannot be modified for a given vintage. They
are the cepage, the soil, the subsoil, and the climate. The
others depend, perhaps, on the variety of yeast, but more
positively on the care and attention given to the vintage, and
ultimately to the wine. These may be modified.
The perfect cleanliness of all the wine-making material,
well conducted fermentations, and, later on, opportune
rackings have more effect than is generally credited on the
final bouquet of wine.
The study of the action of the different races of wine
yeasts is much more complex than that of the various
races of beer yeasts. In the latter case we work on musts,
which may always be reprodaced identically, and even by
sterilization cleared from any organisms which might dis-
turb the result of the fermentation. These conditions
cannot be realized in vinification. We grant that the varia-
tions existing between different vintages are slight, but
they exist, and in the actual state of our knowledge, how-
ever slight these variations may be, no one can say if it is
not to them that should be imputed the great dissimiliarity
observed between the products of their fermentation.
If we introduce into the must one of the factors influencing
the bouquet, as already explained, we will improve it slightly,
but that is all. By using yeast of a particular crit, we
certainly make a slight advance, but the advance made will
be so much the greater as the grapes used more closely
resemble those of that particular cm. This is quite suffi-
cient, we consider, to show that it must not be thought
possible to make Bourgogne wine with Aramon grapes.
VINIFICATIOX. 151
We are inclined to think that cultivated yeasts, develop
in the wines they produce, an aroma peculiar to each of them.
and which certainly enters in part into the constitution of
the bouquet of the wines, issued from the same cms as the
yeasts : but, we emphasi/e. the aroma given hythe ye;ist> i>
more often than not a very poor reflection of the !>ou<|uet of
the grand cms.
The Champagne yeasts, however, have in this respect a
decided effect, the characteristic flavour of champagne (the
sugar exceptedjis met witli in the white wines made in
districts remote from < 'hampagne. hut fermented with yeasts
originating- there. There is in this case an undeniable action
with regard to the specific flavour which the yeast may com-
municate to the wine, and itis to be presumed that Champagne
yeast is not an exception, but that all yeasts, to a greater or
less, extent, act in the same way.
Whatever this action may be, when it is desired to make
wines for immediate consumption (like ours in the South of
France), it is not of much importance whether the yeast
modifies the future attitude to acquire bouquet or not.
Selected yeasts seem to furnish straighter, finer wines, of
good keeping qualities, and this is quite sufficient to justify
their judicious use.
The study of wine yeasts and of the advantages that may
be derived from their application to the different methods of
vinification is far from being exhausted. Kayser, Director
of the CEnological Station at Nimes, has tried for a long time
to throw light on this obscure question alone or in collabora-
tion with Barba. He has already obtained results important
enough to justify the hope that by means of selected yeasts
(the conditions of life of each race being fixed) still better
results than those given to-day may be obtained.
DE-VATTING (DECUVAGE).
This operation consists in separating the fermented wine
from the marc.
The de-vatting is Very easily done, when the casks arc not
too far apart, by placing the cask to be racked in con-
nexion witli the empty cask, and letting the liquid run in
by gravitation until it is at the same level in both, and
then finishing the operation by pumping.
The casks which are to receive the newly fermented wine
must be thoroughly clean. and washed with an abundance of
152 WINE-MAKIXG IX HOT CLIMATES.
water, till quite freed from lees. They should not be sul-
phured, or if they have been, sulphurous fumes should be
completely removed by a current of air.
The new wine after racking still continues fermenting
for a few days, and this must not be checked in any way.
The sulphurous fumes act as a decided check on the fer-
mentation, and this is so much the greater as the liquid is
impoverished as regards its ability to nourish the ferment.
Contrary to what is usually done, the newly racked wine
must not remain more than a week or fortnight in the vessel
it has been racked into. After that time, when the
fermentation has been well conducted, the wines have
deposited, and are ready to be racked into another cask,
which should be slightly sulphured.
It is a common prejudice that sulphuring should not
intervene in the fermentation of red wine. This will be dis-
cussed later on, but we will state now that this prejudice
is without foundation. The practice of sulphuring cannot
but have advantages in the case of both red and white
wines. It is simply a question of the quantity used.
EXHAUSTION OF THE MARC.
The de-vatting leaves in the vat the marc from the vintage
it contained.
The marc still contains after natural drainage a consider-
able quantity of wine which should not be lost. It is
submitted to pressure. This drains it more or less, and
furnishes what is known as u press wine," as compared with
the other racked portion known as '•" taste wine."
PRESSES.
The machines used for the extraction of the wine contained
in the marc are called presses. They are intermittent and
continuous, depending on the method of feeding adopted.
INTERMITTENT PRESSES.
In ancient times planks and heavy stones were all that was
used, but a very insufficient pressure was the result. It is
mainly in the direction of presses that mechanical skill has
been directed during centuries in the cellar, and the ancient
type, with a few modifications, in detail, is still the most
widely used.
The press actually used consists essentially of three parts.
A vertical screw, a horizontal table or base supporting the
VINDICATION.
screw in the centre, and a nut travelling" on the s crew con
stituting the compressing part. (Fig. 39.)
The marc to be pressed is
spread over the table, some-
times supported at the sides
by a screen surmounted by a
cap, and a number of cross
pieces called the load, which
transmits to the mass, distri-
buting it evenly, the pressure
obtained by tightening the
travelling nut.
The compression is obtained by means of levers varying
in shape, some worked in one direction only: others, the most
commonly used, worked with an alternating movement, but
forcing the travelling nut to revolve always in one direction
by means of a ratchet reversing the movement.
The table is made of wood, iron, or cement.
jr>4
WINE-MAKING IN HOT CLIMATES.
Those made of wood would be excellent if it were not
rather difficult to make them staunch and impervious. Those
made of .iron 'are very good, hut should be coated to prevent
the wine acquiring a bad taste by contact with the metal ;
those of cement built on strong concrete are practically ever-
lasting.
• The load of the press should always have a certain elas-
ticity, as it constitutes a pressure accumulator.
If we consider the marc surmounted by a non-elastic load,
when once the pressure limit of the machine is reached we
would have to continue applying pressure unceasingly to
obtain good results. With an elastic load the press may b'e
left to itself, for the pressure continues to act through the
restitution of the force accumulated in the elastic load. The
time that the press can be left to act alone is proportionate to
the deformation of the load under the given pressure. With
regard to this, wooden loads are superior to those of iron.
The substitution of powerful steel springs placed between
the cap and the nut is a decided improvement in intermit-
tent presses, this suggestion is due to Crassous (Fig. 40).*
Fig. 40. -Press with spring load. — Crassous Arrangement.
This idea was first realized in practice by P. Paul, who manufactures these
VINIFICATIOX. 155
The load is dispenses! \virli but not its useful effect, which
on the contrary is {nullified; the cap is fastened to the bolt
by a very simple device and they travel together. This
greatly simplifies the working. But where the main advan-
tage comes in, is in the action of the springs. These are of
the same type as those used for railway-carriage buffers.
Their normal limit of compression is 20,000 kilos, for a 14
or 15 centimetre stroke.
The height of the marc on the table diminishes under the
pressure till its resistance equals the compressing resistance
of the springs, if from that moment the tightening is con-
tinued the pressure is accumulated in the springs, which
become more and more compressed, and is restituted by them
when the tightening ceases, the rap continuing to descend
till the springs have expanded to their normal length.
The stroke is about 14 or 15 centimetres, and this allows
a long enough interval for workmen to attend to other
operations in the cellar.
While an ordinary press with a wooden load requires re-
tightening every quarter of an hour, presses fitted with
accumulating springs continue acting from two to six hours,
according to the pressure and the state of the marc.
The number of springs varies with the surface to be
pressed, and the surface itself varies according to the pres-
sure we desire to obtain.
Generally the marc is cut afresh at the sides to a dis-
tance of about 30 or 40 centimetres in from the circum-
ference, as the case may be. and thrown over the cake
again, and the pressing continued. The pressure is the
same, but as it is distributed on a small surface it is much
greater per unit of surface.
All presses dry the marc to about the same extent, the
perfection of work depends much more on the way it is
done than on the type of press employed.
The opinions of many specialists have led wine-makers
to try and obtain unnecessarily high pressures.
The yield of juice from a given quantity of marc depends
on two factors — the pressure and the time during which it
acts. The second of these factors can in no way be substi-
tuted for the first. It is better to leave the marc longer in
the pi-ess, submitting it to a moderate pressure, than sub-
mitting it to a powerful pressure for a short time.
156 WINE-MAKING IN HOT CLIMATES.
This method of operating- requires the use of a number of
small presses, or of a lesser number of presses capable of
receiving a large volume of marc.
Both large and small presses have their advocates, the
superiority of either type is far from being admitted ; generally
from comparative observations we consider that large surface
presses are preferable. Their working is simpler and the
marc quite as dry as that worked with machines of smaller
surface. We know many cellars where the presses are large
enough to receive the marc from a 450-hectolitre (9,900-
gallon) vat, each dries that quantity of marc without cutting
the cake in 24 hours. Therefore, without any work beyond
the filling, tightening, and emptying, the draining of the
marc is quite as satisfactory as that obtained in less time,
with one or two cuttings.
CONTINUOUS PRESSES.
Ordinary presses, such as those above described, give medium
results, even the best of them, that is if there are any better
than others. The drainage of the marc is far from being com-
plete, as it always retains at the end of the operation about
60 per cent, of liquid. Is it desirable to go to any further
trouble, and will we not by an increase of pressure augment
the yield at the expense of the wine ? We do not think it is
desirable, but the advocates of continuous presses are of this
opinion, for they quote amongst the advantages of these
machines a more perfect exhaustion or drainage of the marc.
In short, continuous presses have been invented with the
objects —
First — To reduce labour.
Second — To reduce the stock of machinery by dispensing
with the use of ordinary presses, which, to treat an equal
quantity of vintage, are more numerous and expensive, and
above all more cumbersome than continuous presses.
Third — To reduce the time of pressing.
Fourth — To increase the yield of press wine.
We must at once state that the increased yield aimed at
is not yet proved to be attained. All the continuous presses
known (with a few rare exceptions), although widely different
in shape, depend on the same principle.
They are composed of two or more cylinders, worked as
crushers if fresh vintage is to be treated, or as light compres-
sors if fermented vintage is to be dealt with.
VINDICATION.
157
After passing through these cylinders the vintage is carried
on hy an Archimedean screw, accumulating it in a perforated
horizontal cylinder, the diameter of which decreases towards
the exit, and is terminated by an orifice small enough for the
marc to form a compact cake or stopper, which can only be
expelled under considerable pressure, A fresh quantity of
marc replacing that expelled acts in turn as a stopper, and
so on as long as the machine is fed. (Fi»-s. 41 to 45.)
158
WINE-MAKING IN HOT CLIMATES.
VILIFICATION.
159
160
WINE-MAKING IN HOT CLIMATES.
VINDICATION.
161
Fig. 45.— Self-acting Carrier of Pepin's Press.
The cylinder may be of conical shape and composed of sled
blades, allowing the diameter of the exit from the cone to be
increased or diminished by means of a movable iron collar. Mi-
lt may be ;is in the Debonno press (the first invented) a tube
of rectangular section, with the angles rounded off, closed
at its extremity by an adjustable roller, the axis of which is
horizontal and perpendicular to the axis of the Archimedean
screw, rising under the pressure of the marc, and offering a
resistance, which may be varied by means of weights carried
on one or two levers connected with the roller.
The use of continuous presses is particularly tempting in
the manufacture of white wine, for it is necessary in this c;ise
to obtain in the shortest time, a separation of the liquid and
solid parts of the fruit, as completely as possible.
There is unfortunately in the working a notable defect — the
yield in juice is apparently greater than that furnished by
an ordinary intermittent press, but the must furnished is
infinitely more turbid, owing to the greater disintegration of
the vintage, to such an extent that if we want to know the
true yield of grape juice, it is necessary to separate from the
liquid obtained from the continuous press, a quantity of solid
matters in suspension, which cannot be regarded as juice.
This quantity is great enough to reduce the true yield of juice
to even less than that obtained by means of an ordinary inter-
mittent press.
And what is more, the pressure on the marc being equal,
the wine obtained by the continuous press has less Jim-**'
than that obtained from the use of an intermittent press.
Whatever be the mode of action of a continuous press,
while travelling from the entrance to the exit the marc is
10649. L
162 WINE-MAKING IN HOT CLIMATES.
submitted to an energetic motion against the internal sur-
faces of the machine ; disintegration of the stalks, seeds, and
skins, often very pronounced, results from this friction.
The organic juices contained in the cells of those organs
pass entirely into the wine, and, as we have shown when
describing the crushers, it is important to leave two elements
of the grapes (stalk and seeds^rintact. The continuous presses
at present known do not overcome these inconveniences.
If we are dealing with white wine, this inconvenience is
still more apparent. We do not know any continuous press
capable of extracting from red grapes a quantity of white
must equal to that obtained by an ordinary crushing, followed
by the usual pressing, without the must in the former case
being more coloured than the latter. This fact is quite
unexpected, for it is generally admitted that the most im-
portant factor of the non-colouration of the must depends
on the rapidity with which the grapes are treated.
It is a factor, it is true, but not the only one to be con-
sidered. It is generally admitted that the colouring matter
of the berry is only soluble in concentrated or diluted alcohol,
and that if we avoid fermentation the colouring will not
occur. The colouring matter contained in the cells does not
pass through the membrane while they are surrounded by
non-alcoholic must, but if we place in the white must broken
cells full of colouring matter, the colouring matter, although
completely insoluble in the must, will diifuse through it in
very minute particles, which it will be impossible to sepa-
rate ; but, what is more, if the insolubility of the colouring
matter is admitted as long as it is protected by the cellular
membrane, it is not so when the colouring matter is bare
and exposed to the action of the must. Duclaux has estab-
lished, by a few experiments, that the colouring matter can-
not be considered as insoluble in the must, but that this
liquid has not got the power of dissolving it through the
cellular envelope.
These various inconveniences delay the general adoption
of continuous presses in the viticultural industry. We hope
that constructors will be able in the future to overcome
them. Continuous presses will then, and only then, become
machines for general use, owing to their advantages, hence-
forth irrefutable.
VINDICATION. 163
EXHAUSTION OF THE MARC WITHOUT PRESSES.
Presses are far from giving every satisfaction, and the
marc treated by them has to be submitted to new manipu-
lations to make piquettes, Or marc spirit, if it is desired to
utilize the wine they still contain.
We studied in collaboration with M. Semichon, Director
of the (Enological Station of the Aude, various means of
increasing the yield of pure wine from fermented marc, and
cannot do better than quote the following extract sum-
marizing our researches on this subject: —
" Under ordinary conditions, in the vinification of red wine,
the marc' remaining in the vat after the racking of the
wine, is placed in the press and submitted to a more or
less greater pressure, during a varying period.
" It is thought that by this operation, all, or at least a
greater part of the wine contained in the marc is extracted.
"Pressure, however, does not give as complete an ex-
traction as is generally thought, for if we determine the
quantity of the wine left in the marc after the operation as
conducted under ordinary circumstances we always find a
in iiiiiimm of 50 per cent, of the weight of the marc. Dis-
tillers know that they generally extract from 100 kilos, of
compressed marc a number of litres of alcohol equal to a
little more than half the alcoholic degree of the wine fur-
nished by that marc.
"It is therefore an important fraction of the total yield
that might be used as wine, for if we admit that the pro-
duction of one hectolitre corresponds to a quantity of 15 to
20 kilos, of compressed marc, it is (taking the minimum of
50 per cent, of wine remaining) a volume of 7 or 10 litres of
wine which may be used for making piquette or marc spirit.
" This is an important loss, which shows that presses are
not perfect instruments as far as yield is concerned. They
are not perfect either with regard to the quality of the wine
they yield. Every wine-maker knows the defects of press
wines in regard to their organoleptic value and keeping
qualities.
" The improvements made in recent years in the manu-
facture of piquettes induced us to apply to the exhaustion of
impressed marc the method which actually gives the best
results for piquettes, and which consists in methodically
displacing the liquid impregnating the marc by an ascending
current of water.
L ^
164
WINE-MAKING IN HOT CLIMATES.
" By causing the liquid piston of ascending water to
displace the wine, we thought that the yield would be
greater than that of any press.
li An almost integral
mechanical displacement is
possible, and can be demon-
strated by a simple laboratory
experiment.
" If in a flask full of wine
we allow a current of water
to slowly flow in to the lowest
part, the wine is lifted by the
water, while the line of de-
marcation of the two liquids
remains sharply defined if the
experiment does not last too
long. If the wine is coll ected,
we notice that the diffusion
zone is very narrow, and that
the alcoholic strength of the
liquid experimented upon
becomes only appreciably
lower in the last portion col-
lected. In an experiment
made with a flask of three
Fi 46 litres capacity (Fig. 46) filled
with wine of 1O4 per cent,
alcohol, we gathered :—
1 litre, containing 10*4 per cent, of alcohol.
1 „ „ 10-5
500 c.c. „ 10-3 „ „
300 „ ., 10-05
400 „ „ 3'51 per cent., average of
eight trials of 50 c.c. each.
" The three litres of wine experimented upon contained
312 c.c. of pure alcohol, and the displacement gave —
104 c.c. of pure alcohol with the 1st litre.
105 „ „ „ 2nd „
51 -5 „ ,, ,, 500 c.c. following.
31'5 „ ,, „ 300 „
14-04 , 400
VINDICATION. 165
" A total of 306*05 c.c., which shows a loss of 2 per cent,
only.
" 95*5 per cent, of the alcohol has been extracted in the
shape of pure wine equal to that experimented upon, that is
to say, of 10*4 per cent, alcohol.
" It will be noticed that in this experiment the second
litre is of higher alcoholic strength. This difference is small
enough to be attributed to an error of determination. We
do not believe it, however, for we have always noticed this
slight increase of the strength in the numerous experiments
made. We are unable to explain this constant fact, and
can only record it, pointing out that its constancy cannot
be explained as a mere coincidence.
" This shows, when dealing with liquids alone, that it is
possible to displace, without mixing, and without any other
help than water, more than 95 per cent, of the wine con-
tained in the vessel. Will the experiment be as simple if
the wine to be displaced impregnates a spongy more or less
continuous mass such as marc ?
" Evidently not, for new factors come into play. We must
differentiate between the wine simply wetting the exterior
of the tissues, and that contained in the tissues.
." The former is displaced almost as easily as in the case of
liquids, the latter can only slowly come out of the tissue by
a kind of dialysis through the membrane of the cells, or
even through the skins, if we have to deal with badly-
crushed vintage.
" We made several displacement experiments with solid
matters, porous or otherwise, such as broken glass, cotton,
sponge, pumice stone, &c., saturated with wine, which showed
very quickly that we could not hope for as good results as
in the case of liquids alone.
" We merely quote the results of these experiments as
references, and did not stop to study them completely, as the
marc alone interested us.
" The causes which prevent us obtaining an integral
yield in the displacement method applied to grape marc,
are —
1st. The diffusion or mixing of the wine and water.
'Jnd. The difficulty the wine encounters in traversing
the walls of the tissues bv a kind of dialvsis.
166 WINE-MAKING IN HOT CLIMATES.
" We determined by numerous experiments, under varying
conditions, the rapidity of the diffusion of wine in wjitcr.
We will not insist on the results obtained, but draw the two
following conclusions : —
1st. There is an advantage in having a rapid displace-
ment, that is to say, an ascensional rapidity of
the liquid piston amounting from 8 to 10 centi-
metres per hour.
2nd. There is an advantage in operating on the marc of
well-crushed vintage.
" In the laboratory we obtained, on small quantities of
marc it is true, a yield of pure wine notably higher than
that given by the presses.
" In current practice, however, the marc cannot be treated
with the same care that is possible in a laboratory experi-
ment, but by modifying the arrangement, and by increasing
the number of displacement tanks and arranging them in
batteries as is already done for the diffusers in certain
industries, we may expect a satisfactory enough yield for the
process to remain applicable.
" The experiments were made on a large scale, but not,
however, large enough,* and it will not be possible to do this
till next vintage.
"With four displacing tanks, each holding 100 kilos, of
marc, we obtained results comparable with those of the
presses. (44*4 litres of pure wine per 100 kilos, of drained
marc, while 45 litres were obtained with the presses, that
is to say, about 65 per cent, of the wine contained in the
marc.)
" We think that these results would already be ad-
vantageous, for they dispense with the labour of pressing,
and give an equal yield ; but the course of the operation
enables us to foresee that by doubling the number of tanks,
or even by taking six only, the yield in pure wine would be
increased, and reach that of the laboratory experiments made
on the marc, that is to say, about 85 per cent, of the total
wine contained in the marc.
" We must add that the quality of the wine so obtained
is superior to that of press wine. It has not the same
* With a sufficient number of tanks (eight or ten) we might greatly increase
the ascensional speed of the water.
VINDICATION. 167
harshness resulting from the crushing of the organic tissues,
neither its defects of preservation resulting from the im-
purities in suspension in the liquid.
"The quantity of wine to be utilized in the shape of
piquette or spirit, will be reduced to 3 per cent, in place of
7 or 10 per cent.
" We used in our experiments the following arrangement:—
Four tanks made from casks with the heads knocked out, of
about J 20 litres capacity, provided with a screen forming a
false bottom, were placed in communication in such a way
that the liquid entering in the bottom and centre of the first
one, overflowed by a side aperture in the upper part, to
pass into the second tank, where it penetrates into the
middle of the bottom, and so on.
" The four tanks so arranged were charged with marc, and
the displacing commences ; at the third we might have
already drawn pure wine, but we only did this at the fourth
at the rate of 45 litres per 100 kilos, of vintage. The first
tank is then considered as exhausted, the slightly pink-
coloured water it contains is racked and sent back to the
water tank, while the feeding is made directly on the second
tank, which now becomes the first ; charged with fresh marc
the vat we have just finished with becomes the fourth, and
so on, each cask becoming in turn the first and last of the
system.
"The limited quantity of water which remains at the end
of the operation in the shape of piquette may serve to
extract the wine from an unlimited quantity of marc.
" We consider that a battery of eight tanks would give
much better results, the working would be the same as that
described ; it might be facilitated, however, by adding a
ninth tank, for the charging and discharging to be made
without stopping the displacement operations.
" The zone of diffusion of wine and water is spread over
the first two or three tanks, and is preceded by a volume of
pure wine, sufficiently extended to allow it to be collected
without any admixture of water.
"This diffusion zone is so much the greater as the vintage
is less crushed, we even think that this factor (perfection
of crushing) is so important that the method would be in-
applicable in the case of an uncruslied vintage.
"We tried to obtain a more rapid and better displace-
ment by the use of a liquid denser than water, and with
168 WINE-MAKING IN HOT CLIMATES.
that object worked with solutions of common salt of strength
varying between 1 and 10 per cent. The yield in wine is
not increased, and it has the inconvenience of leaving tails,
that is to say, portions of piquette too salty to be of any
nse.
" We do not pretend to have made conclusive experi-
ments on the subject, and we propose to complete them
during next vintage, but such as they are they enable us
to lay down the principles of a method of exhaustion of
marcs more satisfactory than that depending on compres-
sion."
Since the publication of this work, M. Semichon and my-
self have secured the co-operation of several vine-growers
desirous of experimenting with a method which, while
dispensing with the work of the presses, would give a
better result in yield of pure wine, We hope after the
next vintage (1898) to be able to definitely establish the
superiority of diffusion over pressing by the figures obtained
in operating on large quantities.
VINDICATION OF WHITE WINE. 169
CHAPTER V.
VINIFICATION OF WHITE WINE.
The vinification of white wine differs essentially from tlmt
of red wine, in the fact that the transformation of the must
into wine takes place without contact with the solid parts
of the grape.
There are two cases to be considered—
Vinification of the grapes of white cepages.
Vinification of the grapes of coloured cepages.
The white cepages^ most commonly cultivated for the
manufacture of white wine in the south of France, are the
Picpoul, Terret-Bourret, and Clairette.
All red grapes are eligible for making white wine, except-
ing the Tinto varieties and Bouschet hybrids (having red
coloured juices).
VINIFICATION OF WHITE VARIETIES.
Is much simpler than the vinification of red cepages. It
consists in crushing the grapes, draining them, placing the
drained marc in the press, and leaving the juice from both
the above operations to ferment. However, there are certain
operations that may improve the finesse and keeping
qualities of the wine, and therefore increase its value.
One of these operations is the debourbage (settling).
This consists in separating the suspended impurities.
Various methods have been proposed for the debourbage —
simple filtration, the application of which is much too
expensive, the must offering great resistance to filtration ;
centrifugating, the effectiveness of which has not yet been
sufficiently proved ; and the simple separation by deposition
and consecutive rackings, the best, most practical, and least
expensive of all.
It is necessary, in order to obtain complete deposition, to
maintain the liquid perfectly still during a sufficient time.
that is to say, to prevent the liquid from starting to fer-
ment.
Low temperature would be a good means of resolving
this question or problem, but would be rather costly. E.
Thomas and myself studied a scheme applicable to ;i daily
quantity of 500 hectolitres, and we arrived at the conclusion
170 WINE-MAKING IN HOT CLIMATES.
that the required result could only be obtained at an extra
expense of 2 francs per hectolitre, evidently incompatible
with the value of the product to be made.
There is fortunately an excellent and cheap means of sus-
pending the fermentation during the required time. This
is by sulphuring.
The gas produced by the combustion of sulphur (sulphur-
ous anhydride, S02) is very soluble in water and must,
and has the property of arresting the reproduction of the
yeast and rendering it inactive during a certain time with-
out killing it, if the amount used is not too great.
It is the exact gauging of the sulphurous acid absorbed
which is the important point in the application of the
debourbage.
We must use sufficient sulphurous acid for the deposition
to ba complete, and yet a small enough amount for the
inactivity of the yeast to cease directly the separation of
the lees has taken place.
Experiments have shown that an amount of sulphurous
acid corresponding to O01 per litre of must does not greatly
retard the commencement of fermentation. A quantity of
0*03 retards the fermentation for 10 or 12 hours. With
0-05 it is retarded for 18 to 24 hours, and with 0-075 it
is retarded from 48 to 60 hours. With O'lO the fermentation
only starts five or six days after treatment. We can, there-
fore, retard at will the start of the fermentation by simply
introducing hi to the must the above-mentioned quantities.
It is not very easy to gauge the absorption of the exact
quantity of sulphurous acid resulting from the combustion of
sulphur. This is why we are often liable when using imperfect
apparatus to sulphur too strongly, which retards the fermen-
tation indefinitely, and therefore the selling of the wine, or
not enough, in which case the fermentation starts before the
debourbage is completed. One or other of these defects is
frequently observed when the operation is simply performed
in a previously sulphured cask.
We studied some years ago the application of various
definite compounds to replace sulphuring — the alkaline sul-
phites, the alkaline earthy sulphites capable of being decom-
posed by the must, and yielding for a given weight, a constant
quantity of sulphurous acid. The results were excellent, but
it is difficult to obtain in commerce at reasonable cost, suffi-
ciently pure chemicals to be used in vinification, and in
VINDICATION OF WHITE WINE.
171
practice the homogeneous admixture of a small quantity of
matter with large quantities of liquid is always difficult to
realize.
Sulphurous jicid diffuses more easily in the must than
the solid sulphites, therefore we have preferred to use it ;md
to find practical means of charging the liquid with the
desired quantity only..
The application of sulphurous acid to the must is called
mutage (numbing), a name originating from the effect it
produces, rendering the must muet (numb).
The machines used for this operation are called muteuses,
mutoiseSj mutoirs.
The mutage, in view of obtaining dry white wines, is only
temporary, and requires much less sulphurous acid than in
the case of the must being required to remain sweet, for
making ultimately concentrated must, grape syrup, or ports.
The ordinary muteuse consists of a vessel in which the
must travels in one direction, and air charged with sulphurous
acid in the opposite direction.
Such for instance is the muteuse of Coste-Floret (Fig. 47).
The must arrives by the tube a, falling in a spray in the
muteuse C, through the perforated plates A B, and absorbs
during its passage the vapours generated by the stove E.
"itf. 4".-Coste-Floret's Muteuse.
172
WINE-MAKING IN HOT CLIMATES.
The must itself forms a liqiu'd joint in the bottom of the
tub D, it is then taken by the suction tub b of the pump F,
and pumped back by the tube c (b.e.).
The muteuse of P. Paul shown in Fig. 48 is almost as
simple. It consists of a box 1 metre 30 c.m. high and
40 c.m. wide. The must arrives at the upper part and falls
on oblique superposed partitions. It is therefore exposed
on a large surface to contact with the vapours charged with
sulphurous acid coming from the stove.
ENTRANCE OF MUST TO BE TREATED
Fig. 48.— Paul's Muteuse
VINDICATION OF WHITE WINE.
173
These two machines may insure the complete dissolution
of the sulphurous acid furnished hy them, but cannot be
considered as capable of gauging the absorption of the sul-
phurous acid with precision, for it is very difficult, not to
say impossible, to furnish them with exactly the required
quantity of sulphurous acid.
The weight of sulphur burnt in a given time is a function
of the speed of the current of air, and the speed for the same
aperture of the valve varies greatly from one operation to
another, even at different times during one operation.
The sulphuring cylinders used at Villeroy by the r<mi-
pagnie des Salins du Midi, which work in a similar way to
the two muteuses described above, have the same defects.
At their vineyards at Bosquet the Compagnie des Salins du
Midi use a different apparatus allowing more exact measure-
ment.
The muteuse used at Bosquet consists of a sidero-cement
chamber d (Fig. 49) in which the necessary weight of
Fig. 49.— Bosquet's Muteuse.
174
WINE-MAKING IN HOT CLIMATES.
sulphur is burnt (half the weight of the sulphurous acid
required) in the shape of sulphured cloth suspended to the
cloth carrier S, which can be raised or lowered. The cham-
ber is then filled with must, and when the gas is absorbed
the valve V is lifted and allows the must to flow into the
debourbage tank below.
With this apparatus fairly accurate measurement and
absorption can be effected, but it is very complicated.
With the exception of the Bosquet muteuse, which cannot
be used in small cellars, the machines above described only
give an illusory measurement. •
Eugene Thomas attempted to substitute an apparatus
allowing the measurement and absorption, by direct sul-
phuring of the vat to be filled with must, the idea being to
prevent the air which is driven out when filling the vat
from carrying away with it any sulphurous acid.
N
B
u
A
Fig. 51.
This was realized simply by using
a kind of funnel, forming a liquid
joint by means of two systems of
tubes, one for the entry of the must,
the other for the air exit. The dia-
grams (Figs. 50 and 51) give an
idea of the arrangement of the
machine.
It works fairly well, but not per-
fectly. The washing of the gas is
done rather spasmodically, which
leads us to fear it operates imper-
fectly. For this reason we tried, in
conjunction with Thomas, to improve
the apparatus.
VINDICATION OF WHITE WINE.
175
The modified apparatus consists of three parts, capable
of being dismounted and fitting together (see Fig. 52).* It
consists of —
A. A cylindrical vessel of the same diameter as the
manhole ; the cylinder carries at its top a hori-
zontal flange resting on the edge of the man-
hole, to which it is luted with plaster. The
annular part at the bottom has a space of 8 to 10
centimetres between the concentric rings.
B. A cylindrical cover B, the sides of which drop in
the annular space, about 14 to 16 centimetres
high.
Fig. 52.— Thomas and Roos Mutoir.
The vertical walls of this cover are cut in embrasures at
the lower edge, to allow the passage of the must, and rise
2 centimetres above the horizontal part, the centre of which
carries an escape chimney 3 centimetres in height.
A second lid or cover C, 4 centimetres in height, with
walls perforated with numerous small holes to divide the
gases and facilitate the washing. This cover is provided at
the upper part with a handle, and inside with a hook E to
suspend the sulphur cloths from. This cover extends over
the walls of the first cover. The diameter of the cylinder ( '.
* This apparatus is constructed by Vidal.
176
WINE-MAKING IN HOT CLIMATES.
should be 1 centimetre greater than that of the cylinder D,
and 1 or 2 centimetres less than that of the cylinder B.
The total depth of the apparatus may vary. We have
adopted 50 centimetres, which is sufficient to prevent the
must from splashing out, even during rapid filling.
The following is the method of operating : — The appara-
tus is placed in the manhole and the upper flange carefully
luted. It is then filled with must till it overflows inside
over D. The required quantity of sulphur is then suspended
to the hook E in the shape of sulphured cloth, or sticks,
placed in a suitable recipient. The sulphur is lighted and
introduced into the vat through D, the cone C resting over
the cylinder D then forming a liquid joint during the com-
bustion of the sulphur. The end of the combustion is shown
by the cessation of bubbling. The sulphur is then removed,
and the pieces B and 0 placed in position. It only remains
then to start filling with must.
The liquid falls over the cover C, and partly passes
through the horizontal perforated parts, filling the liquid
joint between D and C. The excess flows over the sides
of the cover C, forming a thin sheet conducing to effective
•washing. It passes into D through the embrasures at the
base of B, and falls into the vat in a thin layer, offering a
large surface for the absorption of the gases.
Whatever be the quantity of
sulphur burnt in the vat, the absorp-
tion of the sulphurous acid is com-
plete, for no smell can be detected
above the apparatus. The same
arrangement may be used for bun^-
holes. In this case the piece A is
modified, as shown in Fig. 53. It
is prolonged by a conical tube, in
the side of which a small tube is
placed for the exit of the gas evolved
during the filling.
It goes without saying that in this
case, unless the cask be small, . the
introduction and combustion of the
sulphur must be done through the
bottom manhole.
Fig. 53. — Arrangement for
Bung-hole.
VINDICATION OF WHITE WINE. 177
Through the fact that the sulphurous fumes contained in
the vessel are completely absorbed by the must, this appara-
tus may be considered as a measuring and absorption
apparatus.
We know that when sulphur is burnt it produces double
of its weight in gas ; if, therefore, we wish to charge the
must with ri grammes of sulphurous acid per hectolitre we
must burn before filling™ grammes of sulphur, the air con-
tained in the vessel is more than sufficient to produce the
required quantity of sulphurous acid.
Under ordinary conditions of temperature air contains at
least 20 grammes per hectolitre of oxygen, which can burn
20 grammes of sulphur to form 40 grammes of sulphurous
anhydride. This quantity is four times greater than that
required for perfect debourbage, if completely absorbed by
the liquid.
But during the combustion of the sulphur the gas in the
vessel increases in volume through the heat developed by
the combustion. It is, therefore, necessary, in order to
avoid loss and preserve the exactitude of the measurement
and absorption, that the vessel be closed in such a way
that the gas can only escape after having yielded the
sulphurous acid to the must.
At M. Thomas' cellar the arrangement of the vats facili-
tates the introduction of a cast-iron pot filled with sulphur,
which is suspended to the top of the vat at a certain distance
from the manhole, in such a position that the must does not
touch it.
The sulphur is lighted, the apparatus immediately placed
in position, luted with plaster, and filled with must, taking
care to fill up two or three times till the combustion
is over. This is easily noticed by the cessation of bubbling,
the filling of the vat then begins.
When it is necessary to deal with a large wooden cask we
begin by fixing the apparatus. The sulphur is introduced
and lighted at the bottom opening, when the combustion is
finished and the equilibrium established for a column of
5 millimetres of water, the height of the liquid joint, it is
possible without difficulty to open the bottom manhole and
10649. M
178 WINE-MAKING IN HOT CLIMATES.
remove the sulphur recipient, and close the opening. If
this operation is done quickly the loss of gas is negligible.
At this moment the difference of pressure between the gas
in the vat, and the atmosphere, is sufficiently small to be out
of consideration.
To avoid luting with plaster, F. Crassous, Director of the
Compagnie des Salins du Midi, proposed placing under the
flange of the apparatus an india-rubber tube, which, when
compressed by the weight of the apparatus, will insure an
air-tight joint.
We think that the air chamber of the pneumatic bicycle
tire would answer perfectly for this purpose. It could be
inflated to the required amount, and the thin rubber they
are made of would insure the exact adaptation of the tube
to all the irregularities of the wood or masonry. We have
not yet seen this idea applied in practice, and, therefore, can
offer no positive advice about it ; but it would certainly
facilitate greatly the handling of the apparatus.*
To finish the various processes of the application of
sulphur, we will describe a method called pump sulphuring.
This idea is due to M. Senac, Viticulturist of the Departe-
ment of the Gard, which while allowing an exact measure-
ment dispenses with the use of special apparatus.
The principle consists in forcing into the must by means
of a pump all the gas produced by the combustion of a
given weight of sulphur ; in this particular case the pump
not only serves to force the sulphurous fumes into the must,
but also acts as a regulator of the introduction of air, in
such a way that the combustion of the sulphur is propor-
tional to the rate of pumping.
A 120-gallon cask with the head knocked out makes an
excellent sulphur stove, by placing on the ground an iron
pot containing the lighted sulphur, and covering the pot with
the cask, the lower edge of which is slightly raised to allow
the passage of air. The suction tube of the pump is fixed to
the bung-hole, the forcing tube being connected with the vat
* It would be, however, necessary for the rubber tube not to be placed in
contact with the iron hoops, and to fit on the wood only. This case is rather
exceptional, as the centre hoops pass very close to the top manhole.
VERIFICATION OF WHITE WINE.
179
(Fig. 54), the gas resulting from the combustion forced into the
vat is completely absorbed by the must, during the operation
no sulphurous smell can be detected around the stove, nor at
Fig. 54. — Pump Sulphuring.
the top hole of the vat. This is an evident proof of the com-
plete absorption of the gas and of a rigorous measurement, for
it suffices to weigh the sulphur to be burnt. To apply this
met hod to the debourbage of white wine, we begin to force the
gas when the vat contains a few hectolitres of must, the filling
up and the sulphuring continuing simultaneously, the latter
requiring less time than the former. The pump is stopped
as soon as the vat is sufficiently full, and we can then as an
extra, precaution give a few strokes of the pump to complete
the stirring of the mass, and insure the perfect mixing of the
sulphured must with that added subsequently.
FERMENTATION.
When, after sufficient lapse of time the previously opaque
must has become opalescent, the moment has arrived to
separate it from the deposit, and to remove it to the vat where
fermentation is to take place.
During this operation the must should be very energetically
aerated to aJlow the last traces of sulphurous acid to be trans-
formed by the oxygen of the air, and to enable the oxygen to
M 2
180 WINE-MAKING IN HOT CLIMATES.
remain in solution in the must, so as to assist the multiplica-
tion of the yeast. When placed in the fermenting vat the
white must may be left to itself without any danger, through
the debourbage it has been submitted to, the fermentation
starts slowly, and is less active than in the case of red wines.
The time necessary for the complete transformation of the
sugar into alcohol is much longer, and one of the consequences
of this slow transformation is a much smaller elevation of
temperature.
It is only necessary in rare cases to refrigerate white wines
after debourbage^ even in the hottest regions of Algeria, for
independently of the retarding causes we have already ex-
plained, the debourbage has also an advantage in allowing the
must to cool down during the two or three days rest in the
vat, which is always below the outside temperature.
As soon as the fermentation is finished, which is shown by
the cessation of the evolution of gases, the white wines should
be racked and placed in slightly sulphured casks until per-
fectly cleared.
MANUFACTURE OF WHITE WINE FROM RED GRAPES.
The only difference resides in the precautions taken to
insure the non-dissolution of the colour, it is essential :—
First — To avoid incipient fermentation before the separa-
tion of the must, carefully avoiding squashing the grapes
before they are brought to the crusher, and proceeding rapidly
with the operations of crushing and pressing.
Second — To crush the grapes without disintegrating the
skins, so as not to liberate the colouring matter contained in
their cells.
Third — To destroy as completely as possible the colouring
matter which may have been dissolved in the must, and
separate by debourbage the fragments of coloured skin in
suspension.
Therefore, to make white wine from red grapes we must
lightly crush the grapes, separate the juice by drainage, and
then by pressing, reserving the juice to be fermented to red
wine as soon as it becomes too strongly coloured, then pro-
ceed to the debourbage, and finally leave to ferment.
This is the process most generally used, but always fur-
nishes wine too pink to be called white, and not enough
coloured to be called red.
VINDICATION OF WHITE WINE. 181
It is necessary after fermentation to sulphur strongly
several times, to reduce the colour, and it is not possible to
make really white wine without altering the character of the
ta-te through the frequent sulphuring.
To obtain fine white wine from red ccpages, such as Aramon
for instance, the first condition is not to expect too much.
We think it is preferable, when it is desired to make 100
hectolitres of wine from red grapes, to use for the purpose a
quantity of grapes sufficient to make 150 or 200 hectolitres,
the 50 or 100 hectolitres remaining being made into red wine.
By working in this way we obtain white wine as good as
it is possible to make it, considering its origin, and red
wine of excellent quality, if we slightly modify in the
latter case the method of vinification described in the pre-
ceding chapter. We are of opinion that white wine should
not alone be' made from red grapes, but both, so that we
cannot exclusively study the vinification of white wine here,
but rather mixed red and white vinification.
It is evident that, if we take from Aramon vintage a more
or less greater proportion of the must it can furnish, the
proportion of marc and juice in the remaining part will be
very different to what it would have been normally. We
should, therefore, apply to the remaining part a method only
allowing in a lesser degree, the solution of the substances
contained in the marc. By limiting the extraction to 40 per
cent, we obtain from Aramon a colourless juice which may
furnish a good type of white wine made from red grapes.
There is no special rule for the vinification of this must, it is
submitted to exactly the same operations as in the vinification
of white grapes above described, and the same quantity of
sulphur used for the debourbage.
In the vinification as red wine of the remainder of the
juice, not used for making white wine, stemming plays an
important part. We have seen already that the unfavorable
action of the stalks is due to a greater extent to the physical
part played by them in facilitating the penetration of the
marc by the must, than to the substances yielded by them to
the wine.
The solvent power of the must may be considered constant,
but the quantity of soluble matters it extracts from the
marc depends on the surface in contact and the time the con-
tact lasts. It is evident that the surfaces in contact will be
increased in this case, it is therefore necessary to render the
182
WINE-MAKING IN HOT CLIMATES.
marc as impenetrable as-
possible, and to shorten by
half the period of macera-
tion. Blaquiere's machine
(Fig. 55), constructed for
the manufacture of white
wine from red grapes,
crushes, drains, and stems
at the same time. It does
good work, but in our
opinion the proportion of
must separated is too great.
Probably, by diminishing
the length of the drainer so
as to obtain only 40 per
cent of white juice, the
results would be better.
Fermentation starts
very rapidly in marcs in-
completely drained for
white wines, the tempera-
ture rises quickly and
reaches on the second clay
the limit above which the
yeast works imperfectly.
This elevation of tem-
perature is one of the prin-
cipal causes of the failures
in the manufacture of these
wines, the inherent defects
of high temperatures are
still increased in this case
by the greater quantity of
marc in contact with the must. We cannot therefore
expect to obtain red wine with fine colour, and clean taste,
if we do not maintain the vat between the limits of tempera-
ture shown as most favorable, i.e., 28° to 30° C.
This method of mixed vinification — the only one giving
good bright wines up to the present time — might be replaced
with advantage by that which L. Semichon,* Director of the
(Enological Station of the Aude, studied and perfected last
vintage.
* L. ttemichon. Revue de Viticulture, 1897.
VINDICATION OF WHITE WINE. 183
The experiments of Semichon on this subject possess an
undeniable importance for the South of France. We will
quote in extenso this communication, trusting it will be
applied in practice by the viticulturists of the South.
NEW METHOD FOR THE VINDICATION OF WHITE WINES.
"The consumption of white wines has greatly increased
in latter years, raising as a consequence the market value
of this product. For this reason viticulturists have tried
to render practical the manufacture of white wine from
red grapes ; in this direction the efforts of all tended to
obtain the greatest possible yield of pink must from a
given quantity of vintage, but have invariably depended on
the old process of manufacture based on decolouration
with sulphurous fumes.
This process, however, is very defective, the enormous
difference in the bouquet and flavour between pink and
white wines made from the same grapes, already shows
that the sulphurous acid deprives the wine of many of its
qualities, and leaves a disagreeable taste. It acts MS a
reducing agent, and decomposes the colouring matters by
removal of oxygen. "When the wine comes in contact with
air through the various manipulations it is submitted to, it
absorbs oxygen, the colouring matter re-appears and the
wine becomes pink.*
"If, therefore, the white wine made in this way is truly
white and neutral in taste, we may assert that it is in a state
of unstable equilibrium, between two situations equally
defective, the excess of sulphurous acid which gives it a bad
taste, and its inherent defect which renders it pink.
"These two defects are serious obstacles in commerce, and
of such importance that many merchants have given up
luivinu or making white wine from red grapes ; we are
almost obliged now to obtain good table wine to have
recourse to wines made from white grapes.
* As far as the unfavorable action of the sulphurous acid is concerned, we
do not share the opinion of our colleague, for here, as anywhere else, it is a
question of exact measurement of the sulphur used. We have noticed that
the sulphurous acid produced by the combustion of sulphured cloth remains
more evident in the wine than that produced by the combustion of puro sulphur.
This is caused, no doubt, by the formation of sulphuretted bodies, due to the
combustion of the organic matter of the cloth. — L.R.
184 WINE-MAKING IN HOT CLIMATES.
" In 1895, Martinand* studied a more rational method for
the decoloration of must, which seems destined to have,
in practice, a great future. It consists in oxidizing the
colouring matter and precipitating it, instead of simply
masking it by reduction.
" The method of verification he advocates includes five
different phases :—
1. Extraction of the must without taking the colour
into account.
2. Cooling below 15° C. to prevent fermentation
starting.
3. Aeration of the must and oxidation to precipitate the
colouring matter.
4. Filtering under pressure.
5. Fermentation.
" This method presents, in practice, many difficulties — for
instance, the refrigeration to below 15° C., which requires
special machines, and is difficult to apply on a large scale;
and the filtration under pressure, which is tedious and
delicate, requiring expensive apparatus.
" We have been able to modify this method, so as to
render it simpler and more advantageous than the sulphur-
ous acid method. It suffices to dispense with refrigeration,
and proceed to aerate rapidly by causing the must to fall in
a shower in contact with the air, immediately after crushing
or pressing.
" The colour changes to brown, through the oxidation of
the colouring matter, which remains suspended in the
liquid.
" The essential point is that the oxidation be sufficient
for the colour to remain insoluble, in the mixture of water,
alcohol, and acids, constituting the made wine ; the fermen-
tation proceeds in the usual way, and when completed, the
particles in suspension subside slowly. We may, however,
increase the rate of subsidence -by a slight fining, for the
oxidized colouring matter plays the part of tannin.
" It is indispensable in Martinand's method to separate
the colouring matter before any formation of alcohol, how-
ever slight, and that is why he advised the refrigeration of
the musts so as to retard the fermentation, and to aerate
and filter before it started.
* Revue de Viticulture, vol. iv., 1895, and Comptes rendus de ? Academie des
Sciences, 1895.
VINDICATION OF WHITE WINE. 185
a Experiments showed us that this is not indispensable,
and that it is possible to aerate sufficiently before the pro-
duction of alcohol be detectable.
" And, further, the separation of the oxidized colouring-
matter is useless.
" To ascertain the value of this method, we studied it
under most favorable conditions, and made the following
experiments at the Chateau du Pech, belonging to Mrs. de
Riviere, with the assistance of the manager, Mr. Ritouret.
"On the 4th September, 1896, we started to fill, in the
morning, a 300 hectolitre vat with Aramon vintage. After
several hours, the vat being half full, we drew must by the
bottom opening, and divided it into three casks.
"No. 1. A 120-gallon cask, with the head knocked out,
through the contents of which air was forced for one hour.
"No. 2. A 120-gallon cask, strongly sulphured, to make
wine by the old process.
" No. 3. A 120-gallon cask, in which the wine was left to
ferment naturally, to make pink wine.
" The must drawn from the vat had a temperature of
18° C, and was decidedly pink in colour.
" The must, No. 1, after an hour's aeration, became brown
coloured, the oxidized colouring matter remained in suspen-
sion in the state of fine particles, which pass through any
filter ; the next day, 5th of September, it was again aerated
for one hour, the brown turbid must was then placed in a
new cask and left to ferment.
" Ten days after No. 1 was still slightly fermenting, turbid,
but white with slightly yellowish tint ; it was racked, the
colouring matter subsided gradually, and in February the
liquid was of a bright yellow colour with a very slight
turbidity.
" Xo. 2 presented the maximum of decoloration and
limpidity on the evening of the filling up ; ten days after it had
not started to ferment. By error the sulphur had been used
in excess, and we were obliged, in order to make the fer-
mentation start, to rack it several times in contact with air :
during this operation the sulphurous anhydride gave by
oxidation sulphuric acid, which conduced to the re-appear-
ance of the colouring matter ; six weeks after the must was in
tumultuous fermentation, and the colour re-appeared ; now
186 WINE-MAKING IN HOT CLIMATES.
in February it still contains nnfermented sugar, and is the
most strongly coloured of the three.
" No. 3 was decidedly pink, and still slightly fermenting
ten days after ; ten weeks after it was still pink , bright and
dry, and retained these characters.
" The wine made by the aeration process only presents the
difficulty of clarification, and we made several experiments
on this subject.
" First — The filtration is infinitely easier and more rapid,
as might be foreseen, with wine than with must.
Second — The addition of a small quantity of salt, by increas-
ing the density of the particles in suspension, favours their
subsidence ; but we do not advocate this method, as it affects
the taste of the wine.
" Third — A slight fining gives a still better result ; with 10
grammes of isinglass per hectolitre we obtained a bright
wine of fine yellowish colour.
" If a few drops of sulphuric or nitric acid be added to the
wine before fining, it becomes pink, the colouring matter in
suspension being dissolved by the acid ; prolonged action of
air never has this result. If the acid is added after fining,
the wine retains its yellowish colour, whatever may be the
quantity of acid added.
" It is, therefore, certain that it is the colouring matter in
suspension which renders the wine turbid, and that it plays
towards the finings the part of tannin, that the bright wine
fined or filtered will never become pink again, as wine made
by the sulphurous acid process does, for the colouring matter,
instead of being simply masked, is completely separated.
" What degree of aeration is necessary and sufficient ?
" We determined the influence of prolonged aeration, and
obtained the same results as Martinand. We will now show
that the aeration of the must in No. 1 was excessive. The fol-
lowing are the results of comparisons of the musts of three,
wines made in the cellar, taken the evening of the filling of
the vat, and left in glass flasks to finish fermenting naturally,
with five samples of the same must taken the same day from
the bottom of the vat and submitted to aeration, varying in
duration. The aeration was eft'ected by means of a bellows
connected with a glass tube, terminated in a finely-drawn-
out point. These samples were afterwards left to ferment
naturally.
VILIFICATION OF WHITE WINK.
187
" With regard to their colour and classification, they may
be placed as follows : —
Description of Sample.
Wine from No. 2, sul-
phured
Duplicate, not aerated
Aerated one-quarter of
au hour
Wine from No. 3, pink*
Aerated forhalf-an-hour
Aerated for three-quar-
ters of an hour
Aerated one hour
Wine from No. 1 (aerated
for one hour by pump-
ing in a cask)
After One Month.
Pink, in consequence of
excess of sulphuring
Pink, clear ...
Colourless, very turbid
Colourless, turbid
Slightly yellow, turbid
Slightly more yellow, a
little less turbid
Also as above
Yellowish, turbid
After Two Months.
Pink, in consequence
of excess of sul-
phuring
Pink, clear
Colourless, very turbid
Colourless, slightly
turbid
Flask broken
Slightly more yellow,
almost clear
Also as above
Also as above
" These comparisons show that the yellow coloration is
due to a more complete oxidation of the must, and the
clarification of the wine seems to be more rapid as the
aeration is prolonged.
" The aeration made in the cellar on the evening of the
first day was greater than that made in the flask in the
laboratory ; by accident the flask No. 3 was broken, and the
must through this absorbed more air. This was sufficient
to discharge its colour.
"It would appear, therefore, that in the first experiment
in the cellar the aeration was excessive, and that white
wines may be made from Aramon by slightly aerating the
must with the pump, or by letting it fall in a shower
through a perforated plate.
" It is our intention to try this on a large scale next
vintage.
" It is easy to ascertain if the aeration has been suffi-
cient to discharge all pink colour. The following process,
which we adopted in the laboratory, should be used :—
" A few cubic centimetres of the must is passed through
filtering paper ; when the liquid is nearly all through.
a few cubic centimetres of an aijueous solution
containing 10 per cent, of alcohol and 1 per cent.
* The flask broke, and the wine remained in contact with air during one hour.
It was then decanted. These operations were sufficient to render it colourless.
188.
WINE-MAKING IN HOT CLIMATES.
tartaric acid is poured into the funnel. If the
liquid passing through the filter is pink, the aera-
tion is insufficient, and the pumping of air through
the vessel must be continued. The solution used
has a percentage of alcohol and acid equal to or
greater than the wine to be made, so if the colour
is not dissolved in this solution it follows that
it will not be dissolved in the wine.
"What is the value of the wines made by this new
method ? They do not possess the defects of wines made
by the use of sulphurous acid, and after comparing three
wines made at Pech, the following results were obtained :—
"With regard to flavour, the aerated wine (No. 1) is green,
nerveux, and fruity ; No. 2 still contains sugar, which pre-
vents a fair comparison with the two others. It tastes of
sulphur, and has no fruity flavour ; No. 3 is pink, has as
much fruity flavour as No. 1, but is not so nerveux.
" It might be thought that aeration would alter the con-
stitution of the wine. We point out, however, that the
must does not contain any volatile matters liable to be dis-
sipated by the current of air. Here is the result given by
analysis of these three wines : —
No. 1.
10-1
5-76
15-95
1-75
No. 2.
8-0
6-77
57-30
2-65
37-39
No. 3.
10-1
5-34
16-90
2-30
Alcohol, per cent., in vol.
Total acidity, per litre
Dry extract
Ash
Reducing sugar ...
" These results show that the alcoholic strength is the
same for the white and pink wines, whatever process of
manufacture is used. The 37 grammes of sugar in No. 2,
which had not yet fermented, would give about 2 degrees of
alcohol, which would bring the figure for No. 2 to the same
as the others.
" The total acidity is slightly higher in the aerated wines,
but the difference is negligible. The high acidity in No. 2
is due to the sulphurous anhydride transformed into sul-
phuric acid.*
" The dry extract of No. 1 is less than that of the pink
wine No. 3. This is due to the precipitation of the colouring
* The difference is such that it does not seem attributable to the sulphurous
anhydride only; for, if this were so, it would have required such a heavy dose
that fermentation would have been rendered impossible. — L. R.
VINDICATION OF WHITE WINE.
189
matter through oxidation. On the whole, the composition
of wine made by this new process is practically the same
as that of the corresponding pink wines.
" In conclusion, it is to be hoped that this new method of
manufacturing white wines will prove advantageous to both
wine manufacturers and merchants.
" 1st. In vineyards where Aramon is in excess, and where
the wine obtained from it is deficient in alcohol and colour, it
will be possible to transform a portion of the vintage into
white wine, and thus get a better return. On the other
hand, the Aramon being in smaller proportion in the rest of
the vintage the wine will gain in colour. In years of
abundant vintage, where the grapes are large and give
lighter wine, deficient in dry extract and colour, a part of
the must may be drained from the bottom of the fermenting
vat and made into white wine. The remainder, fermenting
with a greater proportion of marc, will consequently be
richer in dry extract and colour.
" 2nd. The total extraction of the must by pressing, as
advocated by Martinand, will dispense with the costly and
complicated plant necessary to extract the limited possible
quantity of slightly coloured must from red grapes.
" 3rd. It is probable that this method will be applicable
to other red cepages, such as Carignan, Grenache, and
Cinsaut, &c., producing wines of higher value ; this will be
tried during next vintage.
" 4th. The trade will obtain white wines of clean taste,
and good keeping qualities, able to be used for the same
purposes as wines from white grapes, and not presenting the
defects of wines made by the use of sulphurous acid."
190
WINE-MAKING IN HOT CLIMATES.
CHAPTER VI.
UTILIZATION OF BY-PRODUCTS.
The by-products of wine manufacture are — the marc from
the press, the lees, and the tartar. Each of these by-pro-
ducts has a definite value, arid bears a certain proportion to
the value of the total vintage.
Marc.
It is necessary to distinguish between marc from white
and red wine.
The latter is usually utilized in the South of France for
the production of piquettes, or the manufacture of spirit ; the
alcohol may be obtained by direct distillation or by the
distillation of the piquettes.
Direct distillation is only possible in the case of red marc,
and is not usually done by the vineyard proprietor, but by
distillers working by contract.
The alcohol obtained from the distillation of marc is very
much in request in the East of France for immediate con-
sumption, but is not thought much of in the South. Its
value is always less than that of wine-spirit (brandy) ; for
this reason we do not advocate direct distillation, as distilla-
tion of piquettes gives a much finer product, and are of
opinion that in our region the marc should only be used for
the manufacture of good piquettes for immediate consump-
tion or distillation, as the case may be.
The object in manufacturing piquette is to obtain in as
small a volume as possible the total alcohol remaining in
the marc.
UTILIZATION OF BY-PRODUCTS. 191
Whatever may be thought about it, however well drained
the marc may be, it always contains a large proportion of
wine.
Analyses made by Boussingault, Barral, Mares, Degrully,
Bouffard, &c., show that the pressed and drained marc
generally contains 70 per cent, of liquid, or, to be more
correct, of volatile matters; in other words, this means that
100 kilos, of drained marc contain 70 litres of wine.
With the new process this figure is decreased, but never
{'nils In-low oo to 60 per cent.
It is therefore absolutely necessary, if we do not extract
this wine from the marc, to utilize the alcoholic contents
in some way or other ; the only really practical means is in
the manufacture of piquette.
There are actually three methods of doing this, of very
unequal practical value, as shown by Prof. Bouffard* :—
1st. Maceration ; 2nd. Sprinkling, or lixiviation ; 3rd.
Methodical washing by displacement.
For these three methods the marc must be disintegrated
and rammed into a suitable vessel.
To apply the maceration method, a certain quantity of
water must be added to the rammed marc, and left in contact
with it during a few hours ; the water is then racked off,
and replaced by a fresh quantity, and so on till the racked-
off water does not extract any more wine.
This is a very defective method, furnishing very weak
piquettes ; it does not answer the desideratum contained in
the definition given, which is to accumulate in the smallest
possible volume the integral quantity of alcohol contained
in the marc.
The second process, sprinkling or lixiviation of the marc,
may be either intermittent or continuous, and is widely
used in the South of France.
A vessel filled with rammed marc is provided with an
open tap at the bottom, and the upper surface of the
marc is sprinkled by means of different devices (like lawn
* Progrks Agricole et Viticole.
192
WINE-MAKING IN HOT CLIMATES.
sprinklers) Fig. 55, amongst which we may note the Bourdil
hydraulic sprinkler, and Paul's piquette sprayer.
Fig. 55. — Hydraulic Sprinkler.
The water descending through the mass diffuses with the
wine contained in it, carrying away the wine by the tap,
yielding piquettes which become weaker as the operation
is continued.
It is necessary in using this method to operate with
great care, stopping the operation when the piquette falls
below 2 per cent, of alcohol. On mixing all the fractions
a mixture of half the alcoholic strength of the original
wine should result.
UTILIZATION OF BY-PRODUCTS. 193
There is in the lixiviation method a serious defect. This
is the drawing downwards of an alcoholic liquid of less
density than water, which has naturally a greater tendency
to rise up. This drawing down is only obtained by estab-
lishing a rapid current of water, which is done at the
expense of the alcoholic strength.
The third system — methodical washing by displacement-
is easily done with suitable vessels, and is free from all the
above criticisms. It exhausts the marc satisfactorily, and
yields from the commencement till almost complete ex-
haustion, piquettes nearly as strong as the original wine, or,
at any rate, by mixing all the fractions a liquid of average
alcoholic strength very near that of the wine results. Figure
;">() (p. 194) shows diagrammatical ly the arrangement to be
adopted. It is easy to fix this up with any vessels or casks,
varying in size according to the quantity of vintage to be
treated.
In methodical washing done by displacement we aim more
at forcing the wine upwards than at obtaining diffusion ;
theoretically the water acts only as a piston, adapting itself
to the irregularities of surface, rilling all the cavities, and
pushing out the liquid, wetting those surfaces or imprisoned
in the cavities.
In practice this does not happen, however, as diffusion
takes place ; but, as we have already pointed out in speak-
ing of the non-pressed marc, the diffusion zone only forms a
layer of a certain thickness, so that we can almost always
obtain pure wine at the end of the system. The essential
point in methodical displacement (per ascensum) — that is to
say, by means of a rising instead of a descending column of
water — is to carefully regulate the rate of flow of the water.
The ascensional speed should always be slow enough not to
drown the marc, as this would simply place the process on
the same level as that of maceration or 'lixiviation.
One of the conditions for success depends on the arrange-
ment of the marc, which must be well disintegrated and
evenly ramniiM 1 .
The vats should be provided with false bottoms, under
which the water enters. The first vat overflows into the
second, the second into the third, and so on. Four vessels
are sufficiently efficacious.
It is easy to explain the good results given by this method.
10649. N
194 WINE-MAKING IN HOT CLIMATES.
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UTILIZATION OF BY-PRODUCTS. 195
Instead of a continuous operation, let us consider the case
of an intermittent one, and the four vessels full of marc, from
wine giving 10 per cent, of alcohol.
If the marc contained 60 per cent, of wine, 100 kilos,
would contain 00 litres. Let us wet or submerge the marc
with as many times 60 litres of water as there are 100
kilos, of marc, and let it remain in contact. The diffusion
takes place progressively, and, after a few hours, the
vessel will contain for each 100 kilos, of marc I'^o litres
of liquid, the alcoholic strength of which will be half that
of the original wine — that is to say, 5 per cent.
Let us now pass 60 litres of this liquid into the second
vessel, also charged with marc containing 60 per cent, of
wine ; after contact the mixture will have an alcoholic
strength not lying between 10 and 0, but between 10 and 5
— that is to say, 7'5 per cent.
Through the same procedure the third vessel charged
with the liquid from the second will yield a piquette con-
taining 8*75 per cent, of alcohol, and the fourth vessel
charged with the liquid from the third will yield a piquette
containing 9*5 per cent.
In a continuous operation the results are the same, or
even better, for in a well-performed operation the liquid over-
flowing from the first vessel into the second would already
have an alcoholic strength above half that of the wine.
In practice it is usual to stop washing the first vat when
the liquid overflowing into the second has become poor in
colour, and contains 1J to 1 per cent, of alcohol. In a
successful operation the alcoholic strength falls rapidly.
In a few minutes to one hour, according to the size of the
vessel, the pianettes fall from 5 or 6 per cent, to 1 per cent.
The water delivery should then be directed into the second
vessel, the first being disconnected, emptied, and recharged
with fresh marc, and connected to the opposite end of the
system.
It is, therefore, the methodical washing by displacement
which seems to be most recommendable. We think it is the
only method enabling rich piqnettes to be obtained, of good
keeping qualities, and also more easily and economically
distilled. The alcohol obtained by distillation of well and
soundly made piquettes has none of the defects of that
extracted from the marc direct ; on the contrary, it possesses
all the qualities which give wine-spirit a higher value.
N 2
196 WINE-MAKING IN HOT CLIMATES.
With regard to, marc from white wines, we must operate
differently; the problem here is reversed, for it is must, a
liquid denser than water, that has to be extracted from the
marc.
Sometimes the white marc is left to ferment as it comes
out of the press, and is later on converted into piquette, or
distilled directly ; in both cases the result is very unsatis-
factory, the fermentations taking place in pressed 'marc are
always bad. The piquettes obtained from it are execrable
and cannot be used for consumption, and the alcohol result-
ing from their distillation does not repay the cost of
production.
The direct distillation of fermented white marc does not
give better results.
It is therefore necessary to treat the marc directly it
leaves the press, to accumulate its sugar contents in water,
and leave the saccharine solution to ferment, distilling it
ultimately.
The operations are performed in the same vessels as in
the case of red marc, but in this instance we must use the
lixiviation method, spraying over the second vessel the
liquid gathered from the first, and so on.
The leaching of the first vat is stopped when the liquid
leaving it does not taste sweet.
It is imperative in this operation to act quickly, to avoid,
as far as possible, too active fermentation in the mass.
As in the case of the treatment of red marc, the exhausted
vessels are emptied, charged again, and placed at the other
end of the system, while the second vessel becomes in its
turn the first. The marc exhausted in the manufacture of
piquette cannot yield anything more, but constitutes a good
food for cattle, and if not used for that purpose may be used
for manure.
The preservation of washed marc for cattle food is more
difficult than that of marc simply taken from the press, for,
in the latter case, the wine or alcohol it contains protects it
in a certain measure against alterations.
It is necessary to take more care for the preservation of
washed marc.
The best method consists in stratifying the marc with
salt in the proportion of 2 to 3 per cent, in vats or silos
compressed tightly, which is easily done by placing a lid
weighted with full hogsheads on top, at the rate of 500
UTILIZATION OF BY-PRODUCTS. 197
kilos, per square metre of surface. Under this small but
continuous pressure the height diminishes considerably,
and a great quantity of water escapes from the bottom of
the vat or silo, the mass becomes very compact, and only
the first few centimetres become affected by fungi.
The marc from white wines may be treated in a similar
manner, the residues from the distillation of piquette con-
tain a great quantity of tartar, but we cannot think of
extracting it. It has, however, a fertilizing value on account
of the potash it contains, and should be thrown in the
manure pit. It is indispensable to mix it with manure, for
in the state it leaves the still it cannot be applied directly
to the soil, as it would destroy the roots and kill the plants
with which it came in contact, unless used in small quantity
or treated with lime to first neutralize the acids.
The direct distillation of marc assures the recovery of
au important part of the tartar it contains, but this slight
advantage does not counterbalance the other imperfections
of the method.
Lees and Tartar. — The lees deposited by both red and
white wines, during the time which elapses between the
fermentation and the second racking, have considerable
value, on account of the bitartr.ate of potash they contain.
The lees from the debourbage, (sedimentation) of white wines
are only fit for manure.
The lees should be treated to extract the wine they
contain before being sold for tartar.
However thick they may be, they contain, when leaving
the cask or vat, more than 75 per cent, of their weight of
wine. The simplest method to extract the wine consists in
filling strong cloth bags with the lees, piling them in the press,
and submitting them to slight but continuous pressure.
The wines gathered in this manner are not of much value,
but may be used for the still. However, submitted to
judicious treatment they improve, and may be used for
consumption.
The pressed lees should be treated for their tartar by the
\vine-inaker. This is a simple and remunerative operation,
for the tartar obtained lias always a higher value than that
of the lees, and what is more, we retain in addition the
residue* from the treatment, which are first-class for manur-
ing purposes. The value of tartar per unit is always less in
the lees than in cream of tartar.
198 WINE-MAKING IN HOT CLIMATKS.
Good lees in a dry state do not contain much more than
25 per cent, of tartar, ;m<l the 25 kilos, of tartar is the only
substance paid for by the buyer when fixing the price of 100
kilos. The remaining 75 kilos, contain about 4 per cent, of
nitrogen, which at the market price of 1*50 fr. per unit brings
the value of the 75 kilos, to 4-50 fr. per unit.
The wine-maker should, therefore, try and extract the
tartar from the lees for two reasons — first, because the tartar
easily obtained at 80 per cent, strength can be sold at
1*40 fr. per unit, while only 1 fr. or 1-10 fr. would be paid for
the tartar in the lees. Secondly, because it retains on the
property an excellent manure, which costs nothing.
It goes without saying, that it is not necessary to treat
the lees every year. One may, after drying, store it, and
treat it every other year according to the quantity.
The extraction of tartar from lees is very simple. It only
requires a large boiler and casks.
The strength of the lees being known (we will see later on
how it is ascertained), it is boiled with water, placing such
a quantity of lees in the water as will represent about 7 kilos,
of pure tartar per hectolitre of water.
With lees of 25 per cent., about 30 kilos, of lees should,
therefore, be added to one hectolitre of water.
After a quarter of an hour's boiling, during which the
mass is stirred, allow it to deposit for a few minutes ; the
liquid is then passed through a piece of canvas stretched
over a tub, and the operation started again ; on cooling
the water previously boiled with the lees, almost the whole
of the tartar in solution is deposited. Each hectolitre of
water used should yield about 6*5 kilos, of tartar, while
a half kilo, remains dissolved, but is not lost, for the same
water may be used again four or five times.
If used a greater number of times it becomes rather
viscous, preventing the rapid deposition of the tartar. It
should, therefore, be renewed after four or five treatments.
The residues remaining on the canvas, and the water, are
sent to the manure pit.
We can, even without much trouble, dispense with the fil-
tration through canvas, and replace it by simple decan-
tation; in this case the boiling must be stopped, the liquid
allowed to remain undisturbed for ten minutes or a quarter of
an hour, then racked and placed in the depositing vessel.
The residue is then removed from the boiler and sent to
the manure pit, or kept dry till required.
UTILIZATION OF BY-PRODUCTS. 199
At the actual market value of tartar* 1*25 fr. per degree in
cream of tartar, and- 90 centimes in the lees. 1,000 kilos,
of lees at 25 per per cent, would give by .this treatment,
deducting the possible loss: —
225 kilos, of tartar, at 1-25 fr. ... ... 281-25 fr.
775 kilos, residue for manure, at 4*50 fr.
per .100 kilos. ... ... ... 34-85 fr.
Total 316-10 fr.
While the direct sale of the lees would only bring in
225 fr.
It is necessary to treat 1,000 kilos, of lees, to boil about
35 hectolitres of water, the fuel used for this operation
represents a sum much smaller than the credit difference.
The labour itself does not add greatly to the expenses,
and the work may be done during bad weather, when the men
cannot attend to the ordinary out-door work. The figures
quoted are exact, assuming that the lees are paid for on
the real percentage of tartar, but this is almost never
done; more often than not the lees are sold without pre-
viously determining their strength, and are in fact fre-
quently sold for almost nothing before the wine they
contain has been separated, that is to say, in the form of
a thick liquid containing 75 per cent, of wine. In this
method of doing business everything is in favour of the
buyer.f
The tartar obtained from the crust deposited in the casks
cannot be submitted to any treatment by the wine-maker, as
the increased value it would acquire by refining would not
compensate for the extra cost involved. As for the complete
refining, it is an operation which only pays on a very large
scale.
The tartar deposited as a crust in the vats, and that
extracted from the lees, should, therefore, only be sold on the
percentage of bitartrate of potash contained ; but it is
necessary for the wine-maker, who cannot wait for the
* July, 1897.
tThe boilers used for the destruction of the pyrale (caterpillar) on the
stumps of vines may be used to furnish the boiling water for the treatment of
the lees. In this case a simple cask may be used for the dissolution of the tar-
tar, taking care, however, to charge the water with a little less lees on account of
the difference of temperature, which will always be less if the water is removed
from the boiler.
200 WINE-MAKING IN HOT CLIMATES.
result of a laboratory assay or accept that given by the
buyer, to ascertain, at least approximately, the value of the
tartar to be sold.
Determination of the percentage of bitartrate of potash in
the crust or lees.
F. Chabert, Analyst at the (Enological Station of the
Herault, has tried to realize the conditions under which
the acidimetric method generally used in laboratories may be
placed in the hands of persons not accustomed to chemical
manipulations ; and, in order not to increase the laboratory
outfit of the cellar, to use for this purpose the apparatus
generally employed for measuring the acidity of the must.
We require, as in the case of the acidimetre,
A burette graduated in tenths of a cubic centimetre.
A titrated alkaline solution of potash or soda.
A glass flask of one litre capacity.
An alcoholic solution of phenolphthalein.
Litmus paper.
Such is the material necessary for testing the tartar.
A thorough sampling is the first condition necessary for a
reliable analysis.
If the tartar is contained in bags or placed in heaps, a
handful is taken from different parts of every bag or heap.
These are placed together, and will form a sample varying
in size according to the bulk of the stock. This first
sample should then be thoroughly crashed, well mixed, and
divided into two parts. One-half is then replaced in the
bags, the other half being re-submitted to the halving
operation, and so on until a perfectly homogeneous mixture
is obtained. An average sample is then drawn off, of four
or five hundred grammes, which is powdered in a mortar,
and serves for the analysis.
Analysts usually operate on very small quantities, but it
is better for persons not conversant with operations of this
class to work on a rather large weight — the possible errors
are then only multiplied by a small figure, and do not
notably influence the results calculated to 100.
By working on 5 grammes of tartar, fair accuracy is
obtained. The indispensable weighing is a delicate part of
the work, for il? must be done with a balance turning to 1 or
2 centigrammes, and such balances are not often found in
cellars.
UTILIZATION OF BY-PRODUCTS.
201
Any pharmacist or chemist can perform the weighing ;
but we think that sufficient use might be found for a small
balance to justify its purchase. The price, however, is a
trifle, and does not exceed 20 francs (16s. 6d.).
The 5 grammes of tartar or lees are placed in the glass
flask, 300 to 400 cubic centimetres of distilled water
added, and the contents boiled. Four or five minutes' boiling
is sufficient to insure the complete solution of the cream of
tartar. An insoluble residue always remains, of varying quan-
tity, according as the operation is made on lees or crust. It is
not necessary to decant, for in this case we should be obliged to-
wash the residue two or three times with 50 cubic centimetres
of boiling water. It is on the solution of tartar and in the flask
itself that the determination is made. Add to the solution >
after boiling, four or five drops of phenolphthaleiu, then while
constantly agitating the contents of the flask add the
alkaline solution from the burette till the red colour appears
and indicates the end of the operation — the change of colour
is readily detected after a few trials. With white tartars it
is so decisive that one drop in excess of the alkaline solution
is sufficient to cause the appearance of the colour. Its
detection when working on red tartars is not so easy ; but
we may use a much surer although rather more tedious
method, that is, by testing from time to time with litmus
paper.
\Vhen the end of the reaction is almost reached the mix-
ture becomes bronze coloured. The appearance of this
colour is an indication that the reaction is almost finished.
If from this moment, after each two or three drops of the
alkaline solution added, we remove a drop of the mixture by
means of a stirring rod and place it on a strip of litmus
paper, the paper will change colour and finally become
pure blue, instead of the red colour it had in the pre-
ceding case. This change of colour indicates the end of
the operation. The analysis is now finished, and it only
remains to translate the figures obtained into definite
results.
To arrive at the change of colour of the liquid, we used
a certain volume of alkaline solution, as determined by the
reading of the burette. Let us suppose that the buivrrr.
filled to zero with the alkaline solution, reads at the end <>f
the operation 15-6 c.c. This means that 15-6 c.c. were used
202 WINE-MAKING IN HOT CLIMATES.
to neutralize the acidity of the tartar ; this acidity is propor-
tion;! 1 to its content in tartar. It suffices, therefore, to know
to what acidity 1 c.c. of the alkaline liquor corresponds, in
order to ascertain by a very easy calculation the richness in
tartar. Let ns suppose, to make this quite clear, an alkaline
liqnor in which each cubic centimetre corresponds to 0*10
gramme of tartaric acid, the ratio between tartaric acid and
cream of tartar is 2*506, which means that 1 of tartaric
acid corresponds to 2*506 of cream of tartar. The alkaline
liquor will, therefore, in this case be equivalent to 0*2506
per 1 c.c. used.
Therefore, as we have used for 5 grammes of the solution
of tartar, 15*6 c.c. of the alkaline liquor, the 5 grammes
contained—
0,2506 x 15*6 = 3*909 gr.
and, therefore, 100 grammes would contain—
3.909x20=78*18 gr.
In this particular case the strength of the tartar is 78*18
per cent.
It is not indispensable for the alkaline liquor to be of
the strength above mentioned. It may be of any strength,
but if too weak, it becomes necessary to use large quan-
tities and unnecessarily prolong the operation. If, on the
contrary, the liquor is too strong, too small a volume is
used, and the slightest error in reading the volume de-
livered would be an appreciable factor in the quantities
used. If, for instance, in the above case we had used a
liquor four times stronger, an error of reading of 0*1 c.c.
would have caused an error of 2 per cent, in the final result,
while, with the solution adopted above, the same error of
reading would only cause a final error of 0*5 per cent.
The figure of 0*10 gr. of tartaric acid per c.c. used in the
above example, allows a sufficiently close approximation, and
we think it is well not to exceed it. The most convenient
limits for the strength of the alkaline liquor correspond to
from 0-05 to 0*10 of tartaric acid per c.c., if the alkaline solu-
tion varies between these limits it may be safely used. It
will suffice in any case to multiply the known strength
equivalent to tartaric acid, by the ratio 2*506 to obtain its
•equivalent in tartar.
UTILIZATION OF BY-PRODUCTS.
203
If, as often happens, the strength of the alkaline liquor
is only known expressed as sulphuric acid, it may be con-
verted to tartarie acid hy multiplying by I v>3. and into
bitartrate of potash hy multiplying the result of the last
multiplication hy 'J-o06.
Example. — Take for example the alkaline liquor known
as normal, very fre<|uently used by analysts, and \vliieh may
be easily purchased from any chemical laboratory, its
strength is <H)4(.) in sulphuric acid per cubic centimetre, that
is to say, that 1 cubic centimetre neutralizes 0*049 of sul-
phuric add, its equivalent in bitartrate of potash is from
what we have seen above 0*049 x 1*53 x2'506=0'188 of bitar-
trate of potash. If 20'6 c.c. of this liquor were required to
bring about the change of colour in a boiling solution of
5 grammes of crude tartar, it means that the sample con-
tains in 5 grammes — O'lss gr. x20'6 c.c. = 3'87 gr.
and for 10Q gr.— 3'87 gr. x20 c.c. = 77'4 per cent.
It is evident from the above that the testing is a simple
operation. We may even use the alkaline liquor used for
the determination of the acidity of the must, for, excepting
the weighing and solution of the tartar, the operation is
similar in every respect. All those accustomed to the mea-
surement of the acidity of must will be able to perform this
operation, with exactitude without further teaching.
It is understood that we only determine by this method
the bitartrate of potash present, and not the bitartrate of
lime, but this is of no importance. The value is always
based on the contents of bitartrate of potash.
We urge upon wine-makers, who usually sell their tartar
without any previous examination, to use the process above
described, that is, if they do not wish to send the sample
to a laboratory. They will very soon see the advantage
resulting from the exact knowledge of the value of the goods
placed on the market. Through the sale of the tartar, and
by the use of the residues from the lees as manure, the
\\ine-grower will every year make a net profit of 40 centimes
per hectolitre of wine produced.
If tartarie acid has been used for the vinification the
figure must he increased. This increase will recuperate a
great part of the expense entailed in the purchase of tartarie
acid,
204 WINE-MAKING IN HOT CLIMATES.
CHAPTER VII.
CARE TO BE GIVEN TO WINE. DEFECTS AND
DISEASES.
Normally constituted wine only requires rackings made at
opportune times, filling up the casks as often as considered
necessary, in order to acquire perfect brightness and be pre-
served against the germs which always exist in every
vintage.
The number of rackings to which wine must be submitted,
cannot be fixed a priori, neither can the way in which the
rackings should be done, that is, either with or without con-
tact with air. This depends on the constitution and future
destiny of the wine ; the rackings should be numerous, and
the aeration more or less intense according to the rapidity
with which we desire to mature the wine.
Racking is simply a kind of decantation or separation of
the clear wine from the subsided lees.
The first racking, which should be done a fortnight after
the de-vatting, separates the wine from a great quantity of
solid matters (yeast cells, vegetable particles in suspension,
various micro-organisms), but it does not usually furnish
bright wine.
This is due to the wine being saturated with carbonic acid
gas which is only slowly liberated. The fine bubbles during
their disengagement keep the light particles of lees in sus-
pension in the liquid. Frequently, where we have to deal
with musts rich in sugar, and which still retain a small
quantity of it after fermenting, a slow after fermentation
continues during several weeks in the racked wine in such a
way that the wine, always bright just after de-vatting, be-
comes turbid again in a few days.
The cold during the winter completely paralyses the work
of the different ferments, and induces rapid sedimentation,
and consequently rapid clearing of the wine.
It is therefore when the wine, after the more or less pro-
longed action of cold, has acquired complete brightness, that
the second racking should be done.
CABE TO BE GIVEN TO WINE. DEFECTS, ETC. 205
In the South of France this generally corresponds to the
middle of January.* If the wines still remain turbid it
means that they art1 defective, ;md they will then have to
be submitted to operations or manipulations somewhat more
complex than simple racking".
The selection of the day on which to perform the racking
is not a matter of indifference. "We should, on the contrary,
always select ;i day when the barometer is high. There is a
saying, in the South of France, that wine should always be
racked or bottled when the mistral wind is blowing. This
custom is very judicious, because when the mistral is blow-
ing, the atmospheric pressure is always high.
Wine always contains carbonic acid gas in solution, al-
though a large quantity is liberated at the first racking ;
long after the wine is found almost saturated with it, because
the lees disengage it slowly but constantly.
The solubility of gases in liquids is so much the greater
as the pressure is higher, the temperature being equal, so
that, if wine saturated with carbonic acid gas remains com-
pletely still and clear on a fine day, when the atmospheric
pressure is high, it is not so when the weather is unsettled,
corresponding to a low pressure, on such days we will ob-
serve a more or less rapid disengagement of gas, which does
not take place without causing the liquid to become turbid.
We should therefore not only choose a fine day for racking,
but, to do it under still better conditions, choose a bright day
preceded by several fine days.
The wine, usually perfectly bright after the racking, almost
always becomes slightly turbid a few days after. This is
due to the fact that several solid matters only exist in
solution in the wine in the presence of carbonic acid gas ;
and that the oxygen, when the racking is made in presence
of the air, renders some of the matters in solution in the
wine insoluble, however, the result aimed at by the racking,
that is to say, the separation from yeast cells, is attained.
The subsidence of the solid matters taking place in the
wine after the racking occurs very quickly, and the lees re-
sulting are not detrimental.
It goes without saying that racked wine should be placed
in thoroughly cleansed casks, rendered wholesome by
sulphuring. The cask should be left open for a tew hours
* In Victoria, in the Northern districts about the end of June ; in the
Southern districts, June to July (Trans.).
WINE-MAKING IN HOT CLIMATKS.
before filling, to allow the sulphurous m-'ul to escape ; this
operation is necessary, for sulphuring, when done to render
the cask wholesome, must be done so heavily that it would
be detrimental to the wine if it were allowed to absorb it.
However, if we should not introduce into the wine a large
quantity of sulphurous acid, it does not mean that we should
not sulphur at all.
Sulphur always exerts a favorable action on both white
and red wines, in spite of the opinions to the contrary with
regard to the latter.
Although it is necessary to sweep out the sulphur fumes
by a good draught before filling, we think it will always
prove of advantage to burn, before filling, a small quantity
of sulphur, which may be fixed at 1 gramme per hectolitre.
Treated in this way, the wines of the South of France are
sufficiently armed to enable them to pull through the
summer, the casks only require to be kept completely filled.
Whenever wine is not perfectly clear and bright after the
January racking (in Victoria about June), it means that it
is diseased. The disease must then be treated at once by
proper methods, to enable the wine to become bright and
clear.
DEFECTS AND DISEASES OF WINE.
It is necessary to distinguish between defective and
diseased wine.
A modification in the taste and physical aspect of wine
constitutes a defect, but not a disease. The defects, especially
those of taste, have a tendency to become attenuated by
maturing. In any case, they do not get worse, while the
modifications due to diseases, almost undetectable to the
senses at first, increase to the extent of completely altering
the constitution of the liquid and render it undrinkable,.it
an energetic treatment does not arrest the further progress
of the evil.
Wines are all the more liable to contract defects or
diseases, as the vintage is less healthy, the vinification less
carefully conducted, and the cellar material less thoroughly
cleansed and looked after.
In this, as in any other case, it is better to foresee the
disease than to have to cure it. The absolute cleanliness of
the cellar material, vessels, crushers, presses, pumps, hoses,
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. ~M)7
and even the cellar and its surroundings, will avoid a great
many of the defects and diseases of wines, and to a greater
extent than one might really think. A proper method of
vinification will do the rest. The sight, smell, and taste,
are all called upon to form an opinion of the wine.
The tasse (Fig. 38) is a marvellous little instrument for
observing wine, the play of light in it is an admirable help.
The smell enables us to detect certain defects which, not
interfering with the colour, would pass unnoticed by the eye.
The degustation or tasting, performed with care, completes
the impressions upon which are based a judgment of the
wine.
The whole mouth, tongue, palate, and even the throat,
serve to define the indications of the smell. By drawing back
the liquid in the rear of the mouth with a movement
similar to that of deglutition, we sometimes notice in an
exaggerated or increased manner characters previously
detected by the smell, and may thus more exactly determine
their nature and intensity.
A yellowish colour is a frequent defect, and is independent
of the cellar material. It is generally due to the abuse of
racking during the course of fermentation.
We know that a great quantity of air is necessary to the
must before the start of the fermentations, but when it has
once started a small quantity only is necessary.
The practice of pumping over the head, excellent in so
far us it gives more body to the wine, is often a cause of the
yellow colour, because it is almost always done in presence
of air, with wines always too hot. Hence the yellow colour
of hastily-matured wine, which depreciates its commercial
value.
The pumping over the head during fermentation is often
useful when the aeration is only necessary for a languishing
fermentation, and when the yeast requires invigorating.
The yellow colour will be avoided if care be taken not to
aerate excessively.
When the harm is done there is no other remedy but
blending with other wines of finer colour and appearance.
When the wine becomes of a bluish-red, more or less
blackish colour, it is a sign of a true defect in constitution.
Insufficient acidity in the vintage furnishes such dull wine,
known as leaden, but the same shades of colour are found in
almost all wines attacked by diseases due to microbes.
208
WINK-MAKING IN HOT CLIMATES.
We have shown two ways of guarding the vintage against
deficiency of acidity, the use of the second crop, and tartaric
acid.
In vintagiug early the resulting wine will always be acid
enough. The first wines made are never leaden ; it is therefore
necessary, when vintaging at normal maturity, to increase
the percentage of acidity by the addition of tartaric acid.
The last wines obtained from acidified vintage are as
bright, fruity, and nerveux as the first made, while they are
more alcoholic.
For a made wine the remedy is still tartaric acid, provided
the leaden appearance is due to a deficiency of acidity, and is
not the first symptom of a serious disease. The leaden
wines resulting from a deficiency of acidity do not present
any peculiarity to the smell, which is not ordinarily the case
with diseased wines, but they show to the taste more
flabbiness, flatness, and rapidly lose their vinosity when
mixed with water. The acidification by addition of tartaric
acid is a lawful and efficacious means of remedying this
defect, but the action of the remedy is incomparably more
satisfactory when applied as a preventative, that is to say,
before the fermentation.
To ameliorate this class of wines, we should proceed by
preliminary trials, on a quantity, to which tartaric acid is
added in fractions of one decigramme, until the eye and
the taste are satisfied with the operation. As a result, we
will soon arrive at the amount necessary to be added to the
wine, which usually lies between 50 and 100 grammes per
hectolitre.
An earthy taste or flavour is also a very frequent defect.
This is detected by the smell and taste, and is rather difficult
to define exactly. The name is of no assistance, for it leads
us to suppose that the defect is due to the soil the wine
originates from. This has always been the popular belief;
it simply means that we have been mistaken for a long
while.
" Of all the earthy tastes/' writes an author, u the most
peculiar are those which are met with in Algerian wines
derived from newly-trenched land, which had, before, borne
Pistacia lentiscus, Jujube, dwarf Jackal Palm (ChamaBrops
hurnilis), &c. Such soil exhales fantastic odours, which
are found again in the wine grown on it, not only smelling,
but also tasting."
CAKE TO BE GIVEN TO WINE. DEFECTS, ETC. 209
We do not believe much in the influence of newly-trenched
soil, for the very simple reason that when the vine arrives
at the productive state the soil is not newly-trenched, and
has had time to get rid of all flavours that might have con-
taminated it.
Five or six years ago, wines with an earthy taste were the
fashion in Algeria, and that whether they proceeded from
old or young vines, from vines planted in ground cleared a
great number of years before, or from newly-trenched ground.
The wines produced from old ground had that defect even
in a more accentuated degree, because they were more
alcoholic.
This is not so any longer. Certain vineyards which during
the last twenty years produced wines having an earthy
taste, now make clean-tasting wines, and this is simply due
to the improved processes and methods of vinrf .cation .
Formerly, the crushed vintage was left to itself, and allowed
to ferment in a happy -go-lucky way, only de-vatting when
the wine seemed to contain no more sugar, which usually
happened fifteen or eighteen days after the fermentation
started. It is entirely to this prolonged maceration, taking-
place at an excessive temperature, that we must attribute
the origin of the earthy taste, and not to the earth itself.
Since the application of the system of refrigerating musts,
which enables regular and short fermentations to be made,
the earthy taste due to newly-trenched ground has dis-
appeared.
In the South of France, the same causes produce the same
effects, but only to a slight extent. The means of avoiding
the earthy taste are very simple, only ferment for five or six
days, and prevent the heating of the vat. If there are no
means at disposal for cooling, and the vat becomes too hot,
de-vat as soon as possible, even at the expense of the colour,
for we believe that it is better to make wine of clean taste,
and free from earthy taste, than wine rich in colour, and
possessing an earthy taste.
The remedy for the evil is almost useless. It consists
in repeated rackings and heavy finings, which only result in
attenuating the evil, without causing it to disappear, and in
turn exhausting the wine ; the practice of blending is better
than anything else.
Wines sometimes develop a putrid smell, similar to that
of sulphuretted hydrogen, causal by the presence of a very
10349. O
210 WINE-MAKING IN HOT CLIMATES.
small quantity of sulphur remaining from the sulphuring
during the summer, or, to the condition of the vat in which
the fermentation was conducted. In the first case it is due to
sulphuretted hydrogen, in the second case it is the result of
more complex sulphuretted compounds, and then the defect is
more tenacious. A very frequent cause of the putrid smell is
the use of compounds for luting the vats, into the composition
of which blood enters. The blood is generally thought to be
more effective when putrefied. It is needless to state that
this idea is without foundation. The sulphuretted taste is
difficult to remove from the wine. We may, however, arrive
at it by strongly sulphuring again, that is to say, by making
the wine absorb sulphurous anhydride*, although it seems
incredible at first. In reality the sulphuretted hydrogen is
destroyed by the sulphurous anhydride, and the wine con-
tracts the smell of the latter, which is very different from
the former, and possesses the advantage of disappearing in
time.
To remove all other abnormal tastes, such as cask or
mouldy taste, the use of olive oil is generally advocated.
The wine is roused with 1 per cent, of olive oil which
suffices to fix to its benefit, or to be more precise, to its
detriment, the foreign taste contaminating the wine.
We think it is only a second-rate method, the success of
which is never complete. The olive oil used must be of the
very best quality, which renders the method very expensive,
anyhow, whatever be the quality of the oil used, the treat-
ment always leaves in the wine, side by side with the more or
less attenuated initial defect, a disagreeable oily character.
Mustard powder used in a quantity of 30 or 40 grammes
per hectolitre, and stirred with the wine, gave us results,
which, without being good, are, however, preferable to those
obtained with oil, we may sometimes succeed in rendering by
this treatment, the consumption of wine possible, which was
otherwise undrinkable.
We have so far spoken of defects which do not lead to a
gradual alteration of the wine. We will now describe the
principal diseases which completely transform the wine if
their evolution is complete.
They are almost always the result of infinitely small
organisms known as microbes, which play such an important
* This reaction proceeds according to the equation —
2H2 S + SO,! = 2H2O + 2 S. (Trans.)
PLATE III.
Disease known as Flower, Mycoderma vini.
Vinegar Disease, Mycodenna aceti.
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 211
parr in our life, although they are so small, and the role ol
which, iinstis i >ected previous to Pasteur's classical researches,
now becomes more apparent every day.
In oenology their importance is considerable. We know
that they are the cause of the genesis of wine, that the mar-
vellous transformation of sugar into alcohol is due to microbes,
but these are salutary microbes. We are going to study now
other microbes of noxious character, causing the destruction
of the work of the first mentioned.
It is curious to study the 'old authors in their explanations
of the diseases of wines. It is a succession of fantastical
interpretations, which they probably did not understand
themselves, and which are certainly unintelligible to lay-
men.
For instance, we read about " the intimate connexion of
the spirituous parts with the saline and mucilaginous mole-
cules," which is about equivalent to the " movement of the
humours" advocated by the old doctors, in treating affections
of which they were ignorant of the real cause.
The Jleur (flower), Plate III., is the most common and
benign of wine diseases.
It only attacks wine when in contact with air ; the sur-
face of the wine becomes covered with white spots, formed
of a multitude of small organisms (microscopical fungi)
which are termed mt/coderma vim, which entangled together
form a regular scum, becoming wrinkled when further
developed.
This fungus is oval-shaped and reproduces by budding,
affecting on a microscopical scale the shape of the branches
of the common large oval-leaved cactus (Opuntia). It derives
its nourishment from the wine, living principally at the ex-
pense of the alcohol, the alcohol being transformed into
carbon dioxide and water, that is to say, consumed, and the
alcoholic strength of the wine naturally diminishes.
However, for the action of the mt/coderma I'ini to be appre-
ciable, it requires to develop on a very large surface, compared
with the volume of the wine, that is to say the ullage of the
cask must be considerable. In ordinary cases where the
flower only extends over a small surface of wine as in an almost
rilled cask, its action is quite insignificant. The case is the
same in a bottle standing upright and badly corked. It is
then only unsightly and does not injure the flavour in any
way.
212 WINE-MAKING IN HOT CLIMATES.
It is not so with acetificatiou or piqure, Plate III., which
develops under exactly similar conditions, and in most cases
follows the flower.
In the case of acetification the general characters are not
so pronounced at the start, instead of a regular scum com-
pletely ohscuring the surface of the liquid, it is a light
transparent veil, a muslin instead of a thick hlanket of flower.
When acetification follows the flower, we observe rents in
the blanket, rents which enlarge every day till the veil lias
replaced the blanket.
This light veil is formed of micro-organisms known as
mycoderma aceti or diplococcus aceti, infinitely smaller than
mycoderma vini, and which can only be detected under a very
high magnifying power.
The cells appear to be shaped like two small balls, joined
together in the form of the figure 8 ; when they take posses-
sion of the wine the small balls join together forming chaplets,
when they become old, the chaplets dislocate and are replaced
by new ones formed of younger cells, while the old cells fall
inert to the bottom of the liquid, forming by their accumula-
tion, a viscous mass known as mother of vinegar. A very
characteristic property of the acetic ferment is its extreme
rapidity of reproduction when the conditions are favorable.
In 24 hours, according to Duclatix,. an almost imperceptible
quantity of mycoderma aceti will cover a surface square metre
of liquid, producing, if we assume the layer to be composed
of one thickness of cells, 300,000,000,000 cells in that short
space of time.
The mycoderma aceti exerts an oxidizing action on alcohol,
transforming it into acetic acid and water.
Directly this action commences, the wine assumes a sour or
vinegar taste. This is a very serious disease, for all the ex-
tolled remedies are only insufficient palliatives, if the altera-
tion is at all marked.
Acetification often results in wine, through the acetification
of the marc during fermentation conducted with a floating
head, and always takes place in casks which are left slightly
ullaged, especially in cellars where the temperature is
elevated.
Certain wines are more liable than others to become
attacked by mycoderma aceti; such are wines in which sugar
is left after incomplete fermentation, wines of low alcoholic
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 213
strength, and wines worn out by age. Press wines are almost
invariably slightly sour, and are very liable to become attacked
by mycoderma aceti, if the casks are as already said not kept
quite full.
The remedies proposed are only palliatives, for, if it is pos-
sible by destroying the cause of the evil through killing the
micro-organisms to stop the progress of the disease, it does
not, however, suppress the acid taste existing before the
treatment.
To destroy the acetic acid formed, lime, carbonate of lime,
or what is the same thing, powdered marble, have been recom-
mended.
This is a bad remedy, and has the great disadvantage of
introducing into the wine a substance (lime) foreign to the
grape. The acid taste disappears, it is true, but its disap-
pearance is not persistent for all time, and the wine contracts
a strange taste which depreciates its value.
The saturation of the acetic acid by certain potash salts, and
particularly by neutral tartrate of potash, answers much better ;
in this operation ordinary tartar (bitartrate of potash) which
gradually subsides, and acetate of potash are formed. In this
case the disappearance of the acid taste persists, under the
conditions, however, that at the same time we stop or prevent
the disease from continuing its development. There are to
attain this end two means, apart from the general principle
of sterilization ; they are to fill completely and close the vessel
airtight, or to burn a sulphur wick in the empty space over
the wine, so as to surmount the wine with a layer of sulphurous
anhydride instead of air. Under these conditions the devel-
opment of the mycoderma aceti is completely arrested and the
wine does not move, as long as there are traces of sulphurous
fumes in the empty part of the cask, so that we may preserve
the contaminated wine for any length of time by the simple
additional precaution of renewing now and then the sulphurous
anhydride.
Acetification is a common disease, but not so frequent,
however, as the tourne (turning), Plate IV.
The tourne, or turning, attacks the tartarir acid, whether
combined or otherwise, and transforms it into new com-
pounds, imparting to the wine characters which entirely
alter its nature. AVe have not to deal in this ease, as in
the two preceding, witli organisms living on the surface of
214 WINE-MAKING IN HOT CLIMATES.
the liquid, and which may be removed by simply protect-
ing the surface, but with organisms living in the midst of
the wine, which therefore render it cloudy, directly they
begin to multiply.
The tourne produces a special or peculiar cloudiness, which
is a very definite symptom of this disease. If we examine by
transmitted light, and in a thin layer, wine attacked by the
tourne, and which has been slightly shaken, a shimmering
appearance similar to the waves on watered silk is notice-
able from the movements of the microbes it contains. This
characteristic is very transient, for the wavy appearance
soon stops after shaking, but it is sufficient to be acquainted
with this appearance to readily recognise it.
The ferment of the tourne has a filamentary shape, very
thin generally, and more or less curved according to its age.
It occasions the decomposition of the tartaric acid, several
different compounds resulting, such as tartronic, lactic, and
acetic acids, and it ends by destroying not only all the tartar
contained in the wine, but also that adhering to the wood or
the vessel containing the wine.
The tourne ferment is a veritable de-tartrater of the casks,
and this is a fact known long since, when wines did not
come out of the cellar directly after they were made, but
were often eventually submitted to the distiller.
Nowadays the disease is more rare, and it very seldom
becomes sufficiently developed to enable us to notice the
complete destruction of the tartar in wine.
The tourne attacks all wines of low alcoholic strength.
After the first invasion of mildew, the wines from mildewed
vines were attacked, even in viticultural regions where
tourne was previously unknown, by an alteration or disease
which was for a long time regarded as altogether different.
Gayon established by experiments and definite analyses that
mildewed wines were simply attacked by tourne.
When the disease is so far advanced that the taste of the
wine is sensibly modified, nothing can be done. In past
days the evil was not very great, because the still enabled
us to turn the diseased wine into fair spirit, easily saleable,
but to-day it is a disaster, for the market value depending
on the alcoholic strength is so low that the loss is almost
total.
If the disease has not made much progress, and if the
wine is still drinkable, the evil can fortunately be stopped
PLATE IV.
Disease known as "Tourne.
Disease known as " Pousse
PLATE V.
Disease known as " Amertume " (Bitter) (Young).
The same (Old).
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. ^15
by the general system of treatment of diseases due to micro-
organisms, which will be briefly described later on.
Pousse (pushing), Plate IV., is the sister disease of tourne,
but is less frequent, and only differs from it in this, that
amongst the products of the destruction of the tartar, pro-
pionic acid and carbon dioxide are formed. Carbon dioxide
is a gas, the same which is liberated during vinous fermen-
tation, and can only be dissolved in wine in limited propor-
tion. If we consider a well-bunged cask filled with wine
attacked by pousse, that is to say by a disease constituting a
veritable source of carbon dioxide, pressure will be developed
inside the cask, the result of which will be the pushing of
the heads outwards, hence the name pousse (pushing). The
pressure becomes so high sometimes that it results in the
bursting of the cask.
Pousse is due to a filamentary microbe, similar in form to
that of tourne, but shorter, thicker, and straighter, while
that of tourne is always more of less curved. If the' disease
has not progressed too far it may be cured by the same
means as those used for tourne.
The disease known as amertume (bitter), Plate V., is very
uncommon in the South of France. This is not due, as is
generally supposed, to the fact that the disease is special to
wines of grand crus, but simply that it requires a longer
time to develop and acquire all its characters, therefore it
can only be observed in old wines, and the wines of the South
of France never get old enough to give the disease time to
develop. As a matter of fact, the wines in the South of
France are more liable to get this disease than any other,
for the conditions of preservation and maturing are always
more unfavorable in a warm climate than in a cold one.
According to the researches of Pasteur and Duclaux,
amertume progressively destroys the glycerine in the wine,
forming volatile acids, amongst which acetic and butyric
predominate. It is probable that these are not the only bodies
formed, for, if this were the case, it would be difficult to
explain the bitterness, sometimes very intense, which charac-
terizes this disease.
Amertume is due to a filamentary microbe, longer and
thicker than those of either pousse or tourne, and which
differs from them by its ramified appearance, which is similar
to the branching of a tree.
216
WINE-MAKING IN HOT CLIMATES.
When the disease is starting, the ferment is more or less
isolated, relatively short and thick, and not ramified. It is
when ageing that it becomes ramified and encrusted with
colouring matter, which renders its detection more difficult,
but at the same time gives it a more distinguishing character.
Amertume is a disease to be feared in wines destined to be
laid down, but it has no importance in the case of wines that
are to be consumed young.
Graisse (fat) is a disease more peculiar to white wines,
and need not be much dreaded. It cannot be very common,
if we judge by the difficulty we find in procuring wine
characteristically attacked. Under its influence white wines
assume a viscous condition, and flow like oil from the tap,
and even, if more developed, like white of egg.
Scientists do not know exactly under the influence of what
decomposition this effect is produced. We can detect under
the microscope chaplets of little balls similar to those of the
mycoderma acett, but rather larger, and surrounded by a
kind of mucilaginous matter, but that is all. A violent
stirring of the wine renders it quite fluid, and the addition
of tannin acts as a temporary cure, as was shown by Francois
very long ago.
The definite cure of this disease, like that of any other
disease caused by microbes, is easy to effect.
A few years ago a new wine disease (but very old, no doubt)
was discovered. It is known as mannitic fermentation, Fig.
57. P. Carles, of Bordeaux, had in 1891 pointed out the
presence of mannite in cer-
tain wines. After a few
experiments, he came to the
conclusion that mannite was
only found in wines made
from figs. According to
him the presence of mannite
in wine indicated adultera-
tion, the substitution or at
least the admixture of
grapes with figs.
Having had an oppor-
tunity of finding and char-
acterizing mannite in wines,
Fig. 57.— Mannitic Ferment. which W6 knew WQTQ made
exclusively from grapes, we
CAEE TO BE GIVEN TO WINE. DEFECTS, ETC. 217
were induced to study its origin, and were able to show that
we had to deal with a disease due to the action of micro-
organisms attacking not only fig wines, but also the pure
juice of the grape.* The same year we were able during a
trip to Algeria to extend and define our observations on the
subject, but were not able to isolate the living organism
which produced among other bodies, that which characterized
the disease, mannite.t
Gayon and Dubourg studied the subject again in 18U4,
and thoroughly determined its evolution. They reproduced
it in healthy wine, by inoculating it with the microbes they
had succeeded in isolating.
Mannitic wines usually contain an excess of sugar, and tl it-
total acidity is very great. The dry extract is very high,
not only through the presence of sugar, but even after the
sugar has been deducted. The bitartrate of potash does
not seem to be attacked, if the wine is only invaded
by the mannitic ferment, but it frequently happens that
the disease develops concurrently with tourne, which
destroys the tartar.
The ferment appears in the shape of short and very small
rods, immobile, which, instead of remaining independent
and disseminated in the liquid, gather together in great
numbers, forming colonies rather difficult to disintegrate.
It only develops in wine containing sugar, for it is from
its decomposition that manuite is formed. This disease is
therefore only to be feared in the case of wines contain-
ing sugar, or musts. It may develop during the alcoholic
fermentation, and seriously alters the wine when the trans-
formation of the alcohol through some cause or other lasts
too long, as happens when the temperature of the vat-
exceeds the limit which wine yeast can support.
The conditions favorable to mannitic fermentation of
musts are naturally found in hot climates, and it was
in Algeria and Spain that this disease was first noticed.
Mannite only appears in French wines in exceptionally
hot years. Contrary to the opinion of certain authors,
mannitic fermentation is not a variety of tour tie peculiar
* Memoires de la Societe des sciences phy. et nat. de Bordeaux. 28th July, 1892
t L. Roos. Journal de pharm. et de chimie. 1893.
218 WINE-MAKING IN HOT CLIMATES.
to sweet wines ; the differences are in fact numerous. The
following are those given by Gayori and Diibourg •:—
1st. The mannitic ferment differs in shape, dimensions,
and mode of grouping of the cells.
2nd. It does not develop in wines free from sugar where
the tourne ferment develops easily.
3rd. The latter does not develop in sweet liquids, especi-
ally in liquids artificially sweetened which are so favorable
to the former.
4th. The volatile acids produced during pure mannitic
fermentation are exclusively composed of acetic acid, while
if this acid exists in tourne wine there is side by side with it,
and in greater proportion, other volatile acids.
5th. While the tartar disappears in tourne wines it remains
unattacked in mannitic wines.
In fact, it is a disease which exists from the commence-
ment, and it is this which renders it so difficult to obviate.
It can only be avoided by attentively watching the tempera-
ture of the vat.*
There is a disease which has attracted considerable atten-
tion in recent years, known as casse (breakage), but the
origin of which does not seem to be due to microbes.
Prof. Bouffard f drew attention to this disease, which he
noticed was common in the 1893 wines, upon which he made
his first studies.
" The wine of a bright and clear colour in the cask becomes
turbid when aerated for three or four hours, and a brown-red
precipitate forms. If the wine is in a bottle kept still, the
decolouration commences on the surface, where a small iride-
scent pellicle of colouring matter is formed which gradually
affects the lower layers of wine, the sides of the glass become
covered with an adherent deposit, and the wine becomes
almost entirely decolourized, assuming a characteristic
yellow-madeira colour. All these deposits consist of
colouring matter, insoluble even in concentrated tartaric
acid solutions.
" The wine does not disengage any gas, as happens in other
diseases. Its taste does not recall in any way pousse or
* Comptes rendus de I' Academic des Sciences. 9th April, 1894.
t Sterilization of the must previous to fermentation, and the use of pure
cultivated yeasts afterwards, is a means of avoiding the disease. (Trans.)
CAEE TO BE GIVEN TO WINE. DEFECTS, ETC. 219
tourne. The taste may be compared to that of wines called
rancid or madeirized, which are the characteristic of very old
age."
Prof. Bouffard concluded that the idea of the action of a
microbe must be set aside, an opinion which has been accepted
since the publication of his work. He was also able to indi-
cate at the same time that sulphurous anhydride and heating
were efficacious remedies.
After Bouffard, various investigators studied this subject.
Goirirand, of the Viticultural Station of Cognac, has shown
that wine subject to casse (breakage) contains a soluble
ferment,* a diastase of the same nature as that recently
isolated by Bertrand and called oxydase, the characteristic
property of which is to fix the oxygen of the air on the
oxidizable niatters with which the ferment is in contact.
The mechanism of casse will then be an indirect oxidation of
the colouring matter, resulting in it becoming insoluble and
therefore precipitating.
Laborde, of the Agronomic Station of the Gironde, pointed
out one of the possible sources of the diastase,! namely, the
products of elimination of the Botrytis cinerea, the special
mould of the grapes which plays such an important part in
the vinification of Sauterne and Rhine wines. The diastasic
cause of the casse would seem to be admitted by every one ;
but Legatu, Professor of the Agricultural School at Mont-
pellier, has just given a new interpretation based on the role
of irouj which has already gained a number of followers.
According to Legatu, casse is not due to a pure and simple
oxidation of the colouring matter, but to the oxidation of
a, ferrous salt, which in that state is incapable of forming an
insoluble combination with the colouring matter, but which
acquires that property by changing to the ferric state.
" This new interpretation, according to him, is not contra-
dictory to the actually admitted influence of an oxydase, but
in the case studied, the part played by this diastase (if it
exists) has not consisted in rendering the colouring matter
insoluble, but in favouring the phenomena of oxidation
which always takes place in diluted solutions of ferrous salts.
The insolubility of the colouring matter follows in consequence
of the formation of a new ferric compound.
* Compies rendus. April, 1895.
t Comptes rendus. 1896.
£ Comptes rendus. June, 1897.
106-19. P
220 WINE-MAKING IN HOT CLIMATES.
Legit tu mid myself tried to give this theory experimental
verification. Our researches are condensed in the following
note, abstracted from the Progrvs agricole et viticole: —
" It is clear that the above note brings a new element of
discussion to the scientific study of casse in wines, but does
not establish upon sufficient experimental basis the part
played by that element.
" It answers the question, it indicates a very plausible
theory, but does not solve the problem or establish that
theory.
" We have endeavoured by experimental researches re-
cently undertaken to gather facts which would throw some
light on the action of iron in the casse of wines.
"At that time of the year the difficulty of procuring
suitable samples of wines limited the extent of our
researches. It is difficult to find wines of good character
not containing any sulphurous acid, and it is not to wines
liable to casse, but already cured, that we should have re-
course in order to systematically reproduce the casse. On
the other hand, the non-cured casse wines have already been
submitted to treatment, to rackings at least, they are par-
tially attacked and their primitive state cannot be deter-
mined. However, the few samples we obtained enabled
us to observe facts which are in perfect accordance with the
new interpretation.
• " It seems actually established that there are two
varieties of casse. First, blue casse, which is observed in
rich wines of an intense colouration, the true type of which
is met with in the Jacquez, vinified without the addition
of tartaric acid ; secondly, the brown casse characterized by
the more or less brownish colour of the precipitate, and
in the partial or total substitution of yellow for the original
colour. As will be seen, this distinction does not seem
fundamental.
" No wine susceptible to complete decolouration by ex-
posure to the air was noticed, one only took a slightly
madeira-red colour.
" It was found to be indispensable to study the precipitate
resulting from casse.
" We were surprised to find in this precipitate so far
considered as oxidized colouring matter a notable amount of
mineral matters, amongst which iron was in considerable
proportion.
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 221
"Examples. — A wine of Montauban attacked strongly by
brown casse, but, however, not completely decolourized, was
left for two days exposed to the action of the air.
" The precipitate formed, collected on a Chambeiiand
candle, washed with distilled water till the washings were
no longer coloured, dried in a vacuum and incinerated
gave —
Mineral matters ... ... 17*3 per cent.
Iron ... ... ... 5*0 „
"Wine made from Jacquez cepage, originating in the
He* ran It, not easily turning blue under the action of the
air, gave, however, for half a litre, 110 milligrames of dry
bluish-black precipitate, in which we found 2 per cent, of
iron together with silica. In this particular case, as with
all Jacquez, the wine had thrown down already a deposit
which was found to be rich in iron.*
" All the precipitates from blue casse have been found to
be rich in iron,.
" We therefore consider, as a constant and well-established
fact that a wine which breaks throws out iron.
" Is it not probable that blue casse is due to formation of
ferric tannate, while brown casse is due to the formation of
oauolate of iron ? The close relation between oanoline and
tanninf adds more weight to the above hypothesis, conse-
quently are we not naturally led to see the cause of the casse
in an excessive amount of iron.
" One of the first confirmations of this hypothesis must
be looked for in the comparison between the intensity of
the casse and the amount of iron. Now, one of us has
already established^ by numerous analyses that the
Jacquez wines, so predisposed to casse, are also in a general
way remark,! bly rich in iron. This is a clue, but the exact
determination of that element in the must and in the wine
* Prof. Bouffard (Ann. de VEcole nat, d' 'Agriculture de MontpeUier, t. IT.
1886) states — "From facts observed, one may admit that the violet matter
(deposited by the Jacquez) is the result of oxidation, and perhaps, as we hope
to prove, a combination with the iron contained in wine, as a kind of tannate of
iron. The precipitation only takes place after the aeration through the staves
of the cask has been sufficient." Is not this the way casse proceeds ? Bouffard
distinguishes, however, this special casse from that we are studying, while it is
only regarded by Legatu and myself as a simple variation.— (L.R.)
t L. Hugounenq. Recherches nouvelles sur les vins. Imp. A. Storck, Lyon.
+ L. Roos, Giraud and David. Analyse chimique des vins de 1'He'rault
RecoKe. 1890. Hull de hi Soc. centrale d'agric. de VHerault.
P Z
222 WINE-MAKING IN HOT CLIMATES.
directly after de-vatting would present more interest. How-
ever, this co-relation has already been verified for the Jacquez,
as also for other samples.
" As a second confirmation, a sound wine (but not charged
with sulphurous acid) should break when we increase the per-
centage of iron, a fact already established in the above note
and confirmed since by new trials with various ferrous salts.
" In the third place, the treatments indicated against the
natural casse, must be of the same value in wines in which
the casse has been induced artificially. Sulphurous acid is
so active against artificial casse that it is impossible to
obtain it even in wines which have simply been racked into
a sulphured cask. Example : A wine upon which trials of
artificial casse remained without results was subsequently
found to contain 32 milligrammes of sulphurous acid per
litre ; re the heating, we have only studied its effect in an
incomplete way, and will only mention that the absolute
efficacy of this cure has been disputed. However, from our
first researches it is evident that wine acquires by heating
the property of holding the iron in solution more perfectly.
There. is therefore in the above results a point strong enough
for an interpretation of casse independent of any oxidizing
diastase to which the disease is to-day attributed.*
" It is interesting to try and produce the phenomenon of
the casse under conditions excluding the presence of
diastase.
"To arrive at this, oenoline free from iron and even
mineral matter was isolated by the Hugounenq process.
The use of strong alcohol for dissolving the oenoline excludes
any diastase. The product of this dissolution was used to
colour an alcoholic solution of tartaric acid containing some
iron introduced in the form of ferrous hydrate. The mixture
became turbid a few hours afterwards, forming a reddish
precipitate similar to that of brown casse. At the same
time the liquid was covered with an iridescent pellicle, as
observed in natural casse, and affected the reddish-yellow
colouration so characteristic of casse wines. This fact leads
us to think that the presence of an oxydase is not indispen-
sable to the casse.
" However, the facts given above seem to have as much
weight as those advanced in favour of the diastase theory.
* Theory of Gouirand, supported by numerous experimenters.
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 223
" We may even produce artificial casse, absolutely similar
to the natural casse, while the oxydases only furnish, accord-
ing to certain authors, a near image.
" And, what is more, the knowledge of oxydases and of
their mode of action was until recently very vague. During
the course of our researches Bertram! * established that a
close behaviour existed between the oxidizing action of
those bodies and of manganese, in the form of manganous
Imlrated salts, as the only conveyer of oxygen in the pheno-
menon of oxydation observed. The intervention of man-
ganese being proved indispensable to the action of the
oxvthiscs, did not surprise us much. We are in presence,
as in our own argument, of a metallic oxide.
" The manganous and ferrous salts have very similar
properties, from the point of view of the transformations
brought about by oxygen. With regard to this, the ferrous
salts have even a more marked activity.
" Manganese exists in wines, but in scarcely detectable
quantities. We cannot define its action in casse, but may
state that the precipitates obtained in the wines affected by
casse naturally, are always free from it. Manganese only
exists in the liquid.
" As we were able in our experiments to produce the casse
in ;i liquid completely free from manganese, we do not
consider for a moment that it is necessary to invoke that
metal to explain the natural casse.
" In all cases the phenomenon of the precipitation remains
a function of the iron.
" In short, in this particular case, we do not see the
utility of manganese united or not to a diastase as an
oxidizing agent ; anyhow, it does not enter into the compo-
sition of the precipitate."
Soon after its publication, Legatu's paper was the object of-
a violent critique from Gazeneuve. This criticism, remark-
able for its vivacity, does not adduce any serious argument
against Legatu's theory, which we found, on the contrary,
strongly supported by the works of various experimenters.
" Sometimes we lose sight of the fact," says Bourquelot,t
"that the oxydases may be produced with oxydizing matters
which cannot be looked upon as true oxidising ferments."
* Comptes rendus de V Academic des Sciences. 14th June, 1897.
f Journal de Pharmacie et de Chemie. May, 1897.
224 WINE-MAKING IN HOT CLIMATES.
Villiers* shows that in a purely inorganic liquid, through
the action of a manganous salt, very important oxidizing
phenomena result, where the manganese can only be looked
upon as an oxygen conveyer, considering the great quantities
fixed through its action.
A. Livache* studied the action of different metallic oxides on
the oxidation of linseed oil, and quotes manganese as the most
active, but similar effects were obtained with other oxides,
notably that of iron, which gave results of the same class,
although taking longer to obtain. Bertrand, to whom is due
the most interesting work on the oxidizing ferments, has just
found a close co-relation between their action and the presence
of manganese in their composition.*
Legatu's theory does not negative the existence of oxidases,
it only establishes that the casse of wines may not be due to
diastase, or at least admitting a casse due to diastase, there is
another, quite similar, in which the oxidizing ferment plays
no part.
The effect of heat in preventing casse is often advanced to
strengthen the hypothesis of a diastase, as soluble ferments are
always paralysed by heating. But we have seen that wine
acquires through heating the property of retaining the iron
compounds in solution. We also know that organic com-
pounds exist, into the composition of which iron enters, and
which do not give any reaction for that metal. Would not,
in this particular case, the action of the heat be to fix the
iron in a state unattackable by oxygen ? Whatever it be, if
we admit, and this is generally admitted even by the advo-
cates of diastase, a casse special to the Jacquez, and closely
related to the excessive quantity of iron those wines contain,
wThy deny the existence and the theoretical interest of a simi-
lar affection in the wines of other cepages, the analyses of
which show quantities of iron equal and even superior to that
contained in Jacquez.
TREATMENT OF DISEASED WINES.
Heating. — Whether due to microbes or not (such as casse),
the diseases above mentioned all give way to heating.
Observations conducted systematically have shown that no
living being, neither any reproductive organ of a living being
(seed, egg, spore) can resist a temperature of 120° C. At
* Comptes rendus. June, 1897.
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 225
that temperature, dry or moist, all life is suppressed; but if,
instead of operating in air or water, we operate in another
gas, vapour, or liquid, the temperature may be considerably
lowered and still remain just as effective.
Thus, in the case of wine, which is, after all, a solution of
alcohol and different acid substances, it is sufficient to raise
it to a temperature of 60° C. (140° F.) for a few minutes to
annihilate any living organism.
Heating is, therefore, a veritable sterilization based upon
the destruction of all living organisms, and we see what can
be expected from the application of such a process.
The description of the machines for the heating of wines,
Pasteurizers, or CEnotherins, does not come within the scope
of this work. The reader will find all desirable information
in the study published by Prof. U. Gayonon these machines.*
We will simply give a condensed account of the conditions
necessary for efficient pasteurization. The wine to be heated
should be almost clear, for the solution of the matters in
suspension, under the influence of heat, is to be feared —
solution which is always accompanied by a defective taste.
We should, therefore, if not filter at least rack, and avoid the
passage of the turbid part through the Pasteurizer.
For the wine to preserve all its qualities, and not to lose
any colour through the heating, it must pass by the required
temperature (60° C.), and come down to its initial tempera-
ture without coming in contact with air, so as to prevent the
action of oxygen taking place during any of the phases of the
operation. The extreme temperature which the wine should
reach must not be the average of very different temperatures
applied to different parts of the wine, but only the average
of very close temperatures. If, for instance, we pass wine
through a coil submerged in constantly boiling water, coupled
with a worm submerged in cold water, although the wine at
the exit may be obtained at the same temperature as at the
entrance, the heating is defective. In this case, the wine in
immediate contact with the metal would be submitted to a
high temperature (almost 100° C.), while that in the centre
of the tube would only be slightly heated. The average tem-
perature resulting from the mixture of these will, no doubt,
be sufficient to insure sterilization, but the wine will have
•contracted a special cooked taste, because certain parts have
been overheated.
* U. Gayon. Etude sur les appareils de pasteurization de vins. Extraitde
la Revue de Viticulture. Feret et Fils. Bordeaux.
226 WINE-MAKING IN HOT CLIMATES.
In order not to lose the beneficial action of paste urization^
and avoid contamination of the wine, it should be passed
direct into sterilized casks. In most cases, washing the
casks with boiling water is sufficient, but the sterilization
is more certain, and it is more convenient in practice to
steam them.
The wine heated under these conditions has nothing to
fear from diseases, and will not acquire as a result modi-
fications of colour or taste. When kept in well-bunged
casks, it may be preserved without further alteration of
any kind, and has even acquired a special resistance to the
germs which might accidentally contaminate it. Heating
has made great strides during the last few years, but has
still greater progress to make, actually pasteurizers are
always to be found in wine merchants' cellars, even of
medium importance ; but they are still rare 'in the vine-
grower's cellar. However, the advantages are so definite,
that little by little they force their way into, and mill very
soon be part of the current material of every cellar.
FILTERING AND FINING.
To cure diseased wine, or to be more precise, to hinder
the development of the disease, we should kill the microbes
causing it, or separate them completely from the wine in
which they exist. Filtering is a solution of this problem,
but is only efficacious if it is perfect, and to be perfect it
requires expensive apparatus provided with powerful me-
chanical appliances.
A large filtering plant was established quite lately at
Algiers. The filters employed were of the well-known type
Chamberland porcelain candle, the results obtained with
this plant were equivalent to those given by heating from the
point of view of sterilization, but this is a remedy only
practical for cellars in the immediate neighbourhood of
such a plant.
Most filters do not insure sterilization. Their effect is
excellent in many cases, but quite useless when we have
to deal with diseases due to microbes. The disease is
almost preferable, when we have not at disposal a good
pasteurizer.
The matters used for fining are distinguished according
to their mode of action. Finings only acting mechanically
I
CARE TO BE GIVEN TO WINE. DEFECTS, ETC. 227
(sand, Spanish clay, paper pulp). Finings forming with
the acids of the wine, partly soluble salts, chalk, marble,.
powdered oysters, plaster (all useless), and last the finings-
coagulated by substances in the wine.
The latter class only are true finings, and should alone-
be used. They are all bodies known in chemistry as
albumenoids, all acting in the same manner, and forming
with tannin insoluble flocculent precipitates of a density
slightly greater than that of the wine, and which con-
sequently only gradually settle to the bottom dragging
down as in a net of infinitely small meshes, all the solid
particles, whatever their tenuity may be, which float in the
midst of the wine. This makes fining a very special class
of filtration.
The different albumenous clarifiers are : several albumens,,
white of egg, blood, milk, gelatine, isinglass.
These substances are the base of all the products prepared
by the trade, and sold more or less modified under various
names and aspects. The commercial liquid finings are always
solutions of these compounds rendered non-putrescible by
the addition of antiseptics, very often sulphurous acid,
combined or not, but, unfortunately, sometimes also bodies
interdictedin the manipulation of wine, and which are found
afterwards in the treated wines, such as boric acid and
salicylic acid. The possibility of getting involved very
innocently in a police prosecution case should render the
proprietor very distrustful of these finings. This is to be
regretted, for the preliminary preparation required by the
albumenoids used for fining is generally very well done by
the trade.
The egg albumenoids are used without any preparation
other than separation from the yolk and beating up with
water.
Fresh blood, or better, serum, that is to say, the clear
amber-coloured liquid which separates after coagulation, is
used without any further preparation.
Natural milk is only used for the clarification of vinegar.
Whites of eggs are usually used in the proportion of two-
prr hectolitre (four per hogshead). Blood, or serum, in a
quantity of 50 cubic centimetres per hectolitre.
In both cases the method of operating consists in diluting
the clarifying matter with a small quantity of water (the
five thousandth part of the volume to be tivatnl), pouring-
228 WINE-MAKING IN HOT CLIMATES.
the prepared mixture into the wine, and energetically rousing
by appropriate means, according to the capacity of the
vessel, and allowing the wine to remain undisturbed until
the complete subsidence occurs of the precipitate formed.
The subsidence takes usually from three to, eight days, after
which racking separates the wine perfectly bright.
Egg and blood albumen are both sold in commerce in a
solid state, but in that form are always expensive, and lose
their main advantage, which is the simplicity of their
manipulation when liquid.
Gelatine requires a rather longer preparation. It is found
in commerce in the shape of transparent sheets, slightly
yellow or quite colourless if the gelatine is pure. It swells
without dissolving in cold water, but dissolves very readily
in warm water. Gelatine is obtained by boiling bones,
tendons, cartilage, and other abattoir waste at a temperature
over 100° C. under pressure.
Dissolved in water, it has the property of forming a jelly
on cooling, if the solution is sufficiently concentrated. We
should, therefore, be careful when preparing it as a simple
solution in warm water, to dilute it enough to avoid coagula-
tion when cold. In the proportion of 5 per cent, the
dissolved gelatine remains liquid at ordinary temperatures.
The liquid clarifiers with a gelatine base, sold in commerce,
are almost always stronger than 5 per cent., but to keep
them liquid they are heated under pressure at a temperature
of 128° C. By this treatment the gelatine loses its charac-
teristic property of forming, with tannin, an insoluble com-
pound, and that of solidifying on cooling.
If, perhaps, it is of some utility for the trade to obtain
-concentrated solutions, it is not necessary for the wine-maker,
and the solutions at 5 per cent., which any one can make
without the use of special appliances, will render the same
services. In cases where the proprietor requires to keep the
.gelatinous solution prepared in this way he should add to
it 1 per cent, of bisulphite of potash to render it
unputrescible.
Two hundred cubic centimetres of this solution are sufficient
to clarify one hectolitre (22 gallons) of wine, the operation
being conducted in exactly the same way as with white of
«gg or blood.
Fish isinglass obtained by the desiccation of the natatory
bladder of certain fish is very recommendable for white
CARE TO BE GIVEN TO WINK. DEFECTS, ETC. 229
wines. Its use seems at first very expensive, as the price of
a good quality is 30 francs per kilogramme, but the quantity
necessary is so small that the price of the fining for one
hectolitre is not, after all, much greater than when using
gelatine.
Two grammes of fish isinglass are ample to clarify one ,
hectolitre of white wine. The preparation of this isinglass
takes longer than that of gelatine. The sheet of dry isinglass
is first split in three thin sections, then placed in a vessel,
covered with cold \vater, and allowed to remain for 10 or 12
hours, during which it swells.
After that the mass is sprayed with boiling water, beating
it continually meanwhile. At first it forms a thick paste,
becoming almost fluid when the total quantity of water
added reaches 50 litres for one kilogramme of isinglass.
The main element for success in this preparation consists
in the thorough division of the isinglass. If we possess the
means of rasping it, and making a kind of coarse powder, a
thick liquid free from lumps is then easily made. If means
of rasping it are not at hand, the emulsion may be heated
for a few minutes, but it is better in this operation not to
let the temperature rise to 100° C.
Two hundred cubic centimetres of this solution of fish
isinglass of 2 per cent, strength will be sufficient to fine one
hectolitre of wine. The 200 cubic centimetres should be
first diluted with half a litre of water, adding it by instal-
ments, the mixture is then further diluted with wine, and
introduced into the cask, stirring energetically during the
iiddition, and then left alone during sedimentation.
It goes without saying that the wine-maker may insure
the preservation of the prepared solution of fish isinglass, in
the same way as in the case of gelatine, by adding 1 per cent,
of bisulphite of potash, and may, therefore, in one single
operation prepare the fining required for a whole year.
Precautions to be taken to insure the efficacy of fining. —
For fining to give good results the treated wines should
remain perfectly still during the whole time necessary for
the deposition of the fluffy precipitate formed through the
action of the tannin in the wine on the albumen or gelatine.
It is sometimes said that wines do not take, or do not take
the finings easily, this may be due to different causes.
One of the most frequent in white wines is deficiency of
tannin, certain kinds of white wines, especially those obtained
230 WINE-MAKING IN HOT CLIMATES.
from red grapes by the fermentation of the first fraction
of drained juice, are very poor in tannin, and consequently
cannot produce the coagulation necessary to insure the
success of the operation. The remedy consists in the
addition of tannin to the wine in a quantity of 25 to 30
grammes per hectolitre.
It is easy to place in evidence a deficiency of tannin by
the following simple process.
Portions of the wine to be fined are placed in two glasses ;
in one in its natural state, in the other with the addition of
tannin. After the tannin is dissolved, add to both in equal
amount (very small) four or five drops of the fining to be
used. If the wine is rich enough in tannin to take the
fining, the precipitation will be almost the same or equal in
both glasses, while if the wine requires the addition of tannin,
the precipitate will be much heavier in the glass to which
tannin was added.
We may again place the fining in one hectolitre of wine,
and stir in a small quantity of dissolved tannin. If the
precipitate does not increase, the wine will not require the
addition of tannin.
Another cause of failure in the fining of wines results from
the wines being saturated with carbonic acid gas, which,
gradually disengaging, forms little bubbles bursting at the
surface, carrying during their upward movement, small par-
ticles of fining, which remain suspended in the wine. This
trouble may be avoided by racking in presence of air, when
the wines abandon enough carbonic acid gas for that re-
maining to keep in solution during slight alterations of
atmospheric pressure.
Finally, another cause of failure is met with in wines
attacked by microbe diseases, if we do not previously
paralyze the microbes. While at work the microbes pro-
duce movements in the wine, by gaseous disengagement or
formation of liquid currents ; these are no doubt slight,
but sufficient to prevent the normal action of the fining.
They may be paralyzed by the use of sulphurous acid
in a quantity of 10, 12, or 15 grammes per hectolitre.
The most convenient way of applying the sulphurous acid
is that already described in the vinification of white wines>
namely, sulphuring with the pump. If the reader refers
back he will see that the operation is easy, and does not
complicate the operation of fining. (See page 178.)
CAKE TO BE GIVEN TO WINE. DEFECTS, ETC. 231
Let us suppose a cask of wine of 200 hectolitres attacked
by tonrne is required to be fined, and that the quantity of
sulphurous acid necessary to paralyze the microbe be 12
centigrammes per litre, or 12 grammes per hectolitre, the
mode of operation would be as follows: — Weigh 1,200
grammes of sulphur, burn it, and force the vapours into
the cask, as previously explained; this being done, place
in a tub the necessary quantity of fining, 40 litres of a
solution of gelatine of 5 per cent, strength (i.e., 200 cubic
centimetres per hectolitre), dilute with an equal volume
of wine, then with the pump used for sulphuring force
the mixture into the cask, and continue pumping air into
it after the tub is emptied to insure thorough agitation,
after that wait till the clarification is complete.
The fining with such a quantity of sulphurous acid pre-
sents evidently certain inconveniences, for the colour
diminishes and the fined wine acquires a decided taste of sul-
phurous acid. However, these faults are only transient, the
colour comes back after one or two rackings, and the sul-
phurous acid taste fades away completely, especially if the
sulphuring has been done with pure sulphur, and not with
sulphured cloths. For the sulphur compounds formed by
the burning of cloth, although in very small quantity, give
rise to a very persistent smell in the wine.
Notwithstanding these inconveniences, the fining after pre-
vious sulphuring is excellent for all diseased wines, which
after .such a treatment will be able to keep, and which other-
wise would certainly have entailed loss.
Sulphuring, followed by fining, is after all similar in its
mode of action and effect to the use of different commercial
mixtures, placed for sale under high-sounding names, and at
prices still more high-sounding. All those which are lawful
are mixtures of sulphurous acid and albumenoids, obscured
under trade names ; many are excellent, and could be recom-
mended if it were not for their exorbitant price. If the
proprietor wishes to use ready-prepared finings, care should
always be taken to apply to firms of repute, and insist upon
a guarantee as to the composition, if it is desired to avoid
the risk of prosecution.
232 WINE-MAKING IN HOT CLIMATES.
APPENDIX.
Extract from " The Vine in Australia," bj Dr. A. C. Kelly.
Published in 1841.
CHAPTEK ON FERMENTATION.
"In the warmer parts of Australia the vintage begins
sometimes in February, and is generally over in March, a
season when the weather is occasionally very hot. It is by
no means an uncommon occurrence for the temperature to
remain for some days above 90° F. during the day, and
never under 80° at night. Must, fermenting under such
heat, rises many degrees above the highest temperature of
the air — ten degrees probably. The effect of this high tem-
perature is by no means so injurious as might have been
anticipated. Much good wine has been made whose tem-
perature during fermentation has risen to 100°'F. The
temperature of 86° is the limit beyond which a sound
healthy fermentation cannot be maintained in beer and other
worts, and such was thought to be the case also with grape
must ; the opinions of modern oeuologues, however, have
undergone a change on this subject. " An acquaintance
with many details with which we are still ignorant is, how-
ever, necessary in order to investigate thoroughly the in-
fluence of temperature upon a well-tasted wine, which
should not spoil with age. The grapes of each country,
ripened under different degrees of summer warmth, and
very unequally rich in constituents, require different
temperatures during fermentation ; and different tempera-
tures are required for grapes which are the product of a
warmer or colder summer. But we are still ignorant on
these points. All we know is, that a high temperature
during autumn promotes fermentation, and a low one is
detrimental to it ; that inequality of temperature during
fermentation is extremely injurious, and not infrequently
spoils the wine altogether."* Baron Liebig, in writing
* Mulder. Chemistry of wine.
APPP]NDIX. 233
to the late Mr. King on the wines of New South Wales,,
says : — " As the wine of Irrawang contains an ample
quantity of saccharine matter, I deem it expedient that you
should allow it to ferment at the highest possible tem-
perature."
The illustrious chemist, however, would surely set some
limit to the temperature. One thing is certain, that it is
only very strong must which can be allowed to rise so
high as it does with us in Australia. The weak n ust of
the North of France and the Rhine, whose specific gravity
may be about 106, would pass into vinegar were it ex-
posed to a temperature of 90° and upwards.
In colder countries large vats are employed as best suited
to maintain the temperature of the fermenting mass, but
they would be objectionable where it is desirable to keep
the vats cool. How to keep down the temperature of the
fermenting must, is the most difficult problem the Australian
wine-grower has to solve. " Experience has taught us
that the temperature of fermenting wine cannot be kept
down by the use of underground cellars, unless the quantity
be insignificant. We prefer a wooden building above ground,
with the means of admitting free currents of air on all
sides. Any accession of heat which a hot day may occasion
is more than compensated for by the cool night air, which
has free admission on all sides. A large body of wine will
rapidly heat an underground cellar, and it cannot be cooled
down again for many days."*
" A free admission of air to the surface of the fermenting
liquor has the effect of keeping down the temperature. To
this we shall revert shortly. Where it is desirable to exclude
the air, as in the fermentation of red wines, some other
means are required to prevent the fermenting liquor from
rising to an excessive heat, as it must do under a tempe-
rature of the air of 90° or upwards. This may be effected by
means of a refrigerating apparatus such as the annexed, which
is sufficiently simple to require no particular explanation. If
is simply a pipe formed like the worm of a still, through
which the cold water from a cistern flows, and is dis-
charged again outside. The entrance and exit parts of
the pipe are placed close together, in order to interfere as
little as possible with the jixing of a false I'nL «ml also
* Rough Notes— Sir W. Macarthur.
234 WINE-MAKING IN HOT CLIMATES.
to facilitate the strengthening it by a frame. By means
of a long flexible tube, to Jit on by a coupling screw, the
apparatus may be applied to a vat at a distance from
the cistern. The supply of water for the cistern must of.
course be from a well or underground tank, whose tem-
perature is moderate ; and care must be taken that it
does not lower the temperature too much. This refrigerator
has been used with excellent effect in this colony, but was
given up from a dread, perhaps a needless one, of the effect
of the metal, block tin, upon the wine. The same apparatus
is used during warm weather in some breweries in Britain,
where great care is employed in conducting the fermenta-
tion, and where it is essential to maintain a steady tempera-
ture. When the temperature is low the same may be used
to keep up sufficient heat in the liquid by passing hot water
through it.
" The chief objection that can be brought against this
refrigerator is the material of which it is constructed. The
powerful action of the tartar upon metals, already alluded
to, forbids the employment of any metallic implements
which are to come in contact with grape-juice. Silver is the
only metal which is not much acted on by tartar ; and a
copper tube, electro-plated at that part which is immersed
in the fermenting must, would, probably, be not too expen-
sive to forbid its use. An iron or copper tube, enamelled,
would also be an excellent material for the purpose. Glass
might be employed for the construction of refrigerators ; it
could be protected by a wooden frame, and as it is only the
portion immersed which is affected by the tartar, the entrance
and exit pipes may be constructed of metal. The only
objection to glass is its slow conducting power, but this may
be so far obviated by giving it a larger surface.
" It is surprising to find so little attention paid to tempera-
ture in the fermentation of wine in these colonies. If the
general principles of fermentation are of universal appli-
cation, we have no reason to treat grape-juice as if it were
an exception ; and expect that it can be fermented success-
fully when we disregard the conditions under which alone a
healthy fermentation can be conducted. Grape-juice cer-
tainly ferments more readily and completely than any other
fermentable substance, and has, perhaps, less tendency to
go into the acetous state ; and wine-makers, trusting too
much to its power to resist the deteriorating influences to
APPENDIX. 235
which it is often exposed, do not consider it necessary to
abide by the laws which regulate the fermentation of other
substances, but take extreme liberties with the grape must.
For example, the temperature of the fermenting must may
rise to 100°, and sometimes several degrees above it, and
the resulting wine may be sound and good. The conclusion
drawn from this is that wine may be fermented at a very
high temperature without injury. Not without injury cer-
tainly, as the following experiment shows : — A quantity of
purple grapes was crushed during very hot weather, the
temperature of the air being above 90° during the day and
never under 80° at night. The must and skins were put
into a vat of 250 gallons, and a false lid placed as usual to
keep down the mark. There was more than sufficient to fill
the vat to the proper height ; and the remainder, about
40 gallons, was put into a small vat (a port wine pipe having
the head out), a false lid was also fitted into this. The fer-
mentation commenced in each the following day, and in two
days the temperature rose considerably during the tumul-
tuous fermentation ; but that of the larger vat was, at least,
8° higher than the temperature of the smaller. After this
the progress of the attenuation showed a marked difference
in the two vats. In the smaller it went on steadily, and in
three days after the height of the fermentation it had fully
attenuated itself, giving a specific gravity of 100, and was
racked off clear and in fine condition ; whereas the larger
vat attenuated very slowly. On the third day after the
violent fermentation its specific gravity was still 102*5 ; the
following day it had come down very little, showing 102,
and was full of yeasty matter floating through it. It was
racked off into casks, to undergo the secondary fermentation ;
and, although eventually it attenuated after some time, it
was an inferior wine to that drawn from the smaller vat.
"It has been often remarked that the first experiments in
wine-making are generally the most successful, but it is easy
to divine the reason of this. The first quantities made are
generally very small, 40 or 50 gallons or less ; the tempera-
ture of so small a body of fermenting liquor seldom rises
high, and the process goes on under much more favorable
circumstances in this respect than in the subsequent vintages,
when the fermentation is generally conducted in quantities
of from one to several hundred gallons, when the increase of
temperature is necessarily greater.
10649. Q
236 WINE-MAKING IN HOT CLIMATES.
" The fermentation of grape-juice is so entirely a natural
process, and goes through its course so perfectly, under
favorable circumstances, that we are apt to become careless,
and say that we are trusting the process to nature when, in
fact, we are counteracting her operations, and going in direct
opposition to the conditions under which fermentation can
proceed with success. There certainly exists in the grape a
vital energy, a sort of vis medicatrix, which not only resists
many evil influences to which it is exposed, but seems also
to correct them when they have occurred.
"To none of the conditions necessary to a sound healthy
fermentation ought we to pay more attention than tempera-
ture ; and there is, probably, none which is so much
neglected. This arises, doubtless, from the difficulty, and,
I may say, the supposed impossibility of counteracting the
excessive heat of the climate. The construction of an
apparatus for keeping down the temperature, of the nature
and form already alluded to, would be neither difficult nor
costly, and of its beneficial influence on the fermenting
process, and the resulting wine, there can be little doubt, for
the great majority of our wines are fermented at too high
a temperature. When we find writers such as Liebig and
Mulder recommending a high temperature for the fermen-
tation of the wines of warm climates, we solace ourselves
with the idea that we are on the safe side in this respect,
forgetting that what these writers would consider a high
temperature is, probably, 86° F., the highest point assigned
to a healthy fermentation ; but supposing that they allow a
higher limit — say 10° above it, still this is far below what
the fermenting vats of these colonies often attain, for in
many cases they must rise 10° degrees higher still, to 106°,
or 20° above the limit already indicated as that beyond
which the fermentation does not go on favorably. This is a
temperature surely never contemplated by any of these
writers, and which no must ought ever to be allowed to
attain.
"The effect of a very tumultuous fermentation in beer,
caused by a high temperature, is thus described by Dr.
Ure * : — l When the action is too violent, these barmy
glutinous matters get comminuted and dispersed through
the liquor, and can never afterwards be thoroughly
* Dictionary of Arts and Manufactures.
APPENDIX. 237
separated. A portion of the same feculent matter becomes,
moreover, permanently dissolved during this furious commo-
tion by the alcohol that is generated. Thus, beer loses not
merely its agreeable flavour and limpidity, but is apt to
spoil from the slightest causes. The slower, more regularly
progressive, and less interrupted, therefore, the fermentation
is, so much better will the product be.' If such are the
results of a too violent fermentation in beer, we cannot
doubt that it must also have an injurious effect on wine.
" The grapes of the warm districts of these colonies, which
attain a specific gravity of 112, or more, are able to bear,
and probably require, a very high temperature to complete
their fermentation ; the exact limit we cannot define, but we
may venture to say that 95° is a temperature beyond which it
would not be advisable to allow any wine to rise, and probably
90° is the highest it ought ever to attain"
238 WINE-MAKING IN HOT CLIMATES.
THE CONTROL OF THE TEMPERATURE IN
WINE FERMENTATION.
By A. P. HAYNE,* DIRECTOR OF VITICULTURE, CALIFORNIA.
BULLETIN No. 117, UNIVERSITY OF CALIFORNIA, 1897.
The Control of the Temperature. — The fermentation of
wine must or the juice of the grape results in the main in the
splitting up of the sugar it contains into almost equal parts
of alcohol and carbonic acid gas. While there are other
products of fermentation, it is not essential for our immediate
purpose to dwell on them in this connexion. The transfor-
mation of sugar into carbonic acid gas and alcohol is a
chemical action caused by minute plants or ferments called
yeast. It is well known that all chemical changes of this
sort produce heat ; and thus it will be seen that the tempera-
ture of a fermenting mass of a sugar solution (grape juice),
while it depends to a certain extent upon the outside tem-
perature, is chiefly dependent upon the amount of heat
generated within the tank itself. The amount of heat then
that is produced in a fermenting tank depends upon, first,
the per cent, of sugar in the must and the quantity of
must ; second, the facilities offered by the tank and air for
carrying off the heat generated by fermentation, or con-
ductivity of the tank walls, the amount of surface exposed
to the air, the circulation of the must within the tank, &c. ;
third, the activity of the yeast cells, i.e., the rapidity of
fermentation.
Percentage of Sugar. — The amount of sugar in the must
varies from year to year in the same place with the same
varieties. In hot countries there is, other things being equal,
more sugar in the must than in cold countries. Some
varieties of grapes give more sugar than others ; and as high
alcoholic strength is, unfortunately, paid for as such by the
merchant, grape growers are apt to select those varieties
that produce the most sugar, and hence alcohol in the wine,
regardless of true quality. While this may be proper
enough in cold climates, it works great injury to the general
reputation of the wines of warmer countries, for alcohol is
* Diplume de VEcole d* Agriculture de Montpellier.
APPENDIX. 239
not the only desideratum in wine. In hot climates there is
almost always, with the excess of sugar, a correspondingly
smaller amount of acid. It is, however, important to note
that very high sugar contents of must and low acid generally
go together, and that they are both, as a rule, undesirable.
Excess of Heat. — The amount of heat generated within
the fermenting tank is very great, being sufficient, theoreti-
cally, to raise above hoilitig point the whole of a must rich
in sugar. Practically, however, the heat is genera ted
gradually : and much of it is carried off by the gas generated,
as well as through the walls of the vat, and from the surface
of the fermenting liquid ; otherwise fermentation beyond a
certain point would be impossible. This fact has taught
wine-makers in warm countries the necessity of a free circu-
lation of air in the fermenting room, unless that air is hotter
than the temperature of the fermenting mass. Hence the
benefit of the practice of fermenting in small packages with
thin walls : first, because of less actual amount or quantity
of heat (calories) generated ; and, second, because of the
facility with which this heat can be carried oft', and thus the
equilibrium between the temperature of the fermenting mass
and the outside air be maintained. This has led many wine-
makers to have their tanks made of small diameter, of great
height, and of very thin material of high conductivity, such
as thin enamelled iron. While this certainly enables the
operator to completely control the temperature, it has proved
far too expensive for general use. But, unquestionably, the
growing custom of using very large tanks is essentially bad
practice.
Activity f]f t/«> Yeast. — The third factor in the problem is
the activity of the1 yeast-cell. There are many circumstances
that modify this activity. First it must be remembered that
the yeasts are plants, and that, in a general way, their
growth (activity) is modified by the same conditions that
affect the higher plants growing in the fields. Extremes
either of heat or cold are unfavorable to their maximum
development. Thus in cold climates the wine-maker keeps
a fire constantly burning in the ferment in g-room. while in
hot countries all his energies are bent on reducing the
temperature to that most favorable for proper fermentation.
It is also noted that the higher plants have different
" optimum " temperatures; for there are tropical plants,
plants of temperate regions, and plants that grow in the
arctic regions. It is the same, within certain limits, with
240
WINE-MAKING IN HOT CLIMATES.
the yeast-plants. This variation is, as yet, but little known,
for it is within but a few years that serious attention has
been given to this branch of science so magnificently set
forth by Pasteur. Suffice it to say that something has been
done, and that the beer brewers have put these principles in
practice with eminent success. Now the yeast-plant of the
brewers splits up sugar into alcohol and carbonic acid gas,
just as the wine-yeasts do, and is influenced by exactly the
same conditions.
In the case of the seeds of the higher plants of all kinds,
activity does not begin until the proper temperature has
been reached. Should the temperature in spring rise slowly,
the growth of all plant life is correspondingly slow ; but so
surely as a sudden great rise in temperature takes place,
plant life will be intensified by it until, when excessive
temperatures are attained, it is either paralyzed temporarily
or the plant may die.
Similarly, if the grapes arrive at the fermenting tank
much heated, then we may look for a sudden violent
development of yeast-plants or fermentation. This is
unfavorable for several reasons : first, because the heat is
generated so rapidly that a due amount cannot be carried
off in time by conduction, and high temperature is reached
very quickly, whereby the yeast may be paralyzed or killed.
But more than this ; within certain limits each degree of
sugar in the must means a corresponding amount of heat
generated in the tank. Now, if fermentation starts in at a
low temperature, say 56 degrees F., the generation of heat
will be slow at first, and the rate of fermentation will be
correspondingly slow, and apparently less heat will be
generated than if started at a higher temperature ; because
much is lost by conduction, although the amount is actually
the same. The starting point was so low that the heat that
was not carried off by conduction is not sufficient, when
added to the initial temperature, to carry it to the killing
point. Let the initial point be 75 degrees F., as is frequently
the case, then the extra heat added by the greater rapidity
of fermentation will carry the temperature, without doubt,
to the death limit. Hence the many efforts made to get the
grapes into the tank in a cool state. Wherever this can be
done, the fermentation usually goes through well ; but
practically this is possible only on a small scale. Hence in
a warm climate like that of California the initial tempera-
ture of the must is always over 60 degrees F., and in some
APPENDIX. 241
cases over 76 degrees F. The danger arising from over-
heating is, therefore, naturally to be expected. Actually,
at all the wineries of this State, over-heating does occur
almost continually, and great financial losses result there-
from.
Nourishment. — But aside from the general climatic con-
ditions, all plants are profoundly modified in their growth
by the nourishment they receive from the soil in which they
grow. Aside from the sugar required to nourish the yeast-
plant, one of the most important factors in the problem of
its growth is the acid. There are other factors, but these
are not essential in this connexion. Now, just as there are
plants that will grow in alkali soil, and others that will
not, so there are yeast plants that will thrive in a non-
acid medium, and others that will not.
Diseases of Wine. — This brings us to the plants that
cause the diseases of wine ; for it should be understood
once for all, that a " spoilt " wine is spoiled not spon-
taneously, but by the growing in it of some minute plant
which uses the substances of the wine to nourish itself,
and to produce both its natural products, most of which
are foreign to normal wine, and unpalatable besides. Thus
the bacteria of putrefaction destroy otherwise edible meat-
arid render it unfit for human consumption. In the same
manner all diseased or " spoilt " wines have been rendered
so by some plant of a lower order than the yeast-plant
that gave it its quality.
Importance of Proper Temperature. — Returning to the
question of temperature, it has been established beyond the
possibility of rational dispute that, in the majority of cases,
those temperatures most favorable to the wine-yeast plant
are unfavorable for the development and growth of disease-
plants or bacteria, and vice versa.
In a general way we may say that the wine-yeast is a
plant of the temperate zone, while the disease bacilli are
plants of the tropics ; the one requiring moderate heat
for its normal growth, and the other requiring a much
higher temperature in order to grow and act at all. This
explains the practice of keeping wine in cool cellars. This
is a very important point. High temperatures are very
unfavorable for normal wine-yeast, and very favorable to
the bacteria which cause wines to spoil. After the limit
of temperature favorable to the yeast-plant has been passed.
the quality of the wine deteriorates with great rapidity :
242 WINE-MAKING IN HOT CLIMATES.
not necessarily because the wine-yeast is actually killed,
nor that its action has ceased altogether ; but that its
activity has been checked, mid that the harmful bacteria
have begun their work ; producing, not alcohol, carbonic
acid gas, glycerine, &c., but their own characteristic pro-
ducts, such as mannite, acetic,, lactic, and butyric acids,
&c., &c.
Paralysis and Death of Yeast-plants. — The degree of
paralysis of the yeast-plant depends upon the temperature
and composition of the must. The absolute point of
temperature at which paralysis or death will overtake the
yeast-plant cannot be fixed absolutely, as it depends upon
the variety of ferment or yeast-plant, as well as upon the
conditions in which it works best. For normal musts
with a normal yeast, the death point is generally from
98 to 100 degrees F. Some varieties of yeast (and
these are few) will stand more heat, most of them suffer-
ing greatly before this point is reached ; the must als;>
should be of a composition naturally favorable to them.
Before this point is reached the bacteria begin to develop,
while the wine-yeast stops growth ; and the wine, if not
spoiled, is rendered of less value than it would have been
had the temperature remained lower.
Effect on Bouquet and Aroma. — It should be noted in this
connexion that, with certain reservations, the general rule
is that the lower the temperature of fermentation the better
the aroma and bouquet of the wine. In other words, the
proper regulation of the temperature of the must during the
first or tumultuous fermentation means the production of a
wine richer in alcohol, of better keeping qualities, and better
quality throughout.
Use of Antiseptics and Antiferments. — With this review
of the general principles governing fermentation, we come
to the practical lessons deducible therefrom. We have had
occasion to note the heavy annual loss to wine-makers from
" stuck tanks," resulting either in the total destruction of the
wine, or the partial loss of its market value. We have also
had occasion to listen to the criticisms of the purchasers of
Californian wine, both abroad and in this country ; and in
by far the greater number of cases the fault found was not
so 'much with the quality (for well-made Californian wine
compares favorably, grade for grade, with any in the world)
but in the unsoundness, i.e. the tendency to spoil on the
hands of the purchaser before reaching the consumer. This
APPENDIX. 243
has led to the use of antisi'j it ics, " anti-ferments," that is
poisons which kill outright or paralyze, not only the wine-
yeast but all bacteria that might intervene, and in some
cases' the consumer as well. The making of wine at high
temperatures is simply inviting the use of antiseptics; for,
as a matter of fact, unsound ivine can only be marketed />//
the use of some powerful agent, to keep the bacteria in check.
Few wine-makers realize the great harm done' to the reputa-
tion of California!! wines by a few unscrupulous or ignorant
dealers who systematically buy up unsound wines, ''doctor"
them, and ship them abroad. The sooner the use of anti-
septics of any kind (except pure wine alcohol) is stopped.
the better it will be for all concerned in viticulture. It is to
be regretted that there is no law enforced that punishes
those who use dangerous drugs in wine.
Stuck Tanks. — A "stuck tank "is a very common occur-
rence at most all wineries in California, as well as in all
countries having similar climates. It means that the yeast
germs that convert the juice of the grape into wine have
suddenly ceased their normal action, and fermentation' proper
has ceased, while bacterian activity has started up ; result-
ing either in the total or partial loss of the wine. One wine-
maker of this State told us that his loss from stuck tanks
amounted in a single season to 10,000 dollars ; and there are
but few who do not suffer to a certain extent from this
trouble.
As has been shown, the commonest cause of stuck tanks
is too high temperature. The trouble is not by any means
confined to California ; but is the curse of all wine-making
countries in the warmer parts of the world, -viz., all
Southern Europe, North and South Africa, Australia, &c.
The wine-maker of these countries has been found to be less
self-complacent than his ( California brother, and has made
serious efforts to control the temperature of fermentation.
Methods of reducing Temperature. — By some wine-makers
the amount of sugar was reduced by the addition of /rnft-r.
This, in many cases proved of great service, but in others
it was not so; for the water also reduces the acid and the
I tody of the wine, and unless there be sufficient acid, nor-
mal fermentation does not take place, save under excep-
tional circumstances. Others tried to reduce the tempera-
ture of the wine by the addition of ice to the fermenting
tank. This had not only the same effect as the addition
of water but proved utterly impracticable in the case of
244 WINE-MAKING IN HOT CLIMATES.
red wine and is not economical. Some tried the use of
metal spiral coils plunged in the fermenting tank through
which cold water was passed. This proved successful in
the case of wine fermenting without skins or stems (white
wine); but was impracticable in all cases where the skins
and stems were left in the tank, owing to the impossi-
bility of sufficiently mixing the hot and cold parts of the
fermenting mass. Others tried metal tanks, but this was
found to be too expensive.
Again, some tried pumping the wine from the bottom
of the tank over into the top and allowing it to spread
out into 'a spray. This accomplished two results: it cooled
the wine slightly (but very slightly) and especially did it
revive the partially paralyzed yeast cells by giving them a
fresh supply of free oxygen. The fatal defect of this
practice was found to be the too great oxidation and
evaporation of the alcohol, which took place at high tem-
peratures, the wine becoming: too highly charged with acetic
acid (vinegar-sour). Nevertheless, this pumping over of
the wine of stuck tanks, or tanks that threaten to stick,
is now widely practised all the world over, and in the case
of a sudden stopping of fermentation it is necessarily done
to supplement the addition of fresh must in active fermen-
tation used to finish the conversion of the sugar into
alcohol and carbonic acid gas.
Experiments at the University. — Convinced of the neces-
sity of controlling the temperature of the fermentation of
wines in this State (just as the brewers do that of their
fermenting wort to a fraction of a degree, always getting
a product the value of which is known beforehand), the
Viticultural Staff of the College of Agriculture set about
to devise some practical method for attaining this end.
It was only after having completed the experiments with
the apparatus herewith described, that we received detailed
data of the European experiments with the refrigeration
of wine. We give below a complete description, first, of
the French apparatus ; second, of the one first devised at the
Experiment Station; and, third, of the one modified as found
advisable after thorough trial.
Apparatus used in other Countries. — Figure 21 (page 116)
represents one of the forms of the apparatus now used
throughout Northern Africa and Southern France. As will
be seen, it consists essentially of two columns, each made up
of nineteen thin, well-tinned, horizontal copper tubes. These
APPENDIX. 245
tubes are 13£ feet long by 1£ inches in diameter. The total
length of the tubes through which the wine passes is thus
nearly 500 feet. These tubes are fitted into solid bronze
castings, closed by means of a bronze plate over a rubber
washer, with thumb-screws. The two columns are connected
by a tube (3 fig. 21) running diagonally from the top of one
column to the bottom of the other, so that the hot wine enter-
ing at the lower end (7 fig. 21) of the first column, and after
'passing upwards and completing the circuit in this column,
passes to the bottom of the second column, from which again
it escapes at the top. Above the two columns of tubes is a
large metal water-box, having two rows of holes in the bottom
corresponding to the two columns, from which cold water is
allowed to drip as the warm wine is pumped through the
tubes. Under the apparatus is a metal box, which catches
the drip of warmed water. Each column of tubes has a
stop-cock (13), which allows rapid emptying of the wine
when pumping is stopped. The apparatus is, as before said,
now actually in use in other countries, and we are indebted
to the excellent report of Messrs. Miintz and Rousseaux in
La Revue de Viticulture for the results of their exhaustive
experiments conducted in France during the past season,
1896, as well as during the season of 1895.
The first defects that strike one in this apparatus is the
unwieldiness and expense, as well as the large amount of
labour required to force a IJ-in. stream of wine through
such a length of tubing at a working rate ; then the amount
of water used in cooling the wine must be very large, unless
the temperature of this water be considerably below that of
the wine. As in the case of the use of ice, it will do well
when all conditions are most favorable.
In a recent article, giving a resume" of the two seasons'
experiments, Messrs. Miintz and Rousseaux tell us that to
work the apparatus a gang of four men, working in relays,
is required to pump 40 hectolitres or 1,060 gallons per hour.
With a motor engine double this amount could be pumped
through, but the quantity of water needed in this case for
the proper cooling of the wine is enormous, amounting to
from one to one-and-a-half times the amount of wine passed
through ; or far more cold water than is generally to be had
at the average California winery.
The reduction of temperature was in some cases very
great, but depended altogether upon the rate of pumping,
246
WINE-MAKING IN HOT CLIMATES.
the amount of water dripping over the tubes, and the initial
temperature of this water. There was an average reduction,
however, of from 10 to 12 degrees F., but in some cases a
maximum of as much as 20 degrees when slow pumping was
practised. The cost of cooling the wine was, on an average,
one-thirteenth of one cent per gallon.
From the careful tests made by these eminent scientists,
the remarkable benefits of cooling the fermenting mass was*
strikingly shown. In all cases a certain lot of the same
must was fermented in the usual way as a check to the
experiment, and in every case the cooled wine was sounder
and of far better quality. Microscopic examination showed
that the uncooled wine was teeming with harmful bacteria,
while the amount of unfermented sugar remaining was very
considerably more than in the case where the wine had been
cooled. The University experiments showed this as strikingly
as did those of Miintz and Rousseaux.
We give below a table taken from La Revue de Viticul-
ture, in which some of these results are set forth. Unfortu-
nately the recent disastrous fire at the Agricultural Building
at the University destroyed all the notes taken at each tank
cooled, so that we can but give the general results. These
results were, however, looked over but a few days before the
fire, and, being compared with those made in' France by
Miintz with his apparatus, were found to be essentially in
accord, as appears from the data given below. We give
below the exact figures obtained by these observers. This
shows the matter to be not of something " theoretical " and
untried, but something that has been tried by several, and
proved to be a practical success.
The experiments were made in the Rousillon district of
France, near the Eastern Pyrenees, during the season of
1896, with Carignane grapes.
— -—
Maximum tempera-
ture of the must
during fermentation.
Alcohol per cent.
Unfermentetl
Sug-ar.
Cooled Wine
96 (F.)
11-00
55 55
96-8
11-45
•59
55 55
99-5
11-50
•65
Uncooled Wine
102-2
10-20
2-60
35 5J
104-0
10-10
3-30
APPENDIX. 247
It will be recollected that experiments made by Prof.
Hilgard at the University, in 1887, gave almost precisely
similar results as to alcohol percentage when hot and cool
fermentations were compared. (See Report of the College
of Agriculture on Methods of Fermentation of 188G-xT.
p. 28.)
The effects of high temperature on the composition of the
wine may be further illustrated by some other analytical
results from the French experimenters, Miintz and Rous-
seaux, who found in 1895 that a wine which had attained a
maximum temperature of 98 '5 degrees F., during fermcnt;i-
tion showed on analysis '066 per cent, of ammonia, while
another wine made from the same lot of grapes, which
attained a maximum of 104 degrees, showed *60 per cent.
Similar results were obtained in 1896, when maxima tem-
peratures of 94 degrees and 104 degrees gave '03 per cent,
and '22 per cent, of ammonia respectively. It is clear,
therefore, that serious chemical differences and defects are
produced in the wine by high temperature fermentations
apart from the swarms of disease bacteria which are always
present in such wine. Of the wines made by Miintz and
Rousseaux in their 1896 experiments, those that were not
cooled threaten to spoil already ; while those that were
cooled are in perfect condition.
EXPERIMENTS MADE BY THE UNIVEESITY AT NATOMA,
SACRAMENTO COUNTY, AND AT EVERGREEN, SANTA
CLARA COUNTY.
Apparatus used. — The results of Miintz and Rousseaux
were amply confirmed by the investigations undertaken by
the Viticultural Staff during the season of 1896 at the
Natoma Vineyard in Sacramento County, and at Mr.
Wehner's at Evergreen, near San Jose. The apparatus
used by us differed greatly from that used by Miiutz and
Rousseaux, and the many others abroad who practised
refrigeration during fermentation at the same time.
Not being able to avail ourselves of the detail of the
numerous experiments undertaken along the same lines
abroad during the past few years, we had to construct our
apparatus independently upon what we considered the most
promising lines; fortunately, as it turned out, committing
few mistakes and obtaining results that show our system
to be far superior to any thus far proposed for California
248
WINE-MAKING IN HOT CLIMATES.
conditions. However, experience has shown us the desirability
of certain changes and modifications as hereinafter shown,
especially as mechanical power for pumping and crushing is
available at nearly all wineries of this State.
The apparatus
shown in figure 2
is the one de-
signed and used
by us in the ex-
periments. It
will be observed
that in so far as
the pumping of
the heated wine
through tinned
copper tubes
goes,
the
princi-
ples are identical
with those of the
French appara-
tus. The method
pumping is
same as is
practice at
wineries for
drawing off the
newly fermented
wine from the
fermenting tank.
The wine is
drawn off from
the bottom of
the tank, and
strained through
a sieve into a
tub, from which
it is pumped
through the ap-
paratus into the
| top of the tank
again. In other
respects there are important differences ; thus, instead of two
columns consisting of 498 lineal feet of tubing, our apparatus
consisted of a single column of only 42 feet of tubing. The
APPENDIX. 249
tinned copper tubing instead of being perfectly round is very
much flattened, thereby giving greater cooling surface to the
same volume of wine, a material improvement on the French
system of round tubes. It consists of fourteen pieces 3 feet
long and 4 inches broad by 1J- inches deep. These tubes arc
fitted into bronze castings, which are closed by plates fitting
over rubber washers, and fastened by thumb-screws, thus
allowing the tubes to be readily cleaned in cases of obstruc-
tions that might occur in the pumping through of the
muddy, partly-fermented must.
METHODS OF COOLING.
Water-box. — In our first experiments the whole apparatus,
that is to say the column of tubes, was fitted into a box, tin-
lined and filled with water. A constant supply of fresh water
entered the box at the bottom, escaping from the top, while
the \vine entered the top of the apparatus and escaped at the
bottom, in order that the coldest mine should come in con-
tact with the coldest water, and vice versd. It is well known
that this arrangement will give the greatest amount of
cooling effect.
It was found that by the use of a very large quantity of
water the wine could be sufficiently cooled, but the excessive
amount of water thus required caused us to abandon this
system. In special cases, where an unlimited water supply
is to be had without too great expense, this system should
be adopted, for though the cost of water-box and installation
will about offset the cost of the blower and canvas sleeve,
hereinafter described, it has the advantage of doing away
with" the necessity of the command of power. In case this
system is adopted, it is well to use a greater length of tubing
than would be required where the spray and the air current
are used. Roughly speaking, the amount of water used in
this case should be from 1 J to 2J- times the volume of wine
pumped through the apparatus.
Drip, Spray, and Blast. — Instead of depending upon the
simple dripping of the water over the tubes to effect the
reduction of temperature of the warm wine, a great saving of
tubing, as well as labour in pumping, was found to be
effected by the use of a fine spray of water carried by a strong
blast of air, thus combining the effects of cold water and
evaporation. The quick evaporation brought about by the
dry air prevailing at our vintage season, when mingled with
250 WINE-MAKING IN HOT CLIMATES.
a fine spray, produces a cooling effect far in excess of what
could be obtained from the ordinary water at the wineries
alone. This is important, for at many of the wineries the
water available is very warm and the difference between the
temperature of the water and the wine to be cooled is so
slight that it would be impossible to effect a proper amount
of cooling, unless enormous volumes of water were used.
The proper proportions between the air blast and the
amount of water sprayed is of the utmost importance. It is
readily understood that a weak blast with a large amount of
coarsely-sprayed water would leave the temperature of the
water almost unchanged when it reaches the cooler, and
would, therefore, amount to little more than the dripping
practised in the French apparatus ; while if the blast be in
excess and the water deficient, the amount of water carried
may not be sufficient to utilize the evaporative power of the
blast, nor to thoroughly wet the tubes. Again, to insure
the maximum cooling from evaporation, the spray should be
so fine that within the short distance from the nozzle to the
tubes the air may become fully saturated, and both cooled
to the fullest extent. Of course, the heavier the blast the
more water spray can be carried and cooled by it. To pro-
duce the requisite fineness of spray, an adequate water
pressure is necessary.
Another factor of the utmost importance is the dryness,
or what is technically called the " relative humidity " of the
air used. During the vintage season this is frequently as
low as 33 per cent, outside of the icinery, and the intense
evaporating effect producible under such conditions should
be utilized by connecting the intake with the outer air. This,
of course, can be done either by a canvas tube stretched by
hoops, or by a board flume.
When, as may happen near the coast, the moist condition
of the air is unfavorable to strong evaporation, the water
temperature, on the contrary, is frequently itself so low that
an energetic spray without a blast may suffice to do the
necessary amount of cooling.
It will be noted, therefore, that the best conditions for
cooling will vary, not only in different localities, but on
different days, and according to the prevailing wind ; so that
it is impossible -to prescribe the exact strength of blast or
quantity of spray that should be used. But a few experi-
ments will determine the best practice in any given locality.
APPENDIX. 251
In our experiments the blast of air was generated by
means of an 18-in. " double " (8-wing) blower, or " exhaust-
fan " reversed. The water escaped from a battery of three
Vermorel nozzles placed immediately in front of the blower.
A conical canvas sleeve attached to the outlet of the
blower and 5£ feet away to the circumference of the cooler-
frame prevents the loss of blast and spray.
The "double" 18-in. blower requires under ordinary
circumstances less than one-half horse-power to run it at a
rate of 1,000 revolutions per minute, and thus, with a free
supply, will pass 3,000 cubic feet per minute through it.
The 24-in. " double " blower requires about the same horse-
power to run it, but requires only 900 revolutions per minute
to send through 5,000 cubic feet in the same time. It should
be remembered that the best efficiency of every blower is
limited to a definite velocity of revolution. The figure-
above given refer to the most favorable velocities for the sizes
mentioned. The one costs 40 dollars (less discount) while
the latter costs 50 dollars. In order that the apparatus may
be available at small-scale wineries, where no steam is used,
it may be well to state that a small gas engine, run with
common "distillate" and giving 2£ horse-power, can be
had for 187 dollars (less discount). The cost of running
such a motor is 1 cent per horse-power per hour; a trifling-
expense, especially as the motor, once started, will run itself,
so that one man can attend to the pumping of the wine and
the running of the engine at the same time. Indeed, with a
little fitting, such an engine could be made to do all the
pumping in the cellar, and there are no labourers who will
do 1 horse-power of work for a cent an hour.
While the French apparatus was movable, ours was of
necessity fixed, but with one man at the pump at Mr.
Wehner's place it was found that he could pump from the
most distant tank at the rate of 1,000 gallons per hour, in
some cases as much as 1,400 gallons. At this rate a reduc-
tion of temperature of from 1 0 to 13 degrees was obtained in
the wine. The temperature was taken at the point where
the wine left the tank and again where it re-entered the
tank after having passed through the cooler.
Precautions. — We found that the much-feared deposit of
cream of tartar on the inside of the tubes was very slight
indeed. It would seem that while warm wine on cooling
.will deposit cream of tartar on the lining of the vessel, wine
10619. R
252 WINE-MAKING IN HOT CLIMATES.
constantly in motion (as when being pumped) will not
deposit much. Even after long use it was found that the
thin coating of cream of tartar on the inside of the tubes
could be removed by pumping the apparatus full of water
and leaving it over night after a few barrels had been pumped
through. The apparatus should be flushed out at least once
in twenty-four hours, for the deposit of cream of tartar, be
it ever so slight, interferes greatly with the conduction of
heat, and anything that has this effect must be carefully
avoided. Even the surface of the tubes should be polished
once a day with ashes or lye, for there forms on the surface
after a day's use a li greasy" film, due to the lubricant neces-
sarily used in the blower, which not only interferes with the
conduction of heat, but causes the water to run in streaks
over the surface instead of spreading over it, much cooling
surface being thus lost.
The seeds and skins should be kept out as well as possible
from the pump and consequently from the apparatus. By
exercising due precaution in this regard, we did not have to
clean the apparatus from this cause once during the entire
trial.
Control of Temperature. — We found, as did Mtintz and
Rousseaux, that when the wine passed 100 degrees F. cooling
was useless, for the ferments or yeasts were too badly
injured to be revived. Thus a tank at Natoma (where the
conditions were unfavorable on account of hot weather) was
fermented with some Algerian yeast, and was allowed to go as
high as 104 degrees F. The tank "stuck" before fermen-
tation was finished, and it could not be revived by cooling.
Miintz and Rousseaux state that if a tank is cooled before
the temperature reaches the danger limit there need be no
fear that a subsequent rise to this limit will take place. We
found at Mr. Wehuer's that under the conditions existing,
when the temperature in the tank reached 88 degrees F., if we
pumped about one-half or two-thirds of the contents of the
tank through the cooler, nothing disastrous ever happened,
although the fermentation kept right on and the rise in
temperature continued, yet it seemed that a sufficient amount
of heat (calories) had been removed from the fermenting
mass to enable it to complete fermentation without reaching
the danger point. This favorable result, however, must
largely depend upon special conditions, and should not be
relied upon so as to relax vigilance.
APPENDIX. 253
Considermg the fact that low temperature fermentation
gives a wine of a different composition from that fermented
at high temperature, and leaving for a moment the killing
of the yeast out of the question, it is evident that it would
pay to keep the temperature constantly below the danger
limit on account of the superior quality of the resulting
wine.
It might not pay in ordinary cases to go to this expense
for quality alone, yet if extra fine wine is to be made, extra
care must be bestowed upon it.
Aeration of the Wine. — It was deemed advisable to aerate
the wine whenever it was pumped over. In order to accom-
plish this, and at tlir same time to prevent the cooled wine
from forming a channel in the cap and passing at once to
the bottom and thus leaving the warmer wine at the top, we
caused the wine to escape from the end of the hose in a
fan-like jet, the direction of which was, from time to time, so
changed as to reach all parts of the cap during the cooling.
In this way the cap was very greatly cooled, which is
important, as it is the hottest part of the fermenting mass
in a tank.
In all cases where the cooling took place at or about
88 degrees F., the tank " went dry " perfectly well, and the
resulting wine was drier and far clearer than in case of the
wine not cooled and aerated. This was especially noticeable
in cases where pure cultures of yeast were used, especially
some of the foreign varieties.
In some cases we tried the use of an extra empty tank
into which the cooled wine from the first tank pumped was
put, and the cooled wine from subsequent tanks was pumped
into the first tank. At the end of a certain time the wine
first cooled was pumped into the last tank. In this way one
avoids cooling the same wine or part of it twice, but an
extra pumping is thus necessitated. The avoidance of cooling
wine that has just been cooled and pumped back to the top
of the tank is certainly an important problem, that must be
solved by each wine-maker according to circumstances. We
would suggest that a storage tank, at a greater elevation
than the fermenting tank, be used as a common receptacle
lor all cooled wine. As soon as a sufficient amount
of wine in any given tank has been cooled, it can bo
returned by gravity, and thus all danger of wasting energy
by pumping the same wine twice through the cooler can
R 2
254 WINE-MAKING IN HOT CLIMATES.
be avoided. It is true that there will be an extra amount
of labour required to force the cooled wine to a greater
level than that of the fermenting tank.
Faults of the Apparatus. — It was found that with our
first apparatus we had made the mistake of placing the tubes
too far apart (2-£ inches), losing thereby a very considerable
amount of air and spray. This we had to remedy for the
time by filling up the space with 2-in. slats ; but this, of
course, caused a great waste of cooling effect. AVe,. there-
fore, in our modified apparatus, recommend that the tubes
be placed 1 inch apart, which is the practical limit for the
successful soldering of the tubes into the castings, more
especially when the tubes are of such greater width as we
now find desirable. The horizontal position, moreover, will
always prove a source of waste, on account of allowing too
ready a passage for the current of air and spray. It was
also found that for large scale operations the cooling capacity
of the apparatus was not adequate.
THE NEW APPARATUS.
In the construction of the new apparatus the need of
greater capacity was first considered. The lengthening of
the tubes, as in the French model, renders it very cumbersome ;
and it, therefore, seemed preferable to retain the same length
of tubes, but to give them an increased cooling surface by
enlarging their dimensions to 5£ inches x 1 J inches, and to use
two batteries or columns placed one behind the other. This
arrangement would serve in any case to utilize better the
cooling current, which must always waste through a single
system of tubes, however placed. Moreover, the increased
cooling surface obtained by widening the tubes does not
involve an increase of friction, as would a lengthening ' of
tubes, to attain the same purpose.
Another modification deemed wise is to have the extremi-
ties of the tubes closed by a single bronze casting instead of
separate castings for each pair of tubes. These castings
are fastened by thumb-screws over rubber washers, as in
the case of the first machine. The advantages are that it
not only requires fewer thumb-screws (and hence allows
greater rapidity in cleaning), but also that the solidity of
the whole apparatus is greatly enhanced, and the necessity
for an extra frame is done away with. We found that with
APPENDIX.
255
the great number of small castings it was difficult to keep
any frame from " giving " a little. (See Fig. 3.)
1 V
I
Relative Position of the Sets of Tubes. — In order to
determine as nearly as possible the various conditions need-
ful to secure the best results, two sets of tubes of twelve
nidi were placed in a convenient frame, and so suspended
256 WINE-MAKING IN HOT CLIMATES.
on chains that both their distance and their relative positions
could be readily changed at will. While this would not
enable us to determine exactly all the best conditions in the
completed arrangement, it would at least enable us to avoid
such mistakes as rendered the first apparatus to some
extent unsatisfactory.
It soon became apparent that so long as the tubes in the
two sets were placed parallel to each other, whether
horizontally, or inclined upwards or downwards, even when
arranged as closely as practically possible, and so as to
break joint, there was a great waste of spray, and therefore
of cooling power, in the rear or the second column. The
obvious remedy was to place them at an angle to each other,
so that the current could be considerably checked and its
direction completely changed before being allowed to emerge
at the rear end of the apparatus. It remained to be deter-
mined whether the relative inclinations should be in the
form of a V or of an A, and what the angle of the inclina-
tion should be. It was evidently not desirable to make this
angle steeper than necessary to accomplish the purpose.
Points observed. — In making the experiments the points
observed were : First, the absence of any considerable waste
of spray beyond the second column ; second, the approxi-
mate equality of the drip of water from both sets ; third,
the diminution of temperature obtainable with varying
strength of spray and blast. We could thus as nearly as
possible estimate the results likely to be obtained by the
apparatus when completed. In all experiments so far
made the two sets were placed as near together as practi-
cally possible. As to the first point it was found that the
least waste of spray occurred when the tubes were placed
1 inch apart in the inverted V (A) position, and that for
this purpose an angle of 30 degrees was sufficient.
Second, it was further found that under these conditions
the drip from the two sets of tubes was most nearly equalized,
and that their entire surfaces remained well wetted.
As regards the third point, it was found that in the
space between the two sets the temperature was mainly
governed by the strength of the blast and the amount
and kind of spray used. In this respect our preliminary
experiments could give only comparative values, since the
APPENDIX. 257
saturation of the air at Berkeley at the time was between
75 and 80 per cent., and the air temperature varying but
slightly above arid below 60 degrees F.
Air Blast and Spray. — No mechanical power being avail-
able at the time at Berkeley, we had to restrict ourselves in
the use of the blower to such a velocity as could be obtained
by the power of two men, which was between 700 and 750
revolutions per minute, obtaining probably about two-thirds
to three-quarters of the effect of the blower, or about 2,000
or 2,500 cubic feet per minute.
It was quickly noted that, as transmitted through the
pyramidal canvas sleeve directly, the distribution of the
wind over the surface of the tubes was very unequal. In-ini:
very strong at the circumference, and almost null in the
middle, on account of the centrifugal action of the blower.
This inequality was effectually done away with by the inter-
position between the blower and the pyramidal sleeve of a
cylindrical sleeve 3£ feet long.
As regards the spray, a comparison of the reduction of
temperatures obtained with the rather coarse spray here-
tofore employed, with that obtained from a standard cyclone
nozzle yielding very fine spray, showed that the latter W.MS
by far the most efficacious, besides which it permits of a
shortening of the pyramidal portion of the sleeve, on account
of the rapic(ity with which evaporation can take place. To
attain this end, however, it is necessary that the pressure
should be sufficiently high; that is, nearly such as is
obtained with spray pumps — not less. Manifestly the coarse
spray carried with it too much of the original high tem-
perature of the water. It was also found, however, that a
single nozzle of this kind does not yield a sufficiently large
quantity of water, and that, therefore, a combination <>r
battery of such nozzles should be used, varying in number
according to the water pressure and the strength of blast at
command. In our apparatus we have adopted five as pro-
bably sufficient.
It is easy to so arrange the battery of nozzles as to
conform to the flare of the pyramidal sleeve, in order not
to naste the sprat/ upon the canvas on the one hand, nor
to leave part of the space unutilized on the other.
Beneath the apparatus should be placed a shallow ln»\
to catch the drip, which should he drained oil' through a
pipe or trough. A screen may he placed in the rear of
258 WINE-MAKING IN HOT CLIMATES.
the apparatus to catch the spray that has passed through,
and may be of boards, sacks, or any thing that is con-
venient. If the apparatus be placed facing a door or
window, no screen is necessary. The current of air in itself
is not objectionable in a hot winery. The drawback to the
free circulation of the current of air and spray is that the
workmen working immediately in front of it after coining
from some hot part of the cellar are in danger of contracting
colds, or even pneumonia.
Conclusions. — Accepting, then, the fact that in California
the tendency is to ferment at high temperatures, on account
of the initial as well as the air temperatures being higher
than in cooler countries, such as the Medoc, Burgundy, the
Rhine, Champagne, &c., and also the fact that in this State
we use exceptionally large fermenting tanks, and that our
musts are, as a rule, very high in sugar, and, in many cases,
low in acid, the simple question is — Shall we not attempt
to overcome these natural defects of our climate, and con-
trol fermentation, just as wine-makers of other countries do
under similar circumstances, and as the brewers have long
done under all circumstances ?
Competition is now so keen that if we would succeed we
must place on the market a wine that is equal, if not superior
to that of other countries. Under favorable conditions we
produce a wine that is equal to any in the world, but under
unfavorable conditions we make wines that are distinctly
inferior.
It is the custom at all the wineries of the State, in case of
the tank threatening to " sick." to pump the wine from
the bottom over the top, at the same time aerating it by
causing it to fall in a spray. Should the cooling apparatus
be used in connexion with this procedure, there would be
no extra cost beyond the original expense of the apparatus,
which will last indefinitely with proper care.
An apparatus such as we recommend will cost very little
compared with the enormous saving that can be effected in a
single unfavorable season. To provide several for use at a
large winery should not cost over 1,000 dollars, while for a
winery of ordinary size an apparatus capable of reducing
the temperature of the wine a minimum of 10 degrees at the
rate of 1,000 gallons per hour, would cost far less. Messrs.
Miiritz and Rousseaux found that the cost of cooling wine in
France with their cumbersome apparatus was one-thirteenth
APPENDIX. 259
of a cent per gallon. This includes four men at 70 cents
per day for pumping, and the wear and tear, interest on the
original cost of the apparatus, and all possible extra
expenses. It would not cost much over one-twelfth of a
cent per gallon in this country, even if we had to buy a
200-dollar motor (2£ h.p.) in addition to the apparatus
itself. It need not cost any more than this, for the motor
takes care of itself when once started, and any extra horse-
power could be used to advantage in pumping wine from one
tank to another.
In conclusion, we wish to express the sincere thanks of the
University to those who helped us with suggestions, money,
and material.
Messrs. Toulouse and Delorieux, of 622 Commercial-street,
San Francisco, constructed the apparatus according to our
designs, and it is due in no small degree to the extra time
and trouble bestowed by them upon its construction and
modifications that the experiments proved successful.
Mr. D. M. Doub, of 137 First-street, San Francisco, came
forward in the most public-spirited manner, loaning us
several of the u blowers " and " exhaust-fans " needed. But
for such liberality the experiments could not have been
undertaken.
The Pelton Water-wheel Co. also helped us not only with
the loan of machinery, but also by making for us on the
shortest possible notice such alterations as were suddenly
found necessary.
Mr. J. Henshaw Ward provided for our exclusive use at
the Natoma Vineyard 150-00 dollars worth of the best wine
hose, not otherwise obtainable.
Mr. J. H. Wheeler and Mr. J. Rennie, the lessees of the
Natoma Vineyard, allowed us to use part of the vintage and
cellar.
To Mr. Win. Wehner, of Evergreen, we are especially
indebted, not only for the use of the cellar, vintji.iiv.
labourers, &c., but for the hospitality and attention he
bestowed upon us. The kindness and assistance we received
at his hands was exceptional.
Descriptions of the apparatus used abroad are ghvn ,M long-
side of the form we have devised, so that rlic wiiir-mnktT
may choose between them.
All that we desire is that some kind of effort shall be
made to control temperatures, be it the use of ice, water,
260
WINE-MAKING IN HOT CLIMATES.
air, or anything else ; for it is certain that if the tempera-
ture is controlled there will be an improvement of from 10
to 1 00 per cent, in the quality of Californian wine.
The Viticultural Staff of the College of Agriculture will
cheerfully confer and advise with any persons interested in
this subject, and assistance in the construction or working of
coolers of any sort will be given. While we think that our
apparatus is better than any of the rest, all that we desire
is that there be some sort of cooling apparatus used, and
if our efforts contribute to the attainment of this end we
will be satisfied.
APPENDIX.
THE METRIC SYSTEM.
MEASURE.
The Metric System takes for its basis the distance from
the Equator to the Pole, dividing this into ten million parts.
One such part is a metre. The words denoting multiples
of the Metric standards are derived from the Greek, and
those denoting divisions, from the Latin, thus : —
10 metres equal one decametre.
100 „ - „ hectometre.
1,000 „ „ kilometre.
10,000 „ „ myriametre.
iV of a metre equals one decimetre.
T^ „ „ centimetre.
millimetre.
WEIGHT.
The weight of one cubic centimetre of water at 4°C. is the
standard, and is called a gramme.
1 0 grammes equal one decagramme.
100 „ „ hectogramme.
1,000 „ „ kilogramme.
TV „ „ decigramme.
» ,» centigramme.
„ „ milligramme.
FLUID MEASURE.
The volume of a cubic decimetre is the standard, and is
called a litre.
1 00 litres equal one hectolitre.
TV „ „ decilitre.
•rta » » centilitre.
™W » » millilitre.
The hectolitre is the wholesale standard for wine. One
hectolitre of water weighs 1 00 kilos.
262
WINE-MAKING IN HOT CLIMATES.
THE METRIC AND BRITISH SYSTEMS.
METRIC MEASURES.
One metre = 39-37079 inches.
One decimetre = 3'937
One centimetre = 0*3937 „
One millimetre = 0-0394
Millimetres
= Inches.
Centimetres = Inches.
Millimetres.
Inches.
Centimetres.
Inches.
Centimetres.
Inches.
1 =
0-039
1
zz
0-394
10 =
3-94
2 zz
0-079
9
—
0-787
20 zz
7-87
3 =
0-118
3
=
1-181
30 zz
11-81
4 =
0-157
4
=
1-575
40
15-75
5 —
0-197
5
—
1-969 50 =
19-69
6 zz
0-236
6
—
2-362
60 zz
23-62
i —
0-270
7
—
2-756
70 zz
27-56
8 =
0-315
8
—
3-150
80 zz
31-50
9 zz
0-354
9
=
3-543
90 =
35-43
METRES = FEET.
Metres. ft. in. Metres. ft. in.
1 zz 3 3g 10 zz 32 10
2 - 6 6jf 20 zz 65 7
3 zz 9 10 30 zz 98 5
4 = 13 li 40 zz 131 3
5 zz 16 f> 50 zz 164 0
6 zz 19 8 60 zz 197 0
7 zz 22 Hi 70 - 230 0
8 zz 26 3 80 — 262 0
9 zz 29 6i 90 zz 295 0
Metres.
100
200
300
400
500
600
700
800
900
ft.
328
656
984
1,312
1,640
1,968
2,297
2,625
2,953
yds.
109
219
328
437
547
656
766
875
984
APPENDIX.
263
SQUARE METRES = SQUARE FERT = SQUARE YARDS.
Square metres.
Square feet.
Square yards.
•0929
*~*
1
—
—
1
—
10-76
=
1-190
2
—
21-53
—
2-39
3
—
32-29
=
3-59
4
—
43-06
—
4-78
5
~~
53-82
—
5.98
6
—
64-59
—
7-18
7
=
75-35
— .
8-37
8
—
86-11
—
iK);
9
—
96-88
—
10-76
9-29
—
100
—
10-76
10
~
107-64
— .
11-96
20
—
215-29
—
23-92
50
~~
538-21
—
59-80
92-90
—
1,000
—
59-80
100
~
1,076-43
— •
119-60
500
=:
5,382-15
—
598-02
1,000
—
10,764-30
=
1,196-03
Square feet.
Square yards.
Square metres.
9
1
—
•84
10
—
.1
—
•929
18
—
2
—
1-67
27
—
3
—
2-51
36
—
4
—
3-34
45
—
5
—
4-18
54
=
6
=
5-02
63
—
7
—
5-85
' 72
—
8
—
6-69
81
—
9
—
7-52
90
—
10
=
8-36
100
—
10
—
9-29
180
—
20
—
16-72
450
=
50
—
41-80
900
—
100
—
83-61
1,000
—
100
~*~
92-90
4,500
~~
500
—
418-05
9,000
IT
1,000
rz
836-10
264 WINE-MAKING IN HOT CLIMATES.
CUBIC METRES = CUBIC FEET = CUBIC YARDS.
Cubic
Cubic
Cubic-
Cubic
Cubic
Cubic
metres.
feet.
yards.
metres.
feet.
yards.
1 =
35-32
= 1-31
9 =
317-85
—
11-77
2 •—
70-63
zz 2-62
10 =
353-17
—
13-08
3 =
105-95
= 3-92
15 =
529-75
—
19-68
4 zz
141-27
= 5-23
20 =
706-33
—
26-16
5 rz
176-58
= 6-54
50 =
1,765-83
—
65-40
6 zz
211-90
= 7-85
100 =
3,531-66
—
130-80
V zz
247-22
= 9-16
500 =
17,658-29
zz
654-01
8 zz
282-53
= 10-46
1,000 =
35,316-58
—
1,308-02
1 cubic metre of water at 4° C. weighs 1,000 kilos.
1 cubic foot = 0*0283 cubic metre.
1 cubic yard = 0-7645 cubic metre.
COMPARATIVE PRESSURE PER SQUARE CENTIMETRE
AND PER SQUARE INCH.
Grammes per
square centimetre.
Lbs. per
square inch.
Kilos, per Lbs. per
square centimetre. square inch.
50
—
0-71
1
= 14-22
100
—
1-42
jg
= 28-45
200
=
2-84
3
zz 42-67
300
—
4-27 4
zz 56-89
400
—
5-69 5
= 71-11
500
— .
7-11 6
zz 85-34
600
_
8-53 7
- 99-56
700
—
9-96 8
zz 113-78
800
—
11-38 9
- 128-01
900
—
12-80 10
i|
= 142-23
METRIC WEIGHTS.
One decigramme
One gramme
One decagramme
One hectogramme
One kilogramme
1-543 grain.
15-4323 grains.
0-353 oz. avoirdupois.
3-527 ozs. „
2-2046 Ibs.
APPENDIX.
265
OUNCES AVOIRDUPOIS TO GRAMMES.
Ozs.
t =
1 =
2 =
3 =
4 =
5 =
6 =
7 -
Grms.
= 14
28£
57
85
113
142
170
198
Ozs.
8
—
Grins.
227
9
~
255
10
~
283
11
~
312
12
=
340
13
~~
369
14
—
397
15
—
425
16 or lib.
~
454
METRIC FLUID MEASURES.
One hectolitre
One decalitre
One litre
One decilitre
One centilitre
One millilitre
22-01 gallons.
2-201 „
0-22 „ or 1-76 pint.
3oz. 4dr. 10-4min.
2dr. 4-9min.
16'9 minims.
One pint
One quart (2 pints)
One gallon (4 quarts)
One peck (2 gallons)
One bushel (8 gallons)
quarter (4 bushels)
0-5679 litre.
1-1359 .,
4-5435 „
9-0869 „
36-34766 „
2-9078 hectolitres.
266
WINE-MAKING IN HOT CLIMATES.
Conversion of
Thermometer
Scales.
ii
£
it
I
- r
215- ^
-
-
• -
^ [
~
~. y(>
:
-
7^1
1
i
-
I8fr r
1 80
--
f
•
: -
60--
165 5
:
-
:70
_;
ITft- r
-
I
no |
:60-
50= =
4 -Il\ -
: .
-3
-
:
!
-•50
-te-
-
no |
I —
-=E
:
"K>
I
:
^Jff:
-
;
-^0
- ;
80 f
"ia-
j
-
70-
= ^20
-
-
;
Olr-
^~
I
AA~
u 10
~t& =
Dlr =
-
\
j
-_
- ;
•fO =
~-e-
— E
30"g
-
-
20 |
-^ =
'-
:dO
1OE
iff:
;
Salleron's Portable Mustimetre.
INDEX.
GENERAL INDEX.
TRANSLATORS' PREFACE ... ... ... ... i
CHAPTER I.— Fermentation ... ... ... ... ... 3
Alcoholic fermentation ... .. ... ... ... 4
Vinous fermentation ... .. ... ... ... 8
CHAPTER II.— Study of the Grape ... ... ... ... 12
Maturation ... ... ... ... ... ... 12
Formation of sugars in the grape ... ... ... ... 13
Composition of ripe grapes of different cepages in the South of
France ... ... ... ... ... ... 19
Composition of grapes of the principal cepages of the South of
France ... ... ... ... ... ... 26
Aramon cepage ... ... ... ... ... ... 26
Carignan cepage ... ... ... ... ... ... 28
Petit Bouschet cepage ... ... ... ... ... 30
Picquepoul blanc cepage ... ... ... ... ... 32
Matters brought to the vat by 100 kilos of vintage ... ... 34
CHAPTER III. — Vintage ... ... ... ... ... 36
Determination of sugar ... ... ... ... ... 37
Determination of acidity ... ... ... ... ... 39
Mode of operating ... ... ... ... 42
Influence of the time of vintage on the quality of wines ... 45
Improvement of certain vintages ... ... ... ... 53
Deficient acidity ... ... ... ... ... ... 54
CHAPTER IV. — Vinification ... ... ... ... .. 56
Vinification of red wine ... ... ... ... .. 56
Crushers ... ... ... ... .. 56
Stemming ... ... ... ... ... .. 65
Stemmers ... ... ... ... .. .. 66
Advantages of stemming ... ... ... ... .. 68
Vatting... ... ... ... ... ... ... 72
Aeration of the vintage ... ... ... ... ... J72
Contribution to the study of vinous fermentation. — Influence of
temperature (L. Roos and F. Chabert) . ... ... 76
Opinions of various authorities as to the best temperature for
fermentation ... ... ... ... ... ... 78
Methods and apparatus employed ... '.. ... ... 81
Study of fermentations ... ... ... ... ... 84
Influence of temperature on the yield of alcohol ... ... 86
n n n work of different yeasts ... 90
// n a loss of alcohol ... ... 91
n n n total acidity of wine ... 92
Action of temperature on the yeast ... ... ... 92
Influence of the temperature on the quantity of nitrogen ... 93
Influence of the temperature of fermentation on the yield in
alcohol ... ... ... ... ... ... 98
10649. S
268
WINE-MAKING IN HOT CLIMATES.
Page
CHAPTER IV. — Vinification — continued .
Influence of the temperature of vinous fermentation on the
qualities of wine ... ... ... ... ... 103
Influence of the temperature of fermentation on the keeping
quality of wine ... ... ... ... ... ... 106
Refrigeration of musts during fermentation ... ... ... 107
Study of various must refrigerators ... ... ... 115
Method of taking the temperature of a fermenting vat . . . 126
Fermenting house ... .*.. ... ... ... 130
Fermenting vessels ... ... ... 131
Fermentation ... ... ... ... ... ... 133
Pollacci's experiments ... ... . ... 134
Duration of vatting ... ... ... ... ... 145
Various additions to the vat ... ... ... ... 147
Acidification ... ... ... ... ... 147
Plastering ... ... ... ... ... ... 148
Phosphating ... .. ... ... ... 148
Selected yeasts ... ... ... ... ... 149
I)e-vatting (Decuvage) ... ... ... ... ... 151
Exhaustion of the marc ... ... ... ... ... 152
Presses ... ... ... ... ... 152
Intermittent presses ... ... ... .. ... 152
Continuous presses ... ... ... ... ... 156
Exhaustion of marc without presses ... ... 163
CHAPTER ~V .— Vinification of 'White Wine ... ... 169
Vinification of -white varieties ... ... ... 169
Fermentation ... ... ... ... ... 179
Manufacture of white wine from red grapes ... ... 180
New method for the Vinification of white wines ... ... 183
CHAPTER VI.— Utilization of By-products ... ... ... 1 90
Marc ... ... ... ... ... ... 190
Lees and tartar ... ... ... ... ... ..." 197
Determination of the percentage of bitartrate of potash in the
crust or lees , ... ... ... ... ... ... 200
CHAPTER VII. — Care to be given to Wine. — Defects and Disease* 204
Defects and diseases of wine ... ... ... ... 206
Treatment of diseased wines ... ... ... ... 224
Heating ( Pasteurizing ) ... ... ... ... ... 224
Filtering and fining ... ... ... ... ... 226
Precautions to be taken to insure the efficacy of fining . . . 229
APPENDIX.
Extract from " The Vine in Australia," by Dr. A. C. Kelly, 1841.
Chapter on fermentation ... ... ... ... ... 232
The control of the temperature in wine fermentation, by A. P.
Hayne, Director of Viticulture, California, Bulletin No. 117,
University of California, 1897 ... ... ... ... 238
The metric system ... ... ... ... ... ... 261
The metric and British systems ... ... ... ... 262
Conversion of thermometer scales ... ... 266
INDEX.
269
ALPHABETICAL INDEX.
A.
Acetification ...
Acid, sulphurous (used in vinification of white wine)
Acid, sulphurous (use in diseases)
Acid, tartaric (addition of)
Acidification...
Acidimetre ...
Acidity (defect of )
Acidity (determination of)
Acidity (influence of temperature on total acidity of wine)
Advantages of stemming
Aeration of vintage ...
Albumen (fining of wine)
Alcohol (influence of temperature of fermentation on the yield of) ...
Alcohol (influence of temperature on the loss of)
Alcoholic fermentation
Amelioration of vintage
Amertume (disease of)
Analysis of sugar in must
Analysis of acidity in must
Apparatus used for the study of fermentation at constant
temperature
Apparatus used for collecting the alcohol carried away mechanically
during fermentation
Aramon (composition of grapes)
Arrangement of Coste-Floret, for fermentation ...
Arrangement of Ermens, for refrigeration
Arrangement in the laboratory showing the displacement of wine
by water
Auto-regulator for fermentation
Auto-regulator fixed on vat
Automatic registering apparatus for gas liberated during fermenta-
tion, of Houdaille
Blood, its use in fining
Bouquet of wines, its origin
Break jet, for spraying must
By-products, utilization of
B.
C.
Cambon's apparatus ...
Care to be given to wine
Carignan (composition of grape)
Casse (disease of)
Climagene chimney
Climagene chimney. Dessoliers (arrangement of cellular bricks)
Clarifying of wines
Colour of wine (yellow colour) ...
Colouring matter of grapes
Page
212
170
230
54
147
40
53
39
92
68
72
228
86
92
4
53
215
37
39
81
91
26
137
108
164
142
143
83
227
23
139
190
141
204
28
218
112
112
•_>•_>»;
207
22
270
WINE-MAKING IN HOT CLIMATES.
Page
Composition of must ... ... ... ... ... ... 20
Composition of ripe grapes of principal ctpacjes .. ... ... 34
Composition of principal cepayes ... ... ... ... 26
Composition of experimental wines (stemming) ... ... ... 70
Composition of medium-sized canes (table) ... ... ... 16
Composition of medium-sized canes (diagram) ... ... ... 17
Composition of stalks ... ... ... ... ... ... 19
Composition of seeds ... ... ... ... ... ... 24
Continuous press ... ... ... ... .. ... 156
Contribution to the study of vinous fermentations ... ... 76
Contribution to the study of vinous fermentations (conclusions) .. 98
Correction of the saccharine strength of must ... ... ... 54
Crushers ... ... ... ... ... ... ... 56
Crusher (side view of Blaquieres) .... ... ... ... 59
Crusher (top view of Blaquieres) ... ... ... ... 60
Crusher (front view of Blaquieres) ... ... ... 59
Crusher (arrangement of cylinder on vat) ... ... ... 57
Crusher, drainer, and stemmer (side view of Blaquieres) ... 67
Crushing ... ... ... ... ... ... ... 56
Debourbage ...
Defects and diseases of vines ...
Determination of the strength of crude tartar in lees
De-vatting
Diplococcus aceti
Disease of acetification (vinegar)
Disease of amertume (bitter)
Disease of casse (breakage)
Disease of fleur (flower)
Disease of graisse (fat)
Disease of pousse (pushing)
Disease of tourne (turning)
Diseased wines, treatment of ...
Diseases, treatment used in
Diseases of wines
Drainage of marcs
Drainage of marcs without press
206
200
151
212
212
215
218
211
216
215
213
224
224
206
152
163
K.
Earthy taste . . .
208
F.
Fermentation
Fermentation (alcoholic)
Fermentation (duration of)
Fermentation, experiments of Pollacci . . .
Fermentation (products of alcoholic)
Fermentation (with single submerged head)
Fermentation (with multiple submerged heads)
Fermentation (arrangement of Coste-Floret)
Fermentation, mannitic
Fermentation, vinous ...
Fermentations (contributions to the study of vinous)
133
4
145
134
6
136
136
137
216
8
76
INDEX. 271
Page
Fermentation (opinions of different authors as to the best tempera-
ture of vinous) ... ... ... ... ... ... 7^
Fermenting vats ... ... ... ... ... 131
Filling of casks ... ... '... ... ... ... 204
Filtering ... ... . . ... ... ... ... •_'•_><;
Fleur (disease of) ... ... ... ... ... ... 211
Formation of sugar in grapes ... ... ... ... ... Hi
G.
Gelatine, its use in the fining of wine ... ... ... ... 228
Glucometre, Guyot ... ... ... ... ... ... 37
Graisse (disease of) ... ... ... ... ... ... 216
I.
Influence of temperature of fermentation on the total acidity of wine 92
Influence of temperature of fermentation on the loss of alcohol ... 91
Influence of temperature of fermentation on the yield of alcohol ... 98
Influence of temperature of fermentation on the quantity of nitrogen
iu wine ... ... ... ... ... ... ... 93
Influence of temperature of fermentation on the quality of wine ... 103
Influence of temperature of fermentation on the composition of wine ' 86
Influence of temperature on the action of yeasts ... ... 92
Intermittent presses ... ... ... ... ... ... 152
L.
Leaden-coloured wine ... ... ... ... ... 207
Lees, of wine ... ... ... ... ... ... 197
M.
Marc, utilization of ... ... ... ... ... ... 190
Manufacture of white wines ... .- ... ... ... 169
Manufacture of white wine, new process for ... ... ... 183
Manufacture of white wine from red grapes ... ... ... 180
Manufacture of red wine ... ... ... ... ... 56
Matters brought to the vat by 100 kilos of vintage ... ... 34
Matters, colouring of grapes ... .. ... ... ... 22
Milk, its use in fining ... .. ... ... ... 227
Must, its composition .. ... ... ... ... ... 20
Mustard powder, use of ... ... ... ... ... 210
Mustimetre, Salleron ... ... ... ... ... ... 38
Mutage ... ... ... ... ... ... ... 171
Muteuses ... ... ... ... ... ... ... 171
Muteuse, Coste-Floret ... ... ... ... ... 171
Muteuse, P. Paul ... ... ... ... 172
Muteuse, du Bosquet ... ... ... ... ... 173
Muteuse, Thomas and Roos ... ... ... ... ... 17-">
Muteuse, Thomas and Roos, arrangement for the bung hole ... 17»>
Mycoderma aceti ... ... ... ... ... ... -1'J
Mycoderma vini ... ... ... ... ... ... 211
0.
Opinion of different authors on the best temperatures of fermenta-
tion
Origin of the perfume of wine ... ... 23
Olive oil, its use in diseases of wine ... .. ... 210
272
WINE-MAKING IN HOT CLIMATES.
P.
Petit-Bouschet, composition of grape ...
Phosphating . . .
Picquepoul, composition of grape
Piquettes
Piquettes, plan of arrangement for
Plastering
Pousse
Precaution to be observed to insure success in fining
Presses, continuous ...
Presses, type of continuous
Presses, intermittent
Presses, type of ordinary
Press, with spring load
Pumping the must over the head
Q.
Quality of wines, action of acidity on ... ... ...
Quality of wines, influence of the time of vintage on ...
Quality of wines, influence of the temperature of fermentation on
R.
Racking ... ... ... ... ... ... .
Refrigeration, arrangement of Ermens ... ... ...
Refrigeration of must during fermentation ... ...
Refrigerators for must during fermentation ... ...
Refrigerators for musts, trials of ... ... ...
Refrigerator, Andrieu ... ... ... ...
Refrigerator, Muntz and Rousseau ... ... ...
Refrigerator, Paul ... ... ... ... ...
Refrigerator, Rouviere Hue ... ... ... ...
S.
Saccharomyces apiculatus ... ... ... ...
Saccharomyces cere visse ... ... ... ...
Saccharomyces ellipsoideus .. ... ... ...
Seeds, grape, composition of ... ,.. ... ...
Smell, putrid, in wine ... ... ... ...
Stalks, grape, composition of ... ... ... ...
Stemmers ... ... ... ... ... ...
Stemmer, arrangement on vat ... ... ... ..
Stemming ... ... ... ... ... ...
Stemming, when necessary ... ... ... ...
Stemming, composition of wines experimented on ...
Sulphuring ... ... ... ... ...
Sulphuring with pump ... ... ... ...
Sugar, determination of ... ,.. ... ...
Sulphite, alkaline, uses of ... ... ... ...
T.
Table showing the nitrogen content of wines made at different
temperatures ... ... ... ... ... ... 94
Tables, comparing fermentation at different temperatures ... 95
Tap — Trabut, for aeration of musts ... ... ... ... 140
30
148
32
190
194
148
215
229
152
156
157
152
153
154
138
47
45
103
152
108
107
108
120
124
116
117
122
9
6
9
24
210
21
66
66
65
68
70
230
231
37
170
INDEX.
273
Page
Tartar, crude, determination of ... ... ... ... -_>oo
Temperature of fermenting vat, measurement of ... ... 12<>
Temperature of fermentations, opinions of various authors on the
best ... ... ... ... ... ... ... 78
Thermometer, self -registering ... ... ... ... ... 127
Treatment of diseased wines ... ... ... ... ... 224
Trials of must refrigerators ... ... ... ... .. ll.~>
Tube, acidimetric, Salleron ... ... ... ... ... 40
Turbine, aero-crushing ... ... ... ... ... 61
Type of continuous press ... .. ... ... ... l.">7
Type of intermittent press ... ... ... ... ... l.~i.'{
U.
Utilization of by-products
Utilization of by-products, marc
Utilization of by-products, lees and tartars
190
190
197
V.
Vats, arrangement of fermenting
Vessels used in fermentation ...
Vintage
Vintage, aeration of ...
Vintage, improvement of certain
131
36
72
53
W
Wines, care to be given to
Wines, treatment of diseases of
Wines, leaden colour of
204
224
207
Y.
Yeast, action of temperature on
Yeast, beer ...
Yeast, wine ...
Yeast, composition of
Yeast, influence of temperature on the work of different
Yeasts, selected
Yellow colour of wine
92
6
8
7
90
14!)
207
By Authority: KOBT. S. BRAIN, Government Printer, Melbourne.
PUBLICATIONS RELATING TO VITICULTURE,
BY W. PERCY WILKINSON.
THE ALCOHOLIC STRENGTH OF VICTORIAN WINES EXHIBITED AT THE
MELBOURNE INTERNATIONAL EXHIBITION 1888.— Official record, Mel-
bourne Centennial International Exhibition, pp. 305-317, 8vo.
Melbourne, 1888-9.
THE ALCOHOLIC STRENGTH OF VICTORIAN WINES. — Journal of the Board
of Viticulture, No. 5, pp. 81-96. Melbourne, 1892.
THE SUGAR STRENGTH AND ACIDITY OF VICTORIAN MUSTS, WITH
REFERENCE TO THE ALCOHOLIC STRENGTH OF VICTORIAN WlNES. —
Part 1. Report of the Australasian Association for the Advance-
ment of Science, pp. 306-315. Adelaide, 1893.
Part 2. .Proceedings of the Royal Society of Victoria, pp. 89-118.
Melbourne, 1894.
ACIDITY IN MUSTS. — Editorial Note. — Translated from the Revue de
Viticulture, pp. 239, 240. 1895. The Australian Viqneron, pp.
330, 331. Sydney, 1895.
REFRIGERATION IN WINK-MAKING. — A. Barbier. — Translated from the
Revue de Viticulture, pp. 374-376. 1895. The Australian Vigneron,
p. 379. Sydney, 1896.
WINE-MAKING IN HOT CLIMATES.— U. Gayon. — Translated from the
Revue de Viticulture. January, 1896. The Australian Vigneron,
pp. 386, 387. Sydney, 1896.
A RESUME OF MM. MUNTZ AND ROUSSEAUX'S STUDIES ON THE IMPORT-
ANCE OF REFRIGERATION OF MUSTS IN WINE-MAKING. — Translated
from the Revue de Viticulture. 1896. Extract from The Australian
Vigneron, p. 20. Sydney, 1896.
SALICYLIC ACID IN WINE (LAWS IN EUROPE RELATING TO). — The Aus-
tralian Vigneron, pp. 63, 64. Sydney, 1896.
THE ESTIMATION OF FUSEL OIL IN SPIRITS : OFFICIAL METHOD OF THE
GERMAN GOVERNMENT. — Extract from The Australian Vigneron,
p. 8. Sydney, 1898.
AMERICAN VINES : THEIR ADAPTATION, CULTURE, GRAFTING, AND PRO-
PAGATION.— By P. Viala and L. Ravaz. Translated abridgement of
the second French edition. — By W. Percy Wilkinson and Joseph
Gassies, pp. viii., 88. Melbourne, 1897.
AN EXAMINATION OF THE WINES RETAILED IN VICTORIA. — Australasian
Association for Advancement of Science. Melbourne, 1900.
BY RAYMOND DUBOIS.
THE COMPOSITION OF NATURAL WINES. — A paper read before the Aus-
tralasian Association for Advancement of Science. Melbourne, 1900.
m
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