Full text of "Chemistry And Technology Wines And Liquors"

m Rfi

\\
V

O Af\

/ \

. ,^"

"Xi

"Tiiaf

i 1

ose

--,
s

Aft

too

/
/

<* on

i n

^Tx"

i n

/
/
/2S

^^^

195 [

53.5
D.

[a]

Optical Polarisation. D 386

FIG. i.

coloration with iodine in the solid state, is not readily attacked
by diastase, and is scarcely soluble in water at 120 C. If, how-
ever, it is heated with water under pressure at 150 C. it dis-
solves fairly readily; the solution can be filtered, gives a blue
coloration with iodine and is completely converted into maltose
by malt extract at 56 C. It is probable that the amylose and
amylopectin are not homogeneous (C.R. 1908, 146, 542). Schry-
ver and Thomas (Bio. J., 1923, 77, 497)1 have found that cer-
tain starches contain small amounts of hemicelluloses, and Ling

12 SUGARS AND STARCH

and Nanji (J.C.S. 1923, 725, 2666), state the ratio of amylose
to amylopectin is constant and is equal to 2:1, although their
absolute percentage will vary according to the proportion of
hemicellulose in the starch. For practical purposes, the progress
of the hydrolysis or conversion of starch paste is shown by char-
acteristic chemical and physical changes. The thick paste loses
its colloidal nature and rapidly becomes more limpid, the con-
centration (e.g., osmotic pressure) of the solution increases,
although the dissolved carbohydrates become specifically lighter,
and the solution becomes distinctly sweeter in taste. If tested
with a weak aqueous solution of iodine, the deep sapphire blue
given by the original starch paste changes as the hydrolysis pro-
ceeds, passing into violet, then to a rose red which in turn
changes to a reddish brown which grows steadily lighter, until
just before complete hydrolysis is reached, it disappears alto-
gether. A few drops of the solution poured into strong alcohol
give a copious white precipitate during the early stages of the
conversion; as the hydrolysis continues the amount of the precipi-
tate becomes less until near the end when no precipitate is
produced.

If the conversion products are tested polariscopically, it will
be found that there will be a progressive fall in specific rotation
values from that of starch paste (202) to that of dextrose
(52.7). The Fehling test shows no copper reduction with
starch paste, at the beginning of the hydrolysis, but progressively
increases till the maximum reducing power is reached when all
of the converted products are finally transformed into dextrose.

CHAPTER II
THEORETICAL CONSIDERATIONS. ENZYMES

At the beginning of the preceding chapter the statement was
made that fermentation results from the action of living bodies
on suitable organic compounds. The actual instruments of the
conversion, however, are not living cells but constitute a group of
special chemical compounds which are built up or secreted by the
living cells and which are called enzymes. We know that these
enzymes are not living bodies because the changes which they
produce can be effected in the entire absence of any live cells.
Yeast juice, for example, even when totally free of yeast cells
can cause the fermentation of suitable sugar solutions. The ac-
tivity of the juice diminishes in the course of time, and both in
rate of fermentation and in total fermentation produced; the
extract or juice is much less efficient than an equivalent amount
of living yeast.

Description. As a class, the enzymes are unstable, nitrog-
enous compounds of a colloidal nature and of great chemical
complexity. Only t\vo enzymes, urease and pepsin, have been
isolated in a fairly pure state. The exact chemical composition
of the enzymes is still unknown. They are not necessarily pro-
teins although many of them have certain properties common to
proteins. Their most important characteristic is the ability to
produce chemical changes in other substances without themselves
being changed. This is what chemistflf s call catalytic power. An-
other name for the enzymes as a group is chemical or soluble
ferments.

Specific Action. When enzymes are considered separately
rather than as a class it is found that their individuality manifests
itself in two ways; a combination of one special enzyme with one
special substrate (material to work on) is required for each par-

14 ENZYMES

ticular result. However, it is possible to classify enzymes to
some extent by the type of reaction which they produce, as
follows :

GROUP ACTION

1. Hydroxylases Invertase hydrolyses cane sugar. Amylase

hydrolyses starch.

2. Esterases Hydrolyse esters, including the lipases which

act specifically on fats.

3. Oxidases Produce oxidation.

4. Reductases Produce reduction as e.g. reduce aldehydes to

alcohol.

^5. Carboxylases Split off carbon dioxide from organic acids.

6. Clotting enzymes Thrombase, which clots blood. Rennin, which

clots milks.

It is now customary to name enzymes after the compound on
which they act with the addition of the ending "ase."

There are also known some cases in which enzymes tend to
prevent rather than produce a reaction. In the majority of cases
their action as catalysts is positive. That the action is truly
catalytic is shown by the fact that the rate of reaction is directly
proportional to the concentration of the enzymes, but the total
amount of action is independent of the amount of enzyme,
provided a sufficient time is allowed; and provided also that the
enzyme is not decomposed by other means. As a rule a small
amount of enzyme cannot decompose unlimited amounts of sub-
strate, since most enzymes are relatively unstable. Hence, if only
a small amount of enzyme is used the reaction slackens and
finally ceases, owing to decomposition (autolysis) of the enzyme
before all the substrate has reacted.

Conditions of Functioning. Enzymes are sensitive to high
temperatures, e.g. y when heated to below 100 C. their activity
is completely destroyed. They are, however, resistant to many
antiseptics which destroy protoplasm and kill fermenting organ-
isms. Some germicides, such as formaldehyde, tend to destroy
, enzymes.

1 Preparation. Enzymes are concentrated by precipitation
from their solutions by the addition of alcohol or acetone, or by

SELECTIVITY 15

the addition of salts such as ammonium sulphate; by precipitation
after adjustment of the solution to a definite pH; or by adsorp-
tion by such materials as alumina, silica gel, fullers' earth, etc.
Often combinations of these procedures are used. The resulting
products, however, are often contaminated with other enzymes
and with inactive impurities, all of which makes the study of their
reactions difficult.

Selectivity. The action of enzymes is essentially selective,
in this respect differing from the action of inorganic catalytic
agents. The following tabular representation of the reactions of
the trisaccharide, raffinose, will illustrate this:

SUGAR CATALYST PRODUCTS

Raffinose Acid Dextrose, fructose, galactose

Raffinose Diastase Melibiose, fructose

Raffinose Emulsin Galactose, sucrose

In general, esters, amides, carbohydrates, glucosides, etc. are
all hydrolyzed by hydrochloric acid. Lipases will hydrolyze es-
ters but not carbohydrates. Maltase will hydrolyze maltose but
not sucrose. Even slight differences in the configuration of two
sugars will be sufficient to affect their reactivity with a particular
enzyme.

It will be seen that the activities of the hydrolytic enzymes
are so specific that great care must be exercised to provide those
enzymes which, working on the available materials, will produce
the desired results. While this circumstance is of great theo-
retical importance, it enters into practical consideration rather
rarely. As a rule each naturally occurring saccharide or other
hydrolyzablc substance is accompanied by its own specific hydro-
lytic enzyme so that it can be made available for natural utiliza-
tion. The enzyme does not necessarily exist as such in the tissue,
but may be present as a so-called zymogen, which liberates the
enzyme under suitable conditions, such as a wound to the organ-
ism or the presence of an acid.

Co-enzymes. Very often also there are required the pres-
ence of two factors, the enzyme and the co-enzyme to produce
the fermentation. For example, it has been shown by Harden

1 6 ALCOHOL-PRODUCING ENZYMES

and Young (J.C.S. 1905 Abs. II; iog and ibid. 1906, I; 470)
that yeast juice can be separated by dialysis into two fractions
which when recombined are equal in activity to the original juice,
although neither by itself will cause any fermentation. The
dialyzable fraction, the co-enzyme, is resistant to boiling, but dis-
appears from yeast juice during fermentation, or when the juice
is allowed to undergo autolysis. It is decomposed by acid or
alkaline hydrolyzing agents, by repeated boiling, and by the lipase
of castor beans. The presence of both an enzyme and a co-
enzyme has been found necessary in other fermentations, e.g., in
the action of lipase it has been found that a co-enzyme which is a
salt of a complex taurocholic acid is required.

Alcohol-producing Enzymes. As can be inferred from the
above, the number of types of enzymes required to carry on a
practical fermentation may vary from one to three or more, ac-
cording to the substrate to be fermented.

Zymase, which carries on the final conversion of the mono-
saccharide to alcohol and carbon dioxide in accordance with the
chemical equation:

Dextrose (or fructose, etc.) Alcohol Carbon Dioxide

C 6 H 12 O 6 ^ 2C 2 H 5 OH + aCO 2

is always necessary.

A hydroxylase such as maltase or invertase is usually needed
to convert maltose or sucrose respectively into mono-saccharide
sugar. This conversion follows the formulation

Disaccharide (Sucrose, Water Hexoses (Dextrose,

maltose, etc.) fructose, etc.)

CigH^Oii + H 2 O i CgH^Og + CgH 12 O6

Finally another enzyme may be needed to saccharify, i.e.,
hydrolyze, the starch into maltose. Successful fermentation de-
pends very largely upon the supplying of the required enzymes at
the proper stage in the operation, and in the necessary amount to
produce the desired result. Further consideration of these topics
will be found under the captions of Yeast and Malt.

CHAPTER III

THEORETICAL CONSIDERATIONS. FER-
MENTATION

Alcoholic fermentation is a subject which has attracted the
study of many chemists, even some of the greatest. Many days
of research have been devoted to define completely the reactions
which take place in this chemical transformation, and various
theories have been advanced to explain the steps which occur.
Despite all this work, our knowledge of its mechanism is still in-
complete. We know that fermentation commences with sugars
in the presence of certain other materials, ferments or enzymes;
and we know most of the end products. But we do not know
how these products result, why they result, or what are the inter-
mediate steps in their formation. A completely satisfactory
explanation still has not been found in answer to these questions.

General Requirements. Sugar, water, the presence of a fer-
ment, and a favorable temperature, usually 75 F.-85 F. and
never over 90 F. are inescapable requirements. There are other
limiting factors. The ferments or enzymes are known to be
chemical compounds. They have not been analyzed completely,
however, nor synthesized, and we are dependent for their pro-
duction upon living plants, the yeasts. The reactions follow the
law of Mass Action to the extent that as the concentration of the
alcoEol approaches 14-16% the reaction slows down and finally
stops. The law of Mass Action states that in a reversible reac-
tion the final state reached depends on the relation between the
concentrations of the initial and end materials. However, at-
tempts to reverse the process of fermentation have been successful
only in the minutest degree.

Oxygen does not appear to enter into the fermentation
reaction, but the presence of air and particularly aeration of the
fermenting liquor, the substrate, do have a noticeable influence.

1 8 FERMENTATION

Essential Nature. Whatever the starting point, in all cases
the desired result is the presence of all of the sugars in a form
suitable for conversion into alcohol. As previously stated, this
process is called alcoholic fermentation. This change was be-
lieved by Lavoisier (1789) to follow the formulation:

C 6 H 12 O 6 = 2C 2 H 5 OH + 2C0 2

Hexose Ethyl Alcohol Carbon Dioxide

It was shown by Pasteur (1857) ^at this formulation actually
accounts only for about 95% of the sugar consumed. Glycerin,
organic acids and traces of other by-products account for the
balance. This figure of 95%, however, does represent the yield
of alcohol which is obtainable under favorable conditions and
represents also the upper limit of the result of good commercial
practice in the production of alcohol, either potable or industrial.

Since their time, the combined labors of many students have,
on the one hand, added somewhat to our knowledge of the
mechanism of fermentation; and on the other hand, have de-
fined some of the by-products as well as some of the minor
prerequisites to success.

Products. Pasteur found that the actual yield from the fer-
mentation of 100 pounds of sugar was as follows:

Alcohol .............................. 48.55 Ib.

Carbon Dioxide ....................... 46.74 Ib.

Glycerol ............................. 3.23 Ib.

Organic Acids ........................ 0.62 Ib.

Miscellaneous ......................... 1.23 Ib.

100.37 H>-

The fact that the total weight of fermentation products ex-
ceeds slightly the weight of sugar fermented is explained by the
absorption and fixation of small amounts of water to make cer-
tain of the by-products. According to Pasteur some sugar is
also utilized by the yeasts in building new yeast cells.

In general, the chief products of vinous fermentation may be
stated to be: alcohol and carbon dioxide (accounting for 94-95%
of the sugar), glycerol 2.5-3.6%, acids 0.4-0.7%, and, in addition,

CONTROLLING FACTORS 19

an appreciable quantity of fusel oil (higher alcohols), some
acetaldehyde and other aldehydes and some esters. Among the
minor products of fermentation maybe listed the following which
have been identified:

Formic Acid
Acetic Acid
Propionic Acid
Butyric Acid
Lactic Acid
Ethyl Butyrate
Ethyl Acetate
Ethyl Caproate, etc.

Rate of Fermentation. The ratio of carbon dioxide to al-
cohol produced and the ratio of yeast formed to alcohol produced
both vary at different stages of the fermentation. They depend
both on the age of the yeast and on the age of the fermentation.
Slator, J.C.S. (1906), 89; 128, and ibid. (1908), 93; 217 has
shown that the rate of conversion of dextrose into alcohol and
carbon dioxide by yeast is exactly proportional to the amount of
yeast present and, with the exception of very dilute solutions, is
almost independent of the concentration of sugar. Slator and
Sand, Trans. Ch. Soc. (1910) 97; 922-927 have further de-
veloped and explained this fact by showing that the diffusion of
sugar into the yeast cell is so rapid even in dilute solutions that
more sugar is present in the cell than can be fermented at any
instant. Various yeasts will ferment levulose (fructose) at the
same rate as that at which dextrose is fermented. Similarly,
maltase-containing-yeasts will ferment maltose solutions at the
same rate as if dextrose were being fermented.

Controlling Factors. The factors which really govern the
rate of fermentation, then, are two: the concentration of yeast
and the temperature. The latter is of the greatest importance.
Taking as a unit the amount of fermentation produced at 32 F.,
six times as much will result in the same time at 77 F., and
twelve times as much at 95 F. However, the rates of forma-
tion of undesired by-products and of autolysis of the yeast also
increase objectionably as the temperature is raised, hence it is

20 FERMENTATION

usual to set an upper limit of 90 F. on the fermentation. Since
heat is evolved during the process, this requires that the rate
must be so controlled that either natural radiation or artificial
cooling will keep the temperature within the desired limits.

Inorganic Requirements. Various inorganic constituents
must also be present in the fermenting liquor. Some of these,
phosphates in particular, play a part in the mechanism of fer-
mentation. Others are necessary to provide food for the yeast,
nitrogen compounds, calcium, potassium and manganese, etc. In
addition there is a still incompletely defined compound called
"bios" which appears to be essential to success. Most of these
are present in sufficient amounts in the raw materials of the fer-
mentation industry although it is probable that close study of their
occurrence might be rewarded by increased yields and/or im-
proved products.

Mechanism. The role of phosphates especially is of interest
since it shows that the fermentation proceeds by steps instead of
immediately in the sense of the equation

C 6 H 12 O 6 z^2C 2 H 5 OH 4- 2CO 2

Harden and Young, J. Ch. Soc. (1908) Abs. i, 590 were the first
to show that the addition of phosphates (disodium phosphate) to
a mixture of yeast juice and dextrose resulted in both an initial
acceleration and in an increased total fermentation. They also
showed that there was an optimum concentration of phosphate,
deviations from which in either direction resulted in a diminished
rate of fermentation. It is assumed that a hexose-di-phosphate
is formed as follows:

C 6 H 12 O 6 + 2Na 2 HPO 4 -> C 6 H 10 O 4 (PO 4 Na 2 ) 2 + aH 2 O

It is this compound which breaks down into alcohol and carbon
dioxide and regenerates the sodium phosphate. The latter can
then again combine repeatedly with the sugar, sensitizing it to
the breaking down action of the enzyme until the fermentation
is complete. It has been shown by careful experiments that dur-
ing the period of increased fermentation the amounts of alcohol
and carbon dioxide produced are stachimetrically related to the

MECHANISM 21

quantity of added phosphate in the ratio C 2 H 5 OH : Na 2 HPO 4 .
Since the filtered enzyme plus phosphate will not of themselves
induce fermentation, it follows that phosphate is not the co-
enzyme. On the other hand, in the entire absence of phosphate
no fermentation occurs even though both enzyme and co-enzyme
are present. Arsenites and arsenates cause some acceleration of
the fermentation, but they cannot be used in place of phosphates.
They appear rather to act as accelerators in the decomposition of
the dextrose phosphate.

It has been found by further investigation that there is ap-
parently another step in the fermentation reaction in which the
dextrose di-phosphate splits into two moles of triose mono-phos-
phate. It should be particularly noted that the immediately
preceding study of the mechanism of the action of yeast juice is
not directly applicable to the action of yeast. E.g. } Slator (loc.
cit.) found that phosphates are without accelerating effect when
living yeast cells are employed.

Many other suggestions have been made regarding the inter-
mediate steps in the conversion of dextrose into alcohol and
carbon-dioxide and the nature of the intermediate products.
Biichner and Meisenheimer, B. (1905), 38; 620, suggested that
lactic acid is the first product of the action of zymase on dextrose
since it is known that this acid is formed in muscle tissue by the
oxidation of glycogen, which is a polydextrose. They added to
this theory the assumption of a second enzyme, lactacidase, which
carries on the decomposition of the lactic acid into ethyl alcohol
and carbon dioxide; cf. Bio. Z. (1922), 128 ; 144 and 132 ; 165.
This suggestion was based on the observation that a concentrated
solution of dextrose when treated with alkali yields about 3%
of alcohol on exposure to sunlight. Under similar conditions a
more dilute solution gives a 50% yield of lactic acid.

Another suggestion is that dihydroxy-acetone, CO(CH2OH) 2
is the first result of the splitting of the hexose molecule. It has
been shown by Biichner and Meisenheimer, B. 43; 1773 and by
Lebedew, B., 44; 2932. Cf. also Franzen and Steppuhn, ibid.,
2915 that dihydroxy-acetone is fermentable by yeast. It has also
been shown that dihydroxy-acetone and glyceraldehyde can, under

22 FERMENTATION

suitable conditions be condensed to form a hexose so that there
is every probability that the reaction is reversible. Again, the
suggestion has been made that glyceraldehyde, C(HO)'
C(HOH) C(H2OH), by the loss of water yields an enolic
compound CH : C(OH) CHO called methyl-glyoxal ; which, by
the addition of water can yield either lactic acid or even ethyl
alcohol and water. On the other hand, the above mechanisms,
although plausible, appear improbable as important parts of the
fermentation reaction since it has also been shown that glycer-
aldehyde is only slowly fermented while methyl-glyoxal and lactic
acid are unacted upon by yeast juice or yeast.

Neuberg, Deut. Zuckerind. (1920) 45, 492, has shown that
yeast contains an enzyme, carboxylase, which is capable of elimi-
nating carbon dioxide from a-ketonic acids, and therefore suggests
that pyruvic acid CH 3 CO COOH represents the initial splitting
product of fermenting hexose. The reaction, then, proceeds with
the decomposition of the pyruvic acid into acetaldehyde and car-
bon dioxide, and the aldehyde is reduced by the yeast to ethyl alco-
hol. In support of this theory it has been shown that the addition
of pyruvic acid to a fermenting liquor increases the yield of alco-
hol. The presence of glycerol, which may function merely as a
yeast preservative, is required. It is also known that there is pres-
ent in yeast an enzyme which is capable of reducing aldehyde.
However, the conversion of the hexose into pyruvic acid is diffi-
cult to formulate logically.

Neuberg and Arinstein, Bio. Z. (1921), 117; 269 and 122;

suggest the following steps for the fermentation:

1 i ) Dextrose ^ Water + Methyl-Glyoxal-Aldol

C 6 H 12 O 6 ^ aH 2 O + CH 3 CO CH(OH) CH 2 CO - CHO
This keto form changes to the enol-form

CH 2 : C(OH)- CH(OH) CH 2 CO CHO

(2) Methyl-Glyoxal-Aldol ( keto form ) + Water ^

Glycerol 4- Pyruvic Acid

CH 2 :C(OH)-CH(OH) CH 2 CO-CHO + aHO^

CH 2 (OH) CH(OH) CH 2 (OH) + CH 3 CO COOH

BY-PRODUCTS 23

Part of the pyruvic acid is converted by the action of carboxylase and
reductase into alcohol and carbon dioxide.

(3) Methyl Glyoxal + Acetaldehyde + Water ^

Alcohol + Pyruvic Acid

CH 3 CO CH : O + CH 3 CHO + HoO ^

CH 3 CH 2 (OH) + CH 3 CO COOH

In support of this exposition Neuberg cites the three different
courses taken by the fermentation according to conditions :

(a) Normal in fairly acid media with over 90% yields

C 6 H 12 O 6 - 2C 2 H 5 OH -f 2CO 2

(b) In the presence of sulphites (to fix aldehyde)

C 6 H 12 6 - C 3 H 5 (OH) 3 + CH 3 CHO + CO 2

bonate)

2C 6 H 12 6 +H 2 - 2C 3 H 5 (OH) 3

-f 2CO 2 + C 2 H 5 OH + CH 3 CO 2 H

In reply to the objection that acetaldehyde and pyruvic acid are
not so readily fermentable as dextrose, Neuberg suggests that the
reaction takes place with one of their tautomeric (enolic) forms.

By-products. Glycerol. The preceding formulations of the
fermentation reaction indicate readily the production of glycerol.
Biichner and Meisenheimer have shown that it is formed in sugar
solutions even by the action of yeast juice without the require-
ment of living yeast cells. It is known also that by the addition
of sodium carbonate or sulphite and by selection of the most
suitable yeasts a yield of 25% or more of glycerol on the weight
of sugar fermented can be obtained.

Fusel Oil and Succinic Add, etc. It has been shown that this
group of by-products derives not from the sugar but from other
materials present in the fermenting liquor. F. Ehrlich in many
researches (1904-1910) has shown that the higher alcohols and
aldehydes, which when mixed we call fusel oil, are formed by the
deammination of amino acids resulting from the hydrolysis of
proteins. Thus isoamyl alcohol, which is the chief constituent of
fusel oil, is closely related to leucine, amino-isohexoic acid, and
active amyl alcohol is similarly related to isoleucine, a~amino-/3-

24 FERMENTATION

methyl-valeric acid. Both of these acids are formed in the
hydrolysis of proteins and both, according to Ehrlich, are trans-
formed into the corresponding amyl alcohols in the presence of
sugar by the action of pure yeast cultures. The gross reaction is
formulated as follows:

(CH 3 ) 2 CH CH 2 - CH(NH 2 )- COOH + H 2 O

(CH 3 ) 2 CH CH 2 CH 2 (OH) + CO 2 + NH 3

In a similar manner the other amino acids react; tyrosine, /?-p-
hydroxy-phenyl-a-amino-butyric acid yielding p-hydroxy-phenyl-
ethyl alcohol, tyrosol; while phenyl-alanine, a-amino-/?-phenyl-
propionic acid, yields phenyl-ethyl alcohol. Succinic acid, for ex-
ample, which is of usual occurrence in fermented liquors is
probably formed by a similar reaction from glutamic acid with the
additional step of oxidation in the process.

These changes take place only by the action of yeast but not
by the action of yeast juice. This fact points to the importance
of these reactions in the life process of the yeast cell. A similar
conclusion results from the fact that no free ammonia is found
at the end of the reaction, all of it having been consumed in the
building up of new yeast cells. This conclusion is further
strengthened by the fact, also shown by Ehrlich, that if appre-
ciable amounts of simple nitrogenous bodies, such as ammonium
salts, are present in the fermenting liquor these will be used by the
organisms in preference to decomposing the amino-acids. Ehrlich
has found it possible to increase or diminish the amounts of
fusel oil formed by diminishing or increasing the amounts of
ammonium salt added to the wort; and also to increase the yield
of fusel oil by adding larger amounts of amino-acids to the fer-
menting mixture. Practically all amino-acids formed in the
hydrolysis of proteins can be similarly decomposed by yeast cells
provided that sugar is present. As previously stated enormous
amounts of research have been devoted to the mechanism of the
fermentation reaction. Despite this, the complete definition of
the reaction has not been arrived at. The point of interest here
is that there are a large number of factors involved, many of
them known and controllable and necessary to success.

CHAPTER IV

THEORETICAL CONSIDERATIONS. RAW
MATERIALS

General Classification. The preceding chapters have been
devoted to a brief discussion of the chemical background which
is common to all of the fermentation industry. The various raw
materials which, by the application of the principles developed,
are converted into alcohol-containing beverages will be discussed
in the present chapter. The diversity of these raw materials is
very great, since anything which contains sugar or may be treated
to yield sugar, will serve and probably has been applied, to pro-
duce intoxicating liquor. It is possible to classify these materials,
therefore, in two ways. However any classification may err at
times as industrial demands change. The classification may be :

I. According to their function as sugar suppliers or auxiliaries.
II. According to the products into which they enter.

On the first basis we find three groups:

A. Materials which supply preformed sugar for fermentation.

Fruit and fruit juices

Molasses

Honey

Sugar, etc.

B. Starch-containing materials yielding fermentable sugar on treatment.

Cereal grains
Potatoes, etc.

C. Auxiliary materials which contribute neither sugar nor starch.

Spices and other Flavoring matters
Coloring Agents
Blending Agents, etc.

This classification is based on applicability or composition.
On the basis of use the same materials may be reclassified:

26 RAW MATERIALS

A. Materials for the production of distilled spirits.

Cereal grains

Potatoes

Molasses

Flavoring and Coloring Agents, etc.

B. Materials for the production of wines.

Fruit juices and fruits
Sugar, etc.

C. Materials for the production of liqueurs and cordials.

Alcohol

Sugar

Spices and Essential Oils

Coloring Agents, etc.

Distilled Spirits. The materials used for the production of
distilled spirits are further classified according to the types of
product in which they find employment:

American Whiskies
Rye

Barley

Rye
Bourbon

Barley

Corn

Wheat

Scotch Whiskies
Pot Still Type

Barley
Patent Still Type

Barley

Rye

Corn

Oats

Irish Whiskies
Pot Still Type
Barley
Rye
Oats
Wheat

DISTILLED SPIRITS 27

Patent Still Type
Barley
Rye
Corn
Oats

Gin (Distilled)
Barley
Rye
Corn

Kornbranntwein

Barley

Rye

Corn

Wheat
Vodka

Barley

Rye

Corn (In cheaper grades)
Rum

Molasses

Cane Juice

Schnapps

Potatoes
Brandy

Grape juice and marc.

Other fruits (Apples, prunes, cherries, etc.)

Since the entire spirit industry is designed to produce palatable
products, the tabulation given above is not necessarily binding.
Some of the materials listed are very seldom used. Practice may
differ from plant to plant producing the same product or may be
influenced from year to year by changed crop and economic con-
ditions. Owing to the great variety of distilled liquors in flavor
and general character, and the influence on these of both the
materials used and the processes by which they are treated, it
is impossible to be completely general. However, it may be stated
that the important cereal grains to the liquor industry are in
order: barley, rye, corn, oats, and wheat. A short discussion
of these grains including both their botanical and chemical char-
acteristics follows:

RAW MATERIALS

Cereal Grains. Barley. Barley takes the first place in im-
portance in the spirit industry on account of its high production
of the enzyme, diastase, when permitted to sprout (malt). There
are several types of barley which are largely used. These include :

1 i ) a. Hordeum distichum, a two-row type which includes the well-

known varieties Chevalier, Hallett, Hanna.

b. Hordeum zeocritum, two-row fan-shaped barleys of which
Goldthorpe is the leading variety.

(2) Hordeum vulgare, the ordinary six-row barley, such as Manchu-
rian, Oderbrucker, Scotch, etc.

(3) Hordeum hexastichum, which likewise have their flowers on a
spikelet fertile, but on account of the fact that the ears are wide,
the appearance of the head is a hexagon when examined from the
top. These are really six-row barleys. An example of these is
the white barley of Utah and adjoining States.

The average composition of barleys of these three types, to-
gether with data as to weight, are given in the following
tabulation :

TABLE I. AVERAGE PERCENTAGE COMPOSITION OF THREE TYPES OF
MALTING BARLEYS (LE CLERC) *

Type of barley

Mois-
ture,

Water-free basis

Wt.

per
bushel,
pounds

Wt.

per
1,000
grains,
grams

Ash,

Pro-
tein,

Fat,

Fiber,

Pento-
sans,

Starch

Two-row

8. 9

8. 7

2 . Q
3-0
2. 9

ii. 6
11.9

IO.O

2.0
2.0
2.0

5-*
5.8

8-4
9.6
9.0

59.1
58.9
59-9

5*
47
48

38
27
38

Ordinary six-row

Hexastichum

i U. S. Dept. Agr., Bureau of Chemistry. Bull. 124, Le Clerc and Wahl, Chemical studies of
American barleys and malts.

The two-row barleys are chiefly grown in Europe, although
they are raised in this country in Montana, Idaho, New York,
etc., to a limited extent. On account of their relatively high car-
bohydrate content and low protein, they are particularly adapted
to use in the brewery.

CEREAL GRAINS 29

In this country, the ordinary six-row barley is the kind most
abundantly produced, being raised extensively in the States of
the Mississippi Valley. Its relatively high protein content causes
it to produce malt of high diastatic power, and thus fits it espe-
cially to use in the distillery.

A good distiller's barley should be free of dirt and have good
odor and color, small grains of uniform size, a high percentage
of nitrogen, and high germinating capacity. With these charac-
teristics and with proper treatment in the malt house, it is bound
to yield a malt of good character.

Cleanliness is necessary, not only because dirt is not a source
of alcohol, but because it is sure to carry large numbers of bac-
teria and molds, which interfere with the production of a good
malt.

Barley is composed of about 12 per cent husks, 10 per cent
bran, 2.5 per cent embryo, and the rest endosperm or the stored
food for the plantlet. The husks and bran are merely protective.
The germ is the seat of life; it consists of embryonic radicles or
rootlets and the plumula or acrospire. The sprouting of this
germ is essential to the production of malt since this serves to
convert the starch of the endosperm into fermentable sugar. The
endosperm is composed mostly of starch and protein, but both
of these substances are insoluble and non-diffusible and can not
be used directly in supplying food for the young plant. The
agency which renders these soluble and diffusible is an enzyme
or a series of enzymes secreted by the embryo during growth,
one of which, the diastase, dissolves the starch and converts it
into sugar and dextrin, while another, the peptase, acts on the
protein. These enzymes are developed in the growing malt as
the germ's need for food increases. The products of enzyme
action are soluble and diffusible, and can be directly used as food
by the growing embryo.

Barley contains about 65 per cent of fermentable matter;
and at a weight of 48 pounds per bushel one ton should produce
about 98 gallons of alcohol.

Barley, to be considered good, should show a germination
of at least 97 per cent. If below this limit of vitality, it should

30 RAW MATERIALS

be reduced in price, or rejected. Grains which are incapable of
germination are not only useless, but harmful, because they act
as carriers of micro-organisms which may infect the rest of the
grain.

Rye. Rye is, comparatively speaking, a minor crop in the
United States. The only species under cultivation is the common
rye : Secale cereale.

In structure and habits of growth, rye resembles wheat, and,
like wheat, it is grown as both a spring and winter crop. It is
a tall-growing, annual grass with fibrous roots, flat, narrow, bluish-
green leaves, standing erect or decurved and having slender cylin-
drical spikes consisting of two or three-flowered spikelets. The
flowering glumes are long-awned or bearded and lance-shaped,
and are so firmly attached that little chaff results from the thresh-
ing. The individual grains are partly exposed and are longer,
more slender and more pointed than wheat. They are dark,
with a slightly wrinkled surface and are very hard and tough,
requiring more power to mill than any other grain.

The following is an analysis of common rye :

TABLE II

Moisture 1 1 . o%

Ash 2.0%

Protein (N X 6.25) n.6%

Ether extract i . 7%

Crude fiber 2.0%

Pentosans 8.5%

Total sugar 4 . o%

Other carbohydrates 59. 2%

Wt. per 1,000 grains 25.0 grams

Wt. per bushel 56.0 Ibs.

Rye is very largely used in distilleries which produce potable
spirit such as whiskey, gin and vodka, and in the manufacture of
compressed yeast It is also used in relatively small amounts in
the yeast mashes of alcohol distilleries. It is not suited to use as
the chief ingredient of the mash in an alcohol distillery, on ac-
count of the tenacious quality of the mash which it forms. Fur-
thermore, it gives a low yield in proportion to the amount of
starch which it contains. Though it usually contains over 60

CEREAL GRAINS 31

per cent of fermentable matters, it rarely produces over 85 gal-
lons of alcohol to the ton.

Corn. This valuable food stuff is the grain of a gigantic
grass known to botanists as Zea Mays. It originated in America
but subsequently was transplanted to many other countries, prin-
cipally France, Hungary, Italy, Spain, Portugal, South Africa and
Argentine.

There are over three hundred recognizable varieties, some
of which are only a few inches in height, while others are giants
of six feet or more ; some come to maturity in two months, while
others require three or four times as long before their cobs ripen.
There is also great variety in the shape, size, and color of the
actual grain. Some are white as, for example, the Cuzco maize,
others are yellow, red, purple, or even striped, and the varieties
differ among themselves in chemical composition.

The most important maize growing country of the world is
the United States. Many varieties are cultivated, but the chief
may be roughly grouped into four classes. First come the "Flint"
varieties which are most commonly met with east of Lake Erie
and north of Maryland, and the "Dent" varieties which are most
popular west and south of these localities. The "Horsetooth,"
which passes insensibly into the above forms, is grown chiefly in
the South. Lastly, the "Sweet" varieties are extensively cul-
tivated for the green grain. These are boiled and used as
a vegetable and seldom allowed to mature into the ripened
grain.

For the making of whiskey the finest white "Flint Corn" is
preferred. The Kentucky distilleries are extremely careful in
their selection of the raw material. Indian Corn that is grown
along the Ohio and the Kentucky Rivers is especially sought after
by the distillers as being peculiarly suitable. Corn which has been
injured by frost, heat, moisture or mold can readily be used in
the manufacture of industrial alcohol as such damage does not
affect the fermentable content of the grain and it can be bought at
a low price, but it is unsuitable for the liquor industry.

A typical American maize should have the following com-
position :

32 RAW MATERIALS

TABLE III

Weight of 100 kernels 38 grams

Moisture 10.75%

Proteids 10 %

Ether extract 4. 25%

Crude fiber 1 . 75%

Ash 1 . 50%

Carbohydrates other than crude fiber 71 .75%

Dry corn of good quality should yield at least 65% of sugars
and starch and should yield from 98 to 105 gallons of 180
alcohol per ton (shelled).

Oats. Oats is the grain or seed of the cereal grass Avena
sativa. It forms one of the most valuable sources of food for
both man and beast, the nutritive value of the grain being very
high. It is extensively grown in Great Britain, Continental
Europe, Russia and North America.

Practically four-fifths of the oat crop of the United States is
produced in the thirteen states extending from New York and
Pennsylvania westward to North Dakota, South Dakota,
Nebraska and Kansas. Each of these states devotes more than
a million acres to oats. The average yield in the six northern-
most states, New York, Michigan, Wisconsin, Minnesota, North
Dakota and South Dakota is 31.68 bushels per acre while their
total production is slightly less than one-third of the oat crop
of this country. The average yield of the other seven states,
Pennsylvania, Ohio, Indiana, Illinois, Iowa, Nebraska and Kan-
sas is only 29.23 bushels per acre yet they produce more than
half of the entire crop. The difference in yield of nearly two
and one-half bushels to the acre between these two groups of
states is due largely to the fact that the climatic conditions of
the northern group are better suited to the production of the crop.
There is no material difference in soil composition or other fac-
tors affecting the yield.

Oats are grown in the corn belt, which includes all the states
of the second group, largely because a small-grain crop is needed
in the rotation and because the grain is desired for feeding to
work stock. Spring wheat is seldom satisfactory in this district
and winter crops often do not fit well into a rotation which

CEREAL GRAINS 33

ordinarily includes corn, a small grain and grass. Under these
conditions oats are generally grown as the best crop between corn
and grass. This is particularly true in Illinois and Iowa, the
two states producing the greatest quantity of both corn and oats.

There are many factors which reduce the yield of oats in
the corn belt. In general, those varieties of oats which mature
earliest are best adapted to the belt, for early maturing often
enables a crop to escape hot weather, injury from storms, and
attacks of plant diseases. The early varieties also usually pro-
duce less straw and for that reason are less likely to lodge than
the ranker growing late varieties. A number of years ago the
Early Champion and the Fourth Qf July varieties came into
prominence but they are not now extensively grown, for, although
early in maturing, their yield is often unsatisfactory. Burt is a
very early variety much used for spring seeding south of the
Ohio River but little known elsewhere. The type of early oats
now most largely grown in this country is represented by the
Sixty-Day and the Kherson varieties, two comparatively recent
introductions from Europe.

The following is a typical analysis of a variety of oats:

TABLE IV

Moisture 1 1 . 6%

Ash 3.4%

Protein (N X 6.25) 1 1 . 5%

Ether extract 4 . 7%

Crude fiber n.o%

Pentosans 12.0%

Total sugar 1.5%

Other carbohydrates 44.3%

Wt. per 1,000 grains 29.2 grams

Wt. per bushel 32.0 Ibs.

This grain is not too well suited for distillery use because of
the glutinous nature of the mixture which is formed when it is
treated with hot water. It contains about 50 per cent of fer-
mentable substance and might be made to yield about 70 gallons
of alcohol per ton.

Wheat. Wheats have been cultivated by man since before
the dawn of history, and nothing is now known of the original

34 RAW MATERIALS

wild forms from which they are descended. In old legends and
ancient manuscripts wheat is spoken of as familiarly as at the
present day. Nor do we know with any certainly in which coun-
try it was first found; but it seems probable that Central Asia
was the original home of the wild forms from which the culti-
vated species have sprung.

Wheat belongs to the grass family, Pouceas (Germineae),
and to the tribe called Hordeae, in which the I to 8 flowered
spikelets are sessile and alternate on opposite sides of the rachis,
forming a true spike. Wheat is located in the subtribe Triticeae
and in the genus Triticum where the solitary two-to-many flow-
ered spikelets are placed sidewise against the curved channeled
joints of the rachis.

Great diversity is shown by the varieties of wheat grown in
the United States. More than 200 distinct varieties are grown.
Clark ("Classification of American Wheat Varieties" U. S. De-
partment of Agriculture, Dept. Bull. 1074, 1922) divides
American grown wheats into the following groups:

1 i ) Common

(2) Club

(3) Poulard

(4) Durum

(5) Emmer

(6) Spelt

(7) Polish

(8) Einkorn

(9) Unidentified

Within these groups are numerous types of which the follow-
ing more important are arranged in approximate order of pro-
duction and use:

Common

Turkey, Marquis, Fultz, Red Wave, Poole, Fulcaster.

Club

Hybrid (Grown only on Pacific coast)

Durum

In Dakotas and adjoining states

WINE MATERIALS 35

Emmer

Minnesota, Dakotas and adjoining states

Polish

New Mexico and Wyoming
(Not grown much)

Spelt

Not grown to any extent commercially.

The following is an analysis of two typical wheats:

TABLE V

Soft wheat Hard Wheat

Moisture.... = 12.0% 12.0%

Ash 1.9% 1.8%

Protein (N X 6.25) 9.0% 12.4%

Ether extract i.?% *-7%

Crude fiber 2.5% 2.5%

Pentosans 7-% 7-%

Total sugar 2.7% 2.7%

Other carbohydrates 63.2% 59-9%

Wt. per i, ooo grains 38. 7 grams 38.7 grams

Wt. per bushel 60.0 Ibs. 60.0 Ibs.

What has been said regarding the yield of alcohol to be
obtained from rye applies also to wheat and therefore, the latter
has not been much used in distilleries, even at times when it was
relatively cheap.

Wine Materials. The wine industry differs from the spirit
industry, among other things, in that the distinguishing character-
istics of the finished product, wine, are much more closely re-
lated to the individual character of the raw material. Although
almost all wines are made from grapes, the character of a single
batch of wine will depend not only on the variety of grape used,
but even on the special plot of ground on which it was grown and
the climatic conditions in the year of its growth. For this reason
a classification of materials for the wine industry in the same
manner as that given for the spirit industry is not possible. On
the other hand, a means of classification is possible based on the
geographical distribution of the grape varieties which are suc-
cessfully grown for wine production.

RAW MATERIALS

w
S
o

C/3

o
U

\o o o c^

O ^ ^ ^-O co O

o w so 6 t^ 6 o

% T V i -'- -'- T

c2 ~ . "

n O **" O O vr > co

O c< O v/ ^ O vr< > O oo O

x-a cor-O"-""- oooo

& $

tn Q f v ^ooco i ^ooooOcoooO

^ - d-s M co co -

J^J rt
o o

ay t ,., ,^ ^

" " ^^ vo

oovor-o^onoo

bo i

C w

c rt <

WINE MATERIALS 37

Since the United States is geographically so large and offers
for grape culture at one spot or another every feature that can
he found elsewhere, the following tabulation and discussion is
confined to this country. The principles, of course, and possibly
excepting some special niceties, the practice are of universal
application.

The wine industry is somewhat less than 200 years old in
the United States. It has successfully taken root in some of the
Eastern and Middle States and principally in California and
Texas. The first successful cultivation of American wine grape-
vines was carried out in California in 1770 at the San Diego
Mission of the Franciscan Padres. They used a Spanish vine
which had been successfully transplanted in Mexico. The first
real attempt to cultivate the grapevine on a commercial scale in
California was probably around 1861 when the state government
backed Colonel Haraszthy in a trip to the principal grape grow-
ing districts of the world. He visited Europe, Asia Minor,
Persia and Egypt and returned with 200,000 cuttings of vines
which he believed likely to grow in California. A nursery was
established at Sonoma and a study was made of the possibilities
of the transplanted vines. Subsequently, the first State Board
of Viticultural Commission, the United States Department of
Agriculture and University of California, imported other clip-
pings which were also tested. As a result vines were soon dis-
tributed and planted in all suitable localities of the state. Ex-
perienced European grape-growers and wine-makers were then
induced to settle in the state and in course of time the well-known
Californian industry was established successfully. As a result of
this farseeing and well organized undertaking California, today,
is able to imitate the wines of practically any district of the world.

Many attempts were also made in Eastern states to establish
vineyards and to found an Eastern wine industry, procedure be-
ing much along the same lines as those tried successfully in Cali-
fornia. Unfortunately, European grapes will not flourish in
these sections of the United States and all such attempts ended
in disaster. About the middle of the last century Nicholas Long-
worth, Sr., experimented with the native Catawba grape in Ohio

38 RAW MATERIALS

and was so successful that the Ohio River was often referred to
as the "Rhineland of America." This undertaking also came to
a disastrous ending when disease attacked the vines. However,
fresh plantings of American Vine Roots and Hybrids along the
shores of Lake Erie and in Steuben County, New York, and
parts of New Jersey have been more successful.

Geographical Considerations. The choice of a site for
grape production, as indicated previously, depends very largely
on the nature of the soil and the climate. The following tabu-
lation of grapes successfully grown in the United States will illus-
trate this statement:

TABLE VII. AMERICAN GRAPE VARIETIES
Lake Shore District of Ohio

Catawba, Delaware, Concord, Norton

Steuben County, New York

Arranged in the order of merit:

Delaware, lona, Diana, Catawba, Concord, Isabellas, Norton

Southern Texas

Devereux (Black July), Mustang, Herbemont, Lenoir (known as
Burgundy in eastern Texas and Black Spanish in western Texas).

California

Fresno County

Zinfandel, Malvoisie and Fahirzozos.

Zinfandel is considered best grape; color, excellent; flavor and acid,
splendid.

Sonoma Valley

Mission, Riesling, Gutedel (Chasselais), Muscatel, Burger, Zin-
fandel.

The Mission grape has spread over the whole state and is much
used in the production of Hock, Claret, Port and Angelica.

Napa County

Riesling, White, Pineau and Chasselais for dry white wines.
Black Burgundy, Zinfandel and Charboneau for Claret. The first
makes a dark, full bodied and richly flavored wine. The second
has a fine raspberry flavor but an excess of acid and is a little light
in body and color.
Black Malvoisie is tbe best Port wine grape.

WINE MATERIALS 39

Bioletti (California Agr. Exp. Sta. Bull. 193. "The Best
Wine Grapes of California"} has summarized the geographical
and climatic factors which must he borne in mind. While his
statement is with particular reference to California, the principles
which he enunciates are of general validity. He says:

"For the good of the industry at large it is desirable that varieties
should be planted which will produce as large a crop as is compatible with
such quality as will maintain and extend the markets for our wine. These
markets are varied in character. For some, cheapness is the essential
factor; for others, quality. Cheap wines can be produced with profit only
from heavy-bearing varieties grown in rich soil ; wines of the highest qual-
ity only from fine varieties grown on hillsides or other locations where the
crops are necessarily less. It is therefore unwise to plant poor-bearing
varieties in the rich valleys where no variety can produce a fine wine. It
is equally unwise to plant common varieties on the hill slopes of the Coast
Ranges where no variety will produce heavy crops. The vineyards of the
San Joaquin, Sacramento, and other valleys can not compete with the
vineyards of the Coast Ranges in quality, and the latter can not compete
with the former in cheapness.

Each region has its own special advantages which, if properly used,
will make grape-growing profitable in all, and instead of competing each
will be a help to the other. The danger to be feared by the grape-growers
of the Coast Ranges from the production of dry wine in the interior is not
competition, but lies in the bad reputation given to California wines by
the production of spoiled and inferior wines. If the cheap wines of the
valleys are uniformly good and sound the market for the high-priced fine
wines of the hills will increase, and large quantities of the Coast Range
wines will be used for blending with the valley wines to give them the
acidity, flavor and freshness which they lack.

In order to obtain these results it is necessary that varieties suited to
each region and to the kind of wine should be planted. No variety which
is not capable of yielding from 5 to 8 tons per acre in the rich valley soils
or from i l /2 to 3 tons on the hill slopes should be considered. On the
other hand, no variety which will not give a clean-tasting, agreeable wine
in the valley or a wine of high quality on the hills should be planted,
however heavily it may bear. To plant heavy-bearing inferior varieties
such as Burger, Feher Szagos, Charbono, or Mataro on the hills of Napa
or Santa Cruz is to throw away the chief advantage of the location. The
same is true of planting poor-bearing varieties such as Verdelho, Chardo-
nay, Pinot, or Cabernet Sauvignon in the plains of the San Toaquin.

RAW MATERIALS

With these considerations in view, the following suggestions are made
for planting in the chief regions of California:

WINE GRAPES RECOMMENDED FOR CALIFORNIA
For Coast Counties

Red Wine Grapes

1. Petite Si rah

2. Cabernet Sauvignon

3. Beclan

4. Tannat

5. Serine

6. Mondeuse

7. Blue Portuguese

8. Verdot

White Wine Grapes

1 . Semillon

2. Colombar (Sauvignon vert)

3. Sauvignon blanc

4. Franken Riesling

5. Johannisberger

6. Tsaminer

7. Peverella

For Interior Valleys

Red Grapes

1. Valdepenas

2. St. Macaire

3. Lagrain

4. Gros Mansene

5. Barbera

6. Refosco

7. Pagadebito

White Grapes

1. Burger

2. West's White Prolific

3. Vernaccia Sarda

4. Marsanne

5. Folle blanche

For Sweet Wines

Red Grapes

1. Grenache

2. Alicante Bouschet

3. Tinta Madeira

4. California Black Malvoisie

5. Monica

6. Mission

7. Mourastel

8. Tinta Amarelia

White Grapes

1. Palomino

2. Beba

3. Boal

4. Perruno

5. Mantuo

6. Mourisco branco

7. Pedro Ximenez

Finally, a few suggestions as to what "not to do."

Don't plant Mataro, Feher Szagos, Charbono, Lenoir, or any variety
which makes a poor wine everywhere.

Don't plant Burger, Green Hungarian, Mourastel, Grenache, or any
common heavy-bearing varieties on the hill slopes of the Coast Ranges.

LIQUEURS AND CORDIALS 41

Vineyards in such situations must produce fine wines, or they will not be
profitable.

Don't plant Chardonay, Pinot, Cabernet Suavignon, Malbee, or any
light-bearing varieties in rich valley soils. No variety will make fine, high-
priced wine in such situations, and heavy bearers are essential to the pro-
duction of cheap wines.

Don't plant Zinfandel, Alicante Bouschet, or any of the varieties which
have already been planted in large quantities, unless one is sure that the
conditions of his soil and locality are peculiarly favorable to these varieties
and will allow him to compete successfully."

Liqueurs and Cordials. The raw materials for the manufac-
ture of liqueurs and cordials are necessarily classified in a different
manner from those used in the distilled spirit or wine industries.
In general they may be divided into three broad groups with sub-
divisions as indicated:

A. Flavoring Agents

1. Herbs, spices, seeds, roots, and fruits.

2. Aromatic spirits and tinctures.

3. Aromatic waters.

4. Essential Oils.

B. Coloring Agents

1. Vegetable Coloring Matters.

2. "Aniline" dyes. (Synthetic dyestuffs.)

C. Bulk Ingredients

1. Sugar and glucose.

2. Brandies or rectified spirits.

3. Water.

The number of materials included in Group Ai above is
very large; among others the following find principal use:

HERBS, SEEDS, ROOTS, SPICES, BARKS, FRUITS, ETC.

Chinese aniseed Cocoa Caraque

Bitter almonds Cocoa Maragnan

Green an is Mace

Coriander Vanilla

Fennel Figs

Angelica root Cumin

-Angelica seed Calamus, aromatic

Lemon peel Peel of Dutch Curacao

RAW MATERIALS

Orange peel

Anis de Tours

Anis d'Albi

Ceylon cinnamon

Orris

Cloves

Marjoram

Sweet almonds

Nutmeg

Sassafras

Muskseed

Apricot stones

Cherry stones

Dried peach leaves

Dried peaches

Myrrh

Quince juice

Strawberries

Nuts

Pineapple

Angostura bark

In Group A 2 will be found:

Aloes

Saffron

Curacao reeds

Wormwood

Hyssop Flowers

Lemon balm

Cherries

Alpine mugwort

Arnica Flowers

Peppermint

Balsamite

Thyme

Tonka beans

Black currants

Black currant leaves

Quinces

Red Sandalwood

Liquorice wood

Ginger root

Galanga root

AROMATIC SPIRITS

Anis

Angelica root

Angelica seeds

Curacao

Peppermint

Apricot

Lemons

Coriander

Amberseed

Dill

Caraway

Daucus

Fennel

Strawberries

Group A 3 includes:

Orange Flower

Peppermint

Rose

Celery

Aloes

Myrrh

Saffron

Chinese cinnamon

Cloves

Nutmeg

Orange Flowers

Bitter Almonds

Cardamom major

Cardamom minor

Oranges

Nuts

AROMATIC WATERS
Moka

Chinese aniseed
Clove

LIQUEURS AND CORDIALS 43

Group A4 includes the flavoring principles derived from
any of the raw materials listed under the heading of Group A2.
The term "essential oils'* is a generic commercial phrase used to
designate the volatile oils obtained by various processes such as
steam distillation, expression, maceration, enfleurage and solvent
extraction, from the specific plant or part of a plant which gives
them their name. The term is derived from the word "essence"
meaning that in these oils is contained the soul or strength of the
plant. In fact, in some countries, the single word is used instead
of the longer "essential oil." In the United States, however, the
usage is that the term "essence" or "spirits of" applies rather
to a solution in alcohol of the "essential oil." And a new phrase
"soluble essence" has been invented to describe essences which are
completely miscible with water or dilute alcohol without separa-
tion of the oil taking place.

The essential oils exist in all odorous vegetable tissues, some-
times pervading the plant, sometimes confined to a single part;
in some instances, contained in distinct cells, and partially retained
after desiccation, in others, formed upon the surface, as in many
flowers, and evaporating as soon as formed. Occasionally two
or more oils are found in different parts of the same plant. Thus,
the orange tree produces one oil in its leaves, another in its
flowers, and a third in the rind of its fruit.

The volatile oils are usually colorless when freshly distilled,
or at most yellowish, but some few are colored brown, red, green
or blue. There is reason, however, to believe that in all instances
the color depends on foreign matter dissolved in the oils. They
have strong odors, resembling that of the plants from which they
were procured, though generally less agreeable. Their taste is
hot and pungent, and, when they are diluted, is often gratefully
aromatic. The greater number are lighter than water, though
some are heavier; their specific gravity varies from 0.847 to I - I 7-
They vaporize at ordinary temperatures, diffusing their particular
odor and are completely volatilized by heat.

The following is a partial list of coloring agents used in the
production of liqueurs and cordials:

44 RAW MATERIALS

VEGETABLE COLORS

Caramel Indigo (Sulphonated)

Cherry Extract Orchil

Chlorophyll preparations Saffron

Cochineal Vanilla Extract
Cudbear

SYNTHETIC DYESTUFFS

In France the artificial coloring agents used are subject to less
limitation than in the United States, and since France is the
largest producer of cordials the following list is appended:

Rose Bengal Bleu de lumiere

Rouge de Bordeaux Bleu coupler

Fuchsine, acid Malachite green

Bleu de Lyon Violet de Paris (Gentian Violet 36)

It should be noted that not one of these dyes is included in
the United States list of colors certified for use in foods, which
only are permitted to be used in this country in interstate com-
merce and in many states in intrastate commerce. This list which
follows is varied enough to allow for the production of any
desired shade.

CERTIFIED FOOD COLORS

RED SHADES: GREEN SHADES:

80. Ponceau 3R. 666. Guinea Green B.

184. Amaranth. 670. Light Green SF Yellowish.

773. Erythrosine. Fast Green FCF.

Ponceau SX.

ORANGE SHADE: BLUE SHADES:

150. Orange I. 1180. Indigotine.

Brilliant Blue FCF.

YELLOW SHADES:

10. Naphthol Yellow S.
640. Tartrazine.
22. Yellow AB.
61. Yellow OB.

Sunset Yellow FCF.

LIQUEURS AND CORDIALS 45

The numbers preceding the names refer to the colors as listed in the
Colour Index published in 1924 by the Society of Dyers and Colourists of
England, which gives the composition of these dyes. Names not preceded
by numbers are not listed in the Colour Index.

No description is here necessary of the materials which we
have classified as group C above. A description of their specific
employment will be found in subsequent chapters devoted to
manufacturing operations. The same applies to a number of
minor ingredients or materials used for special purposes such as
souring, fining, preserving, sterilizing, etc.

CHAPTER V
YEASTS AND OTHER ORGANISMS

General Statement. In the preceding chapter on Fermenta-
tion it was stated that the production of alcohol is performed by
enzymes which act on the sugars present in the fermenting liquor.
It was also indicated previously that the enzymes which accom-
plish this transformation are representative of a very large group
of such materials which function in every chemical change in-
volved in the life process. The enzymes of value to the
fermentation industry are produced by living plants, yeasts, which
are allowed to grow in the liquor to be fermented and which,
as an incident of their own life process, achieve the desired pro-
duction of alcohol.

Yeasts belong to the second broad group of vegetable
growths : those which do not contain chlorophyll and are, there-
fore^ unable to manufacture their own food. This group is
distinguished from the first group of plants which can extract
inorganic materials from the soil and the air and from these
manufacture their own food. The ability to perform this function
is ascribed to the presence in the plant of a green coloring matter,
chlorophyll.

The group name of the non-chlorophyll bearing plants is
fungi. They are all dependent for their food supply upon the
materials built up by living plants of group one, or upon animal
matter. Among the fungi, which naturally vary in complexity
of structure, are a group of simply constructed plants having but
one cell and which are called yeasts. The cells vary in shape
and size, being round, oval or elongated, but of the order of
0.003 inches in diameter.

Each such cell consists of a transparent elastic sac or mem-
brane enclosing a more or less granular mass of jelly-like sub-
stance which is called protoplasm. The name was originated by

LIFE PROCESSES 47

Purkinje (ca. 1840) to apply to the formative material of young
animal embryos. Later, von Mohl (ca. 1846) used the term
to distinguish the substance of the cell body from that of the
nucleus which he called cytoplasm. In modern usage dating from
Strasburger (ca. 1882) the name protoplasm has been applied to
all of the essential living substance within the cell wall and means
the form of matter in or by which the phenomena of life are
manifested. Protoplasm can exist in many modifications varying
from its usual one of a thick, viscous, semi-fluid, colorless, trans-
lucent mass containing a high proportion of water and holding in
suspension fine granular material. Chemical examination of pro-
toplasm, necessarily after death, has shown that it is composed
largely of protein material. During its life, however, it appears
probable that the chemical composition is both more complex
and more unstable. For our purpose it is only necessary to state
that the protoplasm is that portion of the plant which is alive and
which carries on the vital processes of the plant.

Life Processes. All living organisms exemplify the cycle of
birth, growth, multiplication and death. Starting, for yeast, at
the stage of growth we see the process as follows: When the
yeast is supplied with an abundance of nutrient material, it grows
vigorously and the cellular protoplasm is homogeneous. As the
growth continues and the nutrient material becomes exhausted,
clear, apparently empty, spaces called vacuoles appear in the
protoplasm. Actually these spaces are filled with serum or sap.
At a little later stage, granules appear, some of which are fat
globules while others are more condensed portions of proto-
plasm. Finally, as the cell nears the end of its life, the proto-
plasm shrinks to a thin layer against the cell wall while the bal-
ance of the cell is occupied by a large vacuole. The nucleus of
the cell is rarely visible and does not, for this reason, enter into
our consideration.

While this growth of the single cell continues, multiplication
also takes place at a rapid rate. According as the life conditions
are favorable or not multiplication takes place in one of two

ways :

1. By budding or germination.

2. By endogenous division or ascospore formation.

48 YEASTS AND OTHER ORGANISMS

The first process occurs under favorable conditions when the
yeast is growing rapidly. It consists in a bulging of part of
the cell wall and the pressing of part of the cell contents into
the bulge which is formed. This is the bud. As the bud grows the
wall between it and the mother cell constricts and finally closes
and there are then two distinct cells. Whether the bud-cell stays
in connection with the mother cell depends somewhat on the
conditions of growth but more on the variety of yeast. With
some varieties the bud stays in connection with the mother cell
and itself multiplies through many generations so that long chains
or branching clusters are formed. In all cases the rapidity of
multiplication depends on the vigor of the yeast and the suitability
of the conditions under which it is growing.

In distinction to the method of reproduction just described,
when a vigorous yeast growth is placed into adverse conditions
it prepares to survive by a different mode. The protoplasm of
the cells becomes granular, then divides so as to form separate
masses. These round off and become invested with a wall so
that the original cell wall acts merely as a sac to contain the new
bodies. Because of this last fact the name ascospores is given
them, meaning spores formed within a sac. The conditions re-
quired to bring about ascospore formation are not completely
understood. Usually, however, a suitable temperature, plenty
of moisture and lack of nutrient material will cause young, vigor-
ously growing yeast cells to form from one to four ascospores
each. The spores have remarkable ability to survive under con-
ditions which would be fatal to ordinary cells; such as extremes
of temperature, lack of food, drying out, etc.

When at some future time the spores are placed into favor-
able conditions for growth they germinate and start a new series
of the ordinary type of yeast cells. In germinating they exert
a pressure against the wall of the mother cell which finally breaks
and permits the escape of the new cells. In some cases actual
dissolution of the cell occurs during germination.

.The changes described above are well illustrated in the ac-
companying figure, which shows stages in the life of a favorable
pure culture yeast and also some of the mixed forms.

CLASSIFICATION OF YEASTS

Classification of Yeasts. Although the structure of yeasts is
so exceedingly simple that it seems difficult for varieties to exist,
nevertheless there are many different kinds or species. The dis-
tinctions are partly morphological, i.e., in the physical form of
the cells, and partly chemical, i.e., in the enzymes elaborated by
the cells which, of course, means that the products resulting from

*&.

FIG. 2. True Wine yeast.

i. Yeast cells in fermenting grape juice (mixed forms).

2. Saccharomyces ellipsoideus (spores).

3. Saccharomyces ellipsoideus (old).

4. Saccharomyces ellipsoideus (young).

the action of different yeasts on the same medium or substrate
will be different. When a pure yeast is used in fermentation, an
entirely different result is obtained than from the use of an im-
pure. The flavor is different, as also the odor, and with a pure
yeast the keeping properties are better. For the purposes of the
fermentation industry, yeasts are divisible into two groups:

50 YEASTS AND OTHER ORGANISMS

1. The wild yeasts those which occur in nature; floating in
the air, in the soil, and on^the skins of fruits.

2. The cultivated yeasts which have been selected from the
wild yeasts for their favorable action and are carefully guarded
in laboratory and factory to insure purity of strain.

There are two schools of thought in the fermentation indus-
try and especially among wine makers as to whether it is prefer-
able to use pure culture yeasts or to depend on wild yeasts. On
the one hand it is claimed that pure culture yeast will result in
a more accurately controlled fermentation, in a reduction in the
time and labor required for racking and aging, a cleaner taste
and flavor, and in the ability to select beforehand the flavor
desired.

On the other hand, it is claimed that these advantages are
offset by the necessity of sterilizing the must, pressed grapes and
juice. In practice, however, the benefits derived from the use
of pure culture yeast can often be had without resorting to the
costly operation of sterilization. The pure culture yeasts are
especially advantageous in the manufacture of white and sparkling
wines and in the refermentation of the latter. They are used ex-
tensively abroad for these purposes and have secured some recog-
nition and produced excellent results in some wineries in this
country.

In whiskey distilleries, pure culture yeasts have been used ex-
tensively in recent years. The types are selected for high alco-
hol yields and propagated by the Hansen single-cell method.
There can be no doubt at the present time but that pure culture
yeasts are an absolute necessity for the manufacture of distilled
spirits and very much preferable for the manufacture of wines.

The principal yeasts encountered in spirit and wine manufac-
ture are :

Saccharomyces cerevisiae. The ordinary yeast of the brewer and the
distiller. Two kinds are recognized: (a) top fermentation, and (b) bot-
tom fermentation.

Top yeast, as its name implies, is a type which rises in a frothy mass to
the top of the mash during fermentation. Bottom yeast sinks to the bot-
tom of the vat during fermentation. Higher temperatures favor the for-

MICRO-ORGANISMS FOUND ON GRAPES 51

mation of the former and lower temperatures favor the latter. Distillers'
yeast is a high attenuating top variety.

Saccharomyces ellipsoideus. This is the yeast which converts must, or
grape juice, into wine.

Saccharomyces pastorianus. This also occurs in wine making and when
present during brewing gives a bitter taste to the beer.

Saccharomyces mycoderma. This yeast is the cause of "mother 11 which
appears on the surface of wine or beer after exposure for some days to
the air.

Bakers use either compressed yeast (compressed cakes of
top yeast) or dried yeast (a mixture of yeast cells with starch).
The former has high fermenting capacity and gives uniform
results, but it will keep only a day or two; while the latter retains
its capacity to produce fermentation for a long period. Brewers*
yeast is not desirable for bread making because it is likely to give
a bitter flavor and its activity is slow in a dough mixture.

Pure Cultures. To determine the properties due to a par-
ticular yeast, it must be separated from all other organisms with
which it is associated and when grown thus, free from all con-
tamination, it is then known as a "pure culture. " A commercially
pure yeast is different, as this simply means "free from added
non-yeast matter." This is the condition of most compressed
yeasts as found on the market; they are commercially, but not
bacteriologically, pure, since they have numbers of bacteria and
molds associated usually with more than one yeast variety.

Micro-Organisms Found on Grapes. The surfaces of
grapes in the vineyard will hold any or all of the bacteria and
fungi usually carried in the air and by insects. Many of these,
especially the bacteria, cannot grow in grape juice on account of
its acidity. These, of course, have a negligible effect on the wine.
Others, such as most yeasts and molds and a few varieties of
bacteria find grape juice to be a favorable medium for their de-
velopment. Wine is a somewhat less suitable medium than
unfermented grape juice (must], owing to its alcohol content,
but still, a large number of forms are capable of growing in the
wine. As the wine ages, the less suitable it becomes for the
growth of micro-organisms, but it is never quite immune.

Among the great variety of organisms the only ones desired

52 YEASTS AND OTHER ORGANISMS

are the wine yeasts. Many different types of wine yeast have
been isolated and studied. It has been demonstrated that not
only do slight morphological differences exist, but also that they
vary in the flavor and quality of wine produced and also in the
speed and completeness with which they split sugar and consume
acids. The true yeasts occur much less abundantly on grapes than
the molds. Until the grapes are ripe they are practically absent,
as first shown by Pasteur. Later, they gradually increase in
number; on very ripe grapes being often abundant. In all cases
and at all seasons, however, their numbers are much inferior to
those of the molds and pseudo-yeasts. The cause of this seems
to be that, in the vineyard, the common molds find conditions
favorable to their development at nearly all seasons of the year,
but yeasts only during the vintage season.

Investigations of Hansen, Wortmann and others show that
yeasts exist in the soil of the vineyard at all times, but in widely
varying amounts. For a month or two following the vintage, a
particle of soil added to nutritive solution contains so much yeast
that it acts like a leaven. For the next few months the amount
of yeast present decreases until a little before the vintage, when
the soil must be carefully examined to find any yeast at all. As
soon as the grapes are ripe, however, any rupture of the skin of
the fruit will offer a favorable nidus for the development and
increase of any yeast cells which reach it. Where these first
cells come from has not been determined, but as there are still a
few yeast cells in the soil, they may be brought by the wind, or
bees and wasps may carry them from other fruits or from their
hives and nests.

The increase of the amount of yeast present on the ripe
grapes is often very rapid and seems to have (according to
Wortmann) a direct relation to the abundance of wasps. These
insects passing from vine to vine, crawling over the bunches to
feed on the juice of ruptured berries, soon inoculate all exposed
juice and pulp. New yeast colonies are thus produced and the
resulting yeast cells quickly disseminated over the skins and other
surfaces visited.

The more unsound or broken grapes present, the more honey-

PSEUDO- YEASTS 53

de\v or dust adhering to the skins, the larger the amount of
yeast will be. The same is true, however, also of molds and
other organisms.

True Wine Yeasts Saccharomyces ellipsoideus. In the
older wine-making districts, much of the yeast present on the
grapes consists of the true wine yeast, S. ellipsoideus. The race
or variety of this yeast differs, however, in different districts.
Usually several varieties occur in each district. The idea preva-
lent at one time, that each variety of grape has its own variety
of yeast seems to have been disproved, though there seems to be
some basis for the idea that grapes differing very much in com-
position, varying in acidity and tannin contents, may vary also in
the kind of yeast present. Several varieties of ellipsoideus may
occur on the same grapes. In new grape-growing districts, where
wine has never been made, ellipsoideus may be completely absent.

Besides the true wine yeast, other yeasts usually occur. The
commonest forms are cylindrical cells grouped as S. pasteurianus.
These forms are particularly abundant in the newer districts,
where they may take a notable part in the fermentation. Their
presence in large numbers is always undesirable, and results in
inferior wine. Many other yeasts may occur occasionally, and
are all more or less harmful. Some have been noted as produc-
ing sliminess in the wine. Many of these yeasts produce little or
no alcohol and will grow only in the presence of oxygen.

Pseudo-yeasts. Yeast-like organisms producing no endo-
spores always occur on grapes. Their annual life cycle and their
distribution are similar to those of the true yeast but some of them
are much more abundant than the latter. They live at the
expense of the food materials of the must and, when allowed to
develop, cause cloudiness and various defects in the wine.

The most important and abundant is the apiculate yeast, S.
apiculatus (according to Lindner this is a true yeast producing
endospores). The cells of this organism are much smaller than
those of S. ellipsoideus and very distinct in form. In pure cul-
tures these cells show various forms, ranging from ellipsoidal
to pear-shaped (apiculate at one end) and lemon-shaped (apicu-
late at both ends). These forms represent simple stages of de-

YEASTS AND OTHER ORGANISMS

velopment. The apiculations are the first stage in the formation
of daughter cells; the ellipsoidal cells, the newly separated daugh-
ter cells, which, later, produce apiculations and new cells in turn.
Many varieties of this yeast occur, similar in degree to those
of S. ellipsoideus. They are widely distributed in nature, occur-
ring on most fruits, and are particularly abundant on acid fruits
such as grapes. Apiculate yeast appears on the partially ripe
grapes before the true wine yeast and even on ripe grapes is more
abundant than the latter. The rate of multiplication of this yeast

FIG. 3. Yeasts and injurious pseudo-yeasts.

1. Torulae and pseudo-yeasts.

2. Torulae and pseudo-yeasts.

3. Saccharomyces apiculatus.

4. Saccharomyces pasteurianus.

5. Mycoderma vini (2 forms).

6. Dematium pullulans.

is very rapid under favoring conditions and much exceeds that
of wine yeast. The first part of the fermentation, especially at
the beginning of the vintage and with acid grapes, is, therefore,
often almost entirely the work of the apiculate yeast.

The amount of alcohol produced by this yeast is about 4 per
cent, varying with the variety from 2 to 6 per cent. When the
fermentation has produced this amount of alcohol, the activity of
the yeast slackens and finally stops, allowing the more resistant
ellipsoideus to multiply and finish the destruction of the sugar.

PSEUDO- YEASTS 55

The growth of the apiculatus, however, has a deterring effect on
that of the true yeast so that where much of the former has been
present, during the first stages of the fermentation, the latter
often fails to eliminate all the sugar during the final stages.

Wines in which the apiculate yeast has had a large part in
the fermentation are apt to retain some unfermented sugar and
are very liable to the attacks of disease organisms. Their taste
and color are defective, often suggestive of cider, and they are
difficult to clear. This yeast attacks the fixed acids of the must,
the amount of which is therefore diminished in the wine while,
on the other hand, the volatile acids are increased.

Many other yeast-like organisms may occur on grapes; but,
under ordinary conditions, fail to develop sufficiently in competi-
tion with apiculatus to have any appreciable effect on the wine.
Most of them are small round cells, classed usually as Torulae.
They destroy the sugar but produce little or no alcohol.

A group of similar forms, known collectively as Mycoderma
vini, occurs constantly on the grapes but, all being strongly
aerobic, they do not develop in the fermenting vat. Under
favoring conditions, however, they may be harmful to the fer-
mented wine.

Bacteria of many kinds occur on grapes as on all surfaces
exposed to the air. Most of these are unable to develop in solu-
tions as acid as grape juice or wine. Of the acid-resisting kinds,
a number may cause serious defects and even completely destroy
the wine. These, the u disease bacteria" of wine are mostly
anaerobic and can develop only after the grapes are crushed and
the oxygen of the must exhausted by other organisms. Practically
all grape-must contains some of these bacteria, which, unless the
work of the wine-maker is properly done, will seriously interfere
with the work of the yeast, and may finally spoil the wine. The
only bacteria which may injure the grapes before crushing are
the aerobic, vinegar bacteria, which may develop on injured or
carelessly handled grapes sufficiently to interfere with fermenta-
tion and seriously impair the quality of the wine.

Among the organisms which can infect wine and cause so-
called "diseases" are the following:

56 YEASTS AND OTHER ORGANISMS

Molds. The spores of the common saprophytic molds, Penicillium,
Aspergillus, Mucor, Dematium, are always present on the grapes, boxes,
and crushers, as on all surfaces exposed to dust laden air, and most of them
find in grape must, excellent conditions for development. Botrytis cinerea,
a facultative parasite of the leaves and fruit of the vine, is also nearly
constantly present in larger or smaller quantities. All of these molds are
harmful, in varying degrees, to the grapes and the wine. Some of them,
such as Penicillium, may give a disagreeable moldy taste to the wine, suffi-
cient to spoil its commercial value. Others, such as Mucor and Asper-
gtlius may affect the taste of the wine but slightly and injure it only by
destroying some of the sugar and thereby diminishing the final alcohol
content. Dematium pullulans may produce a slimy condition in weak
white musts, and most of them injure the brightness and flavor to some
extent and often render the wine more susceptible to the attacks of more
destructive forms of micro-organisms.

On sound, ripe grapes, these molds occur in relatively small number,
and, being in the spore or dormant condition, they are unable to develop
sufficiently to injure the wine under the conditions of proper wine-making.
On grapes which are injured by diseases, insects or rain, they may de-
velop in sufficient quantities to spoil the crop before it is gathered. On
sound grapes which are gathered and handled carelessly, they may develop
sufficiently before fermentation to injure or spoil the wine.

The molds are recognized by their white or grayish cobwebby growth
over the surface of the fruit. This consists of fine branching and inter-
lacing filaments known as mycelium. This is the vegetative stage of the
fungus and the active part in the destruction of the material attacked.
When mature, it produces spores which differ for each mold in form, size
and color. The spores are the chief means of multiplication and distri-
bution. They are minute, single celled bodies which are easily distributed
as dust through the air, and are capable, after remaining dormant for a
longer or shorter period, of germinating, under favorable conditions and
giving rise to a new growth of mycelium.

The commonest molds on grapes in California are the Blue Mold, the
Black Mold and the Gray Mold. Usually only one of these occurs plenti-
fully at the same time. Which this one will be depends principally upon
the temperature and humidity. In the hotter regions the Black Mold is
most common during the earlier part of the vintage, later the Blue Mold
takes its place. In the cooler regions only Gray and Blue Molds occur
commonly.

Blue Mold (Penicillium glaucum). This is the common mold which
attacks all kinds of fruit and foods kept for a length of time in a damp
place. It is distinguished by the greenish or bluish color of its spores
which cover the grapes attacked, and by its strong disagreeable moldy
smell. It sometimes attacks late grapes in the vineyard after autumn rains

PSEUDO-YEASTS 57

have caused some of them to split. Grapes lying on the ground are espe-
cially liable to attack. The principal damage of this mold occurs usually,
after the grapes are gathered, while they lie in boxes or other containers.
It will grow on almost any organic matter if supplied with sufficient
moisture and at almost any ordinary temperature. It is almost the sole
cause of all moldiness in boxes, hoses, and casks, and the most troublesome
of all the molds with which the wine-maker has to deal.

The conditions most favorable to its development are an atmosphere
saturated with moisture and the presence of oxygen.

Black Mold (Aspergillus niger). This is very common in the hotter
and irrigated parts of California. It annually destroys many tons of grapes
before they are gathered. It attacks the grapes just as they ripen and is
distinguished by the black color of its spores, which sometimes fill the air
with a black cloud at the wineries where the grapes are being crushed. It
is especially harmful to varieties which have compact bunches and thin
skins, such as Zinfandel. Its effect on the wine has not been well studied
but it is much less harmful than Green Mold. Large quantities of grapes
badly attacked are made every year into merchantable wine. The main
damage done is in the destruction of crop and it is therefore a greater
enemy to the grape-grower than to the wine-maker.

Gray Mold (Botrytis cinerea). This fungus in certain parts of Europe
is a harmful parasite of the vine, injuring seriously leaves, shoots and
growing fruit. The only injury of this kind noted in California is in the
"callousing" beds of bench grafts.

As a saprophyte it may attack the ripe grapes in much the same manner
as the Black Mold. It occurs apparently all over California but seldom
does much damage. It attacks principally second crop and late table
grapes.

Under certain circumstances this fungus may have a beneficial action.
When the conditions of temperature and moisture are favorable, it will
attack the skin of the grape, facilitating evaporation of water from the
pulp. This results in a concentration of the juice. The mycelial threads
of the fungus then penetrate the pulp, consuming both sugar and acid but
principally the latter. The net result is a relative increase in the per-
centage of sugar and a decrease in that of acid. This, where grapes ripen
with difficulty, is an advantage, as no moldy flavor is produced. Two
harmful effects, however, follow: First, the growth of the mold results
in the destruction of a certain amount of material and a consequent loss of
quantity. This is, in certain circumstances, more than counterbalanced by
an increase in quality, as is the case with the finest wines of the Rhine and
Sauternes. For this reason, the fungus is called in those regions the "Noble
Mold." Second, an oxydase is produced which tends to destroy the color
brightness and flavor of the vine. This may be counteracted by the judi-
cious use of sulfurous acid.

YEASTS AND OTHER ORGANISMS

FIG. 4. Wine grape molds.

1. Black mold (Aspergillus niger). (After Duclaux.)

a. Fruiting hyphae.

b. Sporecarp showing formation of spores.

c. Spores.

2. Gray mold (Botrytis cinerea). (After Ravaz.)

3. Blue mold (Penicillium glaucum). (From skin of moldy grape.)

a. Mycelium.

b. Fruiting hypha.

c. Chains of spores.

d. Spores.

CONTROL OF YEASTS

This mold is not of great importance in California as its beneficial
effects are not needed and there is seldom enough to do much harm.

The special organisms which cause diseases in wine include:
Anaerobic organisms such as Dematlum pullulans induce
slimy fermentation which results in "ropiness." These bacteria
attack the sugar, but not glycerin nor alcohol and produce man-
mite, carbon dioxide, lactic and acetic acids and alcohol. Their

FIG. 5. Disease Bacteria of wine.

1. Bacteria of mannitic wine.

2. Bacteria of bitter wine (butyric).

3. Bacteria of vinegar (b. aceticum).

4. Bacteria of lactic acid, young.

(a) Cell of wine yeast.

5. Bacteria of lactic acid, old.

6. Bacteria of slimy wine.

growth is entirely prevented by the presence of alcohol above thir-
teen per cent, free tartaric, tannic or small amounts of sulphurous
acid. The infection is ordinarily not very serious and disappears
under ordinary cellar treatment.

Botrytis and Penicilliiim which when present cause oxidation
of the tannin causing a bitter taste. This is more common in
red wines.

Acetic acid bacteria which cause the further oxidation of al-
cohol to acetic acid and result in a "pricking" taste. This taste

60 YEASTS AND OTHER ORGANISMS

is noticeable even when there is only 0.1-0.15% of acetic acid. A
dry wine becomes practically undrinkable at 0.25% of acetic acid.

Saccharomyces apiculatus will cause some production of alco-
hol but affects the flavor adversely.

Mycoderma vini attack the alcohol changing it to carbon
dioxide and water and hence weaken the wine directly as well as
rendering it more susceptible to infection by other disease organ-
isms. It is sometimes the cause of film.

Control of Yeasts. Control of the growth of these organ-
isms and even to some extent selection of the variety which shall
grow is largely possible by a consideration of the factors affecting
their vigor.

Nutrition. The preferred food of the yeasts is the sweet
juice of more or less acid fruits. Most of them are active agents
of alcoholic fermentation breaking up the sugar into alcohol and
carbonic acid gas. Wine yeast may carry on the fermentation
until the liquid contains 15 per cent or slightly more of alcohol.
Other yeasts, such as ordinary beer yeast cease their activity when
the alcoholic strength of the liquid reaches 8 to 10 per cent, while
some wild yeasts are restrained by 2 to 3 per cent.

Delation to Oxygen. They are aerobic, that is, they require
the oxygen of the air for their development. Most of them are,
however, capable of living and multiplying for a limited time in
the anaerobic condition, that is, in the absence of atmospheric oxy-
gen. It is in the latter condition that they exhibit their greatest
power of alcoholic fermentation. They multiply most rapidly
and attain their greatest vigor in the presence of a full supply of
air. In fermentation, therefore, it is necessary, first, to promote
their multiplication and vigor by growing in a nutritive solution
containing a full supply of oxygen and, then, to make use of
their numbers and vigor to produce alcoholic fermentation in a
saccharine solution containing a limited supply of oxygen. These
conditions are brought about automatically in the usual methods
of wine-making. The stemming and crushing of the grapes thor-
oughly aerates the must. The yeast multiplies vigorously in this
aerated nutritive solution until it has consumed most of the dis-
solved oxygen. It then exercises its fermentative power to break

CONTROL OF YEASTS 61

up the sugar, with the production of alcohol. With many musts
it is able in this way to completely destroy all the sugar without
further oxygen. In other musts, especially those containing a
high percentage of sugar, the yeast becomes debilitated before
the fermentation is complete. In such cases it is generally neces-
sary to reinvigorate it by pumping over the wine or by some other
method of aeration before it can complete its work.

Relation to Temperature. Yeast cells can not be killed or
appreciably injured by any low temperature. They do not be-
come active, however, until the temperature exceeds 32 F. Wine
yeast shows scarcely any activity below 50 F., and multiplies
very slowly below 60 F. Above this temperature the activity
of the yeast gradually increases. Between 70 F. and 80 F.
it is very active and it attains its maximum degree of activity
between 90 F. and 93 F. Above 93 F. it is weakened, and
between 95 F. and 100 F. its activity ceases. At still higher
temperatures the yeast cell dies. The exact death point depends
on the condition of the yeast, the nature of the solution and the
time of exposure. In must and wine a temperature of 140 F.
to 145 F. continued for one minute is usually enough to destroy
the yeast.

The best temperature in wine-making will depend on the kind
of wine to be made and will lie between 70 F. and 90 F.

Relation to Adds. The natural acids of the grapes, in the
amounts in which they occur in must, have little direct effect on
wine yeast. Indirectly they may be favorable by discouraging the
growth of co


Search: Advanced Search	UploadAnonymous User (login or join us)