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~ TeABORATORY cme c
- CHARLES W-MELICK :

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DAIRY
LABORATORY GUIDE

BY

CHARLES W. MELICK, B.S.A., M.S.

Professor of Dairy Husbandry, Maryland Agricultural Experiment Station

FIFTY-TWO ILLUSTRATIONS

NEW YORK
D. VAN NOSTRAND COMPANY
23 MURRAY AND 27 WARREN STREETS

1907

Bs

Copyright, 1907
By D. Van Nostrand COMPANY

Ce

The Plimpton Press Norwood Mass. U.S.A.

EXERCISE
I

IT
Til
IV
Vv
VI
VII
VIII
Ix
x
XI
XII
XIII

XIV

KV
XVI
XVII
XVIII
XIX
XX
XXI
XXIT
XXIII
XXIV

XXV
XXVI

XXVII

CONTENTS

CLEANING AND ARRANGING LABORATORY AP-

PARATUS PREPARTORY FOR USE 1
Cream SEPARATORS 2
SEPARATION OF CREAM 6
Tue Use or tHe Bascock TESTER 9
Tue Use or THE LACTOMETER 18
Trestine THE AcipITy oF MILK . 20
PASTEURIZATION 24
SrargTter MakinG 28
Curp Trst 32
Cream RIPENING 33
Cream GRADING . 36
CHURNING 38
DETERMINATION OF THE WATER Goreme OF

Burrer 49
DETERMINATION OF Gasuie hae, AND Baur OF

Burrer . 57
CHEESE MAKING 61
GoupbA CHEESE 72
CorraGre CHEESE 72
Ick CrEAM 75
Datry BAcrERIOLOGY 79
Mitk Paint 7 89
TEsts FOR PRESERVATIVES . 90
TEST FOR OLEOMARGARINE . 91
REPAIRING CREAMERY MACHINERY . 92
MopiFIcaTIon oF MILK For INFANTS AND IN-

VALIDS : 95
STANDARDIZATION OF Mix 97
Conpensine MILK, MILK Paste, DRIED Mux,

Minx Sugar... 3 100-102

JUNKET, PAPANIZED Gamat Pastr . . 102, 103

ili

iv

EXERCISE
XXVIII

XXIX
XXX

XXXI
XXXII
XXXII
XXXIV
XXXV

CONTENTS

PAGE
Artimipcasrose, Mitk SHaxe, BuTTERMILK
HIGHBALL, BuTTERMILK Por, Koumiss, But-
TERMILK, Moose, Drigp MitkK Cocxrart 104-107
PREPARATIONS MADE FRoM MitK . . . . 107
Sotip Mirx, Soar, PREPARATION FOR Ivy
Porson, A Meruop or Mopiryine MILK FoR

INVALIDS, PRESERVING CASEIN . . . 108, 109
DISINFECTANTS i # @ © & - 209
MeEcHANICAL REFRIGERATION . .. . 110
CREAMERY BOOKKEEPING . eo ee ae LET
Writinc To Patrons. mas Oe f 121

CREAMERY CONVENIENCES . . . . . . 122

DAIRY LABORATORY GUIDE

INTRODUCTION

Tuis laboratory manual is published for the benefit
of the dairy short courses where the classes are largely
made up of farm-boys whose education ranges from
the Highth Grade to High School graduates. Con-
sequently it begins with the most elementary work
and touches only the practical side, with which every
dairy or creamery operator should be familiar.

Dairy classes are usually large, and where the in-
structor cannot give personal attention some students
will not grasp the fundamental principles underlying
the work. By following the outline of the manual
the student may work out for himself these principles
and their application. There is also a growing de-
mand for systematic laboratory work in the short
courses where a large amount of work is crowded
haphazard into a small space of time. The purpose
of this manual, therefore, is to aid the beginner in
obtaining the greatest amount of benefit from the
limited time spent in the dairy short courses.

Exercises in the operation of boilers and engines
are not included in this manual because that work
should be taken up in the mechanic arts department.

Vv

EXERCISE I

ARRANGING LaBoraTory APPARATUS PREPARATORY
FoR USE

Mix potassium bichromate K,Cr,O, and sulphuric
acid H,SO, in equal parts in eight to twelve of
water for a cleaning mixture. Clean all glassware
with this mixture by allowing the articles to stand

= new ~
ASHING But

Ay
WINE a Oe,
ser

Fic. 1.— Bottle washing machine and sanitary wash tank,
showing trap connections. This prevents water from
splashing on the floor and soiling clothes or disfiguring
machinery. The horizontal pipe should be six inches lower
for convenience in stepping over it.

submerged in it for at least twenty minutes. Re-
move them from the cleaning mixture, wash with

a solution of warm water and good washing powder,
1

2 DAIRY LABORATORY GUIDE

rinse thoroughly with hot water and allow them to
drain. Wipe every part of the remaining labora-
tory apparatus with clean waste, also the shelves

mii

om :
Fig. 2. -— Bottle Washer

and drawers to be used, removing every particle of
dust. Arrange apparatus in a neat, convenient, and
orderly manner for future use.

EXERCISE II
Cream SEPARATORS

Carefully examine all parts of each separator, be-
ginning with the frame. See that it is perfectly
level. Why? Note foundation of the separator and
see that it is solid and that the separator is firmly
fastened to it. Take out upper and lower bearings
and wipe carefully with clean waste, oil with clear
separator oil and replace. Determine method of
raising and lowering the bow] for proper adjustment.

CREAM SEPARATORS 3

Examine parts of bowl and put them together.
Place bowl in the machine and adjust cream screw.
Turn screw in to skim thick cream, and out to skim

SS eD

Fig. 3. — Empire Cream Sep-
arator showing Bearings
thin cream. Why? Put on cream and milk covers
and note purpose of float. Adjust oil cups and fill
with proper separator oil. Find speed of bowl by
counting number of revolutions of bowl to one of
the crank. If the crank makes fifty (50) revolutions

4 DAIRY LABORATORY GUIDE

per minute and the bowl makes one hundred and
fifty (150) revolutions to one of the crank the speed
of the bowl is 50 x 150 = 7500 revolutions per

TS

minute. Wash with warm water, using good wash-
ing powder, rinse with hot water and sterilize by
use of steam or boiling water all parts of the separator
and put them away, arranging each so that no two

Fic. 4.— Class in Cream Separating Laboratory, University of Nebraska

CREAM SEPARATORS 5

“dl

pe}

Fic. 5.— Dairy-room, Maryland Agricultural Experiment
Station, Dairy Building; showing correct method of
draining pails and cans; properly rounded cement cor-
ners of room; and student regulating the flow of oil into
the upper bearing of cream separator.

parts touch; they will thus areate and dry without
rusting. Repeat, using each separator, and note
difference in construction.

1G. 6. — Showing Cases for separator parts. These are con-
veniently arranged on the wall of the separator room.
The dust is excluded by means of glass doors. Kansas
Agricultural College Creamery Building.

6 DAIRY LABORATORY GUIDE

EXERCISE III

Take a given number of pounds of milk, separate,
and fill out the following blank:

SEPARATING REPORT

Date. 3 .ehee wares dees eeauvas 190
Name of separator used... 02.06.0000 cece eee e eee eee
Size of separator used .... 6.6... 20 eee ete eee
Rated capacity ............ 2. eee eee eee Per hour.
Actual capacity .............00 02s eee Per hour.
Quantity of milk separated................-...04, Pounds.

Average temperature of milk entering heater.................
Average temperature of milk entering separator..............
Average temperature of cream leaving separator..............
Average temperature of cream leaving cooler.................
Average temperature of skim-milk leaving separator..........
Average temperature of skim-milk leaving pasteurizer.........
Speed of separator bowl: Listed........ j Actual.............
Average test skim-milk 2.0.20... 2.0. cee eee eee eee eee
Average test cream .. 2.06666. eeee

SEPARATOR TEST

SampLe TAKEN FROM ENTIRE RuN

Samples Average
1/2)3]/4)]51|6
‘Time sample taken ...... pealeae|iesl reals vn |Seu|- shuse esos
Temperature whole milk. .|...}...]...|..-|...Jo..] -....cee eee
Temperature skim-milk ..|...]...]...]...).-.f...] ....... eee,
Temperature cream ..... daathertea|eavalieaueifare 4 |asav| sie ce coc ann
Capacity per hour ....... sapailigysie | ave, eleacl tate | tesa || gree atte en teas
Speed of bowl .......... sealves|warlesalscn|ses| nee eers coed y

On TR ener ee ap reesei Instructor.

CREAM SEPARATORS 7

In starting the separator fill the bowl full of luke-
warm water or skim-milk. Why? Start separator
slowly and increase to proper speed in about three to
five minutes. Why?

All cream and skim-milk should be cooled imme-
diately after separating.

OISCHARGE

Fic. 7. — Star Milk Cooler

1. Separate 10 gallons of about 4 per cent milk
at 90° F. and another can of the same per cent milk
at 70° F. Note difference in test of cream and skim-
milk.

2. Repeat experiment, using in one instance no
flush water and in the next the usual amount; just
enough to rinse out of the bowl the milk that remains
after separating.

3. Repeat experiment with separator running in
perfect condition, and again with the bowl unsteady
and vibrating.

8 DAIRY LABORATORY GUIDE

4. Repeat experiment one, using a high speed
of bowl in one instance and in the other a low
speed.

Fig. 8. — Milk Can Washer

5. Similarly separate a can of milk, allowing the
milk to flow slowly through the separator bowl at
about one-half capacity. Then separate

can of milk running at full capacity.
6. Separate a can of milk testing less
| than .2 per cent acid and another can at
| the same temperature but testing 35 per
cent to 4 per cent acid. In every ex-
periment make careful tests of cream
and milk to ascertain causes of varia-
Fic.9.— tion in the test of both skim-milk and

Milk Stirrer
and Aerator cream.

THE USE OF THE BABCOCK TESTER 9

Repeat operation, using each separator in dairy
room and note difference in skimming, simplicity,
and ease of running. Cool cream immediately after
separating.

EXERCISE IV

Tue Use or THE Bascock TESTER

Examine the tester and bottles carefully. Note
that the principle of centrifugal force in tester is
same as that of the separator. Mix thoroughly a

Fie. 10.— Babcock Tester

sample of whole milk of about 60° F. by pouring.
from one vessel to another several times, so as to
obtain an aliquot part of the mixture. Draw a
sample of this milk into a 17.6 c.c. pipette by placing
the mouth over the upper end and sucking the air
out of the tube. When the milk rises above the
17.6 c.c. mark remove the lips from the tube and
place the index finger over the end of the same.

10 DAIRY LABORATORY GUIDE

Allow the milk to drop from the opposite end of the
pipette by loosening the finger slightly until the edge
of the meniscus (rim of the crescent surface) touches

Ss & |i

UuUUypcyecguegny

TUT

Fig. 11.— Whole Milk ‘Fig. 12.— Cream
Test Bottle Test Bottle

the 17.6 c.c. mark. Then place the contents of the
tube into a whole milk test bottle, adding 17.5 c.c.
of commercial sulphuric acid from a graduated bottle

De el <= —=
Lw 0 Zz

Sf]

zz
Fig. 13.— Rack for Babcock Test Bottles
Norte. — For cleaning discolored test bottles add 1 Ib.

good washing powder to a gallon warm water. Fill

bottles one-third full and add 1 c.c. sulphuric acid
to each.

THE USE OF THE BABCOCK TESTER 11

or cylinder, being careful to pour the acid at an angle :
of about 45 degrees down the neck of the bottle so
that it will not cause a violent reaction until ready
to be shaken. Revolve milk and acid with a gentle

Fie. 14. — Pipettes

rotary motion until the curd of the milk is entirely
dissolved. Place bottles in tester, being careful to
put the same number on opposite sides of the tester

12 DAIRY LABORATORY GUIDE

to balance the machine. Oil tester and see that it
runs steadily. Revolve at listed speed for three
minutes. Then fill to the lower part of the neck
with hot water 150° to 200° F. Whirl again for two
minutes and fill to the upper part of the graduated
neck. Then whirl for one minute to a minute and

Fie. 15.— Combined Acid
Bottle and Pipette

a half, and read result at once before fat column
begins to cool and shrink. Read the per cent of fat
at about 120° F. If warmer it will be too high; if
colder too low. Butter fat solidifies at 80° F.

The speed of the tester required to produce the
necessary centrifugal force depends upon the diameter
of the wheel containing the cups. The less the diam-
eter the greater the number of revolutions.

THE USE OF THE BABCOCK TESTER 13

Diameter of Wheel in Inches|Revolutions of Wheel Per Minute

10 1074
12 980
14 909
16 840
18 800
20 759
22 724
24 693

In reading the per cent of fat place the lower point
of the dividers at the lower surface of the fat column,
and the upper point at the upper edge of the meniscus.

Fig. 16. — Correct method of holding dividers
in reading of the per cent of butter fat.
Resting the lower point of the dividers
on the tip of the thumb facilitates steadi-
ness. Balance scales for weighing cream.
Tin box for washing test bottles.

Now placing the lower point of the dividers at the
zero mark, and reading the result at the upper point.

14

DAIRY LABORATORY GUIDE

Uae
4B omnyNosy JO esaTog 9789g YIOX Mon ‘“Surpring Aeq Mon ‘K1opye1oqey Suysay, ATW — ‘LI “diy

t

ee

THE USE OF THE BABCOCK TESTER 15

This measurement gives a correct reading for whole

milk. For cream, take reading from the center of

the meniscus, on account of the larger amount of fat

in neck of cream bottle, and consequently in the
meniscus.

Fic. 18.—Scovell Fie. 19.—McKay
Milk Sampling Tube Milk Sampler
In testing skim-milk an increased proportion of
sulphuric acid must be used on account of the lesser
amount of fat present and the increased proportions
of solids which must be dissolved by the acid. The

16 DAIRY LABORATORY GUIDE

reverse is true of cream. Repeat tests, using cream,
but instead of measuring with pipette, weigh on
cream scales prepared for the purpose, using 18 grams
on account of the difference in specific gravity (com-
parative weight) between milk and cream. A still
more accurate test for heavy cream is obtained by
using 9 grams of cream with about the same quantity
of water and multiplying the result by two (2).
The richer the cream the more fat it contains and
consequently the lighter it is, and vice versa.

The variation between measurements and weights
of a given amount of cream is as follows:

Cream testing 15 per cent equals 8 pounds and 7
ounces per gallon.

Cream testing 20 per cént equals 8 pounds and 64
ounces per gallon.

Cream testing 25 per cent equals 8 pounds and 6
ounces per gallon.

Cream testing 30 per cent equals 8 pounds and 54
ounces per gallon.

Cream testing 35 per cent equals 8 pounds and 3
ounces per gallon.

Cream testing 40 per cent equals 8 pounds and 1
ounce per gallon.

Cream testing 45 per cent equals 7 pounds and 15
ounces per gallon.

Cream testing 50 per cent equals 7 pounds and 144
ounces per gallon.

Repeat; using in first experiment less acid; second
experiment, cold milk; and third experiment, cold
water. Note results. Similarly test butter and

THE USE OF THE BABCOCK TESTER 17

finely pulverized cheese, using 9 grams in each test,
and multiplying the result by 2. Obtain accurate
sample by inserting trier in various places in the
cheese or butter to be tested.

Also test samples of ice cream using a mixture of
equal parts of Conc. hydrochloric acid and glacial
acetic acid.

Hydrochloric acid alone chars the milk sugar on
heating almost as bad as sulphuric acid, and, there-
fore, is useless. Acetic acid alone will not dissolve
the milk solids, but the mixture works perfectly.

When milk has become sour the casein may be
redissolved by adding powdered potash, baking soda,
or liquid ammonia. Care should be taken not to
use too much alkali as it reacts with the acid and
sometimes throws a part of the sample out of the
bottle. Dissolve the potash or soda in water before
using. A volume equal to about 5 per cent of the
volume of the milk will be sufficient to dissolve the
casein. This solution increases the volume of milk
and thus necessarily decreases the per cent of fat.
Measure the volume of milk to be tested, and meas-
ure the solvent before adding. Calculate the de-
crease in the per cent of fat in the following manner:

If 9 cubic centimeters of alkaline solution has been
added to 180 cubic centimeters milk to dissolve the
casein, which is 5 per cent of the milk used (180:9 :
:100:x =5), the mixture gives a test of 3.9 per
cent of butter fat. The test must be increased 0.195
per cent (3.9 X .05 = 0.195). Hence, the per cent of
fat in the original milk is 4.095 (3.9 + 0.195 = 4.095).

18 DAIRY LABORATORY GUIDE

Testing Strength of Acid

Test strength of acid by finding its specific gravity,
which should be 1.82 to 1.83. This can be done by
weighing an exact measured volume of acid and
comparing its weight with the same volume of
distilled water. Then divide the weight of the acid
by the weight of the same volume of water and the
quotient will be the specific gravity of the acid. If
the fat column is very light and contains white
specks the acid is too weak, not enough used, or
milk was too cold. If very dark or if it contains
black specks the acid is too, strong, too much was
used, or milk or acid was too hot. The fat column
should be of a light straw color.

EXERCISE V

UsEe or THE LACTOMETER

The lactometer is used to determine the specific
gravity of a liquid; that is, its weight compared with
the weight of an equal volume of distilled water.
Where a given volume of distilled water weighs one
pound, an equal volume of whole milk weighs 1.029 to
1.033, depending upon the per cent and kind of solids
present. The higher the per cent of fat in milk the less
the specific gravity and vice versa. The specific grav-
ity of milk serum is 1.036. That of fat is 93. The
Quevenne lactometer is generally used. Examine the
lactometer carefully and note enclosed thermometer
and graduations. Place in graduated beaker of milk

USE OF THE LACTOMETER 19

having a temperature of 50° F. Heat milk to 60° F.,
noting changes in lactometer reading. Take sample
of milk for fat test and set it aside. Now add a

Fic. 20.— Quevenne Lactometers

definite proportion of water to the milk in the beaker
and take readings at the same temperatures as before.
What is the difference? Why? Calculate formula

20 DAIRY LABORATORY GUIDE

for obtaining correct readings at varying tempera-
tures. Find solids not fat, and per cent of water as
follows: 4 of fat found in the milk plus + of lactometer
reading equals solids not fat. Total solids are ob-
tained by adding the solids not fat to the fat. For
example: Where lactometer reading is 32 and fat is

3.5 per cent & + =) — 60 4.7) = 871 B74

3.5 = 12.3 = total solids. For finding per cent of
water in milk: solids not fat of normal milk minus
solids not fat in watered milk, multiplied by 100
and divided by solids not fat of normal milk, equals
per cent of adulteration. For example:

S. N. F. Normal Milk — 8. N. F. Adulterated Milk
S. N. F. Normal Milk

xX 100 = per cent adulteration.

EXERCISE VI

Testing Acipiry or MiLtk

The acidity of normal milk is caused by the breaking
down of milk sugar by bacteria and converting it
into lactic acid. The change is supposed to occur
in the following manner:

Milk-sugar. Water. Lactic acid.
CrxH2O01 +H20 = 4C3H.Os

There are several tests for the acidity of milk.
Those most commonly used are as follows:

Mann’s Acid Test.

Farrington’s Alkaline Test.

TESTING ACIDITY OF MILK 21

Van Norman’s Alkaline Test.
Marshall’s Acid Test.

Mann’s Acid Test

Fill a 50 ¢.c. burette to zero mark with tenth
normal solution of sodium hydroxide NaOH. Meas-
ure 50 c.c. of milk or cream to be tested into a
beaker. In the case of cream dilute with water,
the amount depending upon the thickness of the
cream. Add a few drops, two
to five, of indicator; phenolph-
thalein is generally used. Add
the alkali solution to the cream
very slowly, and stir constantly
until a permanent pinkish color
remains in the milk. The per
cent of acid is found by mul-
tiplying the number of c.c. of
alkali solution used by .009, (\
dividing by the number of c.c.
of milk or cream used and mul-
tiplying the result by 100. The

i
explanation of this formula is i
that the alkali of the sodium 2
hydroxide neutralizes the acid Fic. 21.— Acid Bottle
of the milk. 1c.c. of tenth nor- eee
mal solution contains .004 of a gram of sodium hy-
droxide which neutralizes .009 of a gram of lactic
acid. This is obtained from the fact that a normal

solution of lactic acid contains 90 grams of acid in
each liter, or 1000 c.c. Example:

22 DAIRY LABORATORY GUIDE

c.c. alkali 34 xX .009
50 ¢.c. Cream

X100 = .612% acid.

Obtain by means of a pipette a sample of milk
from the top and one from the bottom of a beaker
of milk that has been allowed to stand for several
minutes. Test and note difference. Why?

Farrington's Alkaline Test

Dissolve five of Farrington’s tablets in enough
water to make solution 97 ¢.c. Mix well and measure
out 17.6 c.c. of the milk or cream to be tested, and
add the alkali solution as in previous tests until the
characteristic pink color remains. The number of
c.c. of alkali solution required to produce this result
indicates the number of hundredths per cent acid, -
since 1 ¢.c. of alkali neutralizes .01 per cent of acid
when 17.6 c.c. of milk are used. Therefore the
number of c.c. neutralizer used divided by 100
equals per cent of acid. For instance: If 50 c.c.
solution be used the acidity of the milk in question
is .5 per cent. The Farrington tablets contain alkali
equal to 3.8 c.c. of tenth normal solution and also
the color indicator.

Van Norman’s Alkaline Test

Pour into a 1000 c.c. graduated flask 20 c.c. of
normal caustic soda (NaOH) solution, fill to the
1000 c.c. mark with distilled water, making 50th
normal alkali solution. Put 17.6 ¢.c. of milk or
cream to be tested into a beaker and add four to

TESTING ACIDITY OF MILK 23

five drops of phenolphthalein.t Allow the alkali solu-
tion to drop slowly into the milk or cream being
tested; meanwhile continually stir until a pinkish
color is noticeable which does not disappear imme-
diaetly by continued stirring. The number of c.c.
of alkali solution required to bring about this result
will indicate the number of hundredths per cent of
acid, since 1 c.c. of alkali will neutralize .01 per
cent of acid when 17.6 c.c. of milk or cream is used,
as in Farrington’s Test. Thus if 50 c.c. neutralizer
be used the milk has an acidity of .5 per cent.

Marshall's Acid Test

Carefully mix milk or cream to obtain an accurate
sample as in above cases, and fill a 9 ¢.c. pipette with
one-tenth normal solution alkali as prepared at the
factory. Add from two to four drops of indicator.
Allow alkali solution to drop into the milk, constantly

1 Phenolphthalein is one of the dyes made by a combination
of certain coal tar derivatives (phenols) with phthalic acid; in
the presence of free alkali a chemical combination is formed
having a red color. When a few drops of phenolphthalein
solution are added to milk containing free lactic acid no color
is appreciable in the milk; as the alkali is added the lactic acid
(which has a greater affinity for the alkali than has the phenol-
phthalein) is neutralized; and as soon as it is all neutralized the
slightest further addition of alkali changes the indicator to a
pink color. Shaking, or stirring, during the test is necessary
because the effect of the alkali in producing the red or pink
color in the indicator may be seen locally, where the alkali falls
into the milk, before the acid in the milk is all neutralized. As
soon as all the acid in the sample is neutralized the pink color
remains.

24 DAIRY LABORATORY GUIDE

stirring as in the previous tests until a permanent
pink color remains in the milk. The number of c.c.
used divided by 10 indicates the per cent of acid in

Fic. 22.— Apparatus for Marshall’s
Acid Test

the milk or cream being tested. Thus, if two (2) c.c.
of neutralizer has been used the milk contains .2
per cent of acid.

EXERCISE VII

PASsTEURIZATION

Fill jacketed space of pasteurizer with water and
turn on steam until the desired temperature is

PASTEURIZATION 25

reached; from 150° to 190° F., depending on condi-
tion of milk. Start motion of pasteurizer by throwing
belt on tight pulley, and when the desired speed is
reached open milk inlet. Notice temperature of milk
at the outlet from pasteurizer and regulate by the
connecting steam valve. Draw pasteurized milk off
into sterile cans, placing a clean white cloth or
parchment paper above spout and opening of can
to prevent contamination from the surrounding
atmosphere. Among the pasteurizers in common
use are the Jensen, Reid, Miller-Tyson, Miller, and
Farrington.

The Miuller-Tyson Pasteurizer

The machine is dependent upon centrifugal force
for its action. The film decreases in thickness and
increases in speed as it nears the periphery of the
treating plate. It requires fifteen seconds to com-

26 DAIRY LABORATORY GUIDE

plete the process of -pasteurization, heating to 180
degrees, and cooling to desired temperature.

After pasteurization there is no milk left in machine
and it does not have to be taken apart for cleansing,
but by lifting covers all contact surfaces are in direct
view and can be touched with a brush.

It is said to be equally adapted for the pasteuriza-
tion of sweet milk and thick, sour cream.

The essential point in the construction of a
Regenerator is the employment of a non-conducting,
revolving cylinder which permits the uniting in a
single apparatus, the heating on a water-heated
surface with an effective interchange of heat. The
Regenerator consists of a bank of pipes, perfectly
smooth inside, connected by means of vertical end
plates, and communicating one with the other by
means of sanitary detachable manifolds. The milk
coming from the Pasteurizer passes through this
bank of pipes, entering the same at the bottom,
and being discharged at the top so that the hottest
milk fills the lowest pipe, and as it becomes colder,
the coldest milk leaves at the top to be discharged
to the cooler. The cold milk runs over this bank
of pipes on the outside, striking a pipe first
nearly its own temperature and gradually becoming
hotter as it passes down over the apparatus, finally
getting almost as warm as the milk leaving the Pas-
teurizer. A great saving is therefore effected in the
use of steam on the one hand, and in the use of cool-
ing with cold water or ice on the other. In other
words the heat which has once been imparted to the

PASTEURIZATION 27

Fic. 24.— Regenerator in use in Schier’s Dairy, Baltimore, Md.

milk by means of the Pasteurizer is used to partly
heat the milk which shall enter the Pasteurizer, while
the cold milk helps to cool that which flows from it.
It is obvious that if the service of conduct is large
enough a complete exchange of the two temperatures
must take place.

28 DAIRY LABORATORY GUIDE

EXERCISE VIII

STARTER MAKING

Sterilize a clean-flavored batch of sweet skimmed
or whole milk by running it through a pasteurizer
and heating to about 212° F., preferably two days in
succession. Allow the milk to run into a sterile
quart bottle. Cover spout of pasteurizer and open-
ing in the bottle with clean white cloth or parch-
ment paper to prevent contamination from the
surrounding atmosphere, as in the case of pasteur-
ization. Cover bottle as soon as full and cool to
80° F. Add contents of bottle or capsule of com-
mercial culture and allow to remain at 80° F., until
milk becomes partially thickened, or has the consist-
ency of thick cream. This usually requires from
eight to twelve hours. At this stage it is called
startoline. Pour from the top of the bottle into a
can containing from five to. ten gallons of pasteur-
ized milk the entire contents of the bottle, with the
exception of about one tablespoonful remaining in
the old bottle. Put the spoonful of starter remain-
ing in the old bottle into a clean sterile bottle and

1 Where glass jars are used.a steaming cabinet is, very con-
venient. This should be made to hold three times as many
jars as are required daily. Place one day’s supply in, heat to
from 200° to 212° F. for half an hour. On the following day add
a like number and repeat the heating. On the third day add
another day’s supply and again repeat the heating. The first
jars have now received three applications of heat and are prac-

tically sterile. By replacing each day as many jars as are taken
out a supply of sterile mother starter is constantly on hand.

STARTER MAKING 29

add enough milk to continue the propagation of the
original culture, being careful thereafter to keep
at 70° F. Stir every half hour as before. Mix

ae

<< =I

Fic. 25. — Trunnioned Starter Can. This Starter Can
is trunnioned on its frame in such a manner that
the starter may be drawn off from the top, leaving
the lower, less contaminated portion for propaga-
tion. The agitators serve to keep the starter in a
uniform condition while ripening.

The space between the jacketed sides may be used
for cold water in the summer, and warm water in
the manver to maintain an even temperature about
70° F.

thoroughly the starter and skim-milk in can and
allow to stand at 70° F., until the proper consistency
is reached, when it is ready for use. The following
blank form may be used in this exercise:

30 DAIRY LABORATORY GUIDE

STARTER REPORT

Kind of starter made (Ericsson, Douglas, Hansen, Parke Davis,

ete:;0r natural)! ec ccccs ees cden debe nonce ones eee thes
Number of culture used .........0.0.. 0000 c eee cee eee
Pounds of milk used 2.0... 0.0.0 0c ccc ee teens
Acid test of milk before heating .....................0.0000.
Temperature of heating 2.2.04 sssuy 55 daees sd otea yea ees wes
Time held at this temperature............. 0.000 cece eee eee
Temperature after cooling .............. 0.00000 e eee eee eee
Quantity of culture used ....... 0. eee eee eee
Time of setting ...........0 0... e eee eee SpE sSia Geet sare Aa CESS

ACIDITY OF STARTER

Time Temperature Test
Held at what temperature when ripe .......-.-.-.+.-++05- aes
Describe Mayors 4 1.42 es0e ko cas pane eau es MRR aed yee
Rema tes aaiead nuke 4 on ie eer Gade y Ha eee Ge ees OR EERE Rw Re
(SiPNER): sees Sauievahndd s neal tas aa pete
OOS avalc air other cattlnds Instructor.

In preparing starter it is advisable to keep several
samples of mother cultures propagating. If an incu-
bator cannot be obtained a small cream vat may be
converted into a form of incubator which may be
used for maintaining an even temperature, where
such samples or small quantities of milk or cream
may be kept. These vats are double-lined, having

STARTER MAKING 31

a dead air space of about three inches between the
tin jacket and outer tank. This space surrounds the
entire tin jacket or inner tank, and can be filled with
warm air in the winter and cold in the summer, to
impart uniform temperature to the samples contained
therein. About six inches of water may be kept in

Fic. 26

the tank to aid in maintaining an even temperature.
Ice may be used in summer if obtainable. Of course
the opening E should be closed in the summer. The
accompanying cut represents the vat. EH represents
the opening from below to the dead-air space and
the place for the lamp which is kept burning con-
tinually except when room temperature is 70° F. or

82 DAIRY LABORATORY GUIDE

warmer. The lamp keeps the air warm and at an
even temperature regardless of the weather. In case
of extreme cold weather the burner may be turned
higher than in warm weather. D represents the slats
used in the bottom of the tank which allows the
water to come in contact with bottom of the pails
or bottles used.

EXERCISE IX
Curp Test

Make curd tests by placing in composite sample
bottles, or other convenient glass jars, samples of

Fie. 27. — Curd of Milk from Sterilized Separator

various kinds of milk to be tested. Heat to 90° F.
and add a few drops of rennet, depending upon the

Fic. 28.—Curd of milk from separator merely flushed
with warm water. The milk in both instances was
pasteurized before separating.

quantity of milk used. Place in incubator or warm
room and allow to remain until curdled. Remove

CREAM RIPENING 33

slices of curd with sterile knife and examine for
flavor, odor, etc. Remove whey and allow samples
to remain from eight to twelve hours and examine as
before. Also note presence or absence of pin-holes
and other defects caused by gas forming or putrefac-
tive bacteria.

EXERCISE X x
CREAM RIPENING

After separating and pasteurizing as indicated in
Exercises 3 and 7, add starter as prepared in Exercise
8, the amount depending on the per cent acid in
the cream and the length of time previous to churning.
Keep the cream at 70° F. during cold weather and
60° F. in warm weather, until an acidity of about
.5 per cent has developed. Now cool the cream to
45° F. and allow it to remain at that temperature
for at least two hours, when it is ready to churn.
Why leave at this temperature so long? Heat to
50° F. for churning in summer and 55° F. for churn-
ing in winter.

Formula jor Adding Starter to Sweet Cream, or Cream
which is to be churned vmmediately without
ripening.

Suppose your standard of acidity for ripened
cream is .5 per cent, that of the starter is .9 per cent,
and the standard amount of starter is 10 per cent, the
acidity of the cream on hand is .4 per cent, and that
of the starter is .8 per cent; then

34 DAIRY LABORATORY GUIDE

5X90+.9X10—.4x100
8—4
be used.

= 85 per cent starter to

“4 ¢

temperature of the cream and also keeping it well mixed.

{Soc

Fie. 29. — Jensen Cream Ripening Vat, showing water-pipes for regulating the

Experiment with the use of commercial lactic acid
for ripening cream, using from 10 to 20 c.c. per gallon.

CREAM RIPENING 35

The following blank form may be used in this
exercise :

CREAM RIPENING REPORT

Name and capacity of vat used.......... 0.0... c cece eee aes
Pounds of cream in vat ...... 2... cece eee eee
Pounds of starter added ......... 0... cee eee ee eee eee
Kind of starter used. i .accsnassedycudeeareapiek oxy nenaaus 24
Acidity of starter when used ................ 02s cee eee eee
Number of culture 2.20... cee
Babcock test of cream after adding starter ................-5
Required acidity: a: 25 6 sss dens ee 4 ey Ses eNaRee eee aes ered
Was cream pasteurized? 2.2.0.2... cece eens

TESTS FOR ACIDITY

Time Temperature Test

Time:required ‘to'ripen. s+ 43.2% 254 assem med ey ewe ea
Temperature to which cream was cooled .............+..-0+5
Acid test after cooling............ 0... c cece eee eee
Manner of cooling .............. 0c cece cece teen enaee

BOW ace blow leper el wie lin! alte ie ee ein ee erie ake GR TIES OSE WP Sg oe oe we Bla) Bee eS ee

(Signed) ............00005: Sagegd tie sae
On Ke. cenci tae ican ba wed eae Instructor.

Viscogen

When cream has been pasteurized above 150° F.
its viscosity is reduced by a loosening of the galactase
which holds the fat globules in groups. To restore

36 DAIRY LABORATORY GUIDE

the viscosity add viscogen. The formula for vis-
cogen is 2} parts of sugar, or all that will dissolve
without caramalizing, 5 parts water, 3°; part milk
of lime. Prepare one gallon. Mix thoroughly and
allow to stand for at least twenty-four hours. Vis-
cogen is an alkali and if too much be added it gives
a bad odor and bitter taste. One ounce of viscogen
is sufficient to restore the viscosity in five gallons of
sweet cream. The higher the per cent of acidity the
more it will require. Where viscogen is added to
cream for market it should be labeled visco-cream.

EXERCISE XI
CREAM GRADING

Make acid test; curd test; heat a sample of milk or
cream to 120° F., and note odor. Take lactometer
reading. First-grade cream should test between 30
and 50 per cent butter fat, from 0 to .2 per cent
acid, and have a good clean flavor. Second-grade
cream may test from 20 to 50 per cent butter fat and
have not higher than .3 per cent acid, and fair flavor.
Third-grade cream should not be used for butter-
making.

A test for ammonia in milk or cream may also be
made by adding 10 c.c. of 10 per cent solution of
bichloride of mercury and potassium iodide (Nessler’s
Reagent) to 10 c.c. of milk. A precipitate is at once
thrown down. Filter and add 3 per cent solution of
pure milk of lime until a black precipitate is formed
which disappears with an excess of reagent, This

CREAM GRADING 37

test is seldom used and is unnecessary except where
the water used in the dairy is suspected of being con-
taminated with sewage.

Scrupulous cleanliness should be practised in
bottling milk. It should never be retailed in any
other form. The caps should never -be removed
until delivered to the consumer.

SCORE CARD FOR MILK

Underscore
Perfect Defects
Noted

spt Per cent of fat....|3.5t0o5%|....-.....
Pempesuan tad %){ Solids not fat....- Bebe 10 Be, Vis seticin es

Keeping Quality | ..........-..-.-- Ohgierats sie Dirt
(BOG) Naat Caeecam eden O........ | Ferments
Stn WOO Dae Oto 3000%| High bac-
terial con-
tent

siebeniee ieawets ssacoeess| Bitter
Sugpbarbacnce weare teal Aa aise Flat
Stabl
Flava G0gR) | eerste Clean eas :
S Peaneeeroeeaaer:. | Riss aesees Tainted
sie yeedeee Weedy

38 DAIRY LABORATORY GUIDE

PlaVOP scared ecaieseeier doses sane ee Re oes 40
COmpPOStblon .a'ss:c iets Gea suscd Son aes s vies eee 25
Bacteria... 4 3..ssinca sence spans ine hoe: toutin gemdee 418% 20
AGL 3c. cag eins chante ageamnees oH 5
Appearance of package and contents.......... 10

The score cards used for milk and cream by the
Dairy Division, Washington, D. C.:

CREAM SCORE CARD

FLAVOR ; CONDITION
Taste Smell Cleanliness Acidity Total
0) 30 20 20 100

MILK SCORE CARD

FLAVOR CONDITION
Taste Smell Curd Test Cleanliness Acidity Total
25 25 25 15 10 100

EXERCISE XII
CHURNING

Rinse churn with hot water from 150° to 200° F.,
revolving it from five to ten times, being careful to
‘leave stopper out. Draw off water.and rinse again
in the same manner with pure cold water at about
40° to 50° F., leaving stopper in during the last
rinsing. Draw off water and pour the ripened cream
in, filling churn about one-third full so as to allow
the greatest splash in churning. Add _ vegetable
coloring, the amount depending on the time of the
year and the market requirements. If cows are
receiving no grass and the market demands a high
color, an ounce or 30 c.c. color to each 50 pounds

CHURNING 39

of butter fat may be used. Put cover on tight
and set churn in motion, removing stopper two or
three times during the first part of the churning
to allow the moist air to escape. _

Fic. 30. — Disbrow Combined Churn and Worker with sections
showing butter being worked.

When the butter has gathered in granules the
size of number 4 to 00 shot stop the churn and draw

40

DAIRY LABORATORY GUIDE

off buttermilk. Rinse once, using one-quarter of the
churnful of sterile water, or as pure as can be ob-

Fic. 31.—- Churning and Cream Ripening Department of the

Model Dairy of the Louisiana Purchase Exposition,
showing machinery operated by a 5-horse-power dy-
namo. Thisis the most sanitary source of power ob-
tainable for a creamery. One of the most important
precautions for the beginner in the use of a dynamo is
that of starting and stopping. In starting the current
is first connected with the switch. Then the crank or
starting rheostat is moved slowly over the controlling
box to the magnet which holds it in place, while the
current ison. If the starting rheostat is moved over
quickly the field in the controlling box does not “catch
up’’ with the current immediately and a fuse may be
blown out, or the field overstrained. In stopping the
dynamo, disconnect current by merely throwing off
switch. Never try to move starting rheostat back while
current is on. Use nothing but insulated copper-wire
Ean ences and see that they are kept clean and
tight.

tained, revolving the churn about three times. Draw
off, and if water still has milky color rinse again,
otherwise not. Add salt, depending on the market

CHURNING 41

requirements. One ounce and a half of salt per
pound of butter fat is usually sufficient. See that
salt is kept in a warm place, and to give best re-
sults the salt must not be colder than the butter.

Fig. 32

The condition of the salt has a great effect upon
mottles.'_ Throw workers into gear, using low speed.

1The cause is the uneven distribution of salt. If butter is
churned at a warm temperature the outside of the granules are
chilled while the butter on the inside is still soft. The soft butter
on the inside will take up the salt more easily than the outside
which is harder, and thus produces mottles.

The same condition is obtained by having butter too firm to
work so that it is impossible to get the salt mixed thoroughly
through the butter; or by churning very cold cream and using
warm wash water. Going from one extreme to another in tem-
perature is likely to cause mottles.

42 DAIRY LABORATORY GUIDE

Revolve churn about ten times and allow to stand
for twenty minutes to give the salt a chance to
dissolve evenly. Work ten revolutions more, take
out, and print or pack in cases or tubs which have
been previously scalded and coated on the inside
with paraffin at 250° to 260° F. Why?

In the summer give the Disbrow churn 19 to 20
revolutions. In the winter it is necessary to increase
it to 25 to 28 in order to give the butter the same
amount of working. Where a Victor churn is used,
in place of 9 revolutions as in summer, it will re-
quire 11 to 12 in .the winter.

Calculate per cent of overrun as follows:

Pounds of butter minus pounds of butter fat equals
number. pounds overrun. Number of pounds of over-
run divided by pounds of butter fat equals per cent
overrun; for example, 800 pounds of butter fat make
900 pounds of butter. 900 — 800 = 100. 100 +
800 = 123 per cent overrun.

The following blank form may be used for this
exercise:

Pounds butter-fat computed from exercise No.4 .............
Estimated pounds of butter ........... 0.0.0.0 c cece eee eee
Pounds:of butter made: 2. s4 5 ccc0s pede ss due Miva eee ce aes

Temperature of cream in vat ....... 0.0.00. cece eee eee
Time since cooling ........ 0... cece cece cette tenes
Acid Cest/s ge... au de oan eee Sda gas adele Vee aan Releases

CHURNING 43

Percentage of Pounds overrun on 80,000 ‘Value of overrun

overrun pounds butter fat at 25c. per pound

22.5 18,000 $4,500
22 17,600 4,400
20 16,000 4,000
19 15,200 3,800
18.9 15,120 3,780
18.25 14,600 3,650
18 14,400 3,600
17.82 14,256 3,564
17.8 14,240 3,560
17.71 14,168 3,542
16.7 13,360 3,340
16 12,800 3,200
15 12,000 3,000
14.1 11,280 2,820
13 10,400 2,600
12 9,600 2,400

9 7,200 1,800

8.94 7,152 1,788

8.6 6.880 1,720

7.5 6,000 1,500

5.84 4,672 1,168

In packing a tub of butter first boil the tub in a
strong solution of brine to rid it of all undesirable
bacteria and mold, apply melted paraffin on entire
inner surface and then set in the refrigerator to cool
off while churning. Only the best of circles and
liners should be used and these should be soaked
about twelve hours in a cool brine solution which
has been previously boiled. After the butter has
been properly worked the brine is poured from the
tubs, and the small circles, still wet, are placed in the
bottom of the tub; the liner should then be put in wet
and neatly pressed into place, leaving about an inch

44 DAIRY LABORATORY GUIDE

above.the top of the tub. It should then be turned
down over the rim of the tub to prevent wrinkling
in packing the butter. All wrinkles or kinks should
be carefully smoothed out before putting the butter
into the tub. If the butter is then put in in small
quantities and carefully packed there will be no holes.
Do not pack enough to spoil the grain. After packing
the butter until the tub is rounding full, cut the top
smooth by means of a fine wire trimmer, then turn
the projecting inch of the liner back over the top
surface of butter; place a cheese-cloth circle over
this and cover the latter with the top paper circle.
A single handful of salt should be sprinkled over the
paper circle and the cover nailed neatly on.

RAW MATERIAL SCORE

Quality: oc 4e'sse00 835 2% 9Di os see ee eee eeu
Canis saaeechdesesee tek es a) pitt aata ka oe Susoeaaie is
TOGA 25 dois3.2ahecegak aad LOO: seit obs eee Gee

Name: of Creamery’. 2. ccoss ene oa ness ely ee ea lee eee oe ed ca ale
Post Office........... County.......... Stabe: sre wis dca soot

Inspector.

CHURNING 45

BLANK FORM FOR CLASS IN CHURNING

Kind of color used ........ 00.0. eee ett aes
Kind of salt used... 200... 0 cece cece cee e cece cece eens
C.C. or ounces color per 100 lbs. butter-fat...... Total C.C......
C.C. color per 1000 lbs. milk ................ TotalC.C ....
Ounces salt per lb. butter.................... Totallbs......
Time starting the churn .............0..... 000.2 e eee eee
Time churning finished ...............00. 0000s cece cece eee
Size:of pranulés jc cccesiac pee tia Mi taewned ohana eG dene ETS
Temperature buttermilk .................. 00.00 eee e eee eee
Number washings given ...... 0... 0c cece cece eee eens
Temperature Ist.............. Temperature 2d..............
First working, number of revolutions of churn................

INO: MINUS: peeves dads n Ls de Bae Rae aa RR Eee
Second working, number of revolutions of churn .............

ING: MIDULES' < ace nake Seno rader ie tgaind hatdionGan BELO eS
Interval between workings, minutes...................000.0.
Kind of packages put up .... 6.0... 1c eee eee
Babcock test of buttermilk ..................00 00002
Pounds butter-fat lost in buttermilk .....................0..

(Signed) sacs ve eawiet ea aie ev craw ae as
QUIK, 2acdnacaivauh i eeamey Instructor.

————)

Fic. 33. — Butter Trier

BurreR SCORING

The following score card is generally used for scoring
butter:

46 DAIRY LABORATORY GUIDE

BUTTER SCORE CARD

1st Scoring 2d Scoring Underscore Defects

Perfect Date Date Noted

Curdy
Light
Rancid
Fishy
Feverish
Flavor ....... ABN ra cee coeat sire ceall eeagtetiatn abe se Oily
Weedy
Stable
Unclean ~
High acid
Low acid

Poor grain
Cloudy brine
Weak body
Texture ...... O65 | wavevinweices |s eee sar sen cae Too much brine
Cheesy
Tallowy
Greasy

Mottles

White specks
Color....... votes ALB) [Rd Segoe be agiomie a ue eds Too high

Too light
Streaky or weavy

Too much salt
(Undissolved)
Salt .......... LO) |e venssversicnierdoant ‘ene vi | toamicceain aGudaes. seh Poor salt
Lacks salt
Gritty

( Dirty
| Poorly packed
Package ...... Dil ascesb node deh tibet eFate | east oa aNerR aaa Poorly nailed

Poorly lined
Total ........ TOO) |e csenitvesssavatcn Seated amen aurantaenes? lt Untidy

CHURNING 47

The following score cards proposed by B. D. White
of the Dairy Div. Dept. of Agri., Washington, D. C.,
is a most efficient means of classifying butter-makers
and grading creameries. Score the College Creamery
and members of the Dairy Class accordingly.

In coéperation with Dairy and Food Department in the State of...
CREAMERY SCORE CARD

Scale, Score
f Driveways and

| Grounds.... 2 ......0-.

Outside, 8. { Platforms.... 2.........

Out Buildings. 2 .........

General Ap- Painting. -... wo 2 veewese es
pearance of
P. i 20

crate ec ee De iacehetinic

Inside, 12.. } Ventilation... 5 .........

Painting.....- B sebiennes

Floors, Construction and Condition ........... LOsae ae gue ee

Drainage Disposal ............ 0.00000 e eee 10. 6 et eager ae

Efficiency and Sufficiency ... 10 .........

Arrangement ............... Be ass see Snes ae

Machinery, 50 { State of Repairs ........... Dy Re paunle,

Sanitary Construction ....... 20 sasexedes

Durability ..............04. LO asenzabace: 3

PUIG? 5 aie 'oG Gas hae ae eee 3 Sh aaindacsooee

Water, 10.... Location and Condition of
Well ic sexck Gants gees oe 2) erase ieee

48 DAIRY LABORATORY GUIDE

BUTTER-MAKER’S SCORE CARD

Seale, Score

a Thoroughness 5.........
RIN aa a Records ..... 2 .........
Experience... 5.........
Possotial Be, Training, 14.. | Education... 3.........
Tact........ Oreste

Personal

Personal :
Wevienes 4 Cleanliness, 2.........
Re Clothing. .... 2 pea wer eH
Odors....... Oy erie oS
Grading of Raw Materials, 15 . . | Flavors...... 6 geraawees
Acidity ..... Sceee gases é

From Weighing Can to Cream

Walt wieus 2 tues seed Rdtooecenttasedit ded IB dics aeultrase
Making Starter 10 .........

Starter,25.... {uty of
Method of Starter vaeu 1D swan wees
Making, 50 | Ripening Cream.............. 6 creed eave
Churning soca agape dE sedesean dct fr
Working .................... Bos inte aasbos
Moisture .................00, A otis a es
Preparation of Package....... Dae ioc
Sanitary Condition of Creamery.............. LOS cracisaoniiey
Total........ 100 .........

Remarks. — Write remarks on reverse side.

Name of Butter-maker........ EGTA EWE AG BeBe tw ee ees ee
Name of Creamery’ ¢nc¢ sce sivas cede a cusie es Whe mer sneens
Post Office .......... County.......... State causscaua sass

Inspector.

Remarks. — Write remarks on reverse side.

DETERMINATION OF THE WATER 49

EXERCISE XIII

DETERMINATION OF THE WATER CONTENT OF
ButTTER

Trish Motsture Test

Read carefully the following explanations and test
samples of butter according to directions.

Weigh 10 grams of butter into an aluminium cup
upon a sensitive scale. Evaporate the water by
holding the cup and contents over the flame of an
alcohol lamp. Place a mirror over the cup to catch
and condense the escaping steam. When no more
steam condenses on the- mirror the sample has becn
boiled long enough. Cool and weigh again, the per-
centage of loss being calculated and considered as
water."

Gray's Method

A number of schemes have been tried, some giving
results more or less satisfactory, but one only, that
of Prof. C. E. Gray of the Dairy Division of the
Department of Agriculture, Washington, D. C., has
been perfected to such an extent as to give results
which seem wholly satisfactory. With this method
(requiring apparatus costing only a few dollars)
any one of average intelligence, after a few trials,
may make moisture determinations with comparative

1The weights added to indicate the loss in weight by re-
moval of moisture are so marked that, by adding the figures
upon them, the percentage of water can be determined direct.

50 DAIRY LABORATORY GUIDE

accuracy. The test is described by Professor Gray
in the following manner:

Apparatus

The apparatus required for making the test is as
follows:

Balances. Sensitive to 0.025 gram. A balance
suitable for weighing samples of cream for the Bab-

wit

TAC li

Fig. 34

cock test should be satisfactory for weighing samples
of butter for this test; however, there are many
cream balances in use which are not accurate enough
for weighing either cream or butter samples.
Weights. One 5 gram and one 10 gram.
Graduate. For measuring 6 c.c.

DETERMINATION OF THE WATER ol

Burner. If gas is not readily available an alcohol
lamp may be used.

Paper. Parchment 5 by 5 inches; must be per-
fectly dry.

Special Apparatus. As shown in figures. Refer-
ring to figure 35, A is a flask of a capacity of a little

Fig. 35

over 75 c.c. C is a graduated tube, which is con-
nected with the flask A by means of a rubber
stopper B; F is a glass stopper ground into the
tube C. Each glass stopper is ground to fit a par-
ticular tube and will not properly fit other tubes.
Each stopper and tube should be marked, by the

52 DAIRY LABORATORY GUIDE

manufacturers, to eliminate this danger of using a
tube with a stopper which has not been ground to
fit. The tube C is graduated after the stopper F is
ground in, the zero mark being the end of the stop-
per. Each mark of the graduation represents one-
fiftieth c.c., or when a 10-gram sample of butter is
used each mark represents two-tenths of 1 per cent
of water. His a glass condensing jacket connected
to the graduated tube C by rubber stopper D, as
shown in figure 35, or ground onto the bulb of the
tube C at the point D, as shown in figure 34. The
apparatus shown in figure 1, having the condensing
jacket connected by means of a rubber stopper, is
the form which seems most satisfactory for general
use.

Rubber Stoppers. The rubber stopper B will be
slowly decomposed by the heat and reagent during
the process of making the tests. As a stopper is
rendered unfit for use by making about one hundred
determinations, extra rubber stoppers should be
obtained.

Reagents

Amyl Reagent. A mixture of amyl acetate 5
parts and amyl valerianate 1 part. Must be free
from water-soluble impurities in order to give accu-
rate results. Users not in position to test this
reagent for impurities should insist on a tested
article.

Alcohol (for burning) when alcohol lamp is used.

DETERMINATION OF THE WATER 53

Making a Determination

Preparing the Sample. The sample of butter: is
placed in a suitable container (1-pint Mason jar or
metal cup will be satisfactory). This container is
placed in water at about 100° F. The butter is
stirred with a spatula or spoon until it is about the
consistency of thick cream and no free water can be
seen. Samples of butter should not be left standing
in open containers any length of time before making
water determination, as some of the moisture will
evaporate and the percentage of water shown when
the determination is finally made will be too low.

Weighing the Sample. Place on each pan of the
balances one sheet of parchment paper and balance
accurately. Place the 10-gram weight on one pan
and balance again by placing butter on the parch-
ment paper on the opposite pan, placing the sample
as near the center of the paper as possible.

Transferring Sample to Flask. When exactly
10 grams are weighed out. remove the sample from
the pan, folding it in the parchment paper in such a
shape that the paper and butter may be slipped into.
the flask A. Always use care that none of the butter
is lost in transferring.

Adding Amyl Reagent. Fill the graduate with
amyl reagent to the mark 6 c.c., first being sure that
the graduate is free from water. Place the 6 c.c. of
amyl reagent in the flask with the butter.

Connecting the Apparatus. Connect the appa-
ratus as shown in figure 1 and fill the condensing

54 DAIRY LABORATORY GUIDE

jacket & with cool water to within one inch of the
top. Remove the stopper F.

Distilling off the Water. Caution: Be sure that
the glass stopper F is removed.

Place the apparatus over the flame of the burner,
applying heat to the bottom of the flask A. Ina
short time the butter will melt, running from the
parchment paper into the amyl reagent. The water

. — Heating the sample of butter with
amyl] reagent over alcohol flame.
in the sample then boils and passes as steam into the
tube C, where it is condensed and trapped. Watch
the condensation in the graduated part of the tube
C, and do not let the steam get higher than the
15 per cent mark. If it goes higher than this, remove
the flame, as there is danger of water being lost. If
there is any indication of liability of the mixture in
the flask A foaming over, remove the flame. Foam-

DETERMINATION OF THE WATER 55

ing is usually prevented by 6 c.c. of amyl reagent,
but some samples of butter, especially those of high
moisture, require a trifle more than 6 c.c. In case
of continued foaming, allow the mixture in the flask
to cool, and add about 2 c.c. of the amyl reagent,
and continue heating. After the water in the sample
has boiled out, the temperature rises and the amyl
reagent boils, driving the last traces of water and
water-vapor from the flask and bottom of the stopper.
Some of the amyl reagent is carried into the tube’ C
with the steam, and some is boiled over after the
water has been driven off. This amyl reagent in the
tube is of no disadvantage.

Determining when all Water -has Evaporated.
The time required for driving all water from the
sample is not less than five minutes and with most
samples need not be more than eight minutes. When
the mixture in the flask becomes a brown color and
all the crackling noises in boiling cease, it is safe to
conclude that all water has been driven from the
flask.

Disconnecting the Apparatus. Disconnect the flask
A from the stopper B, place the glass stopper F
in the tube C, giving it a slight turn to insure its
being held firmly; invert the tube C, first being sure
that the mouth of the small tube inside the bulb is
held upwards; pour the water from the condensing
jacket EH, after which the jacket may be removed.

Separating the Reagent from the Water. When
the tube C is inverted the water and amyl reagent
flow into the graduated part of the tube. To separate

56 DAIRY LABORATORY GUIDE

these and to get the last traces of water down into
the graduated part, the tube C' is held with the bulb
in the palm of the hand and the stoppered end away
from the body, raised to a horizontal position, and
swung at arm’s length sharply downward to the side.
This is repeated a number of times until the dividing
line between the water and amyl reagent is very
distinct and no amyl reagent can be seen with the
water or vice versa. The tube should then be held
a short time with the stoppered end downward and
the amyl] reagent in the bulb of the tube agitated in
order to rinse down any water that may be adhering
to the sides of the bulb.

Reading the Test. The reading should not be
taken until the tube and its contents have cooled
so that very little warmth is felt. The water is in
the bottom of the tube, and when a 10-gram sample
is taken the percentage may be read directly. Read
to the lower part of the meniscus.

Other than 10-Gram Samples. With butter very
low in moisture it may be desirable to take a 15-gram
sample, and with butter extremely high 5-gram
samples may be used. The reading multiplied by
ten and the product divided by the weight in grams
of the sample taken equals the percentage of water.

Time Required. To make a determination, inclu-
ding weighing sample, requires from fifteen to
twenty minutes.

DETERMINATION OF CASEIN 57

Cleaning the Apparatus

Flask. The flask may be cleaned by washing
with soap, washing powder, or washing soda in hot
water. It is not absolutely necessary to wash the
flask after each determination; the residue may be
poured out and the flask wiped with a cloth or thin
paper. The flask must always be dry (free from
water) before making a determination.

Graduated Tube. After making the test, empty
the tube C by holding the stoppered end downward,
removing the stopper and allowing the contents to
flow out quickly. In this way the amyl reagent
runs out after the water and carries with it practically
all of the water, which might otherwise adhere to
the tube. The tube, after emptying, should be swung
in the manner described for separating water from
amyl reagent, which will almost completely empty it.
Following this plan it is not necessary to dry the
tube after each determination. Occasionally the
tubes should be washed carefully with a hot solution
of sodium carbonate (sal soda) or other good washing
powder and thoroughly dried before using.

EXERCISE XIV

DETERMINATION OF CasEIN, ASH, AND SALT OF
BUTTER

Carefully weigh a dry porcelain dish or crucible and
place thereon a sample of butter. Weigh and sub-
tract weight of dish. Dissolve ether extract (fat)

58 DAIRY LABORATORY GUIDE

by addition of anhydrous alcohol-free ether. Decant
the ether and repeat until the fat has all been dis-
solved. Allow the residue to dry in the air and
weigh. Cover the crucible and heat gently at first,
gradually raising the temperature to just below red-
ness. The cover may then be removed and the heat
continued till the contents of the crucible are white.
The loss in weight of the crucible and contents repre-
sents casein, and the residue in the crucible mineral
matter. In this mineral matter, dissolved in water
slightly acidulated with nitric acid, chlorine may be
determined gravimetrically with silver nitrate, or
volumetrically after dissolving in water only, using
potassium chromate as an indicator. From the
amount of chlorine, Cl, present the quantity of salt,
NaCl, may be calculated or it may be determined
as follows:

DETERMINATION OF SALT

Weigh in a counterpoised beaker from 5 to 10
grams of the butter. The butter is placed, in por-
tions of about 1 gram at a time, in the beaker, these
portions being taken from different parts of the
sample. Hot water is added (about 20 ¢.c.) to the
beaker containing the butter, and after it has melted
the liquid is poured into the bulb of a separating
funnel. The stopper is inserted and the contents
shaken for a few moments. After standing until the
fat has all collected on top of the water, the stopcock
is opened and the water is allowed to run into an
Erlenmeyer flask, care being exercised to let none of

DETERMINATION OF CASEIN 59

the fat globules pass. Repeat extraction from ten
to fifteen times, using from 10 to 20 c.c. of hot water
each time. The resulting washings contain all but
a mere trace of the sodium chlorid originally present
in the butter. The sodium chlorid is determined in
the separated fluid by a standard solution of silver
nitrate, AgNO, using a few drops of solution of po-
tassium chromate as an indicator.

NaCl+ AgNO,= AgCl+ NaNO,.
23.0 At. wt. of Na
35.5 At. wt. of Cl.

58.5 Molecular wt. of NaCl.
For every 35.5 Cl there are 58.5 NaCl.

When a permanent reddish brown color is obtained,
note the number of ¢.c.’s used. Each c.c. of stand-
ard solution AgNO, used indicates the presence of
.0585 grams of salt.

Example: 10 grams butter in sample, and solution
required 4 c.c. AgNO. 4X .0585=.234 grams. 10X
.234=2.3 per cent salt, or .234+10100=2.3 per
cent.

METHOD FOR THE QUANTITATIVE DETERMINATION OF
Proterps oF MILK

Bogg’s Method

Phosphtungstic acid in hydrochloric acid solution
precipitates instantly all the proteids in a finely di-
vided condition. The precipitate contracts evenly in
a vertical direction and reaches a constant minimum

60 DAIRY LABORATORY GUIDE

volume within twenty-four hours. The supernatant
fluid is perfectly clear and gives no trace of proteid
by any tests. The solution which seems to be the
optimum is composed as follows:

Phosphotungstic acid, 25 grams; distilled water,
125 c.c.

After thorough solution is obtained there is added:

Hydrochloric acid (conc.), 25 ¢.c., diluted with
distilled water, 100 c.c.

This yields 250 c.c. of a 10 per cent solution of
phosphotungstic acid in about 3 per cent HCl. The
solution is quite stable if kept in a dark bottle, and
gives satisfactory results after months of standing.
It is desirable that the components be mixed as
indicated, t.e., the well-diluted HCl added after
solution of the phosphotungstic acid in order to avoid
precipitation.

The diluted milk is poured into the tube to the
mark U, being careful to read from the bottom of
the meniscus. The phosphotungstic acid solution is
added to the mark R, the tube corked and slowly
inverted twelve times to secure thorough mixing;
care being had to avoid shaking roughly and thus
mixing air in the fluid. The tube is then placed in
a rack for twenty four-hours and the percentage read
off at the level of the top of the precipitate. Fractions
of per cent between the graduations are readily
judged by the eye. At dilutions of 1 part in 10,
percentage of proteid is read directly from the scale,
while if the dilution be 1 in 20, we multiply the
reading by two; if 1 in 5, we divide by two.

CHEESE MAKING 61

The optimum solution for human milk is 1 in 10.
That for cow’s milk 1 in 20. If the proteid content
be found extremely low we may use 1 in 5 for human
milk and 1 in 10 for cow’s milk.

The minimum volume of the precipitate is reached
in twenty-four hours. Readings at thirty and forty-
eight hours showed no appreciable variations.

COMPOSITION OF BUTTER

Maximum | Average| Minimum _
Piha cand 85% 84% 80%
WAL? ticicndes ta are ees 16% 12.8% 7%
BGP uae Sh canauee fieeeus 3% 2% 1%
PHOCEIN 4.5 hee ae we ae he 75% 6% 6%
SUSA ss sacade pa celen wien 5% AG, 3%
eh acaht aa beneiaien leak 2% 2%! 1%

EXERCISE XV
CHEESE MAKING

Since the process of making cheese of the various
kinds is based upon the same fundamental principles,
namely, that of condensing the food of milk by
liberating the water, we will merely outline the process
of cheddar, gouda, and cottage cheese making, which
are most commonly used. The process may be re-
peated with variations in acidity of milk for quicker
or slower curing cheese; pressed hard or merely
drained, for hard or soft cheeses, and cut, salted,
and cured in various methods and molds for the
different kinds of cheese desired.

62 DAIRY LABORATORY GUIDE

Cheddar Cheese

Weigh the milk to be used. Take accurate sample
for fat test, acid test, and rennet test. The Marshall
rennet test is perhaps the most commonly used in
the Cheddar cheese process, although the Monrad
test is very efficient. The rennet test is made by
filling the graduated cup to the zero mark with milk
at 86° F. Add 1 c.c. pipette full of 5 per cent
rennet solution. Allow the milk to pass through the
narrow glass bore of the cup and note amount that
passes through before coagulation begins. The riper
the milk the quicker it will thicken, with a corre-
sponding less reading on the scales. The acidity of
the milk should be about .2 per cent for Cheddar
cheese. By once determining the acidity of the
milk and the corresponding rennet test the latter
may be substituted for the acid test in the following
exercises. If milk tests less than .2 per cent acid it
may be ripened with starter. After reaching the
proper acidity pour the milk into vat and heat to
86° F., the temperature at which rennet works best.
Add rennet if in liquid form, two to four ounces to
each 1000 pounds of milk; if in tablet form, dilute
one tablet in one-half pint of cold water and pour in
as indicated on directions. If pepsin be substituted
for rennet, only scale pepsin (strength 1-3000) should
be used. Use .5 of a gram for every 500 pounds of
milk. Dissolve in cold water before adding to milk.
Why? Mix thoroughly and allow to stand until
curdled enough to break clean over a thermometer

CHEESE MAKING 63

slanted at an angle of 45 degrees. Cut first with
horizontal knife, then with perpendicular knife.
Wire stringed knives are preferable. Cook curd by
heating at from 95° F. to 100° F. until it is of a rub-
bery consistency, grits between the teeth, or strings
threads one-eighth inch long when touched to a hot
iron. This usually requires one and one-half hours
from time rennet is added. Stir continuously while
cooking to prevent matting together and assist curd
in heating evenly. Draw off whey and allow curd
to mat by placing on curd rack for five to ten minutes
until firm enough to handle, then pile the curd about
six inches deep and allow that to drain from under-
neath the rack. An even temperature of 95° F. to
100° F. must be maintained to keep up fermentation.
After ten to fifteen minutes the curd will have matted
and can be cut into blocks which are frequently
turned. These should be about six inches wide.
Turn the curd so as to facilitate expulsion of whey,
and when it has a meaty consistency similar to that
of a chicken’s breast it is ready to mill. Mill when
the curd becomes flaky and shows from one to one
and a half inch acid (strings one to one and a half
inches long) on the hot iron. If curd has been
tainted it may be improved by washing with water
at a temperature of 105° F. before milling.

There are numerous kinds of curd mills, including
the Pig, Pohl, McPhearson, Kasper, and the Knife.
The Kasper rotary mill, however, is generally used.
The milling should be done about an hour and a half
after drawing whey, and the salt added about an

64 DAIRY LABORATORY GUIDE

hour and a half after milling. During this time the
temperature should be kept at about 90° F. Why?

ee
Fig. 37. — Gang Cheese Press

The curd should take all the acid it will before
salting, which is indicated by the length of strings

CHEESE MAKING 65°

which will draw out on a hot iron. These should be
about two inches long. Now the curd is ready for
salting. It should be soft and silky. In hot weather
reduce the temperature as much as possible before
salting and putting the curd into the press. Use at
the rate of 24 to 24 pounds of salt per 1,000 pounds
of milk, varying the weight of salt according to the
amount of moisture in the curd, and according to
market demands. Most any of the common brands
of salt are very good. Worcester, Anchor, Ashton,
Diamond, Crystal, Kansas, Genesee, Colonial, and
others are used. To determine their purity dis-
solve a small amount of salt in clear water, and if it
remains clear there is no dirt present. If sediment
settles, or if cloudiness is produced, impurities are
present. Distribute the salt evenly by mixing with
the hands or forked ladle. Stir every ten minutes
to keep salt from settling to the bottom of the pile.
Keep at 90° F. When a velvety feeling is regained,
which usually requires fifteen to twenty minutes, the
curd is ready for pressing. Cool curd to between
80° and 85° F. Why? Place in hoops so that the
bandages are even with edges, turning down over the
circles. Press for an hour by tightening press every
few minutes. The curd will now be pressed together
and it should be taken from the press and the ban-
dages smoothed and neatly trimmed. Soak into
position with warm water if necessary. Place fol-
lowers in carefully so as to make uniform shape.
Press from twelve to twenty-four hours, depending
on the size of the cheese and the pressure. Take

66 DAIRY LABORATORY GUIDE

from press and place in cooling room for about five
to ten days. Dip in melted paraffin at 200° F. to
250° F. and place in cooling room at from 40° to
60° F., having a humidity of from 65 to 80 per cent
(which is the amount of saturation), depending on

‘Fic. 38.— Vat for Paraffining Cheese

the temperature and length of time desired to cure.
The per cent of moisture should be as high as possible
without causing a growth of mold. The humidity
of the curing room is determined by a psychrometer.

The psychrometer is more reliable than the hy-

CHEESE MAKING 67

grometer (or hygroscope) and consists of two ordinary
thermometers fastened side by side with a cup and
wick, or tube of water between, the latter being
turned at the bottom in the form of a small cup and

Fig. 39. — Psychrometer

closed at the top to prevent the water from running
away. In the stationary psychrometer the cup end
contains a wick which also covers the bulb of one of
the thermometers. The temperature shown by this

68 DAIRY LABORATORY GUIDE

thermometer is, of course, lowered more or less accord-
ing to the rate of evaporation from the wick, and this
rate is affected by the relative humidity of the air.
In a saturated air there could be no evaporation and
the thermometers would register alike; in a very dry
air the evaporation would be rapid and the difference
of temperature indicated would be considerable.

TaBLE SHOWING THE RELATIVE HUMIDITY IN THE
Arr oF Curinc Rooms. (King.)

Directions: Notice that the table is in three-column
sections. Find air temperature in first column, then
find wet bulb temperature in second column, same
division. In third column opposite this is relative
humidity.

Example: Air temperature is 50° in first column;
wet bulb is 44° in second column, same division.
Opposite 44° is 61, which is the per cent of saturation,
or relative humidity of the air.

FAHRENHEIT SCALE

Dry | Wet | Rel.|| Dry | Wet | Rel. |] Dry | Wet | Rel. |! Dry | Wet | Rel.
bulb | bulb | hum] bulb | bulb | hum]! bulb | bulb | hum]! bulb | bulb | hum.
32 31 34 29 36 28 39 32

33 33 35 36 37 34 40 37

34 | 46 36 | 43 38 | 40 Al 43

35 | 53 a7 | 49 39 | 46 42 49

41 36 | 60 || 44 | 38 | 56 |] 47 | 40 | 52 || 50 | 43 55
37 68 39 63 41 59 44 61

38 | 76 40 | 70 42 | 66 45 67

39 | 84 41 78 43 | 72 46 74

40 | 92 42 | 85 44 | 79 47 80

43 | 92 45 | 86 48 87

46 | 93 49 93

CHEESE MAKING 69

To Prepare Table for Psychrometer Reading.

See W. B. Bulletin No. 235, Department of Agri-
culture, Washington, D. C., or Smithsonian Physio-
logical tables, p. 155.

Observe, 1, psychrometer reading; 2, dew point.

From table referred to determine relative humidity
as follows: (from dew point reading): Example:
If dew point = 10° C. (50° F.) and temperature of
air = 30° C. (86° F.) the weight of saturated vapor
in air at 10° C = 9.33 grm. per c. m.; the weight of
saturated vapor in air at 30° C=30.04 grm. per c.m.

(This table was made for the sling psychrometer
and does not exactly correspond to the one on the

opposite page.)
‘ sae 9.33
Relative Humidity = 30.04 31.1%

Then prepare table:
Dry Bulb Wet Bulb. Rel. Hum.

30°C 18°C 31.1°C

Moisture can be supplied by sprinkling the floor,
or better still, by hanging up wet sheets that are
constantly supplied with water.

To supply a curing room of 5000 cubic feet capacity
at least 3 cloths 30 inches wide by 12 feet long are
needed. To keep them saturated with water hang
them on pipes with fine holes drilled on the upper
side, and a gutter below to carry off the surplus
drippings. When the cloth gets stiff from sediment,
boil it in water to which a little hydrochloric acid
has been added.

70 DAIRY LABORATORY GUIDE

In cold weather, when the curing room is artificially
heated, there is rarely any danger of the air in it
being overladen with moisture; and there is little
danger of this in summer if the room is cooled arti-
ficially by air circulation through an ice chamber,
because the air in passing over the ice is cooled to a
point at which it can contain little moisture in com-
parison to its capacity when at the higher temperature
of the room. But when the curing room is not
artificially cooled by refrigeration it may often in
summer be overladen with moisture.

Air at 20° F. may contain 1.30 grains of water to
the cubic foot, while at 30° it may contain 1.97
grains, at 40° 2.86 grains, at 50° 4.09 grains, at
60° 5.76 grains, at 70° 7.99 grains, at 80° 10.95
grains, at 90° 14.81 grains, and at 100° 19.79 grains.

Cheese should be cured for from six weeks to a
year, depending on the kind of cheese, market re-
quirements, temperature of curing room, and condi-
tion of cheese when made. The lower the uniform
temperature at which cheese can be ripened eco-
nomically the better will be the texture and quality of
the cheese and the less will be the loss in weight dur-
ing the ripening process. The cheese score card is
as follows:

CHEESE MAKING 71

YIELD OF CHEESE FROM MILK VARYING IN RICHNESS

Lbs. milk Per cent fat Yield of cheese
100 ai 5.5
100 1 6.7
100 2. 8.
100 3. 9.2
100 4 10.9
100 5 12.4
Play Ore 60 cate cuscacis acess aves & euciacaue Beenebets 50
WERCURG to: toch deemed aanedasannee eee 2D)
LSE] UR cceen oe Po Rien ae Moan rOM SMe Spt EADRERED PSE EPRI 10
Color .iaiguwene ee ee paseo eee ees 10
PACKA GC tsi siti Masdashsdd hana arena 5
100 Total

A good flavor should not be sharp so that it will bite
the tongue, but of a mild lasting taste and aroma.
Texture comes next in importance. A good texture
can be determined as follows: The plug should be
smooth, not fuzzy. If the cheese is not fully cured
the plug should bend a little before breaking. When
held between the eye and the light it should be
slightly translucent. If the light does not come
through it, it is a sign of too much acid. If the plug
has round holes in it too little acid has been given the
curd. When pressed between the fingers it should
not stick to them but mold like wax. Cheese should
not be mealy as is the case with highly acid or too
highly salted cheese. Color comes next.. It should
be straight and translucent. Then comes make-up.
A cheese should have square edges evenly bandaged
and clean. Make-up adds considerable to selling value
of cheese as well as appearance.

72 DAIRY LABORATORY GUIDE

EXERCISE XVI
Goupa CHEESE

Repeat Exercise XV, using milk containing less
than .2 per cent acid. Do not use curd mill, but
press without milling or salting. After pressing suffi-
ciently place cheese in a saturated salt solution.
Brine should be strong enough to float cheese. Keep
entirely immersed, or turn every six hours until rind
forms. This usually requires about twenty-four
hours.

EXERCISE XVII
CoTTaGE CHEESE

Ripen 100 pounds skim or whole milk to .8 or
.9 per cent acid. Place in vat and heat to 95° F.
When whey is sufficiently liberated draw off. Drain
curd in cheese-cloth until most of the whey is re-
moved and cheese can be molded. A small amount
of cream mixed into the curd adds materially to its
palatability. Salt to taste and mold in desired
form. With similar variations the following cheeses
may be made, but there is seldom time during the
short course to make more than three or four different
kinds. Nor is it practical, for the main difference
between some of them is the name of the county,
province, or town in which they are made, with only
a slight difference in method of manufacture or curing.
Various cultures of molds and bacteria are frequently
employed in the latter.

SOFT CHEESE 73

The following is a list of some of the different kinds
of cheese:
SOFT CHEESE

Brick cheese ........... 00000. e eee eee eae .. United States
Cottage Cheese: occcyicacecas vege seninns sides United States.
Brickbat: cheese s.:suc0+ gens seca ch ove dens san ee England.
Slipcoat cheese ... 2. c.seess evs swe es eevee ees England.
Fromage blanc (white cheese) ................ France.
Cream cheese ..........2..-0 ee ee cece eee eee France.
Double cream cheese ............-.. 0.000000. France
Coulommier cheese ..............00 00. e ee uee France
Bondou cheese ............ 202-20 c cece eee eee France.
Fromage de Marseilles cheese ................. France.
Pont-L’Eveque cheese...............-...000.. France.
Void: cheese: 22s-ssus see a eae ya Gand esas ee France.
Cantal cheese ..........0 0.00 cece cee ees France.
Livarot cheese ..........0..0 0062 cece ee France.
Menster cheese ... 1.0.0... 000.0 c cece eee ees France.
Gerome cheese ......-....0 0000s eee cece eee France
Mont d’Or cheese .......-...0. 2-0 c cece eee France

Brie Cheese. ....c.he02 sae deny eel tae Dedede aes France.
Camembert cheese ............ 0000000. e eae France.
Roquefort cheese ................ 000000 e eee France.
Neufchatel cheese ............2.0 020: e ee euee France.
D’Arles cheeselets .............0020 cece cece France.
Brinsen. cheese 2.00666 ce en ee eee Hungary.
Mascarporie cheese ............... 00000 e eee Italy.
Fromaggio fresco di Pecora cheese ............. Italy.

ROD DIOaisswac 2 vs Keser & Stee eanamenie a wig ios eekoanens BNA Italy.
Parmesan cheese ............ 00 cee cece eee eee Italy.
Reggrom cheese ........ 6... e cece eee eee eee Italy.
Vaclievin cheese ...........-. 000000 eee eee ee Switzerland.
Bellelay cheese .............. 022 c cece eee eee Switzerland.
Caerphilly cheese ........... 0.0000. e eee eae Wales.
Romatour cheese .......... 00 0c cece cece ee eees Bavaria.
Limburger cheese ...........0 0c cece e eee eee Belgium.

Kaiser aes sicscisti saree viens <eaienine ga ube. yoga wne ed ene Germany.

74 DAIRY LABORATORY GUIDE

HARD CHEESE

Pineapple cheese .............. 0000 cece eee eee United States.
Cheddar cheese: ses cauce eg see eign Kaew gal Gye England.
Stilton Cheese) s.ccgur scx sok eRe Ged a gta eres England
Blue Dorset cheese ..............---00 eee e eee England.
Cheshire cheese ........ ih ege ie eee eRe ear els England.
REX CHEEBE: Sic tana s aatd ceded Sandan eadarke tues France.
Gruyere cheese .............. 22. c eee ee eee France.
Port dis Soltit do-cecccscsccun Songame nn tetene Sees France.
Hdam Chees6-i.2ci-gsoc oases anent tea bat eee d Holland.
Gorgonzola cheese ......... 0... cece eee Italy.

Cacio cavolla cheese ...............0..000000, Italy.
Gouda: cheese . 46522 sHe5e sgcceueseewe reba ees Holland.
Whey cheese ......... 6... eect eee eee es Norway.
Blundeer cheese ..................0000020 0007 Norway.
Old (Norwegian) cheese ............... .2.00- Norway.
Mysort: cheese. ne: case ¢syaecca dened da eee vases Sweden.
Emmenthaler cheese .................-.50005-. Switzerland.
Schweitzer cheese.......... 0... eee eee Switzerland.
Danish export cheese ..............0000 0-000 Switzerland.
Schabzieger (SapSago) cheese ...............-. Switzerland.
Zieger (albumin) cheese ..................0055 Switzerland.
Sera Do Estrella ...--....--. 00.0: s cee eee eee Portugal.

THE FOLLOWING BLANK FORM MAY BE USED
IN CHEESE-MAKING

Wat No roine. a aia oR aes aE ene a eee BERR AG Ree Tee

TOM POLAGUTCs sccsc ge clshiaet tl sobs i oes hae oe aul e a de ee
ACIGIGY: Sits w eayentd haa RA Ros Toile a ela Aan eS
per Centiol fat: se. nes ys sae cea years eames vader oes
Pounds mille ii Vat es wesdiesete Gah dere notine Raed ees

WNL $5 cre teed, cyosee eheens awa aed uate enash Gente arms a tae dtnre ay satieh os

FANG. caceateee vitae tia a Hicalvodss ninth induicdusy Ae a eA MBER tech wan ao oes

ICE CREAM 75

RMN TESE aiid ginng ape gwie ehanalet me enes emaaleegee aeons
Setting; hotifee:2281c.cqeuiemehide pines eteregeasen aa tyes
temperature: coe void ps odes eaewlteae ne gers ecard as

BCIGILYS fc cee ed eede eet esas ee Sea ERR Pea Cees

amount rennet or pepSiN ..... 0.0... cee eee ee eee eee

Curd: Git houn scasccalalt awavoteales (dials svdete Meee omen eae
Steam turned on, hour .......... 0... cece ee eee eens
Time taken to raise temperature to . . . degrees ............
Whey drawn, hour...................- oA aaes Pathe aetotuage ees)
TEMPETAtUTE ~ woes doe da ek ead ew eee es ade deaths

pounds of whey. ccc osgie wise g tote BOs wile weds
per cent of fat in whey ................0.0008.

RTI! + 2c ras bb. gaakt ed snd ea i wate es aeaseaeloeD Seb ee ute 2 orden

KING. sega na akine amend Wa ee BARR ceed TATE

Put to press Jhour’ gc a04.w cuie engine Pom vinn need ayy eh eit
temperature: << cnieswiseewe ede rca we sad eee vite 5

condition of curd ............... eee eee eee

Timea ncpress! a «2 aula ven! asnasdcadey sau ive eeawe agar aotentem ales
Number cheese made.........-..+--0.+-5: Geeke sel secre hota?
Pounds cheese made ........... 00 ccc ccc eee eee eee eee
Temperature of curing TOOM ..... 6. eee eee eee eee
Humidity of curing room ..... 6.6... eee ee ees
FReMaT ICS) ecco dnpelen tte pis aang dluniecdyan acta Mua and gusrare bleu! preheat epi a

EXERCISE XVIII
Icz CREAM

The principle of ice-cream making is the incorpora-~
tion of air while freezing the cream. This is readily
accomplished by the use of the ordinary freezer, which
is so constructed that it retains the cold within the
outer wooden tub and imparts it to the cream
through the inner tin cylinder.

76

DAIRY LABORATORY GUIDE

Fic. 40.— Continuous Ice Cream Freezer. The cream flows

into the first compartment from the supply tank and com-
ing in contact with the cold disks, in which brine solution is
circulating, at once commences to freeze. As the disks re-
volve the cream is kept agitated. The metal fingers sus-
pended between the disks prevent the cream from freezing
on. From the first compartment the partially frozen mix-
ture overflows into the second. The latter compartment is
deeper than the first, and contains in addition to the freez-
ing disks a revolving screw which carries away the cream
as fast as the freezing is completed. This conveyor extends
about 18 inches from the freezer and discharges into the
packing can.

ICE CREAM 77

For 5 gallons of ice cream use 24 gallons of 20 per
cent cream, 24 ounces of flavoring, and 24 pounds of
sugar. Slight variations are frequently advanta-
geous. Place in freezer and put two parts of finely
pulverized ice to one of salt around the cream can.
Salt has a great affinity for water and causes the ice
to melt rapidly. The ice changing from solid to
liquid absorbs heat rapidly. The heat is taken from
the cream and the latter thus reduced to freezing
point. Revolve slowly about 80 revolutions per
minute until cream begins to freeze so as to avoid
churning. Then turn rapidly 120 to 140 revolutions
per minute so as to pulverize it and make a fine
grain, and at the same time incorporate air enough
to give the desired overrun. In freezing the flavoring
is sometimes weakened and it is therefore desirable
to add flavoring as soon as the cream begins to freeze.
Keep the entire top of can continually covered with
ice while freezing. The freezer should never be
stopped until the freezing process is finished, as lumps
of ice may form, causing a granular body. When
the freezer is stopped before the process is com-
pleted, a portion of the air incorporated is likely to
escape, much the same as when half-beaten cream
is allowed to stand. The air escapes and the cream
settles.

Various kinds of flavoring and crushed fruits are
often used in making ice cream and sherbets. Fruit
may be crushed and added to the cream just before
freezing, the same as flavoring is added. The use of
geletina and corn-starch in making ice cream is not

78 DAIRY LABORATORY GUIDE

to be recommended, for cream made with their use
frequently tastes more like custard than ice cream.

Harlequin or Neapolitan Ice Cream

Freeze several freezers of ice cream of various
colors, say one of chocolate, one of strawberry, one of
plain vanilla, and one of carmine color. Freeze until
the cream flows with difficulty, but not so stiff as to
crumble. Spread first one layer the desired thickness,
usually about one-half inch, then another of different
color on top of the first, and so on until the cake is
complete. Place in packer and allow to harden, cut
in desired form and serve. ;

In packing ice cream take the latter from the
freezer with a ladle and deposit with a swinging
motion against the periphery of the packing can
which has been thoroughly cooled by placing fine ice
and salt around the outer space. Thus by retain-
ing the incorporated air the over-run may be main-
tained.

Molding Ice Cream

If molds are used the cream should be packed
closely into them, filling every crack and corner.
The cover should fit over and not into the mold.
Smear the edges with paraffin to keep out salt and
water. Bury molds in crushed ice and salt. A
slightly smaller proportion of salt should be used
than in freezing. Cover ice with wet burlap. Draw
off the brine as fast as the ice melts. Allow to stand
for an hour or more before serving.

DAIRY BACTERIOLOGY 79

EXERCISE -XIX

Dairy BAcTERIOLOGY

Examine microscope carefully under the direction
of the instructor and ascertain difference between
high and low power objectives with different eye
pieces. Manipulate reflector, condenser, and dia-
phragm to ascertain various combinations.

Fic. 41

The above cut represents a portion of a drop of
milk containing F, fat globules, L, leucocytes, Y,
yeast, and B, b, c, s, T, 1 and 2, seven species of
bacteria frequently found in milk. B represents
the hay bacillus group which are among the largest
known species of bacteria, and frequently form
chains; b represents one species of bacillus viscosus

80 DAIRY LABORATORY GUIDE

which forms slimy milk; c represents a common
coccus form; s represents a streptococcus (forming
chains); T represents bacillus typhosus; 1 represents
tetragenococci, and 2, one of the lactic acid group.
Place a drop of water on a clean cover glass by
means of platinum wire, then touch the end of the wire
in a sample of milk, mix with water on a cover glass,
place on clean slide and examine under microscope.
The water dilutes the milk enough to make a clear
field. Examine for fat globules, bacteria, and leucocy-
tes, if present. The latter are from two to ten times
larger than fat globules and an irregular outline. Ex-
amine samples of skim-milk for fat globules. Make
hang-drop slides and examine in the same manner.
To find the correct measurements for microscopic
work place a micrometer in the eye piece, or ocular,
and a stage micrometer (which equals 1-100 mm.)
on the stage of the microscope. Determine the rela-
tion of the divisions of the former to those of the
latter by making the initial lines coincide and count-
ing the number of divisions of the stage micrometer
that is required to make one of the ocular micrometer.
Example: where a § power ocular is used. When
13 divisions of ocular equals 5 divisions of the stage
micrometer, let A equal stage division, and O, ocular
division.
13° equals 5s.
1° equals 35 s.
1s equals .01 mm.
73 8 equals .01° equals .003846 m.m.
1

DAIRY BACTERIOLOGY 81

A plain slide may then be substituted for the stage
micrometer and all measurements taken by means of
the ocular micrometer.

A table may then be constructed in the following
manner which will save time in calculating the meas-
urement of objects:

.5 division .001923 m.m.

.75 division .002888 m.m.
1.00 division .003846 m.m.
1.25 division .004825 m.m.
1.3 division .005012 m.m.
1.5 division .005785 m.m.
1.75 division .006748 m.m.
2.00 division .007712 m.m.
2.25 division .008676 m.m.
2.5 division -009640 m.m.
2.75 division .010604 m.m.
3.00 division .011569 m.m.

Prepare a clean cover glass and place thereon a
drop of water. Transfer a minute portion of decayed
material, starter, or clabber milk, and spread uni-
formly over the surface of the glass and allow film
to dry. When dry, pass cover glass, smeared surface
upward, three times through a Bunsen flame at
about the rate of a pendulum of a clock. The heat
coagulates the albumen around the bacteria and fixes
them firmly to the glass. Place a drop of staining
solution prepared from anilin dyes (gentian-violet,
basic fuchsin, and methylene blue, are most commonly
used) on the glass and allow stain to remain for from
two to ten minutes, depending on the strength of the
staining solution and the kind of bacteria. Rinse in
water. Dry the unsmeared side on filter paper,

82

DAIRY LABORATORY GUIDE

mount film side down in a drop of water on clean
slide and examine. If bacteria are properly stained,
dry both sides with filter paper and mount film side
down in a drop of balsam. Label and preserve.
Prepare cultures for bacterial growth as follows
(after Gorham) :

PREPARATION

OF CULTURE MEDIA

I. Bouillon

II. Gelatine

III. Agar

ee

i

or

oO

. Infuse finely chopped lean

beef for twenty hours with
twice its weight of distilled
water in the refrigerator,
say 1000 grams of meat,
2000 grams of water.

. Make up weight of meat-

infusion (and meat) to
original weight by adding
water —i.e., to 3000 grams
Filter infusion through
cloth to remove meat.

. Weigh infusion, say 1800
grams.
. Set infusion on water-bath,

keeping temperature below
609 C,

. Add peptone, 1 per cent,

18 grams; salt, 0.5 per
cent, 9 grams.

. After ingredients are dis-

solved, titrate; 2 reaction
probably + 2.3 to + 2.5 per
cent.

. Neutralize.

Ditto.

Ditto.

Ditto.

Ditto.

Ditto.

Ditto, and
sheet gela-
tine, 10 per
cent 180
grams.

Ditto, proba-
bly +4.0 to
+5.0 per
cent.

Ditto.

Boil 30 grams of thread

agar in 1 liter of water for

half an hour.

Make up loss

by evaporation to a weight
of 1000 grams.

1,

>

4.

8.

. Ditto, say 900 grams.

Infuse finely chopped lean
beef for twenty hours with
its own weight of distilled
water in the refrigerator,
say 1000 grams of meat,
1000 grams of water.

. Make up weight of meat-

infusion (and meat) to
original weight by ‘adding
water —i.e., to 2000 grams.
Ditto. (See 3.)
(See
4.)

Ditto. (See 5.)

Add peptone, 2 per cent,
18 grams; salt, 1 per cent,
9 grams.

Ditto, probably + 4.5 to

4.7 per cent. (See 7.)
Ditto.
To the 900 grams of meat-

infusion (containing new pep-
tone and salt) add 900 grams
of the 3 per cent agar jelly
described at the head of this
column.

DAIRY BACTERIOLOGY 83

Heat over boiling water or steam thirty minutes.
Restore weight lost by evaporation to original weight
for bouillon and gelatine and twice that weight for
agar. Titrate and adjust reaction to the final point
desired. Sterilize for three consecutive days so as
to kill all germs present, and fill test tubes one-third
full. Cork with sterile cotton and sterilize again.

Certain species of bacteria grow sufficiently well on
media made from beef extract instead of lean beef.
The former requires less work and may be used in
the following proportions:

BovriLton
Beef extract ................... 3 grams
PeplOne sa reg tbe dese aie es 10 grams
Sale oh Ram tuer acuunan ae nd eae toate 5 grams
Water cncares eeateweweadac se aetuny 1000 e.c.
GELATINE
Beef Exbracti: siiee ceudiee ee yaw ete 5 grams
PO ptONe ss seis satel Ga a we oaalae es 10 grams
Balti sac dmanirte bias eateeraaein a 5 grams
Gelatine sag ig tics Guiewhuea sts sees 100 grams
Water sirgvcschy yee e neater esis 1000 c.c.
AGaR
Beefiextract: oc ccce ces swe weep en an 5 grams
Peptone! ci eee re ghee cee stay aes ag eh 10 grams
alt wustak catia es Gaede er seal 5 grams
BAT see sachin kcal hang e Retin ow eene sae 20 grams
Water: ict auinntean tia eo es 1000 c.c

Make potato media by washing sound potatoes and
cutting the ends, and with sterile cork-borer cut out
cylinders of the potato a little smaller than the tubes
to be used. Handle potato under water as much as

84 DAIRY LABORATORY GUIDE

possible to prevent darkening of surface. Cut cylin-
ders into two equal parts by a diagonal cut. Place
in cool running water for twelve to eighteen hours.
This usually renders the potato neutral. Sterilize
in steam sterilizer for thirty minutes on three con-
secutive days. Place in sterile test tubes, slanting
surface upward, and plug with sterile cotton. Steri-
lize once after plugging.

Milk Media

Heat fresh milk for fifteen minutes in steam steri-
lizer at 200° to 212° F. Place in ice-box over night.
Titrate, and if less than .2 per cent acid place in
tubes and sterilize for twenty minutes on four con-
secutive days in a steam sterilizer. If more than
.2 per cent acid reduce to .15 per cent by the addition
of one-tenth normal solution of sodium hydroxide.
Place in sterile test tubes with sterile cotton plugs.
Make cultures of the above media from milk, cheese,
ice cream, and butter from various sources. Note
behavior and color of culture on the various kinds
of media. Make plate cultures of agar and gelatine
by warming them to melting point and adding a
drop of milk. Shake thoroughly and pour into sterile
petra dish and allow to cool. Place in incubator for
twelve to twenty-four hours at 100° F. in case of the
agar plates and 80° F. in the case of gelatine plates.
Examine every few hours or as often as convenient.

Make medium more condensed for quantitative
analysis of liquids.

After washing with cleaning mixture prepared in

DAIRY BACTERIOLOGY : 85

Exercise I, sterilize all empty glassware for at least
thirty minutes at a temperature of 212° F. in a dry
air sterilizer. After turning off the gas allow uten-
sils to remain in sterilizer for ten minutes before
opening the door. Otherwise the cool air coming
suddenly in contact with the hot glass may cause
some of the parts to crack.

Before sterilizing pipettes wash each one thoroughly,
and while the ends are moist roll a piece of clean
cotton to a point and insert in the end of pipette.
Turn the remaining part of the cotton back over the
pipette, and if the latter is moist it will wrap tightly
around the same between the thumb and fore-finger
while revolving the pipette with the thumb and fore-
finger of the other hand. Repeat the operation with
the other end of the pipette.

When using sterile pipette hold in vertical position
and pull lower plug first. This prevents contami-
nation to a great extent.

The media must all be sterilized in a steam sterilizer
in order to prevent evaporation. Sterilize at 212°
F. thirty minutes for three consecutive days to kill
all bacteria which are likely to germinate from the
spores which resist boiling temperature.

Make a quantitative analysis of bacteria in a
sample of whole-milk by drawing into a delicately
graduated pipette .1 c.c. of the milk to be analyzed.
Transfer this into a sterile water blank test tube
containing .9 c.c. of sterile water. After shaking
well, transfer .1 c.c. of this in the same way to a test
tube containing sterile melted agar media. Mix

86 DAIRY LABORATORY GUIDE

well and pour into a petra dish. The solution will
then contain .01 ¢.c. of milk, and the number of
colonies that develop in the petra dish is therefore
multiplied by 100 to obtain the average number of
bacteria per cubic centimeter.

Fic. 42. — Culture of 1-100 c.c. milk from separator which
had been flushed with warm water only.

Measure from .1 to 1 ¢.c. of milk into: test tubes
containing 5 c.c.’s sterile water (water blanks). To
a given number of these add 5 ¢.c. of washing powder
in solution. Pour contents of each tube into test
tubes containing melted agar. Shake thoroughly

DAIRY BACTERIOLOGY 87

and pour into petra dishes. The number of colonies
that develop in each indicates the efficiency of the
disinfectant. The smaller the number of colonies
the more efficient the washing powder.

Fig. 43. — Culture of 1-100 ¢.c. milk from average steril-
ized separator.

Repeat, using a small speck of manure or dirt from
your finger nail. Also make plate cultures from a
drop of milk taken from a cow at beginning and last
‘part of milking. Make plate exposures by filling
petra dishes with melted agar and allowing to solidify.
Expose one, two, and three minutes in open air,

88 DAIRY LABORATORY GUIDE

barn, dairy, and various places of interest. Place in
incubator as before and note results. Determine gas
fermentation by use of curd test and also by placing
sterile bouillon in fermentation tubes. A small test

Fic. 44. — Shows a plate exposed one-half minute during
the process of milking, under cow’s udder treated by
merely brushing with the hand. Each of the little
spots represents a colony of some kind of bacteria.

tube inverted inside of a large one will answer for a
fermentation tube. Add a few drops of milk or
cream to be tested and allow to remain at 100° F.
for twelve to twenty-four hours, and note amount of
gas collected.

MILK PAINT 89

Fic. 45. — Shows a plate exposed one-half minute during
process of milking, under a cow’s udder treated with a
5 per cent solution of carbolic acid. The animal was on
a cement floor and bedding was present. It will be noted
this plate is quite an improvement over plate shown in

Fig. 44.
EXERCISE XX
Mix Paint

Stir into one gallon of skim-milk 3 pounds of
Portland cement and add sufficient paint powder
to impart desired color, and apply to board or fence
post while thoroughly mixed. Note the effect of
this paint upon standing in vessel and the necessity
of constant stirring while being used. Repeat the
experiment, using a small amount of carbolic acid or

90 DAIRY LABORATORY GUIDE

other disinfectant and apply to a board or fence post
in the same vicinity. On the following day secure
cultures from the posts and determine by means of
plate cultures the difference in the number of the
bacteria obtained from the two sources.

EXERCISE XXI

TESTS FOR PRESERVATIVES
HCHO + H,O

Add ‘one drop of formaldehyde to 4 pint of milk
and shake thoroughly. Obtain, by means of a pipette,
17.6 c.c. or any convenient amount of the milk, and
place in Babcock test bottle. Add a similar amount
of sulphuric acid and allow to stand quietly for five
minutes. Note color line at junction of acid and
milk, which should be a distinct purple or violet,
indicating the presence of formaldehyde. Repeat the
experiment using concentrated hydrochloric acid.
Also add a few drops of ferric chloride to aid the color
reaction. Formaldehyde is a colorless, volatile liquid
chemically intermediate between methyl alcohol and
formic acid. When consumed with milk it produces
various intestinal disturbances, and if present in
excessive amounts produces poisoning.

Test for Boracic Acid. H,BO,

Place $ gram or any convenient amount of borax -
in a pint of milk and shake thoroughly. Obtain
sample of milk by means of pipette and place in
small porcelain dish. Evaporate about one-half to

TEST FOR OLEOMARGARINE 91

concentrate amount of borax present. Add as much
alcohol as there is milk present, and ignite. A green
flame indicates the presence of borax.

Test for Salicylic Acid. C,H,O-HCOOH

1. Place a few crystals of salicylic acid in 4 pint
of milk and agitate thoroughly as in the previous.
tests. Pour a small quantity of same in test bottle
and add about the same quantity of sulphuric acid,
with about 30 c.c. of chloroform or ether. These
dissolve the fat present and greatly facilitate the
test. Add a few drops of ferric chloride. The pres-
ence of salicylic acid is indicated by a purple or
violet color similar to that of formaldehyde. The
distinction between these tests being that the color
reaction does not appear in the presence of salicylic
acid unless ferric chloride (Fe,Cl,) be used, but ap-
pears in the presence of formaldehyde in either case.

2. Place 5 c.c. suspected solution in porcelain dish
and evaporate to dryness. Warm residue with one
drop of concentrated nitric acid. Add two or three
drops of ammonia until alkaline. The presence of
salicylic acid is indicated by the formation of a
yellow color or ammonium picrate which will dye a
thread of fat free wool.

EXERCISE XXII

TEST FOR OLEOMARGARINE

Place 5 grams or any convenient amount of oleo-
margarine in a small dish and apply flame. Place in

92 DAIRY LABORATORY GUIDE

another dish a similar quantity of butter. Note the
difference in the manner in which they melt. The
oleomargarine sputters like grease in a frying-pan on
account of the excessive amount of water present.
It does not foam, however, as much as the butter.
The butter melts quietly and foams a great deal.
Also note odor of lard in oleomargarine. Score a
sample of each for flavor, texture, grain, and body.

Test FOR RENOVATED BUTTER

Repeat test for oleomargarine and note the simi-
larity with which renovated butter melts. The dis-
tinction between the two, however, lies in the fact
that when added to a small amount of milk reno-
vated or any other kind of butter may be incorpo-
rated into the milk by heating and stirring. The fat
from oleomargarine, on the other hand, cannot be
incorporated into the milk. If stirred while cold
into cold milk the butter will form in small flakes or
grains in the milk, while oleomargarine will collect
ina ball. The fat from good butter will crystallize
out more perfectly than that of renovated butter.
The latter has a very poor grain and body, the grain
having been destroyed in processes of renovation.

EXERCISE XXIII
REPAIRING CREAMERY MACHINERY

Repair broken belts by cutting broken ends of
belt square so that the parts come evenly together.

REPAIRING CREAMERY MACHINERY 93

Punch holes in a line one inch from cut edges, the
number depending on width of the belt. They should
be about one and one-half inches apart. Punch the
back holes one and one-half inches from first row
and directly between. Begin lacing at middle of
belt. Be careful to have smooth side of lacing next
pulley. The ends are fastened by running them
through small holes punched in line with the lace
holes. Repair broken belt with steel wire lacing by
using only one row of holes on each end of belt.
Also repair with steel belt lacing.

Repair broken belts with glue by cutting each end
off squarely and then cut widthwise, a slant beginning
back two inches from edge of belt, and slant to a
narrow edge. Glue slanting surface of both ends.
Place together and press until dried. Determine the
efficiency of the four methods by daily use.

Determine speed of main shaft and pulleys on
machinery by the following formula:

To Determine Diameter of Pulley on Main Shajt

When the speed of engine pulley is 1000 revolutions
per minute, the diameter of the engine pulley is 5
inches and the speed of the main shaft is 180 revolu-
tions per minute.

1000 x 5 + 180 = 27.7 inches.

To determine the speed of the main shaft when the
diameter of pulley on main shaft and diameter and
speed of engine pulley is given as in above example.

1000 x 5 + 27.7 = 180

94 DAIRY LABORATORY GUIDE

Line up shaft by fastening chalked string along
ceiling parallel to direction of shafting. Snap string
and put hangers up loosely in line with chalk mark.
Place shaft, arranging its position in hangers in a
plane parallel to the floor, and fasten hangers and
shaft securely. Line up machinery to shafting by
holding one end of string so that it touches both
sides of pulley on shaft and tight pulley on ma-
chine.

Repair worn valves by repacking and grinding
when worn.

Repair cement floor by thoroughly mixing, while
dry, one part of cement to two of sand. Moisten
with water until thoroughly wet but without excess
of water. Apply, press thoroughly, and smooth with
trowel. If corners of dairy floor are not rounded,
fill in with cement and smooth neatly as shown in
Fig. 5.

Adjust a small electric battery with bell and
switch connections
above the milk vat and
1B, attach a string with
float on one end and a
weight on the other, as
shown in accompany-
ing cut. When the milk
is being pumped or
drawn from the vat to
‘the separator or pas-
teurizer, the float will lower until the weight on the
opposite end of the string touches the break and

THE MODIFICATION OF MILK 95

rings the bell, thus notifying the operator that the
tank is almost empty.

F represents float. b, brake.
T, tank or vat. 8, switch.
w, weight. B, battery.

See that everything is arranged for convenience,
neatness, and sanitation, and that there is no un-
necessary waste. All corners, joints, seams, and
crevices, in any apparatus in which milk or cream
is to come in contact should be smoothly soldered.
See ‘Creamery Conveniences” Exercise 35.

EXERCISE XXIV

Tue Moopirication or Mitk ror INFANTS AND
INVALIDS

The following is the average composition of various
kinds of milk:

Water | Sugar | Protein) Fat | Ash

COWS) nic Band SRS Sade e 87% 5% 3.3% | 4% 7%
SHEED ak dias geese eae &3.5 3.96 5.74 6.14 .66
Goats: «+ ote esses sles < 86.91 4.45 3.69 4.09 .86
Mares........... eee 90.06 6.65 1.89 1.09 31
Human............... 88.2 6.8 1.50 3.3 .20
Commercial Sweetened

Condensed Milk ..... 27.25 | 12.50] 8.63 | 9.18 | 1.75

Commercial Condensed ;
Milk, Unsweetened-..| 70.44 | 10.96] 8.35 | 8.71 | 1.54

Very few invalids or infants are constituted exactly

96 DAIRY LABORATORY GUIDE

alike, and therefore, although the upper third of milk
in combination with barley water, etc., is frequently
advocated for such use, it must be modified to suit
the individual. In many cases peptone in the form
of peptogenic milk powder must be added to partially
digest the casein.

The average diet for infants, with variations to
meet individual demands, should be as follows:

Four per cent milk and 20 per cent cream is intended
for each formula in the following table:

1 oz. equals 2 standard tablespoonfuls.
1 drm. equals one tablespoonful.

30 gr. equals 4 teaspoonful.

20 gr. equals 4 teaspoonful.

TABLE FOR PREPARING FOOD FOR INFANTS

Age of Infant Cream | Whey | Water | Milk Milk

sugar
First week......... 2drm.|3drm.|3drm. |....... 20 gr.
2d to 6th week ....|2drm.]....... loz. | 3 oz. | 20 gr.
6th wk. to 2d mo... | 4 02. |....... % oz. | 2 oz. | 30 gr.
3d to 6th mo....... $0. |....... loz. | 24 oz. |1 drm.
6th to 7th mo...... Booz. |....... 2 oz. | 34 oz. | 1 drm.
8th to 9th mo...... hoz |....... 14 oz. | 6 oz. | 1 drm.
10th to 14th mo....] $2. |....... 14 oz. | 74 oz. | 1 drm.

Both lime and barley water are frequently substi--
tuted for a part or all of the water, depending on the
patient. They aid in separating the curd of milk but
are somewhat constipating. The greater the per cent
of cream in milk the less constipating, and vice versa.

THE STANDARDIZATION OF MILK 97

Prepare mixtures of the above feeds by each of the
formulas.

Example 1: Prepare a feed for infant four months
old that is constipated, otherwise normal: 24 oz.
4 per cent milk, 1 oz. plain or oatmeal water, 1 oz.
20 per cent cream, 1 dram milk sugar.

Example 2: Prepare a feed for infant four months
old that has diarrhcea, otherwise normal: 24 oz. 4 per
cent milk, 1 oz. barley or lime water, 0 to 4 oz. 20
per cent cream, 1 dram milk sugar.

Similarly prepare feeds for infants of various ages.

The cream for infants should be gravity raised
rather than separator cream, as the latter has a ten-
dency to destroy the natural emulsion of milk and
cream, rendering it less digestible for delicate infants
or invalids.

EXERCISE XXV
Tuer STANDARDIZATION OF MILK

The standardization of milk consists of bringing
the butter fat, content to a certain standard or per
cent regardless of the quality of milk produced.

Example 1: Take 10 pounds of milk testing 4.5 per
cent fat, and standardize to 4 per cent. 10 pounds
milk testing 4.5 per cent = .45 pound butter fat.

A5 + .04 = 11.25 = number of pounds of 4 per
cent milk required.
11.25 —10 = 1.25 = number of pounds of skim-
milk to be added.

98 DAIRY LABORATORY GUIDE

Example 2: 10 pounds of milk containing 3 per
cent fat is to be standardized to 4 per cent. How
much skim-milk must be taken from the whole
milk? ,

10 x .03 = .30 number of pounds of fat in original
milk,

7.5 number of pounds of standardized
milk,

10 — 7.5 = 2.5 number of pounds skim-milk to be

separated from the original milk.

30 + .04

The table on the opposite page by Professor Erf
indicates the quantity of skim-milk to be added to or
subtracted from 100 pounds of milk to make a de-
sired per cent.

To find the pounds of skim-milk to be added or
removed, trace the vertical column of the per cent
of fat desired down to where the horizontal column
representing the per cent of fat in the milk on hand
intersects, and the result will be the number of
pounds of skim-milk to be added or removed, as
indicated by a plus or minus sign before the re-
sult.

To illustrate: If milk containing 4.5 per cent is
desired and milk containing 3.8 per cent is on hand,
then 15.5 pounds for every hundred pounds or 15.5
per cent of the quantity must be separated out as
skim-milk,

99

THE STANDARDIZATION OF MILK

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100 DAIRY LABORATORY GUIDE

Standardizing with Whole Milk

Example 1: 20 pounds of milk containing 3 per
cent fat is to be standardized to 4 per cent fat with
5.2 per cent milk.

04 — 03 = 01
052 — 04 = 012
01 + .012= 833

20 X .8383 = 16.66, number of pounds of 5.2 per cent
milk to be used.

Example 2: 20 pounds of milk containing 5.2 per
cent butter fat is to be standardized to 4 per cent
with milk containing 3 per cent butter fat.

052 — 04 = 012
04 — 038= O01
012 + 01 = 1.2

20 < 1.2 = 24, number of pounds of 3 per cent milk
to be added to the 20 pounds of milk to decrease
per cent fat to 4 per cent.

The same principle will apply in standardizing of
cream.

EXERCISE XXVI
ConpENSING MILK

1. Attach rubber tubing to Bunsen pump and
connect to a strong rounded, quart flask containing
about a pint of perfectly sweet milk which is free
from all taints. Also connect to a graduated glass
tube inserted in mercury to designate the amount of
vacuum produced, which should be about 756 mm.

CONDENSING MILK 101

or 30 inches. Tie rubber and glass connections se-
curely. Heat milk over flame at 130° F. and allow
to boil for from six to eight hours until the milk has a
consistency of very thick cream. Examine and taste.

Fic. 47.— Condensing Milk. (6) block of
wood; (m) mercury in bottle; (c) gradu-
ated cylinder; (s) suction from Bunsen
pump; (t) thermometer; (J) lamp or Bun-
sen burner.

2. Condense milk as above, but allow to remain at
90° F. instead of boiling-point during several labo-
ratory periods until it has entirely dried. Pulverize
with mortar and pestle and examine.

3. Take 10 pounds of curd from the cheese vat.
After removing fat evaporate to dryness in incubator
or oven. Pulverize and feed a small portion to
chickens. Take one ounce of the remaining portion
and boil together with 5 c.c. water. When an emul-
sion is formed boil to a pasty consistency and test
the sticking qualities for glue.

102 DAIRY LABORATORY GUIDE

Milk Paste

Thoroughly mix three parts of casein with one part
of sodium borate (borax), moisten with water and
test for paste. This is frequently used for library
paste. Mix one part of casein with one part of quick
lime, moisten and test for glue.

Dried Milk

Heat 15 pounds of skim-milk in vacuum at 165° F.
until it dries to a paste. Frequently turn until it
forms a crisp and then pulverize.

Milk Sugar

Rapidly coagulate skim-milk by means of rennet
or acetic acid. Filter whey and render slightly
alkaline by the addition of lime water. Evaporate to
about one-half bulk and precipitate albumen by
boiling or with small amount of alum. Remove
by again filtering and evaporate the second time to
about one-sixth of its bulk. Add equal volume of
methyl alcohol, and allow to stand for three to six
hours. A pure white, finely crystalline precipitate
of lactose is thrown down which is removed by filter.
Cool and taste.

EXERCISE XXVII
JUNKET

To 1 small junket tablet add 1 dram (1 teaspoon-
ful) of cold water. Crush tablet and dissolve thor-

JUNKET 103

oughly. Heat 1 quart of pure milk to about 90°
to 98° F. and add sugar and flavor to suit taste.
Add the dissolved tablet to the milk, mix thoroughly,
pour into desired dishes and allow to stand at 90° to
95° F. until solidified. Then place in refrigerator
until ready to serve.

If no junket tablets are readily obtainable substi-
tute a mixture of ten drops of rennet and a few grains
of salt.

Papanized Cheese Paste

This process is patented

Moisten any of the breakfast food cereals and put
in a digester. Heat under’ pressure, not exceeding
three atmospheres, to a temperature not exceeding
_ 134° C., but preferably at a pressure of two atmos-
pheres and a temperature of 121° C. for an hour or
more, depending on the amount of dextrinization
desired. Under the influence of the moisture and
high temperature the starch in the cereals becomes
converted into dextrine. Cut cheese into small bits
and crush into a paste with equal quantity of whole or
skim-milk. One to one-half per cent of soda may be
used and the entire mixture cooked to the desired
taste over Bunsen flame until the cheese is com-
pletely dissolved. An egg may also be added if ob-
tainable.

104 DAIRY LABORATORY GUIDE

EXERCISE XXVIII

ATIMIDCASEOSE
Process patented

Render skim-milk slightly alkaline with lime-water
or sodium carbonate (Na,CO,) and heat to 4° C,
Add just sufficient rennet to coagulate -and filter out
whey. Wash curd. Place in autoclave if obtainable
and subject to superheated steam at a pressure of
100 pounds per square inch, for three hours. Curd
thus prepared is very nutritious and readily assimi-
lated by invalids. Repeat, using 5 pounds of whole
milk and coagulate as rapidly as possible by means
of rennet. Neutralize by baking soda and filter.
Taste filtrate, which is said to be very digestible and
which is often used for invalids.

Milk Shake

To 3 pint of whole or skim-milk add about one table-
spoonful of sugar, about twice that amount of*pow-
dered ice, a pinch of baking soda, and a few drops of
flavoring. Shake well in lemonade shaker and serve.

Buttermilk Highball

Mix 4 pint of buttermilk, 2 pint of ice cream, and
a pinch of baking soda, or an infusion of carbonic
acid gas (CO,). Shake thoroughly in lemonade.
shaker and drink.

KOUMISS 105

Buttermilk Pop

To } gallon of fresh buttermilk add 4} pint of
20 per cent cream and } pound of sugar, also a few
granules of salt. Heat to boiling, stirring constantly
to keep curd well mixed. Add 8 grams of corn-
starch previously mixed with cold water.

Repeat experiment, using } pound of corn meal in
place of corn-starch. Add a pinch of baking soda;
shake well and drink.

Koumiss

To 7 pints of pasteurized milk, either skimmed
or 3 per cent, add 4 ounces of cane sugar and }
cake of bakers’ yeast after pulverizing and dissolving
in about 3 ounces of lukewarm water. Mix thor-
oughly at 95° F. and pour into a long-necked quart
bottle. A champagne bottle answers the purpose
very well. Fasten a light wire over cork to prevent
the escape of air. Allow to cool gradually and
remain at 60° F. to 70° F. for twenty-four to thirty-
six hours. Then it is ready for use. If desired to
keep longer put on ice. A koumiss faucet inserted
in the cork before allowing to ferment greatly facili-
tates opening the bottle for use. The acid developed
in koumiss, like that of buttermilk, has a high
dietetic value, is readily digested, and very nutritious.

Buttermilk

Make buttermilk by ripening skim-milk with starter
at 70° F. until it is slightly coagulated but has

106 DAIRY LABORATORY GUIDE

liberated no whey. Add about 30 per cent of good
flavored buttermilk and churn at 50° to 55° F. until
the curd is entirely emulsified, when it is ready for
use. Repeat, using whole milk instead of skim-milk
and omit the addition of buttermilk.

Drink two glasses of buttermilk daily for a week
and note effect on digestion.

Buttermilk contains about the proper amount of
lactic acid necessary to produce perfect digestion.
It is anti-scorbutic and forms carbonic acid in the
stomach, which unites with the calcium, magnesium,
or potassium salts that are always present in the
food, and forms carbonates which purify the blood by
preserving its alkalinity; while alkaline in reaction
the blood throws off uric and other waste acids which
would otherwise be absorbed. It has, therefore, a
great diuretic and dietetic value. The casein is in a
coagulated, finely divided flocculent state, and is
readily converted into peptones for body use. It
contains enough water to quench the thirst, takes the
place of fresh fruit to a great extent, keeps the body
in a laxative condition, and at the same time furnishes
considerable valuable readily digestible food.

Moose

Make what is known as Moose by adding to 15 per
cent cream about 20 per cent of sugar and flavoring
to suit the taste. Put in a small baking powder can
or small ice cream packer and set in pulverized ice
to which a small amount of salt has been added.
Allow to freeze without stirring.

PREPARATIONS MADE FROM MILK 107

Dried Milk Cocktail

Take a given quantity of skim-milk and add one
per cent of grain alcohol until precipitation of casein
has ceased. Filter the precipitated casein from the
liquid. Dry at from 145° to 149° F. Above this
temperature the albumen may become insoluble.
Pulverize and mix with water, milk, beef-tea, cocoa,
or hot water in proportion about half and half, or to
suit the taste. Where casein has thus been precipi-
tated with alcohol and then dried and redissolved in
water it can no longer be curdled by pepsin in the
stomach. It is converted from insoluble to a soluble
form without losing any of its food value.

EXERCISE XXIX

(This exercise may be taken or omitted at the option of the in-
structor.)

PREPARATIONS MADE FROM MILK

Make plasmon or caseon by precipitating casein
with HCl, neutralize with carbonate of soda.

Make casein of lime by precipitating casein and dis-
solve by phosphoric acid equal to quantity of lime used.

Make nutrose by boiling together in any alkali
solution dried casein and caustic acid.

Make Santogene by mixing 95 per cent glycero-
phosphate of sodium and 5 per cent casein. Precip-
itate casein with acetic acid, wash with methyl
alcohol and dry slowly.

Make eucasine or ammoniacal casein by passing
ammonia through the emulsion of alkaline casein.

108 DAIRY LABORATORY GUIDE

Make eulactol by dissolving proteic vegetable sub-
stance and adding hydrates of carbon, salts, such as
phosphate of calcium, cooking salt, or carbonate of
sodium, and allow to vaporize.

Obtain albumine “‘nikol” from sterilized whey and
dissolve precipitate in soda and render soluble by
treating successively with HCl and alkali.

Mix albumine “nikol’”’ with oxblood 10 to 2.
This mixture is a hygiene albumen frequently used
by people suffering from chlorosis.

EXERCISE XXX

Solid Milk

Prepare solid milk by adding to any desirable
quantity of whole or skim milk 1 per cent of liquid
gelatine. Put up in any desired form, and allow to
solidify at 30 to 50° F.

Soap

Boil 1 pound of milk with any alkali and note
difference in per cent of fat before and after adding.
12.5 per cent of glycerine unites with 87.5 per cent
of fatty acid to form fats. When fat is boiled with
alkali the latter takes the place of glycerine and
forms soap. When boiled again with an acid the
fat returns to its original condition.

DISINFECTANTS 109

Preparation for Ivy Powson

Mix 1 pound of buttermilk with 2 ounces of salt
or all that will dissolve. Apply to parts of skin
affected by poison ivy or similar skin diseases.

A Method for Modifying Milk for Invalids

Heat a given quantity of milk to 86° F. Add
sufficient rennet to coagulate in twenty minutes and
mix thoroughly. After precipitating the casein, filter
out whey and modify with proper per cent of casein
thus obtained to give the percentage of protein
(1.5 per cent) of human milk.

Preserving Casein

Precipitate casein of milk by use of sulphuric or
hydrochloric acid with which a small percentage of
borax or other preservative has been added in pro-
portion of $ to 1 per cent.of the preservative. Dry
and pulverize. Thus preserved the casein is unfit
for food, but may be used in the manufacture of glue
and paint.

EXERCISE XXXI
DISINFECTANTS

Prepare the following disinfectants: Solution of
corrosive sublimate (HgCl,) 1 to 1000; carbolic acid,
C,H,OH, 1 to 20; formaldehyde (HCHO + H,0) 1 ‘to
20. Apply to infected places and note results. Po-
tassium permanganate (KMn0O,) 1 to 20, cold water;

110 DAIRY LABORATORY GUIDE

Wyandotte Dairyman’s Cleaner and Cleanser 1 to
20; Banner Purifying Compound 1 to 20; borax 1
to 20; sal. soda 1 to 20; Fairbanks’ washing powder
1 to 20; Tessico washing powder 1 to 20; gold dust
1 to 20; powdered unslaked lime 1 to 20; powdered
gypsum 1 to 20. Use and note results. Gypsum is
preferable to lime in barns or on any material which
may afterwards be used for fertilizer, for the latter
forms soluble salts with the nitrogen of manure and
liberates a large per cent of the ammonia present.
(NH,),CO, + CaO = 2NH, + CaCO, + HO.
(NH,),SO, + CaO = 2NH, + CaSO, + H,0. This
causes a loss of valuable fertilizer and produces an
offensive odor which milk readily absorbs. Gypsum,
on the other hand (CaSO,), is insoluble with the
nitrogen of manure and is retained until deposited
in the fields.

EXERCISE XXXII

MECHANICAL REFRIGERATION

If refrigerating machinery is in use at the college,
note the kind of machine, whether vacuum, absorp-
tion, compression, or combined absorption and com-
pression. Note principle of refrigeration which is
the production of cold air by the evaporation of liquids
which absorb the heat in vaporizing. Anhydrous
ammonia is generally used on account of its low
boiling point. It liquifies at 30° F. under one atmos-
pheric pressure. It liquifies at higher temperatures
-by subjecting it to pressure. It is alternately evap-

111

MECHANICAL REFRIGERATION

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112 DAIRY LABORATORY GUIDE

orated and liquified so that its use is continuous.
The cycle of its operation starts from the liquid
receiver and enters the refrigerating coils in which it
evaporates, absorbing a large amount of heat. By
means of a compression pump operated by an engine
the ammonia vapors are forced in the condenser coils
where the ammonia under pressure is again liquified
by running cold water over the coils. Here it again
enters the liquid receiver and repeats the cycle. The
amount of refrigeration is regulated by an expansion
valve placed between the liquid receiver and the
refrigerating coils. This valve may be adjusted so
as to admit the condensed quantity of liquid ammonia
to the coils. Note difference between brine system
and direct refrigeration. Take temperatures of brine.
At different regulations of the expansion valve, take
temperature of the room surrounding the brine tank.
If the direct refrigeration system is used entirely, take
temperatures similarly as above directed. Note size
of compressor refrigerating pipes, power required,
expense of operating, etc. After careful examination
of the machine, charge it and operate under direction
of the operating engineer as described by H. H.
Kelley:

“Discharge air with special valves by starting the
compressor and pumping it out by reversing the.
operation of the gas cylinder to that of its working
order. Charge with proper amount of anhydrous
ammonia through the charging valve by connecting
the ammonia cylinder with suitable pipe, and open
the valve. Run compressor slowly with the suction

113

MECHANICAL REFRIGERATION

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114 DAIRY LABORATORY GUIDE

and discharge valves wide open and expansion valve
closed. As soon as one cylinder is empty replace
with another, being careful to close the charging
valve before attempting to remove the empty cylin-
der; opening it when the fresh cylinder is connected.
From 60 to 75 per cent of the full charge is sufficient
to start with, so that any air not having been removed
may escape with as little loss of ammonia as possible.
Add a small amount of ammonia each day until full
charge has been introduced. The glass gage on the
ammonia receiver will indicate the amount of am-
monia present. The appearance of frost on the pipe
leading to the coils and the cooling of the brine or
air in refrigerator in the tank will indicate that
enough ammonia has been introduced to start with.
It sometimes requires applications of heat to entirely
empty the ammonia cylinder. One part of water will
absorb 800 parts of ammonia gas, therefore for use in
case of accident keep a vessel of water handy. After
starting compressor at the proper speed and adjusting
regulating valve, note temperature of delivery pipe,
and if there is a tendency to heat open it wide, and
vice versa. With too light charge of ammonia the
delivery pipe will become heated. The refrigerating
room should be about. 15 degrees lower than the brine
being used, and the temperature of the water dis-
charged from the ammonia condenser should be about
15 degrees lower than that of the condenser. By
placing the ear close to the expansion valve the
ammonia can be heard passing through it. If the
sound is uniform and continuous the machine is

MECHANICAL REFRIGERATION 115

working properly. If too much air is present the
sound will be irregular. Remove air in the same
manner as when charging the system. The presence
of oil or water is detected by shocks occurring in the
compressor cylinder. Oil is removed by an oil

& . . .
separator placed in main pipe between compressor

and condenser.”’

The compressor sucks the gaseous ammonia into
its cylinder, compresses it and sends it into the
condenser. The latter thus describes a continuous
circuit. The same ammonia is used continually. A
five-ton refrigerating machine requires about an 18
horse-power boiler.

The compressor, the most essential part, is a
pumping engine, used to pump the ammonia gas
from the cooling apparatus and compress it and
force it through the condenser at a pressure of from
150 to 185 pounds per square inch. See illustration.

The machinery for pasteurizing and clarifying 2500
quarts of milk and for a refrigerating machine of
five tons, will cost about $2500.

An ice plant which will make two and one-half
tons of ice will have a refrigerating capacity of five
tons; that is, it will cool as much as will five tons
of ice melting in twenty-four hours.

For ice-making, pasteurizing, ice cream making
and running a separator, not less than a 30 horse-
power boiler should be used.

The water used in the condenser is warm and can
be stored up for various purposes.

About a half ton of coal is required daily to make

116 DAIRY LABORATORY GUIDE

two and one-half tons of ice or five tons of refrigerating
capacity. It requires from twelve to eighteen hours
to cool off a room containing 1000 cubic feet and to
make one ton of ice, depending on the perfection of
the insulation, on the outside temperature, and on
the contents of the cold storage room.

Ice ordinarily does not reduce the temperature
below 40° F., but by running the engine continually
the temperature can be reduced as low as desired,
even to zero.

A two-story plant: The brine tank can be placed
right above the cold-storage room, and thus keep it
cool after the machinery stops. A building 24 by
30 feet is ample for a dairy of 2500 quarts capacity.

Direct-expansion system is much cheaper than the
brine system, providing ice is not manufactured for
sale; the brine tank, brine pump, and secondary
system of pipes for brine circulation being dispensed
with, and also a greater efficiency is obtained. Only
about two-thirds of the pipe surface is required to
produce the same effect. See illustration.

A Non-frosting Gage Glass

A device to prevent frost from gathering on the
glass gage is described by R. L. Shipman. The
method is simply to jacket the ordinary form of
gage glass with another glass of larger diameter, so
that there will be an annular space of an eighth of
an inch or so between the glasses. Then place a soft
rubber ring between the glasses at each end, making
air-tight joints. The air thus enclosed between the

CREAMERY BOOKEEPING 117

glasses will contain such a small quantity of moisture
that no frost will appear on the inner glass, and this
air space being such a poor conductor the outer glass
will not be cooled to a temperature sufficiently low
to produce frost. Although a considerable amount
of moisture may be condensed on its outer surface,
this will not interfere in any way with a clear view
of the liquid contained in the inner glass. This com-
bination has been used with temperatures as low as
30° below zero F., and no frost has appeared on the
outer glass to obstruct the view.

EXERCISE XXXIII
CREAMERY BOOKKEEPING

Either single or double entry systems may be used,
but the single entry system is more practical for
creamery accounts; for it eliminates the transfer of
entries and the keeping of more books. The single-
entry system consists of a day book, in which careful
record of all money spent for repairs, supplies, etc.,
and all money taken in from sales of milk, cream,
butter, ice-cream, etc., credits and debits are kept;
an order book, sales book, cash book, and ledger to
which the above are transferred every evening. The
milk sheet, test-book, butter slips, patrons’ state-
ments, etc., are figured at the end of each month,
or according to the custom of the management. The
following blank has been used for several years
by the writer and proved to be very satisfactory:

118 DAIRY LABORATORY GUIDE
STATE AGRICULTURAL COLLEGE

Dairy Husbandry Dept.
CREAMERY PatTRON’s MonrTHLY STATEMENT

Date Date

Butter|p_-
shipped |received Pounds |Test fat Price |Amount | Charges |Items|Check

.

Check herewith .............

A creamery record should be kept by every butter-
maker in order to trace causes of difficulty in ripening
cream, or in churning, and also to aid him in main-
taining regularity of work and uniformity of product.

The following blanks by Professor Erf may be used
for keeping daily records:

CREAMERY BOOKKEEPING

DAILY REPORT IN

Date: From .................

BUTTER MAKING

119

‘ Tues.| Wed

Weather to-day: Fair, Cloudy,
Stormy «sess sesene ys caves an
Temperature .................
Milk, Ist grade, pounds ........
Ist grade, per cent of fat...
1st grade, pounds of fat ...

2d grade, pounds ........

2d grade, per cent of fat ...
2d grade, pounds of fat ....

3d grade, pounds ........

3d grade, per cent of fat ...
3d grade, pounds of fat ....

Pounds of skim-milk ..........
Test of skim-milk
Pounds of fat in skim-milk
Cream received from patrons ....

1st grade, pounds .......
Ist grade, per cent of fat .
Ist grade, pounds of fat...
2d grade, pounds ........
2d grade, per cent of fat ..
2d grade, pounds of fat ...
3d grade, pounds ........
3d grade, per cent of fat ..
3d grade, pounds of fat ...

Pounds of rinse water added to:

Ist grade ............4.
2d grade ..........005.
3d grade ............-.

Acidity before pasteurizing:

Ist grade ..............
2d grade.............6

Thur.

Sat.

120 DAIRY LABORATORY GUIDE

GRADE OF CREAM NO. ()

Mon.

Tues.

Temperature pasteurized .......
Temperature cooled to .........
Acidity after pasteurizing ......
Starter-pounds or per cent added
Acidity of starter when used.....
Cream-temperature cream ripened
Pounds cream to be churned.....
Test of cream to be churned .....
Pounds butter fat..............
Per cent of acidity in cream .....
Temperature of cream .........
How long held at this temperature
Time between pasteurizing and
churning................

Color — Ounces or c.c. color used
Churning — How full was churn
Time required to churn ........
Temperature of butter..........
Temperature of buttermilk .....
Size of granules (very fine, wheat,
peas, lumps) ..............
Shape of granules (round, ragged)
Temperature of wash water .....
Number of times washed .......
Salt — Amount salt used .......
Working — Working time or revo-
lutions se. vas ates eeenes

Pounds fat lost in manufacturing
Pounds butter made ...........
Per cent overrun ..............
Account — No. packages put in
refrigerator ...............
No. packages sold..............
Refrigerator temperature .......
Butter-maker’s score ...........
Expert’s score ..........--.00--
Report from commission man ...

Wed.

Thur.

Fri.

Sat.

CREAMERY BOOKKEEPING 121

EXERCISE XXXIV
WRITING TO PaTRoNS

Prepare a letter for creamery patrons similar to the
following, with variations to suit the circumstances.

We aim to put out the highest standard of dairy
products from this creamery. In order to do this it
is necessary that there should be perfect cleanliness
in all of our operations. We wish to ask all who
have anything to do with milk brought here to co-
operate with us in bringing about the best results.
We desire to make the following suggestions:

1. The milk haulers must keep their wagons free
from dirt and filth.

2. The cow stables should be kept cleaned and
ventilated.

3. The feeding and bedding of cows must be done
after milking, as the dust contains bacteria that will
spoil the milk.

4. The milkers must not. get anything in the pail
from the cow’s udder but milk. To aid in this matter
a damp cloth may be used to advantage in wiping the
cow’s udder before milking, and the first stream from
each teat discarded.

5. In straining the milk use a double strainer
covered pail. The common strainer is not sufficient
to take out the fine particles of dirt. Milk should be
cooled to as low temperature as possible immediately
after milking.

6. After thoroughly washing all pails, pans,
strainers, cans, etc., with good washing powder, they

122 DAIRY LABORATORY GUIDE

must be scalded with boiling water to destroy the
harmful germs.

7. The skim-milk should never be left standing in
the cans. It is best to empty the cans, wash them,
and scald with hot water or steam.

8. Fresh milk should be cooled before mixing with
other milk.

EXERCISE XXXV
CREAMERY CONVENIENCES

A fan in the creamery keeps the air cool, fresh, and
the flies outside.

A low-water whistle alarm on the boiler as required
by the state law of Michigan.

A cord connected to the safety valve on the boiler
and stapled around the periphery of the creamery,
with a weight attached sufficient to pull the valve
open if the cord is ever burned in two. In case of
fire the steam and hot water will aid materially in
extinguishing it.

An automatic scale to show the weight of the milk
as soon as emptied into the weigh can, similar to a
butcher’s scale, with agate bearings.

The butter printing table to be fastened on the
wall, with hinges and drop legs.

Pipe brushes with sectional handles to clean milk
pipes.

A heater regulator to control the temperature of
the milk when separating; also cream when pas-
teurizing.

CREAMERY CONVENIENCES 123

Steam and water connected with hose to wash
vats, walls, and floor. Cases for separator and pas-
teurizer parts hung neatly on the wall near the
machines as shown in Fig. 6.

A case similar to the above for a complete set of
creameryman’s tools.

An oilcloth to cover the engine and separators
when not in use, to keep off the dust.

A clamp to hold small butter tubs and 5-pound
boxes firm when packing them.

A home-made water pump regulator is a most
helpful and economical device. It is made by at-
taching a float on the water tank to one end of
a lever, the other end of which is attached to
the throttle of the pump in such a way that as the
water in the tank rises or falls it shuts or opens
the throttle. This not only keeps the tank full but
the pump adjusts itself to the varying boiler pressure
and to the quantity of water used. The water is
pumped into and drawn out of the tank through a
siphon, so that as soon as the pump starts the water
comes direct from the spring or well.

An adjustable overflow on the water jacket of the
cream vat, made by screwing in a short piece of pipe
and elbow on the inside near the bottom, with a
corresponding rod on the outside to indicate its posi-
tion, and a vertical pipe in the elbow which can be
turned up or down to keep the water the same
height ascream. This enables one to keep a continual
stream of water running around it and saves ice and
time.

124 DAIRY LABORATORY GUIDE

Elevator for carrying boxes, etc., to attic.
The milk can elevator invented by O. B. Schier,
of Baltimore, consists of two endless chains running

Fie. 50. — Milk Can Elevator. Upper Floor

over sprocket wheels, connected by a single shaft at
the lower end in such a way that both chains must
travel at the same speed. Between the chains are
suspended on swivel links a number of swinging

CREAMERY CONVENIENCES 125

platforms to carry the cans from one elevation to
another. They are just far enough apart to allow
a man to conveniently put on the milk cans as fast

Fig. 51. — Milk Can Elevator. Lower Floor

as he takes them from the wagon. The elevator
delivers the cans to a higher elevation or higher
floor continuously as fast as would be possible to

126 DAIRY LABORATORY GUIDE

unload them; while in the regular platform ele-
vators it is necessary to wait until the elevator is
loaded. Thus, it will be seen that the endless chain
elevator saves a great deal of help.

Test bottle rack with perforated top, for shaking
or emptying twenty-four to forty bottles at the same
time. .

Automatic governor brake to stop engine in case
of governor belt breaking or coming off.

Heater for warming water going into boiler; the
exhaust from engine may be utilized for this pur-
pose.

Weigh can gate opener, saves stooping.

Castors on movable vats and creamery appliances.

Steam gage in working room to show boiler
pressure.

Slatted draining shelves for all creamery appara-
tus.

Place ice-box above the refrigerator with a sloping
floor. Connect a drain at the lower side so as to
run the water into a small pipe leading into a vat,
which is arranged with slat shelves that hold one-half
pint, pint, and quart bottles, the water reaching just
to the neck of each. Insert an overflow pipe and
drain the water from this into another vat beneath,
where milk and cream cans may be placed. The
water in the latter vat is allowed to rise to within an
inch of the top of the can before it reaches the over-
flow. Thus, after the ice has been used for cooling
the refrigerator, the ice-water may be utilized twice
for cooling purposes.

CREAMERY CONVENIENCES 127

An electric alarm bell attached by means of a cord
to a float in the milk vat. As the milk is pumped or
drawn from the vat the float lowers and pulls a
metallic weight against a brake which causes the bell
to ring, thus notifying the operator that the vat is
almost empty.

COMPOSITION OF NORMAL CREAM

Total Solids | Solids Not Fat | Fat.
32.50% 6.83% 25.67%
37.59% 6.14% 31.45%
50.92% 5.02% 45.90%
55.05% 4.65% 50.40%
57.99% 4.17% 53.82%
68.18% 3.30% 64.88%
Wale Tiare buen eis tear eer nist antes 68.0%
CB ata cliiene seers ee ka tee ea eee 25.0%
UGA aon os bras eared lad dudes dal Px 4.0%
Proteids) 2.000a44 de eaedees dese anneal 2.6%
SAS sree she wea earns ch tha Roane Meng teint eds AG

100.0%

SW GEOR arentg cn feat devitie, ala Gece Geb ds Sela oapne Me 87%
Hat. Asaaly es ae waves owes eh eilute sakes 4%
Milk Sugar ..42s6es¢aci seam essericcua’s 5%
BPOteldS) aovidale bats osu Poole eas 3.38%
ASI toca secs HRSA een tee oe YOR EOR 7%

AMS CiE ge. dinae win dhe BELO ase taunae 90.39%
Be ares haa ae itbealle 40%
Milk sugar .isaccramee dees ase mase am 3.66%
GLacti@ Acid, occ... sw eau te V ed betes sees 80%
ProteidS: eas, cg csec gape ce hawenwaiate db acaee Se 4.0%

Sh Lh ceed innate hse codes kale aisle 75%

128

DAIRY LABORATORY GUIDE

COMPOSITION OF NORMAL SKIM-MILK

Water cookie eto dineccaed essed ae 90.50%
VAG, iStnncse ata aie wary a deen Peas Eee eee 10%
MilkeSugar sida oso ceased testers: « 4.95%
Casein .riecivseedaawriesea aed onset ees 3.15%
Al BOM Ci 3 5.60 d aes aa een Reciever ents e 42%

ASD «See sie deaigransishina ele a@avees aig ounp chneneahs 78%

APPENDIX TO EXERCISE XV 129

Tur Hyaroperx

With this instrument the Relative Humidity of the air may be
determined without the use of tables. See Exercise XV.

To find the Relative Humidity swing the index hand to the
left of the chart, and adjust the sliding pointer to that degree of
the Wet Bulb Thermometer Scale at which the mercury stands..
Then swing the index hand to the right, until the sliding pointer
intersects the curved line which extends downward to the left
from the degree of the Dry Bulb Thermometer Scale at which
the mercury stands. At this intersection the index hand will
point to the Relative Humidity on the scale at the bottom of
the chart.

Example: The temperature indicated by the Wet Bulb Ther-
mometer is 60°, and that of the Dry Bulb 70°. The index hand
will indicate the Relative Humidity 55° when the pointer rests
on the intersecting lines of 60 and 70 degrees.

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