HISTORY AND EXTENT OF THE INDUSTRY 287-296
Early history, 222; Development of ice-cream in the household,
223; Development of wholesale ice-cream, 224; Extent of the
industry, 225.
LIST OF ILLUSTRATIONS
PAGE
FIG. 1.--Refrigerator room for storing cream and milk in a
large ice-cream plant. (Courtesy of Wheat’s Ice Cream Co.,
Buffalo, N. Y.) 12
FIG. 2.--Filters from sediment tests showing the amount of
dirt in different samples of milk. These are the grades made by
the New York City Board of Health 18
FIG. 3.--Sharples milk clarifier 22
FIG. 4.--De Laval milk clarifier, turbine drive 22
FIG. 5.--View of modern condensory showing hot wells, vacuum
pan, vacuum pump and cooling tanks. (Courtesy of Wheat’s Ice
Cream Co., Buffalo, N. Y.) 26
FIG. 6.--Fruit storage in large ice-cream plant. (Courtesy of
Wheat’s Ice Cream Co., Buffalo, N. Y.) 51
FIG. 7.--Steam jacketed kettle for heating gelatine 53
FIG. 8.--Hand freezer with tub and can cut away showing ice and
salt mixture and beaters and scrapers in the can 82
FIG. 9.--Hand freezer with fly wheel, using salt and ice
mixture for freezing. The capacity of this freezer is five
gallons 82
FIG. 10.--Power driven tub and can freezer using a salt and ice
mixture. The can, dasher and gears are shown removed 82
FIG. 11.--Horizontal brine freezer attached to a salt and ice
brine box. The pump is behind the box 83
FIG. 12.--Vertical belt driven brine freezer connected to ice
and salt brine box. (Courtesy of Emery Thompson Machine and
Supply Co., New York City.) 84
FIG. 13.--Perfection brine freezer, direct motor drive.
(Courtesy of J. G. Cherry Co., Cedar Rapids, Iowa.) 85
FIG. 14.--Progress vertical belt drive brine freezer. (Courtesy
of Davis Watkins Dairymen’s Manufacturing Co., Chicago, Ill.) 86
FIG. 15.--Emery Thompson vertical direct motor drive brine
freezer. (Courtesy of Emery Thompson Machine and Supply Co.,
New York City.) 87
FIG. 16.--Fort Atkinson belt drive brine freezer. (Courtesy of
Creamery Package Manufacturing Co., New York City.) 88
FIG. 17.--Disc brine freezer either continuous or batch.
(Courtesy of Creamery Package Manufacturing Co., New York
City.) 89
FIG. 18.--Side view of disc freezer shown in Fig. 17, showing
brine tank and pump. (Courtesy of Creamery Package
Manufacturing Company, New York City.) 89
FIG. 19.--Freezing discs of freezer shown in Figs. 17 and 18.
The scrapers for removing the frozen ice-cream from the discs
and the screw to force it out of the delivery spout are shown.
(Courtesy of Creamery Package Manufacturing Co., New York
City.) 90
FIG. 20.--A pasteurizer or ripener used as an ice-cream mixer.
Strips are attached to the coils to prevent the settling of the
sugar on the bottom 90
FIG. 21.--Minnetonna starter can or ice-cream mixer. (Courtesy
of Davis-Watkins Dairymen’s Manufacturing Co., Chicago, Ill.) 91
FIG. 22.--Alaska ice-cream mixer. The side is cut away showing
the coils and insulation. The mechanical agitator is seen at
the bottom. The cover fits air tight so that by means of an air
pump and air pressure the mix may be forced to the freezer.
(Courtesy of Creamery Package Manufacturing Co., New York
City.) 92
FIG. 23.--Wizard ice-cream mixer. (Courtesy of Creamery Package
Manufacturing Co., New York City.) 92
FIG. 24.--Emery Thompson ice-cream mixer. (Courtesy of Emery
Thompson Machine and Supply Co., New York City.) 92
FIG. 25.--Two types of ice-cream packing-cans 93
FIG. 26.--Ice spud 94
FIG. 27.--Ice cracker 94
FIG. 28.--Perforated ice shovel 94
FIG. 29.--Ice crusher with tight and loose pulley for
mechanical power. The teeth or picks on the drum may be seen 94
FIG. 30.--The perfection ice cream can washer and sterilizer.
(Courtesy of J. G. Cherry Co., Cedar Rapids, Iowa.) 94
FIG. 31.--Fort Atkinson ice-cream can washer and sterilizer.
(Courtesy of Creamery Package Manufacturing Co., New York
City.) 95
FIG. 32.--De Laval centrifugal emulsor. (Courtesy of De Laval
Separator Co., New York City.) 95
FIG. 33.--Perfection cream maker and emulsifier. (Courtesy of
J. G. Cherry Co., Cedar Rapids, Iowa.) 96
FIG. 34.--Progress homogenizer. (Courtesy of Davis-Watkins
Dairymen’s Manufacturing Co., Jersey City, N. J.) 97
FIG. 35.--Gaulin homogenizer. (Courtesy of Creamery Package
Manufacturing Co., New York City.) 98
FIG. 36.--Sharples centrifugal emulsor. (Courtesy of Sharples
Separator Co., West Chester, Pa.) 99
FIG. 37.--Hand ice-saw 106
FIG. 38.--Ice-plow with marker 106
FIG. 39.--Splitting fork 107
FIG. 40.--Approximate temperatures obtained with different
proportions of ice and salt 108
FIG. 41.--Refrigeration available with different percentages of
salt 109
FIG. 42.--Diagram showing relation of heat to temperature 113
FIG. 43.--Simplest compression system of refrigeration 116
FIG. 44.--Compression system of refrigeration in which the flow
of liquid is regulated by expansion valve and the liquid changes
to a gas in the coil of pipe thereby cooling the brine. The gas
then passes off into the atmosphere 117
FIG. 45.--Complete system of direct expansion refrigerating
system 118
FIG. 46.--Combination of direct expansion and brine storage
tanks. This is the same system as shown in Fig. 45 with the
brine tank (T) added in the refrigerator 120
FIG. 47.--Arrangement where it is desired to use cold brine for
cooling in some machine such as an ice-cream freezer. This is
the same refrigerating system as shown in Figs. 45 and 46 121
FIG. 48.--Diagram of the Vogt absorption refrigerating machine,
showing pipe connections and directions in which the liquids
and gases travel throughout the entire system. (Courtesy of
Henry Vogt Machine Co., Louisville, Kentucky.) 123
FIG. 49.--General arrangement of double pipe absorption
refrigerating machine, showing the connections and the
direction in which the liquids and gases flow. (Courtesy of
York Manufacturing Company, York, Pa.) 124
FIG. 50.--General arrangement of atmosphere absorption machine
showing the connections and the direction in which the liquids
and gases flow. (Courtesy of York Manufacturing Company, York,
Pa.) 126
FIG. 51.--Mixing room in large ice-cream plant. (Courtesy of
Wheat’s Ice Cream Company, Buffalo, N. Y.) 132
FIG. 52.--Battery of freezers in a large ice-cream plant.
(Courtesy of Chapin-Sacks Manufacturing Co., Washington, D. C.) 135
FIG. 53.--Different styles of transfer ladles or scoops 146
FIG. 54.--Plank box for hardening ice-cream in a salt and ice
mixture. The cans are placed in perforated cylinders so that
the cans may be changed and the ice will not fall in and fill
the space 147
FIG. 55.--Still-air hardening-room showing evaporating coils
forming shelves on which the pack-cans of ice-cream are placed
to harden. Other evaporating coils may be seen on the sides and
ceiling. (Courtesy of Brunswick Refrigerating Co., New
Brunswick, N. J.) 150
FIG. 56.--Forced air hardening-room. (Courtesy of Chapin-Sacks
Manufacturing Co., Washington, D. C.) 152
FIG. 57.--Brick ice-cream trowels. Straight and bent handles 158
FIG. 58.--Quart and sectional brick molds. The sectional bricks
hold several quarts 159
FIG. 59.--Brick hardening-room. (Courtesy of Chapin-Sacks
Manufacturing Co., Washington, D. C.) 160
FIG. 60.--Center mold and examples 161
FIG. 61.--Individual ice-cream molds and ice cave for packing
molds 161
FIG. 62.--Babcock milk pipette 185
FIG. 63.--Babcock whole milk test-bottle 186
FIG. 64.--Acid measure for Babcock test 187
FIG. 65.--Diagram showing the motion and position of a
test-bottle while mixing the milk and the acid 188
FIG. 66.--Hand and power centrifuges 189
FIG. 67.--Proper way to read the percentage of fat in a Babcock
whole milk test-bottle 191
FIG. 68.--Babcock cream test-bottles 193
FIG. 69.--Method of reading the percentage of fat in a Babcock
cream test-bottle 195
FIG. 70.--Skimmed-milk test-bottle 196
FIG. 71.--Quevenne lactometer 199
FIG. 72.--Board of Health lactometer 200
FIG. 73.--Nafis acid test 201
FIG. 74.--Apparatus for testing ice-cream over-run by the
Benkendorf method 213
FIG. 75.--Mojonnier tester for fat and total solids 217
FIG. 76.--Mojonnier over-run tester 241
FIG. 77.--Ice-cream packing tubs 252
FIG. 78.--Auto delivery truck for ice-cream 253
FIG. 79.--Ice-cream cabinet with side cut away showing
insulation and perforated cylinders on which the pack-cans of
ice-cream set 254
FIG. 80.--Different styles of ice-cream dishes 255
FIG. 81.--Shipping platform and office of shipping clerk in a
large ice-cream plant. (Courtesy of Wheat’s Ice Cream Co.,
Buffalo, N. Y.) 261
FIG. 82.--Revolving door used for putting the ice-cream into
the hardening-room 263
FIG. 83.--Plan of a small ice-cream plant 273
FIG. 84.--Basement plan of large ice-cream plant 274
FIG. 85.--First floor plan of plant shown in Fig. 84 275
FIG. 86.--Second floor plan of plant shown in Figs. 84 and 85 275
FIG. 87.--A loading platform in a large ice-cream plant.
(Courtesy of Chapin-Sacks Manufacturing Co., Washington, D. C.) 276
FIG. 88.--The value of skylights is shown by the well-lighted
freezing-room, considerable floor space above being sacrificed
for this purpose. (Courtesy of Wheat’s Ice Cream Co., Buffalo,
N. Y.) 277
THE BOOK OF ICE-CREAM
THE BOOK OF ICE-CREAM
CHAPTER I
_GENERAL STATEMENTS ON ICE-CREAM_
Ice-cream is known commonly to-day as a food, although in the past
it was considered and used only as a delicacy or dessert. Because of
the rapid growth of the industry and the large number and varying
amounts of materials that can be used in the making of ice-cream, its
composition may be varied within wide limits. The Federal Government
and most of the States have set standards for ice-cream. Some products,
such as custards, sherbets, ices and the like, are usually included
in the general discussion of ice-creams but technically should not be
classed with them.
=1. Materials used in ice-cream.=--The basis of ice-cream is some
dairy product or a combination of dairy products, such as milk, cream,
skim-milk, condensed milk, milk powder, homogenized or emulsified milk
or cream, and the like. These materials contain varying amounts of fat
and solids not fat, ranging from 0 to several per cent. Either one or
all may be used, as the manufacturer determines, to give the ice-cream
the desired amount of fat and milk solids. The price often determines
the kind and amounts of the different materials to be used. It is
important that these dairy products be clean; otherwise the ice-cream
may have an undesirable flavor.
Sugar in some form must be used to sweeten ice-cream. Granulated sugar
was employed ordinarily before the war. However, in conserving for the
war, it was found that various sirups could be substituted. Corn sirup
was commonly used, and some invert sugar, maple sirup and honey in
smaller amounts.
A large variety of materials may be utilized to flavor the ice-cream.
The extracts commonly employed are vanilla and lemon. Fruits, either
fresh, canned, preserved, dried or candied, may be used as flavoring,
various bread or cake products, such as macaroons, sweetened wafers and
sponge cake, and also caramel and chocolate products, usually chocolate
or cocoa.
A little color of the proper shade to give the product the
characteristic tint suggested by the flavor is commonly added.
If the ice-cream is not consumed as soon as it is made, ice crystals
soon separate, causing it to become grainy in texture. In order to
prevent this, some form of “stabilizer” is added, commonly gelatine.
However, gum tragacanth or some of the prepared ice-cream powders may
be used.
=2. Definition of ice-cream.=--Because of the large variation of
materials, both in quantity and kind, that may be used in its making,
the definitions of ice-cream are more or less elastic. The various
dictionaries give the following definitions: _Webster_,--“Ice-cream is
milk or cream sweetened, flavored, and congealed by a freezing mixture,
sometimes instead of cream the materials of a custard are used”;
_Century_,--“Ice-cream is a confection made by congealing variously
flavored cream or custard in a vessel surrounded with a freezing
mixture;” _Standard_,--“Ice-cream is cream, milk or custard sweetened
and flavored and frozen by a freezing mixture, being usually agitated
by a dasher in the process to make it of uniform consistency.” The
United States Department of Agriculture bases its definition[1] on the
composition of the finished ice-cream. Its definitions are as follows:
Ice-cream is a frozen product made from cream and sugar with or without
a natural flavoring and contains not less than 14 per cent of milk-fat.
Fruit ice-cream[1] is a frozen product made from cream, sugar and
sound, clean, mature fruits, and contains not less than 12 per cent of
milk-fat.
Nut ice-cream[1] is a frozen product made from cream, sugar and sound
non-rancid nuts and contains not less than 12 per cent of milk-fat.
[1] Office of the Secretary, U. S. Dept. Agr., Bul. 19, 1906.
The National Association of Ice-Cream Manufacturers defines ice-cream
and the adulterated product as follows: That for the purpose of this
act ice-cream is hereby defined and standardized:
_First_: Ice-cream is a frozen compound, varied as to kind and
proportion of ingredients within the limits established by custom and
usage.
_Second_: Ice-cream consists chiefly of a sweetened and flavored
mixture of cream, or cream and milk, or milk, with or without added
milk-fat in the form of sound sweet butter or as contained in
condensed, evaporated or concentrated milk or in milk powder, and
with or without added milk solids not fat in the form of skim-milk
powder or as contained in milk powder or in condensed, evaporated or
concentrated skim-milk, or of a sweetened and flavored homogenized or
emulsified mixture of sound, sweet butter, milk powder or skim-milk
powder and water, with the addition of gelatine, vegetable gum, or
other wholesome stabilizer.
_Third_: Standard ice-cream contains not less than eight (8) per
cent milk-fat and the content of milk-fat and milk solids not fat
combined shall not be less than eighteen (18) per cent except when
the ingredients of standard ice-cream include eggs, fruit or fruit
juice, cocoa or chocolate, cake, confections or nuts, such reduction
of the percentage of milk-fat and milk solids not fat as may be due
to the addition of such ingredients shall be allowed.
_Fourth_: When ice-cream is sold or offered for sale without
designation of its kind, quality or grade on a label, brand, or tag
attached to the package or container, or, in case of removal from the
original package or container, by a notice conspicuously posted in
or at the place where such ice-cream is sold or offered for sale, it
shall be deemed that such ice-cream is sold or offered for sale as
of the grade of and for standard ice-cream, or better. That for the
purposes of this act ice-cream shall be deemed to be adulterated:
(1) If in quality or grade it is lower than the professed standard of
quality or grade which it is sold or offered for sale.
(2) If it contains any added poisonous or other added deleterious
ingredient which may render such ice-cream injurious to health.
(3) If it contains any rancid or renovated or process butter, or any
fat or oil other than milk-fat and the fat or oil of contained eggs
or nuts and the fat or oil of substances used for flavoring purposes
only.
(4) If it consists in whole or in part of any filthy or decomposed
substance which may render such ice-cream injurious to health, or is
otherwise so contaminated that such ice-cream is injurious to health.
That for the purpose of this act ice-cream shall be deemed to be
misbranded:
_First_: If the label, brand, tag or notice under which it is sold or
offered for sale is false or misleading in any particular as to the
kind, grade or quality or composition of such ice-cream; or if any
notice to the purchaser required by this act to be given is omitted.
_Second_: If it is sold or offered for sale as the product of
one manufacturer when in reality it is the product of another
manufacturer: or if on the label, brand, tag or notice under which it
is sold or offered for sale there is any false statement concerning
the sanitary conditions under which such ice-cream is manufactured.
So far the description of ice-cream has mentioned only the materials
to be used and in some cases the chemical composition in so far
as percentage of fat is concerned. It is evident that there is
considerable difference of opinion regarding the minimum percentage of
fat that the ice-cream should contain. It would seem that it might not
only be desirable to mention the materials which could be employed, but
also the percentage of fat and total solids or milk solids not fat, by
means of a sliding scale. In the description, no account is taken of
the bacterial-content of the ice-cream. The number of organisms may or
may not give an indication of the quality of the materials used and
the sanitary condition under which the manufacturing and handling is
done. When a bacterial standard for milk is universally recognized and
enforced, then a bacterial standard for ice-cream may be enforced.
It is to be desired that an adequate definition of ice-cream will be
forthcoming and that this definition will be enforced. This will do
much to improve the quality of the product.
=3. Problems of ice-cream-making.=--The successful making of ice-cream
calls for an understanding of the complex factors involved. These
factors are: The production and handling of the milk and the milk
products employed; the chemical and bacteriological composition of the
milk products; the various tests used, such as fat, acid, tests for
swell and the like; the blending of the flavors of the various products
to secure the characteristic flavor desired; the freezing process and
subsequent handling of the ice-cream; the construction and operation
of the machinery. A working knowledge of the combination of the above
factors is necessary to make ice-cream of uniform quality. After the
manufacture, the marketing of the product is a vital question and it
should receive constant attention and study.
=4. Ice-cream-making a science.=--Only recently has the making of
ice-cream been recognized as founded on science. This is probably
because in the past most of the ice-cream was made in small amounts
largely in the household, while now it is manufactured in large
quantities in commercial plants.
In these large plants and in the agricultural colleges, considerable
attention has been paid recently to the making of ice-cream. No
description of the process can replace experience. Description of
appearance of the ice-cream and conditions during the making process,
in terms definite and clear enough to be readily understood by
beginners, has been found to be impossible. Certain principles and
essentials of practice can be presented, which form the foundation for
intelligent work. The more study given to the process, and the better
the underlying principles are understood, the further we will depart
from rule-of-thumb practice.
CHAPTER II
_MILK AND CREAM AS RELATED TO ICE-CREAM_
Several milk products are commonly used in ice-cream, namely: whole
and skimmed-milk, cream, condensed milk, evaporated milk, milk powder
and butter. These may be utilized singly or in combinations. The
most important characteristic of the milk products is their flavor
which should be clean and sweet; if not, it is likely to impart its
undesirable flavor to the ice-cream. Much might be written on the
production, care and composition of the milk and cream. Space will not
permit this, but the essential factors as related to ice-cream will be
discussed.
=5. Method of securing supply.=--The ice-cream industry offers an
entirely different problem from the other branches of the dairy
industry in relation to securing a supply of milk and cream. This is
due to the location. There are usually brokers or commission men who
are willing to handle butter, cheese, condensed milk and other dairy
products which are not comparatively as perishable as ice-cream.
Therefore, the butter, cheese, and condensed milk plants are located
where they can secure easily a supply of raw milk, which is in the
country. On the other hand, there are no brokers or commission men who
handle ice-cream; therefore, the ice-cream is sold directly to the
retailer or consumer. Because of the ease of delivery, the ice-cream
plant is located in the center of population, namely, the city or
village. It has not proved satisfactory, either from the view point of
quality or cost of production, to make the ice-cream near the supply in
the country and ship the finished product to the city.
Due to the location of the ice-cream plant in the city, there are four
ways of securing the raw materials:
1. Buy milk and cream from dealer.
2. Operate creamery in country and get supply from it.
3. Use surplus from other dairy operations, and purchase necessary
balance.
4. Use of homogenized or emulsified milk and cream.
Each ice-cream concern will have to decide, after carefully considering
all the factors, which method is best adapted for its use. Each has its
advantages and disadvantages.
_Buying milk and cream from dealer._
Advantages:
1. No surplus to dispose of.
2. Minimizes labor in the ice-cream plant.
3. Requires less capital.
Disadvantages:
1. Uncertainty of cream supply.
2. No control of quality.
3. Higher cost of cream.
4. No control of fat-content of cream.
5. Must have separate supply of condensed milk.
6. At mercy of cream dealer.
7. Difficult to dispose of any surplus.
_Operating creamery in country and getting supply from it._
Advantages:
1. Certain of known supply.
2. Better control of quality.
3. Easy to dispose of any surplus.
4. Usually a cheaper supply.
5. Can secure cream of desired fat-content.
6. Can pay patrons better price for milk.
7. May make own supply of condensed milk.
8. More independent.
Disadvantages:
1. Requires more capital.
2. Requires more labor.
3. Requires more management.
4. Must deal directly with the dairy-men.
5. Transportation.
6. Must find suitable location.
_Using surplus from other dairy operations and purchasing necessary
balance._
Advantages:
1. Makes an outlet for surplus.
2. Economy of delivery.
Disadvantages:
1. May make too large a business.
2. May not have necessary equipment, especially refrigerator.
3. May not be able to purchase necessary balance of supply.
Disadvantages same as buying from dealer.
4. If side line, may not give it proper attention.
5. May not have surplus only part of year so balance of year do not
care to operate.
_Use of homogenized or emulsified milk and cream._
Advantages:
1. When big demand can quickly make supply of cream.
2. Sweet cream can be secured in localities where it can not be
produced easily, especially the South.
3. Does not necessitate carrying a large surplus of cream.
4. Usually a cheap supply of cream.
Disadvantages:
1. Tendency to try to use butter and milk products of inferior
quality.
2. Because of the physical nature of homogenized cream, try to use
less fat in it.
=6. Quality of milk and cream desired.=--Regardless of how obtained,
the cream and milk should be of the desired quality for ice-cream
manufacture. The cream should be clean flavored and sweet. In some
plants, when the cream is slightly sour, a neutralizer is added,
but this practice should not be followed. Better care, better
holding methods or both should be employed to insure sweet cream.
The refrigerated room in which milk and cream are stored in a large
ice-cream plant is shown in Fig. 1. Cream for ice-cream-making should
not have more than 0.24 per cent of acid by the acid test. (For use
of acid test, see Chapter XIV.) In order to insure sweetness, cream
is usually pasteurized. Pasteurization[2] is heating to a temperature
sufficiently high, usually 145° F. and held at this temperature for
a sufficient period, usually thirty minutes, to kill most of the
organisms in the milk and then rapidly cooling to 50° F. or below.
When pasteurized cream and milk are used, there is not the danger
from disease organisms that there is from raw cream. An “aged” cream
is to be desired for ice-cream-making because it is more viscous. By
“aged” is meant the holding of the cream for a period after separating
before it is made into ice-cream. Usually it is aged for twenty-four to
thirty-six hours. While aging it must be kept cold so it will not sour
and it should not be frozen. It is hard to melt frozen cream and it is
liable to cause the ice-cream to be grainy.
[2] Ayres, S. H., “The Present Status of the Pasteurization of Milk,”
U. S. Dept. Agr. Bul. 342, 1916.
[Illustration: FIG. 1.--Refrigerated room for storing milk and cream in
a large ice-cream plant.]
The demand for ice-cream fluctuates with the weather changes. When
it is hot there is an extensive demand but if the weather rapidly
becomes cool this demand suddenly decreases or _vice versa_. This means
that the ice-cream-maker either must carry or have at his disposal
a variable supply of cream. When hot weather increases the demand,
there may not be time to age the cream or it may be held so long that
it becomes sour. Homogenized or emulsified cream is to be desired for
ice-cream-making because it gives a smoother body and texture to the
product. This is undoubtedly due to the fat globules and other solids
being broken up into smaller particles by the process.
=7. Why milk and cream are not of the desired quality.=--Some milk and
cream has undesirable flavors which may be more or less pronounced.
These are due to: the flavor of foods eaten by the cow; the absorption
of flavors and odors from the atmosphere; the health of the cow; the
bacteria present. If not properly handled, the milk and cream will soon
become sour.
=8. The flavor of foods eaten by the cow.=--The presence of undesirable
flavors in the milk is due many times to the cows eating foods with
very pronounced flavors. Most common of these foods are onion, garlic,
turnips, cabbage, decayed ensilage, various pasture weeds, and the
like. The flavoring oils are volatile and so are able to pass easily
through all the tissues of the animal, and in a short time pass off
through the various excretory channels. During the time that the food
is undergoing digestion, these volatile oils are not only present in
the milk, but all the tissues of the animal. By the time the process
of digestion is completed, the volatile flavors will have passed
away largely. Therefore, if the time of milking and feeding are
properly regulated, a dairy-man may feed considerable quantities of
strong-flavored food, without any appreciable effect on the flavor of
the milk. To do this successfully, the cows should be fed immediately
before or after milking, preferably the latter. This allows time for
the digestive process to take place, during which time the volatile
substances will have passed away. While, if the milking occurred three
or four hours after feeding, these volatile substances would be present
in the milk and so flavor it.
In the case of those plants which grow wild in the pasture and to which
the cows have continued access, it is much more difficult to overcome
the bad flavor in the milk. The only thing which can be done is to
allow the cows to pasture for a short time immediately after milking.
This will make it necessary to supplement the food of the pasture with
dry feed, or to have another pasture where these undesirable plants do
not grow.
=9. The absorption of flavors and odors in the atmosphere.=--Milk,
especially when warm, possesses a remarkable ability to absorb and
retain odors in the surrounding atmosphere. For this reason, the
milk should be exposed only in a surrounding of clean pure air. Some
of the common sources of these undesirable odors are: bad smelling
stables; unclean cows; aërating milk near hog pens, barnyards, swill
barrels, and like odoriferous sources; strong-smelling feeds in the
stable during milking, and the like. The only way to overcome these
undesirable flavors and odors in the milk is not to expose the milk to
them. The safest policy is to remove the source of the odor.
=10. The unhealthy condition of the cow.=--Milk secreted just before or
just after parturition is different in physical properties and chemical
composition from that secreted at any other time during the lactation
period. This milk is known as colostrum. It is considered unfit for
human food, either as milk or products manufactured from the milk. Most
states consider colostrum adulterated milk, and prohibit its sale
fifteen days before or five days after parturition.[3]
[3] N. J. Agricultural Law, 1913, section 30; Mich. Agricultural Law,
1915, section 77; Wis. Agricultural Law, 1913, section 4601-49-5.
Whenever disease manifests itself in the cow, the milk should be
discarded at once as human food. Some diseases are common both to the
cow and man, such as tuberculosis and foot-and-mouth disease. If such
diseases are present in the cow, the milk acts as a carrier for them
to man. Digestive disorders of any sort in the cow are frequently
accompanied by undesirable flavors in the milk. These are not believed
to be due to the food eaten, but to the bad condition of the animal. On
resuming a normal condition, these undesirable flavors disappear. This
is especially noticeable when cows are turned out to pasture for the
first time in the spring, or when they are pastured on rank fall feed,
such as second-growth clover.
=11. The bacteria in the milk.=--The bacteria are microscopic
unicellular plants without chlorophyll. Besides bacteria, there are
other forms of the lowest orders of the vegetable kingdom found
in milk, such as yeasts and molds. The general characteristics of
yeast and bacteria are somewhat similar. Bacteria are very widely
distributed throughout nature. They are so small that they may float
easily in the air or on particles of dust. They are so resistant to
adverse conditions of growth that they may be present in a dormant
or spore stage, and thereby not be recognized readily; when suitable
environments for growth are again produced, germination takes place at
once. They are found in all surface water, on the surface of the earth,
and upon all organic matter. There are a great many different groups
of bacteria, some beneficial and some harmful to man. As they are so
small, it is difficult to differentiate between the beneficial and
harmful groups, except by the results produced or by a careful study
in an especially equipped laboratory. Bacteria have many forms, the
three common forms being: spherical (coccus); rod-like or cylindrical
(bacillus); and corkscrew (spirillum). The bacteria reproduce very
rapidly by fission, that is, a transverse partition forms in the cell
and when this partition is completed, the cell is divided. There are
then two bacteria where there was but one before. In some cases, this
division has taken place regularly in twenty to thirty minutes. Like
other plants, they are very sensitive to a food supply, to temperature,
and to moisture, as conditions of growth. Inasmuch as the bacteria are
plant cells, they must imbibe their food from materials in solution.
They may live on solid substances, but the food elements must be
rendered soluble before they can be utilized. Bacteria prefer a neutral
or slightly acid medium for growth, rather than an alkaline reaction;
however, there are many exceptions to this. The food for bacteria
must contain carbon, hydrogen, oxygen, and nitrogen, together with
small amounts of mineral matters. Organic compounds make available
food supplies. Ordinary milk furnishes a very favorable medium for
the growth of bacteria because it contains an adequate and easily
available food supply. In milk, there are certain groups of bacteria,
which are ordinarily present, but any others which happen to get into
the milk will live and rapidly multiply. Most forms of bacteria are
dependent on temperature as a condition of growth. There is a range
of temperature, more or less wide, at which the bacteria will grow
and multiply with the greatest rapidity. This is called the optimum
temperature and varies with the different groups of bacteria, but for
most it is between 75° F. and 95° F. Growth of most of the bacteria
found in milk will take place between 40° F.-45° F. to 105° F.-115° F.
Above and below these temperatures growth is retarded, and, if carried
to extremes, life will be destroyed. Like plants which form structures
called seeds to carry them through conditions unfavorable to growth,
so some groups of bacteria form spores. The spores are exceedingly
resistant to unfavorable conditions of growth, such as heat, cold,
drying, food supply, and even chemical agents. It is this property
which makes it difficult to destroy some bacteria.
Because of the harmful effect of the micro-organisms in the milk and
cream, precautions should be taken to keep them out. If they do enter,
their growth can be checked by keeping the milk and cream cold. What
has been said regarding bacteria is true of molds and yeasts.
=12. The sediment test.=--The amount of solid material or dirt in
the milk is an indication of the amount of bacterial contamination.
It should be remembered that the strainer will take out the solid
material, but the soluble portion and the bacteria will be left in the
milk or cream. Thus an efficient strainer will defeat the sediment
test. There are several sediment tests on the market. The test consists
of filtering about a pint of milk through a cotton disc filter about
an inch in diameter. The solid material or dirt is left on the filter.
(Fig. 2.) The amount of dirt would indicate the amount of contamination
in the milk. Much improvement in the quality of the milk has been
accomplished by the use of the sediment test, because the cotton discs
with the dirt are posted where each patron can see them and pride
causes the careless dairy-man to take more pains in the care and
handling of his milk.
[Illustration:
1 2 3 4 5
CLEAN FAIRLY CLEAN MODERATELY CLEAN DIRTY FILTHY
FIG. 2.--Filters from sediment tests showing the amount of dirt in
different samples of milk. These are the grades made by the New York
City Board of Health.]
=13. How to prevent the growth of micro-organisms in the milk and
cream.=--Next in importance to clean production in the care of milk
and cream, is the prevention of growth or development of the organisms
in it. This is accomplished by cooling and keeping the milk and cream
cold and covered. If they are produced clean and kept covered, there
are certain to be some micro-organisms in the milk and unless cooled
these will develop and quickly spoil the milk and cream. Ross[4] and
McInerney give the following summary regarding the cooling of milk and
cream:
[4] Ross, H. E., and McInerney, T. J., “Cooling milk,” Cornell Reading
Courses, Vol. V, No. 102, 1914.
“Milk becomes cool, of course, when it gives up its heat to some
substance colder than itself, and in order to have a rapid exchange
of temperatures between two substances it is necessary that they have
approximately the same density. On account of the great difference
in density between air and milk, the latter will cool very slowly
in air even though the temperature of the air is rather low. If milk
is allowed to cool by standing in a cold atmosphere, it will do so
unevenly, and by the time the milk in the center of the can is cooled,
that part near the walls of the can may be frozen. The fat is not
evenly distributed in frozen milk; therefore it is not so good as
normal milk.
“1. The bacteria-content of milk held at a temperature of 50° F.
increases slowly, while the bacteria-content of milk held at 90° F.
increases rapidly.
“2. At a temperature of 90° F. bacteria increase rapidly in milk that
had either a small or a large amount of bacteria in it originally.
“3. Cooling milk by placing the cans in a tank of ice water is a
practical method for use in farm dairies. To cool the milk rapidly it
must be stirred at frequent intervals.
“4. Stirring the milk at intervals of five minutes caused a
sufficiently rapid drop in temperature. Rapidity of cooling due to
stirring the milk at intervals of five minutes and at intervals of ten
minutes was very slight.
“5. When sufficient quantities of ice were used, stirring the water in
the cooling tank had little effect on the rapidity of cooling.
“6. In order to obtain the best efficiency from the conical type of
cooler, it is absolutely necessary to stir the water inside the cooler.
“7. Lower temperatures can be obtained by using brine and ice than with
ice water alone.”
Stocking[5] shows the effect of temperature on the development of the
bacteria in milk by the following experiment: A sample of milk, which
was thoroughly mixed, was divided into six equal parts. The six bottles
were placed in water at different temperatures for twelve hours, at
which time the germ-content of each lot was determined. The six bottles
were then all placed together in a temperature of 70 degrees and
allowed to remain until they curdled. As each sample curdled, the time
was recorded. The difference in the germ-content and the keeping time
is the result of the difference in temperature for a period of twelve
hours only, and shows what may happen easily in milk which is allowed
to stand overnight without thorough cooling.
[5] Stocking, W. A., Jr., “Problems of the milk producers,” N. Y. State
Dept. Agr., Circ. 10, 1910.
TABLE I
Effect of different temperatures for twelve hours on the growth of
bacteria and on the keeping quality of milk
I II
Kept at 45 degrees Kept at 50 degrees
Number of bacteria 9,300 Number of bacteria 18,000
Curdled in 75 hours Curdled in 72 hours
III IV
Kept at 55 degrees Kept at 60 degrees
Number of bacteria 38,000 Number of bacteria 453,000
Curdled in 49 hours Curdled in 43 hours
V VI
Kept at 70 degrees Kept at 80 degrees
Number of bacteria 8,800,000 Number of bacteria 55,300,000
Curdled in 32 hours Curdled in 28 hours
=14. Milk and cream production and handling.=--The following diagram
shows the main sources of contamination and the undesirable methods of
handling by which the quality of milk and cream is impaired:
Sources of contamination and undesirable methods of handling
{ Atmosphere in the stable { Dust from feed
{ { Dust from floor and bedding
{
{ Cows { Exterior of udder and flank
{ { Coat
{
{ Utensils { Dirty utensils
On the farm { { Rusty utensils
{
{ { Dirty clothes
{ Milker { Dirty hands
{ { Wetting the teats
{
{ Cooling { Air and dust
{ { Dirty utensils
Transportation from { Exposed to sun and dust
farm to creamery { Carried in dirty utensils
{ { Allowing milk to stand before separating
{ { Allowing cream after separated to stand
{ Careless methods { before cooling
Creamery { { Not cooling cream to low enough
{ { temperature
{
{ Dirty equipment
{ Use of dirty rusted cars. Allowing to stand on
Transportation from { railroad platforms, in the sun uncovered
creamery to ice-cream { Lack of can jackets
manufacturer { Poor delivery service
{ Lack of refrigerator cars
{ Too long shipments
{ Holding cream too long
Ice-cream manufacturer { Lack of refrigerator space to hold cream
{ Dirty equipment and utensils
The above shows that the producer controls most of the factors which
concern the sources of initial contamination.[6] After the milk leaves
the producer, if it is not properly handled, the organisms in it may
develop or if exposed to dirty conditions more contamination may take
place. The important factors in the production and handling of milk
are: clean utensils, clean healthy cows, small-top milk-pails, proper
cooling and maintaining of low temperature, 50° F. or below. The
importance of can jackets to aid in keeping the cream cold should not
be overlooked, especially when shipping in hot weather. The quality of
the milk and cream is largely determined by the time it is delivered at
the ice-cream plant.
[6] Ayres, S. H., Cook, L. B., Clemner, P. W., “The four essential
factors in the production of milk of low bacterial content,” U. S.
Dept. Agr., Bul. 642, 1918.
[Illustration: FIG. 3.--Sharples milk clarifier.]
[Illustration: FIG. 4.--De Laval milk clarifier turbine drive.]
=15. Clarifier.=--If solid or semi-solid dirt either visible or
invisible is in the milk, it can be removed by the use of a clarifier.
This is a specially devised machine (Figs. 3 and 4) which takes out the
dirt by centrifugal force. It is desirable to clarify milk and cream
for ice-cream-making. Besides removing dirt which gets into the milk
during handling, the clarifier also takes out blood corpuscles and pus
cells which are sometimes secreted with the milk.
=16. The chemical composition of the milk and cream.=--It is not
possible here to discuss in detail the composition of the milk and
cream and the factors influencing it. Ross[7] gives the composition of
milk, cream and skimmed-milk as follows:
[7] Ross, H. E., “Composition of milk and some of its products,”
Cornell Reading Course, Vol. 11, No. 32, 1913.
TABLE II
Showing composition of milk
_Average_ _Maximum_ _Minimum_
Water 87.0 90.69 80.32
Sugar 5.0 6.03 2.11
Fat 4.0 6.47 1.67
Casein 2.6 4.23 1.79
Albumen 0.7 1.44 .25
Ash 0.7 1.21 .35
TABLE III
Showing composition of cream
_Cream high in fat_ _Cream low in fat_
Water 29.0 76.6
Fat 67.5 15.2
Casein } 1.2 3.1
Albumen}
Sugar 2.2 4.5
Ash 0.1 0.6
TABLE IV
Showing composition of skimmed-milk
Water 90.60
Fat .10
Sugar 4.95
Casein 3.15
Albumen .42
Ash .78
From the view point of the ice-cream-maker, the fat and solids not
fat are of special consideration. Each state has standards for milk,
cream and skimmed-milk. (See Table XV.) The federal standards[8] are
as follows: Milk is the fresh clean, lacteal secretion obtained by the
complete milking of one or more healthy cows, properly fed and kept,
excluding that obtained within fifteen days before and ten days after
calving and contains not less than eight and one-half (8.5) per cent of
solids not fat and not less than three and one-quarter (3.25) per cent
of milk-fat.
[8] Office of the secretary, U. S. Dept. Agr., Circ. 19, 1906.
Skim-milk is milk from which a part or all of the cream has been
removed, and contains not less than nine and one-quarter (9.25) per
cent of milk solids. Cream is that portion of milk, rich in milk-fat,
which rises to the surface of milk on standing, or is separated from
it by centrifugal force, is fresh and clean and contains not less than
eighteen (18) per cent of milk-fat.
Milk and cream should be purchased on the fat test and not by measure,
the price being based on the fat-content. For method of testing, see
Chapter XIV.
Because of the variable composition of milk and cream, it is necessary
to standardize them for use in ice-cream-making. For method of
standardization, see Chapter XIV.
CHAPTER III
_MANUFACTURED MILK PRODUCTS AS RELATED TO ICE-CREAM_
Besides the milk and cream, several other manufactured milk products
are used in ice-cream. What has been said previously about the milk
and cream applies also to the milk for these products. The quality,
especially the flavor, is very important.
CONDENSED AND EVAPORATED MILK
There is a difference between condensed and evaporated milk, but
because of their similarity, both in composition and manufacture, they
will be considered together. Condensed milk usually has sugar added to
preserve it, although some ice-cream-makers use it without added sugar,
when it is known as plain in contrast to sweetened condensed milk. The
evaporated milk is usually sterilized in sealed cans to preserve it, no
sugar being added. More condensed milk is employed in making ice-cream
than evaporated milk. The condensed is usually shipped to the ice-cream
manufacturer in bulk, either in milk-cans or barrels.
=17. Method of manufacture.=--The water is removed from the milk by
heating under reduced pressure. The heating is usually done in a copper
pan. (Fig. 5.) This is accomplished by means of a steam jacket on the
bottom and usually one or two steam coils in the pan. Before drawing
the milk into the pan, it is heated in an open copper vessel, by
turning direct steam into the milk. This container is called the hot
well or fore warmer. The temperature varies according to whether plain
or sweetened condensed is being made. The sweetened is heated higher to
dissolve the sugar. The object of heating under reduced pressure is to
reduce the boiling point. At ordinary pressure milk would boil at the
same temperature or a little above that of water. At this temperature
the milk could not be condensed without imparting a pronounced cooked
flavor and caramelizing a part of the sugar.
[Illustration: FIG. 5.--View of modern condensory showing hot wells,
vacuum pan, vacuum pump and cooling tanks.]
The vacuum in the pan is produced by means of a vacuum pump. A vacuum
equal to a column of mercury about 25 inches is usually maintained. The
condenser is located at the top of the pan and is directly connected
with it. As the milk boils, the vapor passes from the pan into the
condenser. In the latter the vapor comes in contact with a spray of
cold water which causes it to condense. The pump carries off the
condensing water and the condensed vapor. When the desired density
is reached, the milk is drawn from the pan and cooled. The proper
concentration of the milk is determined by a special graduated scale
known as the Baumé. A more recent method is an electric resistance.
If sweetened condensed is being made, the sugar is added to the milk,
the mixture of sugar and milk are heated to dissolve the sugar before
drawing them into the pan.
Sometimes the milk is superheated; this consists of turning live steam
into the milk just at the time that the desired concentration is
reached. It gives the condensed milk more of a “livery” appearance,
which is probably due to the precipitation of the albumen.
The length of time required for condensing the milk to the desired
consistency varies with the amount of milk in the pan, amount of
heating surface, size and capacity of vacuum pump, and amount and
temperature of water in the condenser.
=18. Standards for condensed milk.=--The following standards are given
by the United States Department of Agriculture:[9]
[9] Office of the Secretary, U. S. Dept. Agr., Food Inspection,
Decision 170, 1917.
“Sweetened condensed milk, sweetened evaporated milk, sweetened
concentrated milk, is the product resulting from the evaporation of
a considerable portion of the water from the whole, fresh, clean,
lacteal secretion obtained by the complete milking of one or more
healthy cows, properly fed and kept, excluding that obtained within
fifteen days before and ten days after calving, to which sugar
(sucrose) has been added. It contains, all tolerances being allowed
for, not less than twenty-eight per cent (28.0 per cent) of total milk
solids, and not less than eight per cent (8.0 per cent) of milk fat.
“Condensed skimmed milk, evaporated skimmed milk, concentrated skimmed
milk, is the product resulting from the evaporation of a considerable
portion of the water from skimmed milk, and contains, all tolerances
being allowed for, not less than twenty per cent (20.0 per cent) of
milk solids.
“Sweetened condensed skimmed milk, sweetened evaporated skimmed milk,
sweetened concentrated skimmed milk, is the product resulting from the
evaporation of a considerable portion of the water from skimmed milk to
which sugar (sucrose) has been added. It contains, all tolerances being
allowed for, not less than twenty-eight per cent (28.0 per cent) of
milk solids.”
Condensed or evaporated milk should be purchased only on its
composition, both fat and solids not fat. For method of testing, see
Chapter XIV.
=19. Conditions essential for a milk condensory.=[10]--“First. The
plant should be located in a community which is not only thoroughly
adapted in every way to a high standard of extensive dairy farming,
but is already far advanced in such development. The herds of cows
should be large, healthy, well cared for, and of a breed or breeds that
produce a grade of milk reasonably adapted for condensing purposes and
the production of a standard product.
[10] These conditions are taken from the U. S. Dept. Agr., Weekly News
Letter, Vol. II, No. 45.
“Second. In establishing a plant for condensing milk by the vacuum
process it is of primary importance that the location provide an
abundant, steady supply of pure, cold water, independent of the supply
required for boiler use. The quantity of water required to condense
a given quantity of milk will, of course, vary with the operating
conditions, such, for example, as the temperature of the condensing
water and the temperature (or the pressure) of the vapor to be
condensed. A general idea of the importance of water supply can be
obtained from the authoritative estimate that about 3 gallons of water
are required for the condensing of one pound of fresh milk (about one
pint). Difficulty in obtaining an adequate supply of good, pure, cold
water is a cause of serious embarrassment to some of the commercial
condensories now established, and the lack of it has been the cause of
many failures.
“Third. An abundant supply of milk is an absolute necessity. The
exact quantity required daily will, of course, vary with the size of
the plant. Several reliable authorities have estimated that for the
profitable production of condensed milk on a commercial scale the
supply of raw milk to the factory should not fall below 15,000 pounds
a day. This estimate is exclusive of the daily supply of milk normally
required for other purposes by the community. Furthermore, if the
finished product is to be of marketable quality, the milk received at
the condensory must be of exceptionally high grade; that is, clean and
pure. While first-class milk is essential for the manufacture of a
first-class dairy product of any kind, it is absolutely necessary if a
condensed milk factory is to be a success. If a few cans of low-grade
milk are not detected at the receiving platform of a condensory,
the slight defects in the raw milk are multiplied in the process of
condensing it, and the result is practically certain to be the complete
loss of the whole batch, which may represent a financial loss of
several hundred dollars. This statement may be illustrated concretely:
It is claimed by authorities that raw milk containing as much as 0.2
per cent acid (calculated as lactic acid) is not fit for condensing
purposes. This does not necessarily mean that it would taste sour, but
if accepted and condensed in the ratio of 2.25 to 1 (it may be more but
is seldom less), the acidity, increasing in the same ratio, would reach
0.45 per cent, which would be practically certain to cause a sour taste
in the finished product. Every housewife knows that sour milk will
coagulate or curdle on heating, and that the higher the temperature
the more rapid is the curdling process and the finer the curd. This
makes it unfit for cooking purposes. In the commercial production of
evaporated milk, the product must be sterilized in the cans at a very
high temperature in order to insure a good keeping quality. It is
obvious, therefore, that if milk is delivered to the factory with a
slight excess of acidity, it would probably be impossible to sterilize
the product obtained from it without producing a hard curd, which would
make the product absolutely unsalable, and thus a total loss to the
manufacturer. Furthermore, excessive acidity, which is principally
caused by improper care and handling of the milk, is not the only
condition that may render milk unfit for condensing. Other undesirable
qualities of the milk may also be induced by poor health and improper
care of the cows, by the kind and the condition of their feed, and by
many other details of imperfect management of the dairy farms.
“The services of experts thoroughly qualified by training and long
experience in this particular line will be required to detect and guard
against these unfavorable conditions.
“Fourth. Adequate facilities for marketing constitute another essential
to the commercial success of a condensed milk plant. Commercial
success, of course, implies a profitable market for the product--a
market which is readily and directly accessible to the plant without
adding excessively to the cost of manufacture, either in the form of
high freight rates or long hauls from the condensory to a railroad.
As already indicated, the successful manufacture of condensed milk on
a commercial scale requires a large output of the finished product--a
very much larger output than is likely to be consumed in the local
market; therefore, in selecting a location, favorable transportation
facilities to a good market or markets are a consideration of vital
importance to ultimate success.
“Fifth. In establishing and operating a condensory, the necessity of
adequate capital is another important question. The cost of buildings
and equipment will, of course, vary with the purchase of superior or
inferior materials and workmanship, as well as size of the plant, and,
in some measure, the kind of condensed milk to be produced. In any
case, however, the buildings should be thoroughly substantial, more
so than is commonly considered necessary for a creamery or a cheese
factory. The major part of the equipment is a very highly specialized,
more or less complicated, and very expensive type. The proper operation
of the equipment, especially the vacuum pan, and the sterilizer when
the product is sterilized in cans, calls for a high degree of skill
and large experience, if serious losses are to be avoided and a
standardized legal product is to be produced. The cost of buildings,
equipment, and operation of a plant for the manufacture of evaporated
milk (unsweetened condensed milk for household use) will illustrate the
capital required for the manufacture of any other form of condensed
milk. Some reliable authorities have conservatively estimated that
adequate buildings and equipment for a minimum production on a
commercial scale would cost in the neighborhood of $25,000, exclusive
of working capital. The markets for condensed milk at best are very
unstable. Frequently, the manufactured product must be held several
months before it is marketed. In the meantime, the plant must be kept
in operation, for which a very considerable surplus capital must be
provided. The same authorities estimate this item at $10,000. It
therefore appears that in establishing and operating a milk condensory,
capital to the amount of at least $35,000 must be provided. That this
estimate is conservative is indicated by the fact that manufacturers
of condensed milk have stated that a capital of $50,000 is usually
necessary to operate a condensed milk factory.
“Sixth. Commercial success in any manufacturing enterprise usually
requires much more than merely placing the product upon the market. A
demand for the product must be firmly established and a regular trade
developed before success is assured. To attain such a result the new
product must meet the keen competition of similar products already
well established. There are many well-established brands of condensed
milk now on the market. There may be room for many more, but new
brands, regardless of their quality, must expect to overcome strong
competition before a firm foothold is gained. This usually requires
extensive advertising and a competent, vigorous sales force, which
entails a heavy expense. Good salesmanship and advertising must be
continued. The necessity of a thoroughly organized selling organization
should, therefore, not be overlooked.”
=20. Supply of condensed milk for the ice-cream plant.=--From the above
conditions essential for a condensory, it is evident that an ice-cream
plant would not be justified in trying to operate one, unless also they
maintained a large milk and cream receiving plant in the country. It
is the usual practice for the ice-cream manufacturer to purchase the
supply of condensed milk. However, some plants have a condensory in
connection with their country plant, which is operated successfully.
When the supply of condensed milk is purchased, the basis of payment
should be the composition. For the methods of testing condensed milk,
see Chapter XIV.
MILK POWDER
In certain localities, especially the South where it is hard to
secure milk and cream, milk powder and butter are often emulsified or
homogenized to make cream. Milk powder is also employed in the same
way to meet sudden demands for cream. Milk powder is often used in
ice-cream to increase the milk solids not fat and thereby give a firmer
body and a smoother texture. The composition varies in fat from skim to
whole milk.
=21. Standards for milk powder.=--The following standards are given by
the United States Department of Agriculture:[11]
[11] Office of the Secretary, U. S. Dept. Agr., Food Inspection
Decision 170, 1917.
“Dried milk is the product resulting from the removal of water from
milk, and contains, all tolerances being allowed for, not less than
twenty-six per cent (26.0 per cent) of milk fat, and not more than five
per cent (5.0 per cent) of moisture.
“Dried skimmed milk is the product resulting from the removal of water
from skimmed milk and contains, all tolerances being allowed for, not
more than five per cent (5.0 per cent) of moisture.”
=22. Powdered milk processes.=--Two patented processes of making
powdered milk are in general use in this country at the present time,
the Merrell-Soule and the Ekenberg.
=23. Merrell-Soule powdered milk.=[12]--“The desired process must, it
was evident, be one which would not affect the active principles or the
nutritive qualities of milk, nor change its chemical reactions in any
way. The product when reaching the consumer must be, in every essential
quality, fresh milk.
[12] This article is taken from the publication, “Merrell-Soule
Powdered Milk for the Dairy, Creamery and Ice Cream Plant,”
Merrell-Soule Co., Syracuse, N. Y., 1918.
“The methods known as condensation and evaporation, also the earlier
milk powder processes, were efforts to achieve the desired result. But
in none of them was the goal completely attained, as it is to-day in
Merrell-Soule Powdered Milk--the product of a perfected process.
“Liquid Milk is seven-eighths water. Merrell-Soule Powdered Milk
contains approximately 2 per cent of moisture. Transportation cost is
thus reduced to a very small percentage of the expense of shipping
liquid milk. The fact that powdered milk may be shipped by freight,
while liquid milk must go by express or baggage, means an additional
saving.
“The expense of shipping powdered milk is also, of course, much lower
than the transportation cost of the condensed product.
“The Merrell-Soule process reduces the bacteria count to a remarkably
low figure, and it is a demonstrated fact that the bacteria which are
to be found in the fresh-made powder tend to die off, rather than
propagate, during storage.
“Merrell-Soule Powdered Milk is quickly and easily dissolved in water,
and the ‘reconstituted’ liquid milk thus obtained is pure, fresh milk,
with the delicate odor and unmistakable flavor of fresh milk, and with
every chemical reaction and nutritive property of fresh milk retained
unchanged.”
=24. History of Merrell-Soule process.=--“The history of powdered milk
dates back to the middle of the last century, when an inventor named
Grimwade patented, in England, the first commercially usable process.
“He added carbonate of soda to fresh milk, evaporated it in
open-jacketed pans, with constant agitation, until a dough-like
substance resulted; added cane sugar, pressed the mixture between
rollers into ribbons, dried it still further, then pulverized it.
“This process, cumbersome and unsatisfactory as it must have been, was
in practice for some years. Other processes followed at intervals for
half a century, but the real commercial development of the industry
dates back only about twenty years.
“It was in 1899 that a machine for the drying of milk by what has since
become known as the ‘double roll’ process was invented by W. B. Gere,
since deceased, then secretary of the Merrell-Soule Co., and I. S.
Merrell, first vice president of the company. But the ‘dry milk’ which
resulted from this process was not satisfactory, and for that reason
was not put on the market by the Merrell-Soule Company.
“Several other processes were then tried out, but none proved
satisfactory until Lewis C. Merrell, brother of I. S. Merrell, hit upon
the spraying of milk into a regulated current of heated air. This gave
the quality that had been desired, and the next thing was to determine
the commercial value of the process.
“In January, 1905, a building owned by the Merrell-Soule Company at
Fayetteville, N. Y., was equipped, and powdered milk was produced,
in a small way, by this spray process. Enough was marketed, and with
sufficiently gratifying results, to warrant the company in going ahead
with the enterprise.
“Meantime, patents had been applied for, and the patent office had
referred the Merrell-Soule Company to a United States patent granted
in 1901 to Robert Stauf, of Posen, Germany, which seemed to cover the
process. F. C. Soule, president of the Merrell-Soule Company, thereupon
went to Germany and bought not only the United States patent held
by Stauf, but also thirteen foreign patents owned by Stauf and his
associates.
“The wisdom of the purchase of all the patents held by the Stauf
interests has since been amply demonstrated. In 1915, patent litigation
which had been in the courts for three years was decided by the Court
of Appeals in favor of the Merrell-Soule Company, the decision being
based on this company’s possession not only of its own patents, but
also of the basic patents governing the spray process of powdered milk
manufacture.
“Following the success of the experiment at Fayetteville, the
construction of the first Merrell-Soule Powdered Milk factory, at
Arcade, N. Y., was begun in 1906. Before this factory was completed,
it had been discovered that a better product could be obtained by
condensing the milk in a vacuum pan before spraying. This resulted
in new patents covering what was known as the Merrell-Gere process,
embodying the original Stauf method and the improvement mentioned.
“Since then many other improvements have been made at the Merrell-Soule
plants, many other patents taken out. The first powdered milk factory,
at Arcade, was followed by a second, at Little Valley, N. Y., in 1909.
Since then factories have been established at Frewsburg, N. Y., Union
City, Pa., Waterford, Pa., Farmersville Station, N. Y., Warsaw, N. Y.,
Gainesville, N. Y., Attica, N. Y., and Omaha, Neb.
“Consumption of milk has increased from 18,000 quarts per day, in 1906,
at Arcade, to 300,000 quarts per day, at the present time, in the ten
factories. The output of powdered milk has grown from 2,500 pounds per
day, twelve years ago, to a present capacity of 50,000 pounds per day.
“These products include Powdered Skimmed Milk, Butterfat Powders, of
varying butterfat content, ‘Cream Powders,’ which contain up to 72 per
cent. butterfat, and Powdered Buttermilk.”
=25. Uses of Merrell-Soule powder in ice-cream.=--“The ice-cream
manufacturer demands a milk or cream product which is clean, which
will not sour quickly, which is not a breeder of bacteria, and which
gives him the largest percentage of milk solids in proportion both to
its bulk and its cost. All these essentials he finds in Merrell-Soule
powdered milk. Its powdered form insures the greatest possible purity
and cleanness, as is attested by many authorities. There need be no
loss through souring, no sticky, half-empty cans standing around,
gathering flies and breeding bacteria, when Merrell-Soule powdered milk
is used. The ice-cream man makes up just what he needs for the day’s
business. He can make up a big supply of cream, for a sweltering day’s
run, or a small amount for a cool day. A sudden drop in temperature
will not leave him with a lot of cream on hand that must either be used
or spoiled. It has been proved that Merrell-Soule powdered milk shows a
far smaller bacteria count than any other form of milk, and it offers
no breeding place for microbes.
“Merrell-Soule powdered milk can be put to many uses in the ice-cream
factory:--
“1. In the production of milk or cream from powdered skimmed milk,
butter and water.
“2. The production of skimmed milk from powder and water.
“3. The standardization of the milk solids in the ice-cream batch.
“4. Furnishing the necessary skimmed milk solids.
“5. Blending butter and the powdered skimmed milk with liquid whole
milk of any fat content, for the complete total milk solids of the
batch.
“Other uses could be mentioned, but these will give the ice-cream maker
an idea of the importance of Merrell-Soule powdered skimmed milk in his
business.
“Many of the large ice-cream makers are beginning to realize the losses
which they incur every year through using condensed milk to raise the
per cent of milk solids in their ice-cream.
“By the use of powdered skimmed milk they have an easy and accurate
means of holding the solids to any desired percentage.
“Merrell-Soule powdered skimmed milk does not take the place of
gelatines, ice-cream powders and the like, which prevent the ice
crystals in ice-cream, but it does provide the solids, not fats, which
give ‘body and texture’ to the ice-cream and makes it smooth, velvety
and palatable.
“Almost every ice-cream maker has his own formula for his mix, which
gives the best satisfaction to the trade he serves, and for this reason
we will not print any ice-cream formulas. We will be glad, however, to
furnish formulas which have given good results, to any ice-cream maker
who applies to us.
“In our own experimenting, and in practical work in some of the large
ice-cream factories, we have found the powdered skimmed milk to be a
wonderful help to ice-cream makers in a great many ways.”
=26. Ekenberg powdered milk.=[13]--“The Ekenberg process was invented
by Dr. Martin Ekenberg of Stockholm, Sweden. Dr. Ekenberg had
experimented with milk drying for some years, and his father, who was
an eminent chemist, also, had devoted considerable time to this problem.
[13] This description was given by L. P. Bennett, president of the
Ekenberg Co., Cortland, N. Y.
“The Ekenberg process is the result of these investigations, and the
machine which Dr. Ekenberg invented, he called the Ekenberg Exsiccator.
This consists of a single drum with conical shaped ends, revolving in a
vacuum chamber. The milk is introduced into the chamber through various
pipes and is sprayed into the conical or bowl shaped ends of the
revolving drum,--the drum being heated by steam at a low temperature.
The vacuum maintained in the chamber, is from 25 to 27 inches, and as a
result, the temperature in the chamber is low, not exceeding 100° F.
“The milk upon being introduced into the bowl shaped ends is evaporated
to a considerable degree and then passes off into the suction pipe
of a pump, from which the milk is again introduced into the vacuum
chamber, this time upon the periphery of the drum, to which it adheres,
and is then removed by a series of scrapers or knives. It will be
seen that the milk is only upon the drum during about two-thirds of
one revolution. The dried product falls into another chamber which is
separated from the main vacuum chamber by a series of air locks, so
that it may be removed at will from the exsiccator, without stopping
the continuous working of the machine.
“When the dried product is removed, its condition is that of light
fluffy flakes. It is then allowed to stand in a chamber heated to about
90° F. for about one hour, during which time, the lactose crystallizes.
From this chamber it is removed, and then milled in the same manner as
wheat is milled in the manufacture of wheat flour.”
=27. Uses of Ekenberg powder in ice-cream.=--“Ekenflor is the trade
name given to the many grades of powdered milk made from skimmed milk,
partly skimmed milk, or whole milk. In using Ekenberg Powdered Milk for
ice-cream it is not necessary to change the present formulas, but only
to adapt then to the use of milk in dry form.
“The raw milk from which Ekenflor is made is drawn from inspected
dairies and is manufactured in clean sanitary factories and is
therefore of the finest quality.
“Ekenflor does not sour or draw flies, and its use by the ice-cream
maker can not fail to reduce the chance of unsanitary conditions in
his factory and his losses from spoiled milk.
“There is always ‘a feast or a famine’ in the raw-milk market, and
as our powdered skimmed milk keeps almost indefinitely without cold
storage, it is always ready for immediate use, no matter how sudden
or great the demand may be. Its use makes the ice-cream manufacturer
independent of his local supply of milk or cream or condensed milk and
of the local prices.”
=28. Butter.=--For the making of emulsified or homogenized cream,
butter is ordinarily employed to supply the milk-fat. Unsalted butter
that is clean flavored and made from clean cream is to be desired.
If the butter is produced from inferior cream or has any undesirable
flavor, the cream made from it will have the same undesirable flavor.
It is the usual practice to store the butter during the period of low
prices, which is commonly the summer, and then to use it when prices
are high, usually the winter. The question of the kind of butter and
method of storage is a very vital one. It is generally considered that
sweet cream butter holds better in storage. The temperature of storage
should be as near 0° F. as possible.
The successful storing of butter, requires an intimate knowledge both
of market conditions and the desired quality of butter for storage.
The daily prices and movements of butter, in and out of storage,
and the daily receipts in the different markets and the sales, may
be obtained from the daily and weekly reports made by the Bureau of
Markets, United States Department of Agriculture. In New York City, the
market reports are also made in the “Price Current,” published by the
Urner Barry Company. Before storing butter, these reports should be
studied carefully, to make sure that the market conditions will warrant
storage. The quality of the butter can be determined by the market
grades or by the actual examining by an expert butter judge. Usually
when the ice-cream manufacturer purchases butter for storage, the
quality will be determined by the market grade, as personal examination
is seldom possible.
CHAPTER IV
_SUGAR, CHOCOLATE PRODUCTS, FRUITS, STABILIZERS AND FILLERS_
Besides the milk products, a number of other materials are used in
ice-cream. These are embodied in small amounts but their quality is of
vital importance. For this reason they are briefly discussed.
=29. Sugar.=--For sweetening the ice-cream, granulated sugar is usually
employed. This may be either cane- or beet-sugar, and should be free
from all visible dirt. Sugar seems to contain many mold spores and
so should be examined to determine the presence of mold or bacteria.
However, during the war, in order to conserve the supply of granulated
sugar, various substitutes were used, such as corn sirup, invert sugar,
honey and maple sirup.
=30. Invert sugar.=--Ruehe[14] gives the following directions for
making invert sugar:
[14] Ruehe, H. A., “Conserving sugar in ice cream manufacture,” Ill.
Exp. Sta. Circ. 219, 1918.
“Cane sugar (or beet sugar) can be inverted by the simple process of
heating in the presence of an acid. The chemical reaction that takes
place results in the same products being formed as are formed when the
sugar (sucrose) is taken into the human body, the sugar forming equal
parts of dextrose and levulose. The following formula may be used in
making invert sugar syrup of such sweetness that a pound of the syrup
will replace a pound of sugar:
100 pounds of sugar
44 pounds of water
50 grams of powdered tartaric acid
These ingredients are mixed together and boiled for 30 to 35 minutes.
If boiled longer than 35 minutes, the syrup darkens in color and a
flavor develops which tends to make the syrup resemble glucose syrup,
and this is somewhat undesirable. This solution boils at a temperature
of about 221 degrees Fahrenheit. A steam pressure kettle can be used
very satisfactorily or an open candy kettle over a steady fire may be
used. If the solution is boiled too vigorously, there will be too large
a loss by evaporation. Ordinarily the loss will be from 3 to 5 per cent.
“The above formula should make 140 pounds of syrup, and if there is
considerable loss due to evaporation, the syrup can be brought up to
this weight by the addition of water. The resultant invert sugar syrup
is not unlike strained honey in appearance and taste. It contains
about 71.4 per cent of sugar and it tastes considerably sweeter than
a sugar syrup of the same strength. It does not crystallize, and it
mixes readily with the ingredients of the ice cream. It can be used in
the same proportions as sugar, the amount necessary for ten gallons of
ice cream being 6.5 to 7 pounds. It gives very satisfactory results in
freezing and a pleasant flavor in the finished product.
“It can be readily seen that by using the above method the sugar supply
can literally be stretched, for with only 71.4 per cent as much sugar
as is now being used in ice cream, the same degree of sweetness can be
obtained.”
=31. Sugar-saving substitutes.=--Frandsen,[15] while working on
sugar-saving substitutes, reached the following conclusions:
[15] Frandsen, J. H., Rovner, J. W., and Luithly, John, “Sugar-saving
substitutes in ice cream,” Neb. Exp. Sta., Bul. 168, 1918.
“1. Four formulas have been worked out which save from 30 per cent to
50 per cent of cane sugar in the mix:
I. 44 lbs. 17 per cent cream
4 lbs. cane sugar
1³⁄₄ lbs. corn syrup (glucose)
4 oz. vanilla
4 oz. gelatine
II. 44 lbs. 17 per cent cream
2.9 lbs. cane sugar
2.9 lbs. corn syrup
4 oz. vanilla
4 oz. gelatine
III. 44 lbs. 17 per cent cream
1¹⁄₄ lbs. cane sugar
4¹⁄₂ lbs. invert sugar
4 oz. vanilla
4 oz. gelatine
IV. 44 lbs. 17 per cent cream
1¹⁄₄ lbs. corn syrup
1¹⁄₄ lbs. invert sugar
2¹⁄₄ lbs. cane sugar
4 oz. gelatine
4 oz. vanilla
“2. The ice cream prepared according to these four formulas meets the
requirements of good ice cream.
“3. Corn syrup dissolves with difficulty in cold cream. When added to
cream before pasteurizing, it dissolves readily.
“4. In hydrolyzing the syrups, excessive heating should be avoided.
“5. When invert sugar and corn syrup are used as the only source of
sweetening, a rather noticeable syrupy flavor is imparted to the ice
cream.
“6. When invert sugar, cane sugar and corn syrup are used in the
proportions indicated in Formula No. 4, no objectionable flavor is
noticeable.
“7. It is thought that hydrolyzing corn syrup in the presence of an
acid will enhance its sweetening properties.
“8. In addition to saving cane sugar, all four formulas lower the cost
of sweetening per gallon of ice cream.
“9. Corn sugar can replace 50 per cent of cane sugar in the mix.
“10. None of the substitutes so far tried will satisfactorily replace
all the cane sugar in the ice cream mix.”
=32. Cocoa and cocoa products.=--The various chocolate and cocoa
preparations are manufactured from the bean of the tree _Theobroma
Cacao_, of the family of Sterculiaceæ. This tree averages 13 feet in
height, and its main trunk is from 5 to 8 inches in diameter. It is a
native of the American tropics, being especially abundant and growing
under best conditions in Mexico, Central America, Brazil and the West
Indies.
The cocoa beans of commerce are derived chiefly from Ariba, Bahia,
Caracas, Cayenne, Ceylon, Guatemala, Haiti, Java, Machala, Maracaibo,
St. Domingo, Surinam and Trinidad. Besides these, the Seychelles and
Martinique furnish a small amount.
The plant seeds, or beans, grow in pods, varying in length from 23 to
30 centimeters, and are from 10 to 15 centimeters in diameter. The
beans, which are about the size of almonds, are closely packed together
in the pod. Their color when fresh is white, but they turn brown on
drying.
The gathered pods are first cut open, and the seeds removed to undergo
the process of “sweating” or fermenting, which is conducted either in
boxes or in holes made in the ground. This process requires great care
and attention, as on it depends largely the flavor of the seed. The
sweating operation usually takes two days, after which the seeds are
dried in the sun until they assume their characteristic warm red color,
and in this form are shipped into our markets.
=33. Manufacture of chocolate and cocoa.=--For the production of
chocolate and cocoa, the beans are cleaned and carefully roasted,
during which process the flavor is more carefully developed, and the
thin, paper-like shell which surrounds the seed is loosened and is
very readily removed. The roasted seeds are crushed, and the shells,
which are separated by winnowing, form a low-priced product, from which
an infusion may be made having a taste and flavor much resembling
chocolate.
The crushed fragments of the kernel or seed proper are called cocoa
nibs, and for the preparation of chocolate they are finely ground into
a paste and run into molds, either directly or after being mixed with
sugar and vanilla extract or spices, according to whether plain or
sweet chocolate is the end product.
For making cocoa, however, a portion of the oil or fat known as the
cocoa butter is first removed, by subjecting the ground seed fragments
to hydraulic pressure, usually between heated plates, after which the
pressed mass is reduced to a very fine powder, either directly or by
treatment with ammonia or alkalies, to render the product more soluble.
It is held that the large amount of fat contained in the cocoa seeds
(varying from 40 to 54 per cent) is difficult of digestion to many,
such as invalids and children, and hence the desirability of removing
part of the fat.
=34. Composition of cocoa products.=--The chief constituents of the
raw cocoa bean, named in the order of their relative amount, are fat,
protein, starch, water, crude fiber, ash, theobromine, gum and tannin.
In the roasting there is reason to believe a volatile substance is
developed much in the nature of an essential oil, which gives to the
product its peculiar flavor, and is somewhat analogous to the caffeol
of coffee.
Tannin, the astringent principle of cocoa, exists as such in the raw
bean, but rapidly becomes oxidized to form cocoa red, to which the
color of cocoa is due.
=35. Adulteration of cocoa products and standards of purity.=--The
following are the United States standards: “Standard chocolate should
contain not more than 3 per cent of ash insoluble in water, 3.5 per
cent of crude fiber, and 9 per cent of starch, nor less than 45 per
cent of cocoa fat.
“Standard sweet chocolate and standard chocolate coating are plain
chocolate mixed with sugar (sucrose), with or without the addition of
cocoa butter, spices, or other flavoring material, containing in the
sugar and fat-free residue no higher percentage of either ash, fiber
or starch than is found in the sugar and fat-free residue of plain
chocolate.
“Standard cocoa should contain percentages of ash, crude fiber, and
starch corresponding to those of plain chocolate, after correcting for
fat removed.
“Standard sweet cocoa is cocoa mixed with sugar (sucrose) containing
not more than 60 per cent of sugar, and in the sugar and fat-free
residue no higher percentage of either ash, crude fiber, or starch than
is found in the sugar and fat-free residue of plain chocolate.
“The removal of fat, or the addition of sugar beyond the above
prescribed limits, or the addition of foreign fats, foreign starches,
or other foreign substances, constitutes adulteration, unless plainly
stated on the label.
“The most common adulterants of cocoa are sugar and various starches,
especially those of wheat, corn and arrowroot. Starch is sometimes
added for the alleged purpose of diluting the cocoa fat, instead of
removing the latter by pressure, thus, it is claimed, rendering the
cocoa more digestible and more nutritious. Unless its presence is
announced on the label of the package, starch should be considered as
an adulterant. Cocoa shells are also commonly employed as a substitute
for, or an adulterant of, cocoa. Other foreign substances found in
cocoa are sand and ground wood fibre of various kinds. Iron oxide is
occasionally used as a coloring matter, especially in cheap varieties.
“Such adulterants as the starches and cocoa shells are best detected by
the microscope. The presence of any considerable admixture of sugar is
made apparent by the taste. Mineral adulterants are sought for in the
ash.”
=36. Chocolate sirup.=--Ice-cream may be flavored by pouring a
chocolate sirup over it. The following materials are used in making the
sirup:
Powdered cocoa, 1 pound
Sodium chloride, 6¹⁄₂ drams
Granulated sugar, 16 pounds
Shredded gelatine, 2¹⁄₂ ounces
Vanilla extract, 2¹⁄₂ ounces
Dissolve the gelatine in 10 pints of cold water, heat to the boiling
point, then add 15 pounds granulated sugar, stirring occasionally
until dissolved. Triturate 1 pound granulated sugar with the powdered
cocoa and sodium chloride until thoroughly mixed, then add to the hot
solution; boil for ten minutes, stirring constantly; strain while hot
and when cool, add the vanilla.
=37. Fruits.=--Many different fruits may be used to flavor ice-cream.
The principal ones are pineapple, cherry, strawberry, raspberry,
lemon, orange, peaches, and the like. In their season, the fresh
ripe fruit is used as a flavoring. For the period when the fresh
fruit cannot be obtained, the fruit may be canned, preserved without
chemicals, preserved with chemicals, or dried. Only fresh ripe fruits
should be employed, whether used fresh or held in some manner; since
for ice-cream-making the fruit must be broken into small pieces, it
is often cheaper to obtain from canneries small fruits or broken or
crushed pieces.
In some of the large ice-cream plants the fruits are preserved in large
jars (Fig. 6) by the addition of sugar and kept cold but not frozen.
Fruits preserved in this way give the product a flavor similar to fresh
fruits. Fruit extracts may be derived from the fruit, by fractional
distillation in dilute alcohol. These extracts should not be confused
with artificial or imitation flavors. The latter are often coal tar
ethers or esters. In order to obtain the desired flavor, it is usually
necessary to combine fruit extracts with the canned and preserved
fruits.
=38. Nuts.=--Only sound non-rancid nuts should be employed to flavor
ice-cream. For flavoring, the nut meats should be blanched by soaking
in hot water, and then removing the outer coating or covering;
these blanched nuts should then be ground. Often broken nuts can be
secured cheaply. A flavoring extract may be made from the nuts. In
many respects this is desirable because a more pronounced flavor is
obtained. For example, pistachio nuts give a very weak extract. It is
the custom to use pistachio flavoring and color the ice-cream green.
[Illustration: FIG. 6.--Fruit storage in large ice-cream plant.]
=39. Stabilizers and fillers.=--If ice-cream is not consumed as soon as
made, ice crystals will begin to form unless some stabilizer is used.
This is a substance added to ice-cream to prevent the formation of ice
crystals which cause a grainy bodied product. Stabilizers are sometimes
known as “holders” or “colloids” and commonly as “binders.” A “filler”
is some substance added to the ice-cream to cheapen it, usually to
replace the milk-fat and milk solids not fat. A “filler” may serve
the purpose of a “binder” or a “stabilizer,” but a stabilizer cannot
take the place of a “filler.” The common stabilizers are gelatine and
gum tragacanth. The common fillers are the various starches, such as
cornstarch, rice flour, arrowroot, wheat flour, eggs, an excess of
gelatine and the like.
=40. Gelatine.=--Commercial gelatine is an animal product made from
bones, hides, skins, tendons, horn piths, tannery trimmings and any
kind of connective tissue from the animal’s body. Pure gelatine is an
amorphous, more or less transparent substance of vitreous appearance.
It is brittle when dry, free from color, taste and smell. Gelatine and
glue are manufactured from the same materials, more care being used in
making gelatine.
The detail process of making gelatine varies in the different
factories, but the general steps are as follows: Treating and cleaning
the raw material; dissolving gelatine; concentrating; chilling and
spreading; drying; finishing; including grinding and packing. Gelatine
is put on the market in sheet, flake, shredded and powdered form. If
made from clean materials, no objection can be raised against its use
as a food. Gelatine swells in cold water, absorbing five to ten times
its weight of water. This is sufficient water to dissolve it at a
temperature of 85° F. to 90° F. The strength or gelatinizing power of
different samples of gelatine varies within wide limits. The following
is a simple method to compare different gelatines: Take ten grams of
the sample and soak over night in 100 cubic centimeters of cold water.
The next morning dissolve the gelatine at a temperature of 80° C. First
note the odor. It should not be pronounced or disagreeable. Determine
length of time it takes for a 50 cubic centimeter pipette full to run
out. Note the time it takes to gelatinize. Test the strength with a
jelly tester which is a simple arrangement to determine the weight
necessary to force a plunger into the gelatine.
[Illustration: FIG. 7.--Steam-jacketed kettle for heating gelatine.]
=41. Preparing gelatine for use in the ice-cream.=--In order to
utilize gelatine in ice-cream, it must be brought into solution. A
steam-jacketed copper kettle is usually employed for heating the
gelatine (Fig. 7). If a smaller quantity is taken or a special gelatine
cooker is not available, a double boiler or a can set in water can be
used. Whatever utensil is selected to cook the gelatine, it should be
kept clean. In many ice-cream factories, the gelatine cooker is badly
neglected. Before the gelatine is heated, it should be soaked in cold
water. One pound of gelatine should be put into about eight quarts of
water. Some prefer to use milk instead of water. The gelatine should be
stirred into the water rather than the water poured on to the gelatine.
This will to a large extent eliminate the formation of lumps which
would require excessive heating to break them down. The gelatine should
be soaked from twenty to thirty minutes in cold water before the heat
is applied. This soaked or soft gelatine should then be placed in a
water-jacketed heater and heated to a temperature of 165° F. to 170°
F. In case the gelatine is soaked in milk, it should not be heated
above 145° F. A higher temperature is very liable to give it a cooked
or scorched flavor. At this lower temperature, it is advisable to
hold it ten or fifteen minutes to make sure that the gelatine is all
broken down. It is necessary to heat the gelatine to the temperature
mentioned above to secure the best results. The eye cannot determine
when the gelatine is all broken down. There is danger of over-heating;
it should not be held at high temperature for long periods of time nor
allowed to boil. In putting the gelatine into the mix, it should be
done at the above mentioned temperatures for dissolving; not all at one
time, but poured in slowly and with as rapid agitation of the mix as
possible, and it will distribute itself more evenly before it has time
to congeal. A good gelatine will jelly at a temperature of 85° to 90°,
according to the proportions used; so that when pouring gelatine into
a mix with a temperature probably of 45° or 50°, it is very liable to
harden and make the ice-cream lumpy.
=42. Gum tragacanth.=--This is a compound gum obtained from a shrub, a
species of Astragalus. In July or August the leaves are stripped from
the shrub and a hole made in the bark. The shape of the hole regulates
the form of the gum, a longitudinal cut making the leaf or flake form,
a puncture the thread form, and an irregular hole a knob-like mass. The
gum is gathered by the natives. Dry weather gives a whitish colored gum
which is best; wet and dusty weather give an inferior yellowish gum.
Gum tragacanth will absorb fifty times its weight of water. For use in
ice-cream, the gum is soaked in water, one ounce of gum absorbing two
quarts of water. At least twenty-four hours should be allowed for this
absorption. Before being put in the ice-cream, the mixture should be
strained to remove any lumps. If it is not all to be used as soon as
soaked, a gum stock may be prepared by adding sugar at the rate of two
pounds for each quart of water. This will act as a preservative. Gum
tragacanth is odorless and tasteless. Just how it acts as a binder is
not known.
=43. Other substances used as binders.=--Two plants, Irish and Iceland
moss, are sometimes used as binders. The former is a sort of algæ and
the latter a lichen. They are both very low in food value.
=44. Eggs.=--In some kinds of ice-cream, eggs are necessary to give
the characteristic body and texture. When eggs are employed, it is
usually as a filler, since it is possible to reduce the percentage of
either the milk-fat or milk solids not fat or both. The usual practice
is to separate the yolks and whites of the eggs. The yolks are cooked
with the cream if used and the whites beaten and added just before the
ice-cream is frozen. Eggs usually give ice-cream a smooth texture and a
firm body. They also impart a characteristic flavor.
=45. Starchy fillers.=--Several starchy substances, such as cornstarch,
rice flour, arrowroot and wheat flour, are sometimes used in large
quantities and so become fillers. They give a characteristic starchy
flavor to the ice-cream. They are often employed to cheapen the
product. The starches are ordinarily cooked before using but sometimes
are mixed with the sugar and used without cooking.
=46. Prepared ice-cream powders.=--A large number of prepared
substances, both powders and liquids, is on the market. These are often
used in the place of some other binder. They may contain any or all of
the materials previously mentioned, and in addition they often contain
sugar to give both bulk and weight. These powders are usually added to
the ice-cream by mixing with the sugar. Many times, in proportion to
the results obtained, they are found to be expensive.
=47. Rennet.=--Another binder is some form of rennet. Its use is not
common and is ordinarily in combination with other materials.
CHAPTER V
_FLAVORING EXTRACTS_[16]
[16] This article on flavoring extracts is furnished by the Joseph
Burnett Extract Co., Boston, Mass.
Because of the distinct taste which the flavoring extract imparts to
the ice-cream, it is important that it be of good quality. The vanilla
extract is most common, but lemon, orange, pistachio, almond, various
fruit, and others are used to some extent.
Flavoring extracts are prepared commonly by grinding or chopping the
sources of their various flavors and steeping or dissolving them in
alcohol; or by distilling them, wholly or fractionally; or, when
necessary for any reason, simulating them by chemistry, or by the use
of a flavor source to all intents the same as the original.
VANILLA EXTRACT
Extract of vanilla, properly made, is the pure essence of the vanilla
bean, dissolved in alcohol.
Although there are fifty or more kinds of vanilla plant, the only
one with a fruit suitable for use in flavoring extract is _Vanilla
planifolia_, so called by botanists for its flat leaves. It is a native
of the valley of Mazantla, in Vera Cruz, Mexico, seemingly the only
place where conditions of soil and climate suffice to bring it to its
highest point of cultivation. The other vanillas, native to various
parts of Spanish America, are fit only for use in perfumery and soap,
because, though aromatic, they are rank in taste.
=48. Nature of vanilla plant.=--The plant of vanilla is an orchid,
having roots in the air as well as in the ground. It clings to trees
or frames, twining around them as it grows, and favors most a light,
loose soil, well drained, with “quilted sunshine and leaf-shade,” a
condition naturally brought about by the foliage of the protecting
trees. In Mexico it is grown from cuttings set out in the forest, one
to a tree; this support, together with 70 to 90 degrees of continued
heat, frequent rains, and a final dry season being needful to its best
growth. Frost is deadly, and in too close planting disease is likely to
ravage the crop.
After eighteen months, the vine is clipped to check its growing until
it bursts into flower, which occurs in September. The stem of the
vanilla is thick and round, the leaves large, smooth and pointed,
the flower beautiful, much resembling the tuberose, and delightfully
fragrant.
Formerly the blossoms were fertilized by a small bee, which carried
the pollen from one to another, for the plant is of two sexes. At
present this is done by hand--a better way, inasmuch as only the best
flowers need be fertilized, the plant thereby keeping vigorous and
healthy. Artificial pollenizing developed from transplanting vanilla in
the island of Reunion, where the crops originally failed for lack of
insects to carry the pollen.
Following each blossom comes a small pod, but most of these pods fall
off. The remaining ones mature in about six weeks, growing in bunches
of six to ten, and resembling bananas, being five to ten inches long,
yellow green, and banana-like in shape. They are watery and tasteless,
without the pleasant aroma of vanilla, the well-known taste and smell
of which must be brought out by curing. If left on the vine, they ripen
slowly, but usually they are picked before they ripen, as otherwise
they split in curing. When this happens they are known to the trade as
“splits,” and are considered undesirable on account of their full and
heavy flavor.
=49. Curing vanilla beans.=--After picking, the Mazantla beans are
transported to Papantla, the largest town in the valley, to be cured.
The process is laborious, and although somewhat primitive, very simple.
The beans are exposed on frames to the sun by day and by night are
wrapped in blankets under cover. This continues, in fair weather, for
about a month; then the beans are dried indoors for forty days more,
until they turn a deep rich brown in color, and become delightful to
the smell. If the weather is wet, they are moistened, blanketed, and
heated in ovens, the heat being moderate and varied with the size of
the beans; after which they are by turns exposed to the air and heat
until cured. The sun drying is preferred, as it gives the beans better
keeping qualities. Such is the process in effect, but in fact each bean
is treated separately; for proper curing, to bring out the desired fine
qualities of taste and smell, is of the utmost moment; and only native
judgment, or the skill born of long handling, ever gives the real
adroitness. Badly cured beans lack any stable taste or smell, and are
likely to become moldy. Their use in trade is made possible, in this
case, by scraping and chopping them up with poor and broken beans and
those that fell early from the vines; then they are sold under the name
of “Mexican cuts,” chiefly to manufacturers of cheap extracts.
=50. Marketing vanilla beans.=--The long fine beans, resembling thin
cigars, are molded, pulled, and tied in bundles of 100 to 150, varying
in length from six to eleven inches, and in weight from twelve to
twenty-four ounces. The bundles are packed forty to a tin, and shipped
four tins to a case in sweet-smelling cedar boxes. The entire Mexican
output is consigned to the United States, where it brings from seven to
ten dollars a pound.
The Aztecs knew the properties of vanilla, and are said to have
called the plant thilxochitl. They used the bean in making chocolate,
through which it became familiar to their Spanish conquerors, and thus
to Europe. The name vanilla is derived from the Spanish word vaina,
meaning sheath or pod, and the suffix -illa, little. The use of vanilla
in chocolate was its only notable one for many years, although during
that time great medical properties were claimed for it. It was not
until the eighteenth century that some person now unknown discovered
its general utility for flavoring.
=51. Production of vanilla beans.=--Vanilla cultivation in Mexico was
in the hands of the Indians for centuries, but in 1896 the government,
claiming they had no title, drove them off and sold the land to Greeks,
who now control the industry there.
Almost every European power has tried to grow vanilla in the tropics,
outside of Mexico. Many of the early trials were failures; none has
been a complete success, at least in so far as rivaling the fine
quality of the Mexican product is concerned. Cuttings were transplanted
in the island of Reunion and grown by artificial pollenizing, as has
been said, but the resulting beans were not as good as the parent
beans of Mexico. Reunion was formerly known as Bourbon Monarchy, but
the French, who had every reason to hate the name, rechristened the
island; the beans, notwithstanding, are still called Bourbon beans.
Vanilla grows in Reunion much as it does in Mexico, except that it
takes longer to develop. The great difference is in the curing, for
there, owing to the climate, the sun treatment is inexpedient. The
beans, placed in baskets, are plunged into hot water for about twenty
seconds, drawn out to drain for as many minutes, and then wrapped in
blankets to be sunned during the warm hours for five to eight days.
They are housed at night as in Mexico, but drying is also hastened
chemically with chloride of calcium (the basis of lime). After curing,
the beans are straightened, graded by size, smell, and soundness,
bundled and packed in tins which weigh, when ready for export, from ten
to twenty pounds each.
Tahiti exports a particularly inferior quality of beans. They are
grown from Mexican or Bourbon slips, but the change of soil and
climate imbues them with an unmistakable rankness, to which, up to
within a few years, were added careless growing and packing, in nowise
improving them. Although inspection by the French colonial government
has somewhat bettered the care of these beans, their flavor is probably
unchangeable. Tahiti beans are all shipped to the United States, whence
those not used are reshipped to Europe. They are sorted here into three
grades: pink label, best; white, fair; green, poor; but the only real
difference is their length and appearance.
A small crop of beans grown from Mexican slips is raised in the island
of Guadeloupe; they are known to the trade as “South Americans,” and
are of low quality, without the finer characteristics of good vanilla.
The average world’s production of vanilla is as follows:
Mexican:
Whole beans 240,000 pounds
Cuts 80,000 „
Bourbon:
(From all sources) 700,000 „
Tahiti 450,000 „
South American 25,000 „
Total 1,495,000 „
=52. The ingredients of vanilla extract.=--Vanilla beans, glycerine,
sugar and alcohol are the only ingredients requisite or advisable in a
vanilla extract; consequently the excellence of such an extract rests
in the quality of the beans and of the alcohol employed, and in the
means and skill devoted to employing them.
The process at its best is chopping or grinding the beans and treating
them with dilute alcohol of 20 to 70 per cent strength, in the
proportion of one part of the bean to ten parts of the liquid, the
alcohol acting as a solvent. The old-fashioned and as yet unequaled
way is to treat the beans by steeping and dissolve out the soluble
matter. The chopped beans are placed in a cask and the dilute alcohol
poured over them; they are then left to soak for one to twelve weeks,
when the extract is drawn off and the sugar added to it, and it is
either bottled immediately or aged. Aging greatly improves it, but few
manufacturers care to assume the added cost.
Another method of obtaining the extract is by distillation; that is,
by evaporating and condensing the liquid in which the beans have been
steeped. There is also a machine which effects the result more rapidly
by pumping the liquid steadily through the chopped beans, at an even
temperature. Many other means are also employed. They are all cheaper
than the old-fashioned way, but have nothing to recommend them from the
consumer’s point of view. Distillation, for example, might ruin the
delicate flavor of choice Mexican beans; while no process would ever
impart one to Bourbons or Tahitis.
=53. The chemistry of vanilla.=--Given the highest grade of Mexican
beans and pure cologne spirit--the trade name for doubly distilled
alcohol--with the old-fashioned method of compounding them, and
there remains to vanilla extract-making only the knowledge and skill
available in the process. These, however, are far from comprising the
whole secret of success. Although seemingly a matter of chemistry,
extract-making has always been a stumbling-block to the chemist.
Chemically, there is no difference between the richest Mexican beans
and the wretchedest Tahitis, but to even a normal nose the difference
is striking and immediate.
There is still much to be learned about the chemistry of vanilla. Its
flavor is known to be due to natural vanillin, the chief flavoring
principle of the plant, and to certain gums and resins, but of these
last next to nothing is known. Yet if aptitude and experience still
play the leading part in well-made extracts, chemistry without question
takes the center of the stage in the adulterated ones.
Under the present law (1913), an extract may be sold as “extract of
pure vanilla” if it is made of genuine vanilla beans; consequently
“Mexican cuts,” “splits,” and rank Tahitis can be and are sold under
this label; whereas some extracts, though strictly speaking not
adulterated, are really worse than some adulterated ones. These “cheap
vanillas” are made possible by the difference in cost between fine
Mexican beans and poor defective ones, or beans of other growth; a
matter, as a rule, of four or five dollars a pound; and are readily
exposed by a comparative test in cookery or on the tongue.
=54. Adulteration of vanilla extract.=--A common adulterant of
cheap vanillas is artificial coumarin. Real coumarin is an aromatic
crystalline substance found in the Tonka bean or cumaru. Tonka beans
were formerly rampant in imitation vanillas, but their present high
price, due to their use in cheap tobacco, has practically curtailed
this activity. The Tonka, with its real coumarin, was bad enough--the
theory has even advanced that hay fever is due to the presence in the
air of coumarin from plants--but artificial coumarin, as flavoring, is
worse. It is a powerful drug; a coal tar product, heart depressant and
active poison.
Artificial vanillin produced by chemistry also is employed plentifully,
not only in substitution but also for strengthening weak pure extracts.
The real vanillin is one of the odorous principles of the vanilla bean,
taking the form of tiny crystalline needles of hot bitter taste. It
is imitated chemically by combining oxygen and eugenol, a colorless
compound from oil of cloves, of bay, of cinnamon leaves, or of
allspice; or by coniferin, a compound ether obtained from wood. Lacking
the necessary gums and resins, it does not taste like real vanilla, and
needless to say, its composition is not such as to inspire confidence.
Coumarin and vanillin are ordinarily used together in adulterating; the
mixture is then sweetened and artificially colored, with prune juice
added. This sometimes brings a substantial profit of 150 per cent to
its manufacturer.
Fortunately detection of these subterfuges by simple means is not
difficult. A suspected extract can be tested by holding a tablespoon
of it over a lamp or other flame until about two-thirds of the liquid
has evaporated; then, if on adding water to the remaining third until
the spoon is full, the extract remains clear, undoubtedly it is not
vanilla but an artificial product. Taste and smell, if one is familiar
with true vanilla, are often test enough; coumarin in particular can
be recognized by its odor, which is like that of Indian grass or “wood
grass.”
The best test for the quality of vanilla is to pour a few drops on a
lump of sugar, and then suck the extract through the lump. To determine
the relative values of two or more extracts, a separate lump should be
used for each. The distinction between good and bad will then be marked
sharply. Finally, to avoid adulterated extracts, the label should be
read carefully.
LEMON AND ORANGE EXTRACTS
Owing to its refreshing aroma, convenience in use, and low cost, lemon
extract holds popular favor as second to vanilla.
Extract of lemon is made by dissolving lemon oil, chiefly from skin
of the fruit, in alcohol. To conform to the government standard, the
compound must contain at least 5 per cent of the oil.
The world’s yearly yield of lemon oil is about two million pounds, of
which southern Italy and Sicily produce the most, although there is
some output from France and Spain. The best is shipped from Messina.
=55. Preparation of lemon oil.=--Lemon trees flower in the summer,
and the fruit is picked from November to February. As the oil from
the later fruit has the richer color, many makers prefer it, but the
earlier oil has the finer flavor.
Lemon oil is extracted most satisfactorily by washing and paring the
lemon skin so that it comes off in one piece, and then pressing it
against a clean sponge. The sponge absorbs the oil, and when full is
squeezed into a container from which the oil is filtered and packed in
sealed copper vessels, holding either ten or twenty-five pounds, for
shipment.
In France the fruit is sometimes rolled about in vessels driven full
of spikes, the oil running into a receptacle below. Another method is
to press the whole fruit in a large vat, add water, and distill the
resulting mixture. This has been tried in California, although without
success, since the oil thus secured is very bitter, tasting strongly of
turpentine.
=56. The chemistry of lemon oil.=--The oil is known to contain a large
amount of terpenes or principles chemically like turpentine, which
would account for such a taste or smell in a poor or stale product.
These, with 6 to 10 per cent of citral, the chief flavor-giving
constituent of lemon oil, would seem to identify the peculiar lemon
taste; although there are certain unknown esters, or compound ethers,
corresponding to the salts in metals, which also are taken to be
factors of it. Citral is found in exactly the same form in limes,
mandarins, and oranges.
Adulteration of lemon extract consists usually in either lowering
the required amount of oil, or using in place of it citral, oil of
lemon-grass, or some other natural oil containing citral. These
substitutes naturally fail to give the true flavor, because they are
lacking in terpenes, and presumably in the esters just mentioned. Many
makers, to weaken the extract, lessen the alcohol; this indicates that
their product cannot be made of lemon oil, because this will not
dissolve in dilute alcohol. In most cases, weakened extracts are made
of citral.
Terpenless lemon and orange extracts are made from lemon and orange
oils from which the terpenes have been removed. They are much in favor
among makers of low-grade flavors because they are soluble in very
weak alcohol, and because considerably less oil is needed to make the
extract. On account of the removal of the terpenes, the flavor is of
course quite different from that of the true oils.
Using stale lemon oil in extract is not against the law, but no one
is likely to buy more than once a product so compounded, for its foul
taste of turpentine will ruin any cooking in which the extract is used.
To test lemon extract a little should be poured from the bottle, the
cork replaced, and the bottle shaken for a few seconds. If the bubbles
disappear at once, there is no water in the extract, and it is probably
pure. If they disappear slowly, there is water in it, and the extract
can contain no lemon oil. Or a teaspoonful of the extract may be added
to a glass of water; if small drops of oil come to the surface, and the
water, on standing, becomes cloudy, the extract is probably pure. But
if the extract dissolves immediately, leaving the water clear, it is
not pure, and contains no lemon oil.
No adulterated extract of any kind is really cheap. It is an actual
fact that in a test of an adulterated lemon extract against a pure one
costing twice as much, the pure one at but double the cost was found to
be ten times as strong, in addition, of course, to its having by far
the better flavor.
=57. Orange extract.=--Like lemon, orange extract must contain at
least 5 per cent of the fruit oil. The only chemical difference
between orange and lemon oil is that the former has an infinitely
small proportion of flavoring esters not found in lemon. The two
fruits are grown in the same countries and in the same way, the
methods of producing the two oils are identical, and the tests for the
adulteration of the one extract hold good for the other.
=58. Fruit extracts.=--Raspberry, strawberry, cherry, apple, pineapple,
banana, and other familiar fruit flavors constitute a class of
flavoring extracts similar in character and similarly made. They can
be derived from their respective fruits, although previous to 1911
this was thought impossible. Up to that time, imitation extracts had
been compounded chemically from coal tar ethers and esters, and ether
was added often to give them pungency. They all tasted alike and none
of them tasted like any fruit. One difficulty in making real fruit
extracts was the lack of the essential oils in the several fruits;
another, the change brought about in the delicate esters, the cause
of the flavor, by cooking, since great heat destroys them. Pure fruit
extracts are in every way immeasurably superior to the old unwholesome
and unhealthful ether preparations, of which purchasers should beware.
Fruit flavors labeled artificial or imitation are of the type; if not
labeled, they can be detected by the odor of ether rising when the cork
is drawn.
CHAPTER VI
_CLASSIFICATION OF ICE-CREAMS_
Because of the large variety of materials used and the different
methods of blending and preparing them, it is desirable to have
a classification of ice-creams. Several[17] classifications have
been made but the following, based on the materials used and the
method of preparing them, seems best adapted for general use. These
classifications have been based on the materials employed, the
flavoring materials used, and the form in which the ice-cream was put
up for market.
[17] Mortensen, M., “Classification of ice cream and related frozen
products,” Ia. Exp. Sta., Bul. 123, 1911; Washburn, R. M., “Principles
and practice of ice cream making,” Vt. Exp. Sta., Bul. 155, 1910;
Frandsen, J. H., and Markham, E. A., “The manufacture of ice cream and
ices,” Orange Judd Co., 1915.
=59. Classification of ice-cream.=--The following is based on the
materials used; the subclasses are divided according to the flavoring
materials.
I. Plain ice-cream, often known as Philadelphia ice-cream, is made from
cream, sugar, and flavoring, with or without condensed milk or some
stabilizer. This class may be subdivided as follows:
(1) Plain--flavors are used such as vanilla, chocolate, caramel,
coffee, mint, maple.
(2) Fruit--fresh or canned fruits are employed for flavors, such as
peaches, strawberries, cherries, pineapples, raspberries.
(3) Nut--nuts such as walnuts, almonds, chestnuts, pistachio, furnish
the flavoring.
(4) Bisque--materials are used for flavoring such as macaroons,
marshmallows, grapenuts, sponge cake.
(5) Mousse--rich whipped cream sweetened and flavor folded in,
sometimes eggs are used.
II. Cooked ice-cream, often known as French or Neapolitan, is made from
cream, sugar, eggs, and flavoring. As custards they sometimes contain
flour or cornstarch. This class may be subdivided as follows:
(1) Parfaits or French--flavors such as vanilla, chocolate, and the
like are the most common but various fruits are sometimes used.
(2) Puddings--these are highly flavored with various dried and candied
fruits, nuts, and spices and eggs.
(3) Custards--these contain flour, cornstarch, or other similar
ingredients and are almost always flavored with vanilla.
III. Sherbets and ices are made from water or milk, sugar, often egg
albumen and a stabilizer, and flavored with fruit juices or other
natural flavorings.
(1) Ices--made from water, sugar, and some natural flavoring without
eggs or a stabilizer. This may include granites and frappés. Granites
are frozen with little agitation, while frappés are only semi-frozen to
a slushy consistency.
(2) Water sherbets--made the same as ices with the addition of
egg-whites and sometimes a stabilizer. If the whole egg is used, they
are sometimes called souffles.
(3) Punches--ices or water sherbets flavored with liquors or highly
flavored with fruit juices and spices.
(4) Milk sherbet--made from whole or skimmed-milk, sugar, and
egg-whites, with or without a stabilizer and flavored with some natural
flavoring.
(5) Lacto[18]--made from skimmed or whole sour milk instead of sweet
milk but in other respects resembling milk sherbets.
[18] Mortensen, M., “Lacto, a frozen dainty product,” Ia. Exp. Sta.,
Bul. 140, 1913.
=60. Receipts for ice-cream.=--A large number of receipts or formulas
for ice-cream might be given. Each manufacturer usually has a receipt
for his own use, which is slightly different from any other. Ordinarily
ice-cream manufacturers employ the same classes of materials but
in different amounts. The receipts given are typical of those used
and give satisfactory results. So far as possible receipts will be
given which use the various materials and at the same time vary the
composition.
=61. Vanilla ice-cream.=--These receipts may be used as a basis for
other ice-creams by substituting other flavors. These provide a basis
for all plain ice-creams.
Receipt No. 1.
40 lbs. 20 per cent cream
9 „ sugar
4 oz. gelatine dissolved in 4 lbs. water
4 „ vanilla
Receipt No. 2.
32 lbs. 20 per cent cream
8 „ whole or skimmed-milk condensed
9 „ sugar
4 oz. gelatine dissolved in 4 pounds of water
4 „ vanilla
Receipt No. 3.
26 lbs. 18 per cent cream
14 „ skimmed-milk condensed
8 „ sugar
4 oz. gelatine dissolved in 4 pounds water
4 „ vanilla
Receipt No. 1 will test from 14-15 per cent of fat. Receipt No. 2 will
test 13-14 per cent fat if whole milk condensed is used and 11-12 per
cent of fat if skimmed-milk condensed. Receipt No. 3 will test 8-9 per
cent of fat.
=62. Chocolate ice-cream.=--Either chocolate or cocoa may be employed
to give the chocolate flavor. Some manufacturers prefer one and some
the other. A thick chocolate sirup may be purchased from some flavor
manufacturing concerns. A pound to a pound and a quarter of chocolate
or cocoa is sufficient for a ten-gallon mix. The chocolate or cocoa
may be softened in either water or milk. The cocoa forms a liquid much
easier. The best way to prepare either is to put it into a double
boiler and cook until a thick sirup is formed. About two quarts of
milk or water is sufficient for a pound or a pound and a quarter of
chocolate or cocoa. This can be used with the mixes given for vanilla
ice-cream. Some manufacturers of ice-cream prefer some vanilla with the
chocolate, believing that it imparts a better flavor.
=63. Caramel ice-cream.=--This may be made by substituting caramel
flavor for the vanilla in each receipt. The flavor may be obtained by
caramelizing or carefully burning sugar or by adding prepared caramel
flavor. The amount of either which should be used depends on the
strength of the flavor.
=64. Coffee ice-cream.=--Ice-cream may be flavored by the addition
of coffee. The amount to use will depend on its strength. The coffee
should be strained and only the liquid portion added. It may be
substituted for the vanilla in the receipts.
=65. Maple ice-cream.=--Maple sirups or prepared maple flavor may be
used to flavor ice-cream in place of the vanilla. The amount depends
on the strength of the materials used.
=66. Fruit ice-cream.=--Various flavors of fruit ice-cream may be made
by substituting the fruit for the vanilla in the receipts already
given. Either the fresh fruit or the preserved or canned ones may be
used. In many cases the fruit sirups or extracts are employed either
alone or with the fruits. It is usually customary to add a small
amount of color to mix with the fruit in order to give the product
the characteristic fruit color. This is not necessary but adds to the
appearance of the ice-cream. The amount of fruit necessary depends on
its flavor; for example, fruits with a very pronounced flavor, such as
raspberry will go further than a fruit with a very delicate flavor such
as peach. Usually two quarts of preserved fruits are enough to make ten
gallons of ice-cream. The fruit should be chopped before adding.
=67. Nut ice-cream.=--Various nuts may be employed to flavor ice-cream
but they are not commonly used alone. The most common is pistachio. In
this case the nut itself is not utilized ordinarily but an imitation
flavor, and the ice-cream colored green. This is a trade custom.
=68. Bisque ice-cream.=--Various bread products may be used to flavor
ice-cream, the result being called bisque. The common material is
macaroons, but other materials such as sponge cake, grape nuts, and
dried cakes may be added. The material should be dried and then ground
through a food chopper before it is added to the ice-cream.
=69. Mousse.=--This differs from the other plain ice-creams as the
cream is whipped first and the flavoring then folded inside. Various
flavors may be used, but maple is the most common.
_Mousse foundation_
4 eggs
20 egg-yolks
1 lb. sugar
2 qts. whipped cream
Cook sugar to heavy thread. Beat the eggs and yolks and pour sugar in
slowly. Beat on ice until cold. Add whipped cream, mixing thoroughly.
Fruits and nuts may be added.
=70. Cooked ice-cream.=--No basic receipts can be given for Class
II as for Class I, in which the various flavoring materials may be
substituted. Most of the cook-books give numerous receipts which belong
to this class. In fact there are so many receipts for cooked ice-creams
that only a few of the better ones can be given; they are usually made
in small quantities.
=71. Parfait.=--The use of eggs makes an ice-cream of different flavor
and body. This is the main difference between parfait and the plain
ice-creams in Class I. Usually the eggs are cooked either in all or a
part of the mix before they are added to the freezer.
Receipt No. 1.
40 lbs. 20 per cent cream
10 „ sugar
4 oz. vanilla
8 doz. eggs well beaten
Beat the egg-yolks till smooth, add the sugar, and beat again till it
is dissolved. Beat the whites to a stiff froth and stir into the yolks
and sugar. Mix all with the cream and cook in a double boiler to a
temperature of 180° F. for fifteen minutes. Cool to 40° F., add vanilla
and freeze.
Receipt No. 2.
40 lbs. 28 per cent cream
10 „ sugar
4 oz. vanilla
8 doz. eggs well beaten
2 qts. crushed strawberries
Beat whole eggs together, add to the mix and freeze, or the whites
may be beaten separately if desired and added after the mix is partly
frozen.
Receipt No. 3.
40 lbs. 25 per cent cream
12 „ sugar
4 oz. vanilla
4 lbs. chopped walnut meats
yolks of 8 dozen eggs
Beat the egg-yolks till smooth, add the sugar and beat again. Then
add to the cream and cook in a double boiler to 180° F. for fifteen
minutes. Cool, add the balance of the mix, and freeze.
Other nuts or fruits may be substituted for those mentioned in the
above receipts.
=72. Puddings.=--This product is usually very rich and is a combination
of cream, sugar, eggs, spices, various fruits and nuts.
Receipt No. 1.--Nesselrode
32 lbs. 28 per cent cream
10 doz. eggs
10 lbs. sugar
6 oz. vanilla
4 lb. chopped walnut meats
3 „ „ candied cherries
3 „ „ „ fruits
4 „ „ raisins
Cook the egg-yolks with the cream. Beat the whites and add when partly
frozen.
Receipt No. 2.--English Plum