MILK COOKERY 154
Soups 155
—Cream Soups 155
—Cereal Cream Soups 157
—Milk Chowders 158
—Milk Stews 158
Milk Cereals 159
Luncheon and Supper Dishes 159
—Creamed Dishes 160
—Souffles 161
—Cheese Fondu 161
—Milk Toast 162
Cheese Dishes as Meat Substitutes 162
Cheese Salads 166
Cottage Cheese 167
Milk Breads and Biscuits 170
Desserts 172
Junkets 179
Milk Beverages 181
Miscellaneous Suggestions 184
The Thermometer 184
Weights and Measures 185
End Notes 187
Bibliography 188
------------------------------------------------------------------------
INTRODUCTION
The conception of this “Story of Milk” dates many years back. In his
life-long study of problems connected with dairy farming and milk
industries in two of the world’s greatest dairy countries, Denmark and
the United States, the author has felt the need of a concise handbook
covering this interesting subject. In his forty years of work in the
manufacture and distribution of dairy and milk-food preparations he has
been brought constantly into contact with men and women interested in
the production of milk and has found a persistent demand for a book that
might be consulted by anybody in regard to questions related to these
greatest of all foods, which are, or ought to be, a most important part
of the daily diet of children and adults alike, at all times,
everywhere.
There was a time during the war when, frightened by the soaring of the
price which had remained remarkably low for many years, much too low in
fact compared with the cost of other food, people began to cut down the
consumption of milk to an alarming extent. Even the National Food
Administration for a short time recommended saving in the wrong place,
forgetting that, at the highest figures reached during the temporary
shortage, milk was still one of the cheapest of foods and that it was
absolutely indispensable for growing children and exceedingly beneficial
for men and women who were called upon to exercise their physical and
mental powers as never before. But with men like Dean Russell of the
Wisconsin Agricultural College in the Department and Dr. Graham Lusk of
Cornell University representing the United States on the Inter-Allied
Council of Alimentation, the Food Administration could not long maintain
this mistaken attitude but quickly joined the College authorities and
the representatives of the dairy industry in advocating a liberal use of
milk. And the Department of Agriculture sent out over the country a
large force of demonstrators to show the people how to use milk in
making cottage cheese and many other ways, and Agricultural Colleges,
Farm Bureaus and Home Economics Agents worked hand in hand with
Washington in disseminating the knowledge of handling and utilizing
milk.
A genuine interest has been aroused in our country in the economy and
conservation of food, and in “The Story of Milk” the author hopes to
place at the disposal of the student of Domestic Science a comprehensive
book of reference which may open the eyes of many to the fact that there
is no more interesting subject than “Milk” in connection with the study
of the welfare and physical improvement of humanity, and that milk and
its products should be used to a much greater extent than heretofore.
It would make a long list of references if the author should mention the
sources on which he has drawn for information beyond his own life-long
experience in the dairy and related industries. He desires to express
his sincere appreciation of the kindness and ready response of
institutions and friends to whom he has appealed for photographs and
cuts which have enabled him to illustrate the text so liberally. In the
back of the book will be found a brief bibliography of standard dairy
literature in which students may find material for further information.
Many interesting data and several excellent illustrations have been
obtained from the bulletins and collections of the Department of
Agriculture in Washington and the Dairy Schools at Ithaca, N.Y.,
Madison, Wis., and Ames, Ia.
The Chapter on Milk Cookery was written and classified by the author’s
wife, whose practical experience will make it useful alike to
housekeepers and students of Domestic Science.
J. D. FREDERIKSEN.
Little Falls, N.Y.,
April, 1919.
------------------------------------------------------------------------
HISTORICAL
Milk and its products have been known and used from time immemorial. In
the Bible milk and milk foods are mentioned in some thirty places. In
Gen. 18:8 we read: “... and he (Abraham’s servant) took butter and milk
and set it before them ...”; 1 Sam. 17:28: “And Jesse said unto David,
his son: ... bring these ten cheeses unto the captain of their thousand
and look how thy brethren fare....”; Prov. 30:33: “For the churning of
milk bringeth forth butter,” etc.
Though in some of these passages butter is mentioned it is hardly
probably that this product was really made or used at the time under the
climatic conditions in Palestine. More likely it was various kinds of
curd and cheese which the translator called butter. At any rate, the
Hebrews of that far-off day coveted milk and its products among their
most valued foods. From Egyptian, Greek and Roman history it appears
that knowledge of cheese goes back to the most ancient times and that it
was made from the milk of sheep, goats, cows, asses, mares, in fact from
all domestic animals; in the far North, Lapps and Eskimos still make it
from the milk of the reindeer, the Arabs use camel’s milk, Llama cheese
is famous in the Cordilleras and Zebu cheese in Ceylon and India.
Even in ancient times the great food value of dairy products was
recognized. Plinius tells of Zoroaster that for twenty years he lived
exclusively on cheese, and Plutarch calls cheese one of the most
nourishing of foods.
As time went by, the cow excelled all other domestic animals in capacity
for the production of milk and by constant use through centuries for the
one special purpose,—by care in feeding, breeding and selection,—special
breeds of cattle were developed which gave milk in extraordinarily large
quantities.
[Illustration:
From Maelkeritidende, Copenhagen
]
[Illustration:
Thomas R. Segelcke, father of scientific dairying in Denmark
]
[Illustration:
L. B. Arnold, noted dairy expert and writer, of Herkimer County, N.Y.
]
In the cold climate of the northern countries where butter will keep for
a long time it has been made for centuries. The illustration above is
from a mural painting in an old church in Finland. Evidently at the time
when that was built the devil already played havoc with the churn and
even up to the days of our grand-fathers his Satanic Majesty was often
accused of preventing the butter from “coming.”
Not until the middle of the nineteenth century did dairying take its
place among the important industries of the world and science begin to
be applied in its development. Between 1860 and 1870 Thomas R. Segelcke,
the “Father of Scientific Dairying” in Denmark, introduced the
thermometer in churning instead of the rule of thumb and started the
keeping of records in the manufacture of butter. N. J. Fjord started a
series of experiments in the creameries, continued through the next
decades, and which became models for similar work throughout the world,
covering pasteurization, ice houses and cold storage, comparison between
various systems for raising the cream, separators, feeding rations,
etc., and Denmark developed its agriculture and dairy industry to an
enviable position. About the same time Dr. Schatzman applied scientific
methods in cheese making in Switzerland and Jesse Williams started the
first American cheese factory near Rome, N.Y., while L. B. Arnold, X. A.
Willard, Harris Lewis, Harry Burrell and many other progressive dairymen
made Herkimer County cheese famous.
From New York, dairy farming spread rapidly westward through Ohio to
Michigan and Northern Illinois, where butter making was developed around
Elgin, and to Wisconsin, where Governor Hoard preached the gospel of
progress, Babcock invented and gave to the world the famous test that
bears his name and Russell made a specialty of dairy bacteriology.
[Illustration:
J. H. Monrad, the “Pen and Ink” buttermaker of New York Produce Review
]
[Illustration:
Governor W. D. Hoard, of Wisconsin, promotor of progressive methods of
dairying
]
[Illustration:
J. A. Ruddick, Dairy Commissioner of Canada
]
J. H. Monrad, Assistant Dairy Commissioner of Illinois, student, writer
and lecturer on dairy subjects, collected and indexed one of the most
complete and valuable libraries of dairy literature found anywhere,
which after his death in 1915 was taken over and installed in special
rooms by Chr. Hansen’s Laboratorium in Copenhagen, where a librarian is
keeping it up to date and it is open to the public.
In Canada, Dairy Commissioners Jas. W. Robertson and J. A. Ruddick, D.
M. McPherson, the “Cheese King,” and others contributed to an enormous
development of the manufacture of high-class cheese, and in New Zealand
and Australia similar progress was made.
Business and science have vied with each other in increasing the output
of dairy products and improving their quality. In the table below,
showing estimates for 1917, some interesting figures are given of the
amount of milk produced in the United States and the uses to which it is
applied.[1]
_Uses to which milk is put (calculations based on estimates)_
───────────────────────────────────────────────────────
Item Lbs. of Milk Per Cent
───────────────────────────────────────────────────────
Product of 22,768,000 cows at 84,611,350,000 ──
3,716 lbs. per an.
Disposition of milk product: ─────
1,650,000,000 lbs. of butter 34,663,850,000 41.0
(at 21 lbs. milk)
420,000,000 lbs. of cheese (at 4,200,000,000 5.0
10 lbs. milk)
975,000,000 lbs. of condensed 2,437,500,000 2.9
milk (at 2½ lbs. milk)
210,000,000 gals. of ice cream 3,150,000,000 3.7
(weighing 6 lbs. to the
gallon, 10% fat)
100,000,000 persons; 45% at 36,500,000,000 43.1
0.7 lb. a day (cities) farms
with dairy cows, 30%, 1.5
lbs. per day; other farms
and small towns, 25%, 1 lb.
a day, approximately
17,500,000 calves, whole milk 3,660,000,000 4.3
(estimated) requirement
─────
Total 84,611,350,000 100.0
Although the table accounts for all the milk produced, it does not tell
the whole story, since the preparation of a number of products results
in the formation of vast quantities of by-products that are not used to
the fullest advantage for human food.
New York City alone consumes 1,600,000 quarts of milk a day, but even
this enormous quantity means only 0.6 pint per capita. The consuming
public has been slow to realize the value of milk and its products, and
too much emphasis cannot be laid upon the fact that even at the largely
increased cost of all dairy products they are still some of the cheapest
and the most healthful of foods, especially for growing children, and
should be used in much larger quantities.
------------------------------------------------------------------------
THE STORY OF MILK
------------------------------------------------------------------------
THE STORY OF MILK
CHAPTER I
PRODUCTION, COMPOSITION AND CHARACTERISTICS OF MILK, MILK FERMENTS,
PASTEURIZATION
DAIRY CATTLE
[Illustration:
Holstein
]
A number of typical but widely different breeds of dairy cows have been
developed in various dairy countries, each owing to the soil and the
climatic conditions of its home, as well as to the skill and fancy of
the breeders, its characteristic features, form, color, etc.
[Illustration:
Herd of pure-bred Holstein cows on a farm in central New York
]
=Milk-Breeds.=—The black and white _Holstein-Friesians_ (which, by the
way, had their home in Holland and not in Holstein) are known for their
large production of not very rich milk, while the _Guernseys_ and
_Jerseys_ give milk exceedingly rich in butter-fat. A good Holstein cow
will give from 7,000 to 10,000 lbs. of milk in a year, containing from
3¼% to 4% butter-fat. Some of them produce as much as 20,000 to 30,000
lbs. in a year—nearly 4,000 gallons—just think of it! Jersey cows will
usually not produce as much in quantity as the Holsteins but Jersey milk
often contains 5% or 6% or more butter-fat, and a few of the best have
been known to produce 800 to 900 lbs. of butter in one year, an amount
equal to the cow’s own weight. The red _Danish_ cow is an exceedingly
good and highly bred milk producer which, however, has not been
introduced in the United States, but the Scotch _Ayrshires_ and the
_Brown Swiss_ are other well-known dairy breeds which are in favor with
many American farmers.
[Illustration:
Guernsey
]
But, alas! too many herds of dairy cattle average less than 5,000 lbs.
of milk per cow per year and do not pay for their feed.
[Illustration:
Jersey cows
]
[Illustration:
Red Danish
]
[Illustration:
Ayrshire
]
[Illustration:
Shorthorn, beef-strain
]
Many native cows respond, however, to good care and feed and with a
thoroughbred bull a satisfactory herd can readily be built up from
carefully selected native stock. Such continued cross-breeding is more
apt to succeed than attempts to cross two thoroughbred breeds because
the characteristic features in full-blooded animals are so strong as to
invariably predominate in the progeny over the less pronounced forms and
tendencies inherent in native cows. But where two full-blooded animals
are mated and the strong characteristics in each are fighting for
predominance the result is apt to be a poor, ill-proportioned offspring
as the result of atavism.
[Illustration:
Shorthorn, milk-strain
]
=Beef-Cattle.=—Cattle bred and developed for the purpose of producing
beef rather than milk are called by contrast beef-cattle. As examples of
beef-cows look at the _Shorthorns_ or the _Herefords_ or the _Polled
Angus_ at the next State Fair you visit and notice the square, deep,
smooth body with muscles and fat strongly developed in contrast to the
loosely built, bony milk-cow with its tendency to turn all its food into
milk at the expense of the body. There are, however, also among the
Shorthorns, strains of good milkers, but as a rule these beef-breeds are
not selected for the dairy farm, and “dual purpose” cows are not usually
profitable.
=Food and Water.=—The natural food for the dairy cow in summer is grass,
and where rich, succulent grass and clover grow in abundance, as on the
fertile meadows of Holland and the Channel Islands, or the Swiss Alps,
the highly cultivated Danish farms, the eastern and middle-western
states of America, etc., dairying early reached its highest development.
As the value of milk and its products for human food became more
generally recognized and all-the-year-round production was forced, it
was found necessary to feed the cows heavily in winter too, not only
hay, but also grain and succulent food such as beets and corn-ensilage
(green corn cut, stalks, cobs and all, and packed in a silo), and
science was taken into play to formulate _Balanced Rations_ containing
the proper amounts and proportions of the various nutrients—Protein, Fat
and Carbohydrates. It is not the place here to go deeper into this
problem which has long been a subject for thorough research and
experiments. In fact, more attention has been paid to the feeding of
cattle than to the proper nourishment of human beings, and much of what
we know about the latter has been deducted from experience and study on
the dairy farm, and from laboratory work along that line. In the chapter
on “Milk as a Food” we are taking up food values, etc., in relation to
the feeding of children and men. Suffice it here to say that the same
fundamental principles apply to the feeding of calves and cattle for the
production of milk and beef. And we wish to emphasize the fact that,
with due consideration to the proper proportion between the various
groups of nutrients, it is much more important that the food is
succulent, appetizing and easily digestible than that the ration shall
be accurately balanced.
[Illustration:
Cutting ensilage and filling the silo
]
This fact, long well known to practical breeders and dairymen, has
recently been confirmed by Dr. E. V. McCullom to whose experiments
further reference is made in the chapter on milk as a food for children.
He shows that there is a very great difference in the quality of Protein
and Fat from various sources and that there is “Something Unknown” in
butter-fat, for instance, which is absent in most other fats and which
is vital for the growth of the child as well as for the proper
nourishment of man. This unknown but essential substance is also found,
in small quantities, in the leaves of certain plants, as in alfalfa,
while it is absent in the grain of the cereals.
[Illustration:
An abundant crop of alfalfa hay; cut three times during the summer.
Supplies protein in the ration
]
In modern dairy farming _alfalfa_ is considered an indispensable source
for protein, and corn-ensilage or beets for carbohydrates, while bran,
cottonseed meal or oil cake, malt-sprouts, gluten, distillers’ grain,
etc., may be used to advantage in various combinations.
[Illustration:
Cows milked with machine
]
Contrary to a general impression one cannot feed fat into the milk. A
large amount of oil cake or other food rich in fat in the daily ration
does not increase the percentage of butter-fat in the milk. Rather, it
depends largely upon the breed and to some extent upon the period of
lactation. Provided the food agrees with her digestion and keeps the cow
in a good, healthy condition, the composition of the milk is not changed
to any appreciable extent by a change in make-up of the food.
It goes without saying that to produce from 20 to 50 lbs. of milk a day
the cow must have an abundance of _fresh, pure water_ to drink and she
should not have access to stagnant water.
=The Barn= must be clean, light and well ventilated and the cows should
be milked with clean hands into a clean pail which is covered as far as
possible so as to prevent dust from falling into the milk, or with one
of the excellent milking machines which are now frequently used in large
dairies. The milk is strained and cooled immediately after milking.
[Illustration:
Milking machine
]
[Illustration:
In the partly covered milk-pail dust does not fall as readily as in
the one entirely open
]
=Milking.=—The cows are usually milked twice a day; occasionally, when
the highest possible yield is desired, as in important tests, three or
four times. The first five days after the birth of the calf the
milk,—the Colostrum so called,—is not normal and should not be used for
human consumption. It may be fed to the calf. The first three to four
months the yield of milk generally is higher than later, when it
gradually drops until after about ten months it stops altogether and the
cow goes “dry” at least for some six weeks before dropping the next
calf. The highest annual yield may be obtained by having the cows “come
in” in the Fall or early Winter and feeding them well all Winter to keep
up an abundant flow of milk. Then, when they come out on pasture in the
Spring,—in the latitude of the Great Lakes about May 15th,—the fresh,
rich feed will stimulate production and give it a fresh start so that
the milk-pail may continue to be filled during the next few months and
the shrinkage of the yield will not occur until the time when the
pastures dry up. The cow will then go dry in the early Fall, when feed
is scarce. Usually, however, the cows are allowed to “come in” in the
Spring and the yield of milk begins to shrink in the late Summer with
little or nothing in the Winter.
[Illustration:
Milking on a Danish farm
]
=Test the Cows.=—To ascertain if a cow pays for her feed the amount and
the quality of the milk should be tested and computed for the year. If
the milk from each cow cannot be weighed every day it may be done
regularly once a month or preferably oftener. If it is weighed morning
and evening once every ten days it is easy to keep the account by
multiplying the number of pounds by ten and adding the totals for the
year. Occasionally the milk may be subjected to the Babcock Test to
ascertain its richness; three or four times during the period of
lactation is sufficient.
Where farmers do not have time to do the testing themselves they often
combine and hire a young man or woman, trained in an agricultural
college, to go around from farm to farm and do the work. These experts
not only test the yield and the percentage of fat but also weigh and
compute the feed so as to help the farmer make up his rations and
calculate whether each cow pays for her feed or not. The members of
these associations meet and compare notes and a friendly rivalry is
stimulated which may do much toward increasing production. As a matter
of fact, where Cow Test Associations have been introduced, both yield
and quality of the milk have been largely increased.
[Illustration:
Dr. Bernhard Bang of Copenhagen, Denmark
]
=Healthy Cows= alone can be depended upon to produce sanitary milk. In
many herds of milk-cows tuberculosis is prevalent, and constant
vigilance is necessary to prevent its spread. The _Tuberculin Test_
discovered by Koch is invaluable for the purpose of ascertaining the
presence of tuberculosis. It is not necessary, however, to kill every
infected animal. Only where the lungs or the udder is affected and a
physical examination shows an advanced stage of the disease such radical
means are advisable. When the tuberculin test was first introduced many
valuable herds were wantonly and foolishly killed off because some of
the highly developed dairy cows showed reaction to the test while
worthless scrubs were allowed to live and spread the disease. For only
the intelligent and public-spirited owners of fine herds submitted their
cows to the test, a reaction to which, under ill-advised regulations,
permitted state officials to condemn the infected herds. In Denmark Dr.
Bernhard Bang introduced a system of isolation of the infected animals
which together with _Compulsory Pasteurization_ of the milk from such
cows has proved efficient for the eradication of tuberculosis, and the
_Bang Method_ is now generally recognized as the proper way of handling
the matter.
COMPOSITION OF COW’S MILK
Cow’s milk contains on an average in 100 lbs.:
87 lbs. of water
4 lbs. of butter-fat
3¼ lbs. of casein and albumin (protein)
5 lbs. of milk sugar
¾ lbs. of ash (mineral matter)
100 lbs. total.
It consists therefore of 87% water and 13% “solids,” 4 of which are fat
and 9, “solids—not fat.” =Butter-Fat= is found in milk in the form of
minute globules suspended in the liquid. As fat or oil is lighter than
water (has less specific gravity) it naturally floats and the fat
globules therefore soon rise to the top when milk stands at rest,
forming a layer of _cream_ which may be skimmed off from the _milk_. In
chemical composition butter-fat is very nearly the same as other animal
and vegetable fats, but the slight variation may make a lot of
difference in digestibility and palatability as well as in nutritive
value, and it is a mistake to consider Oleomargarine, Butterine,
Nut-Butter and other substitutes for butter “just as good” because a
chemical analysis shows them to contain “almost” the same elements or
compounds. These products may be good and legitimate if sold for what
they are, but should never be allowed to be sold or served for what they
are not, genuine butter.
[Illustration:
Composition of cow’s milk
]
=Casein and Albumin= are the proteids or nitrogenous matters of the
milk, in chemical composition and in food value much the same as the
protein in beans and peas or in meat, or the white of eggs. Casein is
present in much larger quantity than albumin and is distinguished from
the latter by being precipitated by rennet, which has no effect on
albumin. Casein may also be precipitated by acids, while it required
boiling as well as acidity to throw the albumin out of solution.
=Milk-Sugar= is related to the vegetable sugars, glucose, cane sugar,
etc., and remains in solution in the whey which separates out from the
cheese-curd when milk is curdled with rennet or acids. The whey also
contains the mineral matters or _ash_, which consists largely of
phosphate of lime, of use to the young in building up bones. When whey
is boiled down to a thick syrup and left to stand, the sugar will
crystallize out and may be separated from the liquid, still holding in
solution the mineral matters.
[Illustration:
Fat globules as they appear under the microscope
]
=Mineral Matters.=—These may be gathered as _ash_ by boiling off the
water from this liquid or from the whole milk and burning the rest, as
all the constituents except the ash belong to what in chemistry is
called organic matter, which disappears in the air by burning.
[Illustration:
Dr. S. M. Babcock of Madison, Wis.
]
HOW TO TEST MILK
Milk may be adulterated or decreased in value either by skimming or by
watering. In either case the percentage of the most valuable
constituent, the butter-fat, is diminished. It is upon this fact that
the most practical test, the Babcock, is based.
[Illustration:
Babcock test outfit
]
=The Babcock Test.=[2]—By treating a sample of milk with strong
sulphuric acid the butter-fat is liberated as an oil. By subjecting the
mixture to centrifugal force the light butter oil is separated from the
rest of the milk and the percentage can be easily determined.
Centrifugal force had already been used in the Fjord Cream Test, but it
remained for Dr. Babcock to work out the splendid practical and reliable
test which bears his name and in which he has given to the world an
invention of incalculable value.
[Illustration:
A two-bottle machine
]
=Sampling.=—Whether it is new milk or skim milk or buttermilk or cream
that is to be tested the first thing to observe is to take a _truly
representative sample_. The liquid must be thoroughly mixed by pouring
it several times from one vessel to another, or stirring vigorously.
It may not always be convenient to make a test immediately when the
sample is taken. In the creamery where the milk is paid for according to
its fat contents, samples are taken every day from every patron’s milk
and it would take too much time for the butter maker to test all of
these samples before they would spoil. A preservative, corrosive
sublimate,—poisonous but all right for the purpose,—is therefore added
and all the samples of one farmer’s milk for several days or a whole
week are put together in one glass to be kept and tested at one time.
This is called a composite test and has proven entirely satisfactory.
=The Lactometer= has been used to discover adulterations, depending upon
the difference in specific gravity of the various constituents. The
specific gravity of whole milk is about 1.032 which means that, if a
certain volume of water weighs 1.000 weight units, the same volume of
whole milk weighs 1.032, the same volume of butter-fat weighs, say,
.900, or of cream about 1.000, and of skim milk 1.036 units. If the
Lactometer shows a sample of milk to have a higher specific gravity than
1.032 it may therefore be suspected of having been skimmed. But it will
readily be seen that by removing from whole milk some of the cream and
adding water, the specific gravity can easily be brought back to normal
for whole milk. This test is therefore unreliable and has been discarded
with the advent of the Babcock.
[Illustration:
The acidemeter
]
=Acidity Test.=[3]—The acidity, or sourness, of milk or cream, which
depends upon the amount of lactic acid developed in it, may be tested by
a liquid normal alkali or by the Farrington Alkaline Tablets, a solution
of which added to sour milk neutralizes the acid. A few drops of an
indicator, Phenolpthalein, added to the milk, turns it pink when all the
acid has been neutralized, and the amount of alkali solution used shows
the percentage of acid in the milk. This is quite important in preparing
“starters” for ripening the cream in butter making or milk in cheese
making, and in the manufacture of “Commercial Buttermilk,” etc.
There are other tests used in scientific dairying as the _Fermentation
Test_ to ascertain the relative purity of milk, the _Casein Test_, etc.,
but the above are those mostly used besides the _Bacterial Count_ which
is mentioned under the chapter on “Milk Supply,” and the _Rennet Test_
described under “Cheese Making.”
FERMENTS
Two classes of ferments are of importance in connection with milk: (1)
“unorganized” or chemical ferments, the “enzymes,” and (2) “organized”
ferments such as bacteria and yeast.
_Enzymes_
=Rennet.=—Among the unorganized ferments, _Rennet_ or _Rennin_ is highly
important on account of its power of coagulating or curdling milk by
precipitation of the casein. Rennet is extracted from the stomach of the
suckling or milk-fed calf, where it serves in digesting the calf’s food.
It is in the market in the form of a liquid extract as well as a dry
powder compressed into tablets (Rennet Tablets and Junket Tablets). The
characteristics and use of rennet are described under “Cheese Making” in
Chapter III.
=Pepsin= is another enzyme the office of which in the process of
digestion is to dissolve albuminoids. It is not considered identical
with rennet though in an acid solution it will curdle milk. It occurs in
the stomachs of grown animals fed on solid food and is usually produced
from hogs’ stomachs.
Bacteria
Everywhere, in the air, in water, in the soil, and clinging to every
object in the world, are minute organisms known under the common names
of _bacteria_ or _microbes_. In contrast to rennet and the other
“unorganized” ferments, bacteria belong to the “organized” class. Some
are harmful, producing putrefaction, dissolution, poisons or disease;
others are beneficial, leading to desirable fermentations and changes;
others again are indifferent, neither good nor bad, but harmless.
As the milk comes from the cow it is almost free from bacteria, but milk
makes an excellent soil for many of these organisms to grow in, and they
soon get in, to multiply with enormous rapidity at any temperature from
60° to 100° F.
=Lactic Acid Bacilli= are bacteria of special importance to the
dairyman, for they convert sugar of milk into lactic acid and produce
various more or less agreeable flavors. They are also powerful
germicides and scavengers, destroying or neutralizing the products of
other bacteria which in the absence of these bacteria and the lactic
acid produced by them would play havoc with the food and produce
putrefaction or disease. Everybody who handles milk knows that pure sour
milk or buttermilk in which lactic acid bacteria abound keeps well for a
long time, free from other fermentations which have no chance to develop
in their presence. It is due to this purifying property that Metchnikoff
recommended Bulgarian sour milk as a health food, asserting that it
prevents harmful fermentations in the digestive channel.
The Control of Bacteria
The principal means at our disposal to prevent or control and regulate
bacterial growth are:
_Cleanliness_, _Heat_, _Cold_ and _Disinfectants_.
=Cleanliness.=—Only the most scrupulous cleanliness will prevent
contamination. Hence the necessity of thorough scouring and sterilizing
of all utensils, and the need for fresh air and pure water.
=Heat.=—The prevention of fermentation in milk by heating is called
“sterilization” or “pasteurization” according to the intensity of the
heat and the length of time the milk is subjected to it. Boiling
destroys almost all bacterial life. Some germs require, however,
exposure to a much higher temperature, up to 250° F. (boiling under
pressure), to be entirely eradicated, but for all practical purposes a
thorough boiling is considered sufficient to eliminate all danger of
contamination. Such boiling is usually termed _Sterilization_.
[Illustration:
Effect of heating milk to various temperatures.
Published by the Toronto Board of Health
]
=Cooling= checks bacterial growth and but few germs thrive at a
temperature below 50° F. The following table and diagram[4] show how
quickly bacteria multiply in milk at ordinary room temperature, 68° to
70°, which emphasizes the importance of keeping milk cool.
_Relative growth of bacteria when held at different temperatures_
──────────┬──────────┬──────────┬──────────┬──────────┬──────────
│ No. of │ │ │ │
Tem. of │ bacteria │ At end │At end of │At end of │At end of
Milk │ per c.c. │of 6 hrs. │ 12 hrs. │ 24 hrs. │ 40 hrs.
│ at │ │ │ │
│beginning │ │ │ │
──────────┼──────────┼──────────┼──────────┼──────────┼──────────
°F. │ │ │ │ │
50 │ 10 │ 12 │ 15 │ 41 │ 62
68 │ 10 │ 17 │ 242 │ 61,280 │3,574,990
──────────┴──────────┴──────────┴──────────┴──────────┴──────────
[Illustration:
Milk cooler
]
If the milk had contained 1,000 bacteria per cubic centimeter at the
beginning, the part held at 50° F. would have contained 4,100 bacteria
at the end of 24 hours, while that held at 68° F. would have contained
6,128,000. The effect of temperature upon the growth of bacteria is
shown graphically in the cut.
But even _frost does not kill_ the bacteria. If milk which has been kept
sweet or at the desired degree of sourness by cooling is allowed to get
warm again, the bacteria which have been kept dormant will get a fresh
start. For this reason milk and cream for city supply should not only be
cooled strongly, but must be kept thoroughly chilled up to the time they
are used, which means that they should be delivered cool to the
consumer, and kept on ice in the house, never being allowed to warm up
until used.
[Illustration:
The diagram (after Conn) shows the rapidity with which bacteria
multiply in milk not properly cooled. A single bacterium (a) in 24
hours multiplied to 5 (b) in milk kept at 50° F.; (c) represents the
number that develop from a single bacterium in milk kept 24 hours at
70° F.
]
=Disinfectants.=—Antiseptics, such as benzoate of soda, formalin,
boracic acid, etc., are not permissible _in_ milk, but _disinfectants_
such as soda, lime, washing powders, etc., should be freely used in
cleaning utensils, bottles, floors and walls where milk is handled, so
as to prevent as far as possible any infection.
PASTEURIZATION
[Illustration:
Louis Pasteur, French scientist and originator of the process of
pasteurization.
]
Pasteurization depends upon the fact that almost all bacteria, and
especially the disease-producing species, are checked in their growth
and made harmless, if not totally destroyed, by instantaneous exposure
to a temperature of 175° F., or a more or less prolonged exposure to
lower temperature, for instance for 20 minutes to 157° or 30 minutes to
145°. These lower temperatures are recommended in the case of new milk
to be consumed as such, in order not to change its digestibility.
Pasteurizers with “holding devices” are therefore largely taking the
place of the “continuous” sterilizing machines, which allow only
momentary exposure to the highest temperature.
Whatever method is used it is essential that after the heating is
finished the milk should be cooled as quickly as possible to a
temperature sufficiently low to prevent development of the germs that
have not been entirely destroyed by the heat and which, if the milk is
left for any length of time at a temperature favorable for bacterial
life—anywhere between 65° and 110°,—will begin to grow again. Cool the
milk to below 60° and if possible to 50° or 40°.
Sometimes a second pasteurization is practiced, the milk being purposely
allowed to stand at 70° to 80° for 12 to 24 hours after the first
pasteurization for the germs which escaped destruction to develop into
full-grown bacteria. They are then killed by the second heating before
the milk is finally chilled to stop any further growth.
Pasteurization can be done by placing the milk in any tin or enamelled
or glass vessel, set in another vessel containing water (a double
boiler). Heat until the milk has reached the desired temperature, hold
it at that temperature the necessary time, and then place the vessel in
cold running water or in ice water until the milk is thoroughly chilled.
It is not advisable to place the hot milk in the ice box as cooling in
air is too slow. Not until it is thoroughly cooled in water is it safe
to put it in the ice box to _keep_ it cool.
[Illustration:
N. J. Fjord, Danish investigator
]
In the seventies Prof. N. J. Fjord, in Denmark, applied to milk the
process which had been developed by Louis Pasteur in France to give
keeping quality to wine and beer. A Danish dairy expert, J. Moldenhauer,
now connected with the New York State Department of Agriculture, first
brought the process to this country and used pasteurization in a city
creamery in Kentucky. American experiment stations established the
temperatures and the time of exposure necessary for best results, and no
one has done more for the introduction of pasteurization than the New
York philanthropist, Nathan Straus, who has established pasteurizing
plants and milk distributing stations in many localities, thereby
contributing so largely to the lowering of the death rate among the
children of the poor.
[Illustration:
The Straus Pasteurizer
]
[Illustration:
A continuous pasteurizer
]
The following directions are given by the Straus Pasteurized Milk
Laboratories of New York for the pasteurization of milk for babies:
1. Only use fresh, filtered milk, which has been kept cold, and proceed
as follows:
2. Set the bottles, after they have been thoroughly cleaned, into the
tray (a), fill them to the neck, and put on the corks or patent
stoppers.
3. The pot (b) is then placed on a wooden surface (table or floor) and
filled to the three supports (in the pot) with boiling water.
4. Place tray (a), with the filled bottles, into the pot (b), so that
the bottom of the tray rests on the three supports, and put cover (c) on
quickly.
[Illustration:
Milk cooler
]
5. After the bottles have been warmed up by the steam for five minutes,
remove the cover quickly, turn the tray so that it drops into the water.
The cover is to be put on again immediately. This manipulation is to be
made very quickly, so that as little steam as possible can escape. Thus
it remains for twenty-five minutes.
6. Now take the tray out of the water and cool the bottles with cold
water and ice as quickly as possible, and keep them at this low
temperature till used.
7. Before use, warm the milk—in the bottles—to blood heat. Never pour it
into another vessel.
8. The milk must not be used for children later than twenty-four hours
after pasteurization. Never use remnants.
In a _Continuous Pasteurizer_ a constant stream of milk is fed into the
machine, heated by flowing over a metal surface with steam or hot water
on the opposite side, and cooled by running over a cooler furnished with
a stream of cold water or ice water.
PURE CULTURES
[Illustration:
Professor V. Storch, originator of pure cultures for ripening cream
and milk
]
Before 1890 it was supposed that the flavor of fine butter depended upon
certain volatile oils and acids peculiar to butter-fat. In the early
nineties Professor V. Storch of the Danish Experiment Station showed,
however, that it was due rather to the products of bacteria and he
isolated the lactic acid bacilli which would produce such exquisite
flavor even when perfectly neutral and tasteless butter-fat was churned
with milk acidified or ripened with a pure culture of these bacilli. In
this country Dr. H. W. Conn of Wesleyan University, Storrs, Conn., did
much to advance the theory and practice of ripening cream with a pure
culture starter.
“Pure cultures” are produced in the bacteriological laboratory by
picking out under the microscope colonies of the desired species of
bacteria, planting them in a sterilized medium and allowing them to grow
under the most favorable conditions and with the exclusion of all other
germs.
[Illustration:
Streptococcus lacticus (Storch, No. 18)
]
[Illustration:
Bacterium lactis acidi (from Storch)
]
When such a culture has reached its maximum growth it is transplanted
into a larger quantity of a sterilized medium containing proper
nourishment for the particular organism. In the bacteriological
laboratory, where alone absolute sterility of utensils and medium, and
entire exclusion of foreign infection are possible, the culture may
remain pure while this inoculation and propagation are repeated over and
over again. But when the propagation is carried on in the house or the
dairy, for instance in preparing starters or buttermilk, such absolute
cleanliness is impossible and in the long run infections will creep in
from the air or from the utensils and after a while it becomes necessary
to start with a new “pure culture.” How often such renewal must be
resorted to depends largely upon the surroundings and the care of the
operator. Usually it must be done after a week’s time, although it is
surprising to find milk preparations made by the simplest processes
equal in purity to those prepared with the assistance of bacteriological
science and technique. This is, for instance, the case in Bulgaria,
where the famous Yoghourt sour milk is prepared pure without special
care and in Denmark where the country is fairly permeated with the
lactic acid bacilli used in ripening the cream for the celebrated Danish
butter and where careful buttermakers often maintain their starters for
months or even for years without “renewal.”
[Illustration:
Typical lactic acid bacteria
(L. A. Rogers)
]
There are many different varieties of bacteria which convert sugar of
milk into lactic acid, at the same time developing flavors more or less
agreeable and characteristic for the various products. In the
bacteriological laboratory certain species are selected which will
produce the results desired for the particular purpose in view.
=Starters.=—Beginning with a commercial dry culture in the form of a
powder as generally used in the creamery or the cheese factory as well
as for the preparation of commercial buttermilk, or with buttermilk
tablets as used in the ordinary household or the hospital, such culture
is added to a small quantity of thoroughly pasteurized milk. If fresh,
sweet skim milk is available it is preferable to whole milk as the
butter-fat in the latter only interferes with the process; but either
can be used.
Milk for starters should be strongly pasteurized by being kept at a
temperature near the boiling point—at least 180°—for 40 to 60 minutes,
then cooled to the degree at which it is to be set, usually between 65°
and 75°, somewhat higher for the first propagation with the pure culture
than for the subsequent transplantings when the bacteria, more or less
dormant in the dry powder or tablets, have attained full vitality. Some
species of bacteria, as the Bacillus Bulgaricus, require higher
temperatures—90° to 100° or even 110°—than others. The culture having
been thoroughly incorporated in the milk by vigorous and repeated
stirring or shaking, the milk is left at rest in an incubator or a
waterbath or wrapped in paper or cloth in a warm room where an even
temperature can be maintained, until it is curdled, which may take 18 to
24 hours or even longer for the first propagation.
One part of this curdled milk is now added to 5 or 10 parts of fresh
pasteurized milk and set to ripen in the same way as described above,
possibly at a little lower temperature, and this is repeated every day,
thus maintaining the “Mother Starter.” After the second or third
propagation the bulk of each batch is used as a starter in the larger
lot of material to be ripened, be it cream for butter or milk for cheese
or for commercial buttermilk, while a little is taken for maintenance of
the mother starter as described above.
The _amount of starter_ to prepare every day depends upon the amount of
milk or cream to be ripened and the per cent of starter used in same.
For instance, if you have ten gallons of cream to ripen every day in
which you wish to use about 10% or 12% starter, or one gallon, take a
little less than one pint of the first or second propagation for one
gallon of milk; the next day use one pint of this to add to a gallon of
fresh starter milk, and the remaining gallon to add to the ten gallons
of cream, and so on every day.
If you have 4,000 lbs. of milk in the cheese vat to ripen with 2% or 80
lbs. starter, prepare 88 lbs. of mother starter. If, on the other hand,
you wish to make only a quart of buttermilk every day, take, say, two
buttermilk tablets, crush them thoroughly in a spoonful of pasteurized
milk and stir this into a tumblerful of the same milk; let stand till it
is thickened the next day and use a tablespoonful of this thickened milk
in a quart of fresh pasteurized milk which when ripened is your
buttermilk, from which you take out a tablespoonful for starter in the
next batch, and so on. In this case there is no “mother starter” except
that perhaps the first tumblerful prepared with the tablets may be
called so, but afterwards the starter is taken right out of the finished
product every day.
The process may be modified to suit special purposes and local
conditions, but the following precautions should be strictly observed:
(1) to interrupt the ripening immediately by quick and intense cooling
as soon as it has reached the proper point in case the ripened product
is not used at once, and (2) to _keep_ it ice-cold until it is used. If
this is done, it may be kept for two or three days without deterioration
if it is not convenient to make it fresh every day which, however,
should be the rule.
------------------------------------------------------------------------
CHAPTER II
MILK SUPPLY AND CREAMERY PRODUCTS
In the first chapter the composition of cow’s milk and the nature of its
constituents have been considered, the most important tests for its
richness and purity have been described, and the ferments have been
mentioned which instigate changes for good or for bad, together with the
means at disposal for regulating their activity. To use these means
intelligently in handling milk and its products is the key to the
dairyman’s success.
We shall now briefly consider the various steps that are of importance
in modern dairy industry.
MILK SUPPLY
In the first place, the farmer must furnish pure, clean, unadulterated
milk, fresh from the cow and cooled immediately after milking. His cows
must be healthy.
=Bovine Tuberculosis.=—Many milk-cows, for the very reason that they
have been bred with the one purpose in view of turning all their food
into milk and wasting as little as possible in building up the body, are
more or less weak-chested and apt to suffer from tuberculosis. Unless
this disease is so far advanced as to affect the general health of the
cow, or it has spread to the milk organs, the udder and the teats, it is
not so dangerous as has heretofore been supposed. It is now held by the
great majority of physicians that bovine tuberculosis is hardly ever
transmitted to grown persons and seldom to children. Neither is it
hereditary. Nevertheless, wherever it is possible to have the herd
tested with tuberculin, segregating, if not killing, the animals which
show by reaction that they are somewhat tuberculous, it should be done.
Milk from such cows should always be pasteurized.
=Milk as a Disease Carrier.=—A greater danger lies in the fact that,
warm as it comes from the cow, milk is an ideal medium for human disease
germs to grow in, and may thus become a great conveyor of such germs.
For this reason it is of the greatest importance that the milkers are
healthy and clean, that the udders and teats be free from dirt, and the
milk pail covered as far as possible; the barn must be clean, and every
source of infection excluded. This fact also points to the advisability
of pasteurization. On page 23 a chart is shown, published by the Toronto
Board of Health and indicating the temperatures at which various germs
of disease are made harmless.
=Bacterial Count.=—The test for clean milk now mostly used is the
“Bacterial Count,” the number of bacteria—or rather colonies of
bacteria—found in a cubic centimeter of the milk. It would be better if
the nature or quality of the bacteria could be taken into consideration
as well as the quantity, but that being as yet impracticable, the next
best thing is to depend upon the number. Ordinary good milk often
contains hundreds of thousands of bacteria in a cubic centimeter, but
where the greatest cleanliness is observed the number may be less than
1,000.
=Certified Milk= is now sold in many cities which, according to varying
city ordinances, is guaranteed to have less than 10,000 or 20,000 or
30,000 bacteria, as the case may be.
[Illustration:
Counting the bacteria in a cubic centimeter of milk
]
The cost of producing certified milk places it beyond the reach of the
great majority of consumers. But such care and cleanliness as can be
observed by the farmer and the milkman without extra expense should be
insisted upon, and milk which nevertheless contains a large number of
bacteria can be made safe by pasteurization.
=The Sanitary Code.=—The regulation of the production and delivery of
milk in cities and towns as well as at creameries and cheese factories,
the “Sanitary Code” established by state and municipal health
authorities, has been very effective in improving the quality of the
supply. So enormous have been the improvements in caring for and
handling the products by the large establishments engaged in the
delivery of milk as to make the increase in cost seem trifling compared
with the great benefit to the public health secured by these agencies.
=New York State Milk Grading.=—The New York State Board of Health
prescribes a grading for milk offered for sale, the most important
features of which are as follows:
_Certified._—Must be produced under specially sanitary conditions
approved by a county medical commission.
_Grade A Raw._—Cows must be tuberculin tested and milk must not contain
over 60,000 bacteria per cubic centimeter.
_Grade A Pasteurized._—Cows must be subjected to physical examination
and milk must not contain more than 200,000 bacteria before, nor more
than 30,000 after pasteurization.
Other grades permitted under the rules, all subject to inspection and
approval of the authorities, are:
_Grade B Raw._
_Grade B Pasteurized._
_Grade C Raw._
_Grade C Pasteurized._
Deliveries must be made within a certain time after production or
pasteurization, barns and milk stations are inspected, and altogether
such safeguards are employed as to make the supply exceedingly safe and
reliable.
=City Delivery.=—In villages and small cities the milk supply is still
to a large extent in the hands of farmers who come to town early in the
morning peddling their milk, often at considerable waste of time for
horse and man. Or a number of peddlers go over the same route so that it
takes a dozen wagons to cover a town where three or four could do it.
As long as there was no efficient regulation as to price and quality
such waste was perhaps unavoidable, as competition on the part of the
producers and distributors was the only means of protection for the
consumers. But lately state and municipal control is being exercised to
such an extent as to largely eliminate the danger of poor milk and
exorbitant prices. Further development of organized delivery systems so
much to be desired for sanitary as well as for economical reasons, may
be looked for as soon as normal conditions return after the close of the
war. The delivery of milk is one of the things that in the interest of
public health must be under the strictest official control, and
_co-operation_ between farmers and consumers is the logical system for
elimination of unnecessary expenses of distribution and for prompt and
satisfactory service. Their interests are or should be identical and
both classes are hurt by inefficient and wasteful delivery.
In the large cities there has grown up an industry which largely
monopolizes the milk supply and which until lately was powerful enough
to dictate prices and conditions both for producers and consumers.
Several attempts have been made from time to time by farmers to combine
to regulate prices and dictate the terms to the middlemen. Such attempts
have, however, invariably failed as long as they were built on false
economic principles and prompted by selfish interests only. No farmers’
association can be strong enough to ignore the law of supply and demand,
and it is only quite recently that the _Dairymen’s League_ has succeeded
in influencing the market by taking into consideration the actual cost
of production of milk as worked out by the agricultural colleges, and
fixing the price on a scientific basis. There is one other element
entering into the causes on which the price to the consumers depends,
namely, _Transportation_, and while municipal boards of health are
looking after the sanitary conditions and prevention of adulteration,
State and Federal authorities are stepping in as moderators or
arbitrators to reconcile the interests of the _Producers_, the _Railroad
Companies_, the _Distributors_ and the _Consumers_. The next step in the
development will no doubt be towards full co-operation between producers
and consumers and, to a large extent, elimination of the “middlemen.”
It should not be forgotten, however, that while the much abused
middlemen in time past have been able to dictate terms and prices and
have often abused the privilege; they have at the same time used their
influence and power to improve the milk supply. As the supply of oil and
gasoline has been perfected and cheapened by the all-powerful Standard
Oil Co. as a monopoly crushing all competition, so the “Milk Trust” has
improved the distribution of milk and has built up the magnificent
sanitary plants in which milk is handled, pasteurized, bottled and
distributed in a way that might not have been possible without the
monopoly. It has served a good purpose, but has at the same time
acquired such power that official control has become necessary for the
protection of producers and consumers alike, and the time may be near
when these two classes will combine and take the matter into their own
hands so that the distribution may be done at actual cost.
[Illustration:
Milk station in the country where milk is received from the farmers to
be shipped to the city
]
=Milk Stations= are plants erected in dairy sections in the country
either by the city milk supply houses or by co-operating farmers, where
the milk is delivered and handled so as to make it ready for shipment to
the city. As in the creamery and the cheese factory, the milk is
carefully examined and, if it is not sweet and pure, it is rejected and
sent back to the farm. Any impure flavor remains in the cover for some
time and is easily detected by smelling of the cover as soon as it is
removed from the can.
A sample is taken and put aside for the Babcock test and perhaps another
for the Fermentation test. Each farmer’s milk is weighed in the _Weigh
Can_ and run through a cheese-cloth strainer. The further treatment
varies in different plants. The milk may simply be cooled by running it
over a cold water or brine cooler and placing it in shipping cans in the
refrigerator or in ice water until the milk-train comes along to pick up
the cans. Or it may be clarified by running it through a centrifugal
machine, the same as a separator, in which, however, cream and milk are
not separated, but impurities are thrown out by the centrifugal force
and deposited on the wall of the bowl, and the purified milk may then be
pasteurized and bottled before being shipped to the city.
[Illustration:
Receiving milk at the milk station
]
Arriving in the city in iced cars the milk is taken to one of the
elaborate plants in which it is pasteurized and bottled, if that has not
been done at the country station. The machinery used in these plants is
getting more and more perfect and expensive and leaves little to be
desired as to sanitary requirements and economy in handling.
Pasteurizers, bottling machines, bottle-washing machines, conveyors,
etc., are wonders of ingenuity, and one needs only to see one of these
modern plants to understand that in a large city milk can only be
handled to advantage in expensive establishments.
=Skim Milk= is one of the cheapest of foods and under proper regulations
its sale should not be prohibited. The reason why in times past skim
milk has been discredited and excluded from sale was that, as produced
by the old methods of raising the cream, before the advent of the
separator, it was always more or less old and sour before it was
available and certainly before it could be distributed to consumers.
Under such conditions it was hardly ever fit for human food. But when
produced by the separator and pasteurized and cooled immediately
after—within a few hours after milking, which is entirely feasible—it is
an excellent and nutritious food for adults and even for children over
two years of age. Ripened with a pure culture of lactic acid bacteria,
it makes a healthful, refreshing drink, like buttermilk. Only when it is
allowed to sour without proper care or control does skim milk, as whole
milk does, become unfit for food or drink. On a cold winter morning when
men are going to work (or perhaps are looking for work which they cannot
find), and children are on their way to school, often underfed, a
street-corner wagon or stand where boiling hot, fresh, sweet skim milk
might be distributed at a cent or two a glass would be a blessing in any
city.
[Illustration:
Pasteurizing and bottling milk in a Borden plant
]
CREAM
When new milk is left at rest the cream will rise to the top and after
12 to 24 hours a cream-line can be seen in the bottle. This cream-line
is sharper and more easily seen in raw milk than in pasteurized milk and
its absence is not always a sure sign of lack of richness or purity of
the milk. By cooling the milk thoroughly so that it will keep, almost
all the cream will be at the top in forty-eight hours and can be skimmed
off. The cream can be used for coffee or on cereals or fruits or
puddings; the skim milk left will still hold ½% or more of butter-fat
and can be used to drink or for cooking.
=The Separator.=—On the farm or in the creamery the cream is no longer
raised by gravity, that is, by letting the milk “set” either in shallow
pans on the kitchen shelf or in deep cans in ice water, but the fresh,
warm milk is run through the separator in a continuous stream.
[Illustration:
Early conception of the separator
]
It was noticed that the rising of the cream due to the difference in
specific gravity between the butter-fat and the milk-“serum” (the watery
solution of the other constituents) might be greatly hastened by
subjecting the milk to centrifugal force. This physical phenomenon was
taken advantage of in the first conception of the separator where it was
shown that if a pail of milk was whirled around like a stone in a sling
the heavier milk-serum would be thrown towards the bottom of the
separator pail with so much greater force than the lighter cream
(butter-fat mixed with a small part of the serum) that the separation
which would take 48 hours in the milk at rest, could be accomplished in
a few minutes when exposed to centrifugal force. From this early crude
attempt the continuous _bowl-separator_ was developed and still later a
number of divisions in the bowl were designed which increased the
capacity and efficiency of the machine wonderfully. The most successful
separator was designed by Dr. Gustaf De Laval of Sweden and the machines
bearing his name are used all over the world where butter is made. But
there are many other excellent separators on the market.
[Illustration:
Dr. Gustaf De Laval of Sweden, inventor of the separator bearing his
name
]
In the machine the milk is separated instantaneously by centrifugal
force and runs out through two tubes, one for cream and the other for
skim milk. A small modern hand machine will take care of from 200 to
1,000 lbs. of milk an hour, and power machines are built to separate
6,000 lbs. or more. By regulating the cream-outlet a heavier or lighter
cream can be produced.
[Illustration:
Hand separator
]
Suppose we are separating some milk containing 4% butter-fat. If ⅛ of
this milk is separated out as cream and contains all the butter-fat, the
cream will be eight times as rich in butter-fat as the original milk;
32% of the cream will be butter-fat. Such cream is called “32% cream.”
If we take ¼ as cream, we get a cream four times as rich as the milk, a
“16% cream.” So out of 100 lbs. of milk we can take 12½ lbs. (⅛) of 32%
cream, 25 lbs. (¼) of 16% cream, etc.
Although the skim milk is really valuable as a food, it is worth but
little commercially; the cream containing the butter-fat is the
expensive part of the milk, and we must be prepared to pay for the cream
all that the milk would have cost.
=Percentage of Butter-Fat.=—The “richness” of cream or milk and their
value depend upon the amount of butter-fat in them. So cream or milk is
often called “30% cream” or “20% cream” or “4% milk” according as 30% or
20% or 4% of the fluid is butter-fat; 30% cream is quite rich; ordinary
market cream varies between 18% and 40%, though it may fall below 18%,
or it may be sold as a very expensive article as high as 60%. Rich milk
may contain more than 6% of butter-fat and skim milk less than 0.1 of
one per cent. The average for good whole milk is between 3% and 4½%.
For a long time scientists and scientific dairymen were the only ones to
speak of milk and cream in terms of percentage of butter-fat. Now,
however, people are beginning to realize how valuable a part of the milk
the butter-fat is and are paying more attention to the actual percentage
of butter-fat in the cream or milk they use. So it is no longer unusual
to see a dairyman advertise cream of a certain percentage or to hear a
housewife ask for it specifically.
=Standardizing Cream.=—For ice cream or for preparing modified milk for
babies, it is often desirable to dilute rich cream to a certain lower
standard. The following simple steps can be taken to find out how much
milk to add for diluting:
1. From the test—fat-percentage—of the rich cream subtract the test
desired.
2. From the test desired subtract the test of the milk used for
diluting.
3. Divide the first difference by the second, and the result will be the
number of pints (or pounds) of milk to be added for each pint (or pound)
of the rich cream.
For instance, you may want to thin some 30% cream to 10% for making ice
cream. The milk to be added is skim milk. Then:
1. 30 - 10 = 20.
2. 10 - 0 = 10.
3. 20 divided by 10 = 2. So for each pint of rich cream you may add 2
pints of skim milk.
Or you may wish to thin the 30% cream with whole milk, which has 4%
butter-fat. Again:
1. 30 - 10 = 20.
2. 10 - 4 = 6.
3. 20 divided by 6 = 3⅓. So you may add 3⅓ pints of the whole milk to
each pint of the 30% cream and still have a 10% cream.
=Pasteurized Cream= does not look as rich as raw cream, and fresh, sweet
cream appears to be thinner than when it is 24 hours old and slightly
ripened. So it is well, when buying cream, not to judge by appearances.
Demand of the milkman that he furnish you cream of a certain percentage
of butter-fat and see to it that you get what you pay for. If you have
no Babcock tester the milk inspector will test the cream for you.
=Whipped Cream.=—For whipping, cream must be fairly rich, from 24% to
32%, and it must be cold. Fresh, sweet cream does not whip as readily as
that which has been kept for 12 or 24 hours in ice water. There is no
other secret connected with the process. Use a rich cream, suitably
cooled and aged, and with a good beater there can be no trouble in
getting a fine, stiff whipped cream. If the cream is too thin or too
warm it may not become stiff. Sometimes, when it is beaten too long, it
turns into butter and buttermilk.
[Illustration:
Installation in a Danish creamery.
From the separator at the right the cream runs through the continuous
pasteurizer which forces it up over the cooler whence it runs into
the cream-vat at the left.
(From Boggild—Maelkeribruget i Danmark)
]
=Emulsified Cream.=—One of the recent additions to the already elaborate
machinery used in the creamery, the milk supply or the ice cream
business, is the _Emulsifier._ To be sure, emulsifiers were used thirty
to forty years ago to mix animal and vegetable fats—oleomargarine oil,
lard and cottonseed oil—into skim milk for “Filled Cheese” or for
Butterine, but lately they are serving new purposes in the milk
industry. By forcing melted butter-fat or oil mixed with water or skim
milk through exceedingly small apertures under high pressure, or
otherwise breaking up the mixture, an emulsion can be formed in which
the fat globules are much finer even than those in natural milk or
cream, and separation can be prevented. The force used in these
emulsifiers may be produced by powerful pumps, or a steam jet, or
centrifugal force under high speed; whichever system is used the
machines answer the same purpose, to produce a permanent emulsion in
which the oil or fat will stay in suspension even after cooling. In some
milk supply plants and ice cream factories all the cream is emulsified
and the system has especially been applied since the advent of the milk
powder. It is now a not infrequent practice to run the new milk through
the separator, make sweet, unsalted butter from the cream, and milk
powder from the skim milk, and to ship or store these products
separately where or until cream is wanted and then bring them together
again by running them through the emulsifier with a suitable amount of
water. At first thought this process would seem impractical and
uneconomical. But it has proven good business because in many cases and
places skim milk powder and butter keep better separately or can be
shipped at long distance to better advantage than new milk or cream or
condensed milk. In ice cream factories business may be dull in cold
weather and cream is perhaps not provided and not available, when
suddenly a hot spell brings orders for large quantities. With a stock of
skim milk powder and butter on hand in the refrigerator, and an
emulsifier to mix these products, cream can be produced on short notice
and there will be no danger of shortage.
ICE CREAM
Ice cream has fast become the national dessert served on all festive
occasions, winter and summer. Originally it meant a frozen mixture of
sweetened and flavored milk and cream, but the name has long been
applied to all kinds of frozen delicacies in which cream enters as a
constituent. Not even there has the line been drawn, but gums, gelatine,
cornstarch, eggs and other “fillers” have been substituted or added to
thicken the mixtures and give “body” to “creams,” which have but little
relation to the genuine emulsion of butter-fat from cow’s milk.
Standardization has been attempted by National and State food
authorities with varying success of enforcement. While the application
of the name to a great variety of frozen desserts has no doubt become
legitimate by long usage it may properly be demanded that as an article
of merchandise “ice cream” shall contain at least 8% to 12% butter-fat
and that no ingredients dangerous to health enter into its manufacture.
[Illustration:
Hand freezer
]
=Freezers.=—The freezing is usually done by contact of the material with
metal cooled on the other side by a “freezing mixture” of salt and ice
which produces temperatures far below the freezing point of water while
air is whipped into the cream by the rapid motion of the beater. A great
variety of excellent freezers of this kind for hand or for power are on
the market which answer the purpose for making ice cream at home or at
the ice cream parlor.
Coarse-grained salt and crushed ice, mixed in the proportion of 1 part
salt to 4 parts of ice, are constantly filled into the space surrounding
the ice cream can, and the brine produced by the melting of the mixture
is gradually drawn off from the tub. In a good freezer the operation
should not take over fifteen minutes. When the cream is frozen to a soft
mush, stop the beater and scrape down the hard particles which may have
accumulated on the sides of the can, add any ingredients which may be
better incorporated at this stage than mixed into the original material,
such as crushed fruit or preserves, and finish the freezing without
carrying it too far.
Remove the beater, stir the cream which should still be soft enough to
handle, and pack in ice with only a little salt. Or the cream may be
transferred from the freezer can to the shipping can and packed in it.
If bricks are wanted the soft cream is packed in molds of the desired
shape and size and buried in the freezing mixture to harden.
In modern ice cream factories _Brine Freezers_ are generally used. In a
_Refrigerator Plant_ intensely low temperatures are produced by the
vaporizing of compressed ammonia or carbonic acid in an ice machine, and
brine circulating in iron pipes is cooled by such medium and may, in
turn, cool the air in the _Cold Storage_ room, or the cream in the
freezer, or pure water in metal boxes for the manufacture of _Artificial
Ice._ It has been attempted to make the brine freezers _continuous_, the
cream mixture being fed into the machine at one end and discharged
frozen at the other. But this system has not so far been successful, and
intermittent or batch freezers are most practical yet both for hand and
for power.
[Illustration:
Power brine freezer
]
Rich material, frozen in a good machine, whether intermittent or
continuous, will expand from 50% to 100%, and the original material
should not fill the freezer can more than half full.
The manufacture of ice cream has been the subject of study and
experiments for years in the Dairy Department of the Agricultural
College at Ames, Iowa, where Professor M. Mortensen has worked out a
comprehensive classification from which any manufacturer may readily
choose his formulas, modifying them to suit his local conditions and
special problems. The outline kindly furnished the author by Professor
Mortensen is so interesting and instructive as to be well worth copying
substantially in full, leaving out the “Ices” in which no milk or cream
is used and which are therefore not of special interest in connection
with the purpose of this book—the use of more and better milk.
[Illustration:
Ice cream factory
]
CLASSIFICATION ADOPTED AT IOWA EXPERIMENT STATION
Considering the work of former writers as well as names used by business
men, the following classification was worked out by the station:
I. Plain Ice Creams.
II. Nut Ice Creams.
III. Fruit Ice Creams.
IV. Bisque Ice Creams.
V. Parfaits.
VI. Mousses.
VII. Puddings.
VIII. Aufaits.
IX. Lactos.
Explanation and Formulas
I. _Plain Ice Cream_ is a frozen product made from cream and sugar with
or without a natural flavoring.
Formulas are given for making ten gallons of finished ice cream.
_Vanilla Ice Cream_:
5 gallons 25% cream
8 lbs. sugar
4 oz. vanilla extract
_Chocolate Ice Cream_:
5 gallons cream
10 lbs. sugar
1½ lbs. bitter chocolate
4 oz. vanilla extract
_Maple Ice Cream_:
5 gallons 25% cream
6 lbs. cane sugar
2 lbs. maple sugar
2 oz. caramel
4 oz. vanilla extract
_Caramel Ice Cream_:
5 gallons 25% cream
8 lbs. sugar
12 oz. caramel
4 oz. vanilla extract
_Coffee Ice Cream_:
5 gallons 25% cream
8 lbs. cane sugar
Extract from 1 lb. coffee
_Mint Ice Cream_:
5 gallons 25% cream
8 lbs. cane sugar
1 pt. concentrated Creme de Menthe syrup
Few drops green coloring.
II. _Nut Ice Cream_ is a frozen product made from cream and sugar and
sound non-rancid nuts.
_Walnut Ice Cream_:
5 gallons 25% cream
8 lbs. cane sugar
4 oz. vanilla extract
4 lbs. of walnut meats.
According to this general formula the following nut ice creams may be
prepared by substituting different kinds of nut meats:
_Chestnut Ice Cream_
_Filbert Ice Cream_
_Hazelnut Ice Cream_
_Pecan Ice Cream_
_Peanut Ice Cream_
_Almond Ice Cream_
_Pistachio Ice Cream_.
At times pistachio ice cream is made from oil of pistachio instead of
from the nuts. If thus prepared, it will come under the head of plain
ice cream.
III. _Fruit Ice Cream_ is a frozen product made from cream, sugar and
sound, clean, mature fruits.
_Strawberry Ice Cream_:
5 gallons 25% cream
8 lbs. sugar
½ gallon crushed strawberries.
Employing the same formula the following creams may be made by merely
substituting other fruits and berries for the strawberries. The amount
of sugar may be varied according to the acidity of the fruit.
_Pineapple Ice Cream_
_Raspberry Ice Cream_
_Cherry Ice Cream_
_Peach Ice Cream_
_Apricot Ice Cream_
_Currant Ice Cream_
_Grape Ice Cream_
_Cranberry Ice Cream_.
Preparation of _lemon_ and _orange_ ice creams cannot be included under
this general rule. These creams may be prepared as follows:
_Lemon Ice Cream_:
5 gallons 25% cream
10 lbs. sugar
2 pts. lemon juice
1 pt. orange juice
_Orange Ice Cream_:
5 gallons 25% cream
10 lbs. sugar
2 qts. orange juice
½ pt. lemon juice.
IV. _Bisque Ice Cream_ is a frozen product made from cream, sugar and
bread products, marshmallows or other confections, with or without other
natural flavoring.
_Macaroon Ice Cream_:
5 gallons 25% cream
8 lbs. sugar
4 oz. vanilla extract
5 lbs. ground macaroons.
From this formula we can make:
Grape Nut Ice Cream
Nabisco Ice Cream
Sponge Cake Ice Cream
Marshmallow Ice Cream.
V. _Parfait_ is a frozen product made from cream, sugar and egg yolks
with or without nuts or fruits and other natural flavoring.
_Walnut Parfait_:
4 gallons 30% cream
Yolks of 10 dozen eggs
14 lbs. sugar
4 oz. vanilla extract
4 lbs. walnut meats.
From this formula by substituting the nut meats we can make:
_Filbert Parfait_
_Almond Parfait_
_Peanut Parfait_
_Hazelnut Parfait_, etc.
By substituting the same proportion of fruits as are used for fruit ice
cream, for the vanilla extract and nut meats, fruit parfaits such as
strawberry, raspberry and cherry parfaits and others may be prepared.
_Coffee Parfait_:
4 gallons 30% cream
Yolks of 10 dozen eggs
14 lbs. sugar
Extract from 1 lb. coffee
_Maple Parfait_:
4 gallons 30% cream
Yolks of 10 dozen eggs
4 lbs. maple sugar
10 lbs. cane sugar
2 oz. caramel paste
_Tutti-Frutti_:
4 gallons 30% cream
Yolks of 10 dozen eggs
14 lbs. cane sugar
4 oz. vanilla extract
3 lbs. candied cherries
3 lbs. candied assorted fruit
3 lbs. pineapple.
VI. _Mousse_ is a frozen whipped cream to which sugar and natural
flavoring have been added.
_Cranberry Mousse_:
2 gallons 30% cream
4 lbs. cane sugar
1 qt. cranberry juice
¼ pt. lemon juice.
From the same formula combinations may be made with various other fruit
juices and natural flavors, such as coffee, vanilla, maple, caramel,
pistachio, etc.
_Sultana roll_, as indicated by the name, is made in a round mold. The
center of the mold is filled with tutti-frutti, and the outside with
pistachio mousse.
VII. _Pudding_ is a product made from cream or milk, with sugar, eggs,
nuts and fruits, highly flavored.
_Nesselrode Pudding_:
3 gallons 30% cream
10 dozen eggs
10 lbs. cane sugar
4 oz. vanilla extract
6 lbs. candied cherries and assorted fruits
4 lbs. raisins
4 lbs. macaroons
_Manhattan Pudding_:
3 gallons 30% cream
10 dozen eggs
12 lbs. sugar
2 qts. orange juice
1 pt. lemon juice
4 lbs. walnut meats
4 lbs. pecan meats
4 lbs. cherries and assorted fruits
_Plum Pudding_:
3 gallons 30% cream
10 dozen eggs
10 lbs. sugar
2½ lbs. chocolate
4 lbs. cherries and assorted fruits
2 lbs. raisins
2 lbs. figs
1 lb. walnut meats
3 teaspoonfuls ground cinnamon
½ teaspoonful ground cloves.
VIII. _Aufait_ is a brick cream consisting of layers of one or more
kinds of cream with solid layers of frozen fruits.
Fig aufait may be made from three layers of cream of various flavors
with two layers of whole or sliced figs. It is most satisfactory to
slice the figs lengthwise in halves.
Other aufaits may be made from a variety of preserved fruits and berries
and combined with different creams.
IX. _Lacto_ is a product manufactured from skimmed or whole sour milk,
eggs and sugar, with or without natural flavoring.
Formulas for lactos may be found in Bulletin No. 140 published by the
Ames Station.
As an example, the following mixture will make 5 gallons of
_Cherry Lacto_:
3 gallons lacto milk
9 pounds sugar
12 eggs
1 quart of cherry juice or concentrated cherry syrup
1½ pints lemon juice
“Lacto Milk” is the same as described under “Commercial Buttermilk” and
“Thick Milk,” pages 81 and 82.
The sugar is first dissolved in the lacto milk. The eggs are
then prepared. The whites and yolks are kept in separate
containers and each lot is beaten with an egg beater. Both the
yolks and whites are then added to the milk. The mixture is
thoroughly stirred and strained through a fine wire gauze. The
fruit juices are added last. The freezer is now run until it
turns with difficulty when the paddle is removed. The brine is
removed and the freezer repacked with ice and salt and left for
an hour before the contents are served.
Orange, Mint, Pineapple, Maraschino, Raspberry or Grape Lacto
may be prepared by substituting any of these flavors for the
Cherry.
X. _Ices_ are frozen products made from water or sweet skimmed or whole
milk, and sugar, with or without eggs, fruit juices or other natural
flavoring.
Ices may be for convenience divided into _sherbets_, _milk sherbets_,
_frappes_, _punches_ and _souffles_.
_Milk Sherbet_ is an ice made from sweet skimmed or whole milk with egg
albumen, sugar and natural flavoring, frozen to the consistency of ice
cream.
_Pineapple Milk Sherbet_:
6 gallons milk
20 lbs. sugar
Whites of 2 dozen eggs
1 gallon pineapple pulp
1 qt. lemon juice.
Milk sherbets of various flavors may be prepared according to above
formula by substituting other flavorings.
The formulas presented above have been given mainly for the purpose of
making clear the difference between the various groups. Numerous other
formulas may be prepared on the same general outline.
* * * * *
Prof. Mortensen’s formulas are mostly made out for ten gallons of ice
cream. It is hardly necessary to call attention to the fact that they
can easily be adapted to any smaller quantities by reducing each of the
ingredients alike. For instance, to make:
_1 gallon of Plain Vanilla Ice Cream_, divide the figures given above by
10 and use:
2 quarts 25% cream
¾ lbs. sugar
½ oz. vanilla extract.
To make:
_1 quart of Strawberry Ice Cream_, divide by 40 and use:
1 pint 25% cream
3 oz. sugar
Crushed strawberries to taste.
[Illustration:
Professor Mortensen, behind the vat at the left, giving a lesson in
the making of ice cream at Ames
]
It will be noticed that in the formulas worked out at Ames as above,
very rich cream is used,—with a fat contents of 25% or 30%,—which makes
exceedingly rich ice creams and great expansion in freezing. The
ordinary ice cream maker will usually employ cheaper material, mixing
some milk in the cream and standardizing the material to suit his local
trade. Also most housekeepers making ice cream at home will find it
convenient and economical to use a mixture of milk and cream and in
doing so one must not expect so much expansion.
In many places outside of dairy sections cream is scarce and _condensed
milk_ is substituted to a large extent. Lately milk powder has come into
use and _Emulsified Cream_ has become popular. Skim-milk powder and
unsalted butter may be kept in stock and be available at any time, and
by means of an _Emulsifier_ they are united again into a product
identical with the milk or cream from which they were originally
separated.
=Junket Ice Cream.=—By setting a mixture of milk and cream with a
solution of Junket Tablets and allowing it to jelly before freezing, the
body of the cream may be improved so that a material of comparatively
low fat-percentage will make a very good ice cream, rich enough for most
people and especially well suited for invalids and children. Ice-cold
milk or cream is rather hard to digest for a weak or delicate stomach
because the action of the rennet in the digestive juice is imperfect and
slow except at blood-temperature. In Junket Ice Cream, however, such
action takes place before it is eaten and the digestive ferment of the
stomach is relieved of that function. For that reason Junket Ice Cream
is considered healthier than the ordinary frozen products and may be
indulged in freely by children and invalids.
The following are examples of tested Junket Ice Creams:
Vanilla Ice Cream
Dissolve two Junket Tablets in a tablespoonful of cold water,
heat two quarts of milk and one pint of cream lukewarm in which
has been dissolved one cup of sugar and two teaspoonfuls of
vanilla flavor, then add the dissolved Junket Tablet, stir
quickly for one-half minute and pour into ice cream can, let
stand undisturbed ten or fifteen minutes or until set. Pack with
ice and salt and freeze.
Pistachio Ice Cream
Excerpt from an article by Alice Bradley in “Woman’s Home Companion”
This is the best ice cream for the money that we know. It may be
made ready for the freezer early in the morning, and kept in the
ice box until it is convenient to freeze it. It is quite
possible to utilize cream that is not perfectly fresh.
Put in the can of the freezer one pint of milk, one-half cup of
heavy cream, one-third cup sugar, one teaspoonful vanilla,
one-half teaspoon of almond extract, a few grains of salt, and
vegetable color paste to make a delicate green color. Set the
freezer in a pan of hot water. As soon as the mixture is
lukewarm, add one Junket Tablet dissolved in one tablespoon cold
water. Mix thoroughly and let stand until firm. Put in the ice
box until ready to freeze, then put can in the freezer tub,
adjust the crank, put in three small measures of ice that has
been crushed in a heavy bag or shaved fine with an ice shaver,
cover this evenly with one measure of rock salt, add three
measures more of ice and one of salt, let stand five minutes and
then turn the crank of the freezer for about ten minutes, when
it may be turned a little more rapidly. Continue the turning
until the mixture is firm.
Remove the dasher, pack ice cream solidly into the can, surround
with four measures of ice to one of salt, cover with heavy
burlap bag or newspaper and keep in a cold place until needed.
Be sure the opening in the side of the freezer tub is not
plugged up, so that any surplus of salt water will drain off
instead of getting into the freezer. It may be necessary to
repack the freezer if the cream is frozen very long in advance
of the meal. The cream may be put into a mold, set in the
fireless cooker kettle, surrounded with ice and salt and left in
the fireless cooker all day. Peel peaches, cut in thin slices,
sprinkle with sugar and set in the ice box to chill. To serve,
place peaches in chilled dessert glasses, cover with ice cream
and garnish each with a candied cherry.
In the following recipes the cream is added after the junket prepared
from mixtures of milk, sugar and flavors has been partly frozen, a
method which is preferred by many.
Coffee Ice Cream
Make a cup of very strong coffee, add it to two quarts of warm
milk in which one cup of sugar has been dissolved, taste in
order to see if the flavor is strong enough, add three dissolved
Junket Tablets, stir quickly for one-half minute, pour into ice
cream can and let stand undisturbed ten or fifteen minutes or
until set. Pack with ice and salt; freeze to a thick mush before
adding one pint of cream, then continue freezing.
_Simmons College Peach Ice Cream_
Heat two quarts of milk lukewarm in which has been dissolved one
cup of sugar and two teaspoonfuls of vanilla flavor, add two
dissolved Junket Tablets, stir quickly for one-half minute and
pour into ice cream can, let stand undisturbed ten or fifteen
minutes or until set. Pack with ice and salt; freeze to a thick
mush before adding one pint of cream and crushed and sweetened
peaches, then continue freezing. Save the needed amount of
peaches to serve on top of ice cream.
Frozen pudding, strawberries, bananas, or pineapple, may be added in
this way when making any Junket Ice Cream.
_Orange Sherbet_
Heat two quarts of milk lukewarm in which has been dissolved two
cups of sugar, then add two dissolved Junket Tablets, stir
quickly for a minute and pour into freezer can, let it stand ten
or fifteen minutes before packing with ice and salt; freeze to a
thick mush, then add juice and grated rind of six oranges and
continue to freeze.
=Raspberry Sherbet= may be made in the same way by substituting for the
juice and rind of oranges one quart of crushed and sweetened
raspberries, and
=Pineapple Sherbet= by substituting two cups of grated and sweetened
pineapple.
_Custard Ice Cream_
When cream is scarce many housekeepers substitute a mixture of eggs and
milk. The following is a good standard recipe which can be varied by
using different fruits and flavors the same as in any of the above
combinations.
1 quart milk
4 eggs
2 teaspoons vanilla (more if desired)
2½ cups sugar
1 quart cream (or rich milk)
Scald milk, add sugar, then add the well-beaten eggs. Cook until thick,
remove from fire and cool. Be careful not to cook too long or it will
curdle. Then add the cream and vanilla and freeze.
BUTTER
As everybody knows, butter is one of the oldest and most important
products of the dairy industry and since the middle of the nineteenth
century, when science was first applied to it, the art of buttermaking
has gradually been developed to a high degree of perfection, while the
taste for fine butter has grown apace with its manufacture.
Between 1840 and 1850 the large estates in Holstein, then connected with
Denmark, were known for their fine dairies and excellent butter, made in
a practical way without much attention to the reason for the rules that
were gradually worked out.
A class of superior dairymaids was educated on these large farms, many
of whom were hired by progressive farmers on the Danish islands where an
effort was made at that time to introduce better methods of dairying.
The practical handicraft of these imported expert dairymaids was
supplemented and regulated by the scientific work of Professor Segelcke
and his pupils and from the Sixties buttermaking became an art in
Denmark which was subjected to the most searching study and
improvements. Danish butter soon captured the English market where
previously Isigny (from Northern France) and Dutch butter had commanded
the highest prices, and Danish sweet butter put up in sealed tin cans
also became known all over the world as the only butter that would stand
export to the Tropics.
In this country Orange County, N.Y., first produced a high-class article
and, later, Elgin, Ill., became the center that stood for the top of
perfection. Thence the industry soon spread over the middle western
states, largely populated by Scandinavian immigrants many of whom were
skilled buttermakers, educated in the old countries. Even up to this day
it is noticeable that the list of prize winning buttermakers at the
National Dairy Shows and other exhibitions is largely made up of
Scandinavian names. In Minnesota, for instance, as fine butter is now
made as anywhere in the world.
_Dairy Butter._—In the early days of the industry butter was made at
home on the farm. The milk was set in shallow vessels,—in the Holstein
and Danish dairies in wooden tubs 24 inches in diameter placed on the
stone or concrete floor in the milk-vault, a cool cellar partly
underground,—or in tin pans on the pantry shelf. After 36 to 48 hours
the cream was skimmed off with a flat scoop, often both cream and skim
milk being sour.
About 1860 the deep tin can was introduced, set in cold running water
or, where ice was available, in ice water. This was a great improvement
over the shallow setting system. It was now possible to raise most of
the cream in 24 hours leaving not to exceed ½% butter-fat in the skim
milk, and to have both cream and skim milk sweet.
_Centrifugal Creaming._—But the climax of perfection was not reached
until the separator (see under Cream) was invented about 1879 and cream
was raised instantaneously. For a long time it was the object of the
manufacturers to produce _power separators_ of larger and larger
capacity, handling from 6,000 to 10,000 lbs. of milk an hour.
=Co-operative Creameries= were established, taking in 20,000 lbs. of
milk and more a day. But in thinly settled sections where the roads were
poor it was expensive to haul the milk a long distance to the creamery
and _hand separators_ were introduced, each farmer skimming his own milk
fresh from the cows and delivering the cream, only, to the creamery.
This system has the advantage of leaving the skim milk on the farm in
the very best condition for the calves and hogs and of saving time and
expenses in transportation. It has the disadvantage that many farmers
can hardly be expected to handle all of these separators as skilfully
and cleanly as the creamery expert can run his one or few machines, and
consequently that the skimming is more or less imperfect—more butter-fat
being left in the skim milk and more impurities in the cream than in the
whole-milk creamery. But in practice the advantages of the hand
separator and cream-gathering system seem to be greater than the
disadvantages and it is rapidly taking the place of the whole-milk
creameries.
_Ripening the Cream._—Butter may be made by churning whole milk, but
usually it is made from cream that has been “ripened” or soured by
standing for about 10 hours at a temperature of from 65° to 75° F.
Modern buttermakers often pasteurize the cream and then add a “starter”
to sour it. By preparing the starter with a pure culture of lactic acid
bacteria one can get the desired acidity and aroma, and exclude
undesirable flavors (as to Pure Cultures and Starters, see under
“Bacteria” and “Commercial Buttermilk”).
[Illustration:
Sanitary Cream Ripener showing coil swung up into cleaning position
]
The process of ripening requires considerable skill and attention and is
one of the most delicate functions the buttermaker is called upon to
perform. In the first place the cream must be faultless, sweet and pure
before it is set to ripen, so the buttermaker will have full control of
the fermentation. For, if it is already turned or partly fermented, no
skill will avail to bring it back to perfection. But with a first class,
pure cream the operator has it in his power to turn out perfect butter.
In the big western creameries cream is often collected from farms at a
distance of a hundred miles or more and in warm weather such cream is
likely to arrive at the central plant in more or less advanced
condition. It is therefore difficult for the _centralizers_ to make
really first-class butter while the “whole-milk creamery” as well as the
farmer handling his own milk are in position to control the ripening
from the beginning,—starting with pure material and being able to
develop the desired flavor and acidity in the cream.
After adding the starter to the cream it must be kept at a uniform
temperature of 65 to 75° during the ripening process and it must be
watched carefully and occasionally stirred gently until the consistency,
aroma and acidity are as desired. Then it should be cooled quickly to
stop further fermentation and if it is not to be churned at once it
should be kept cold until churning time. Usually it is safer to set the
cream in the morning and hasten the ripening so it will be completed in
the evening rather than to leave it overnight warm. For, if it is
finished in the evening, the cream may be cooled and placed in ice water
overnight and one is sure to have it in good condition for churning in
the morning. But it is quite feasible for the experienced operator to
regulate the process so the cream will not be fully ripened in the
morning until he is on hand to watch it and see that the process does
not go too far. Taste and smell will tell when it is just right, and the
_acid test_ may also be applied to determine when to stop the
fermentation. An acidity of .5% is usually desired. When the condition
is right, chill the cream, cooling it to below 50°—preferably down
towards 40°—and leave it in ice water or in the refrigerator until
churning time; then temper it to the proper temperature for churning.
Even if it is to be churned soon after the ripening is completed it is
best to chill it and then raise the temperature to the point wanted for
churning. This gives a better “grain” and “body” to the butter than if
the ripened cream is just cooled to the churning temperature, and is
especially desirable when the cream has been pasteurized.
[Illustration:
Branch of the Annatto tree
]
=Coloring.=—When the cream is ready it is poured into the churn and a
little butter color is added. Some people prefer butter very light or
even uncolored, but usually 1 to 2 teaspoonfuls of a standard butter
color[5] to 10 gallons of cream will be found right, varying according
to the season and the breed of cows furnishing the milk. The butter-fat
in Guernsey and Jersey milk is naturally highly colored, while that in
Holstein milk is comparatively white. When the cows are on fresh pasture
in the early summer the butter-fat is more highly colored than when they
are on dry food. The amount of coloring to be added to the cream is
regulated to overcome such variations and make the butter of uniform
color all the year round.
[Illustration:
Adding the butter color
]
=Churning.=—Hundreds of varieties of churns have been constructed from
time to time; 2,000 years ago Pliny described the old dash churn much
the same as still occasionally used on the farm, and the principle
involved in the process has not been changed. The object is to make the
fat globules conglomerate into grains that can be collected and leave as
little butter-fat as possible in the buttermilk.
[Illustration:
Old Arabian churn made out of the skin of a goat
]
[Illustration:
Ancient churn
]
[Illustration:
Danish churn
]
The best temperature for churning varies from 48° to 56° and must be
determined by local conditions and experience. To allow plenty of room
for the cream to shake about, the churn should not be much more than
half full. When the globules of fat suspended in the milk stick together
and form granules as large as good sized pin-heads it is time to stop
the churn and drain off the buttermilk. If the butter fails to “come” in
half an hour or forty minutes it may be because the cream in the churn
is too warm or too cold. A little cold or warm water, as the case may
be, can be added as a simple remedy.
[Illustration:
Churning room in a large modern creamery
]
Toward the end of the process care must be taken that the churn is
stopped at the right moment, when the butter will separate clear from
the buttermilk. After the buttermilk is drawn off pure cold water is
poured into the churn and the butter granules are rinsed in it. This
water again is drawn off and fresh cold water put in.
[Illustration:
Butter worker
]
=Working the Butter.=—The butter can now be taken out with a sieve and
worked on the butter-worker, or it may be worked in the churn. “Working”
the butter consists in squeezing out the buttermilk and kneading the
butter into a smooth but not “greasy” mass. If it is too warm and if it
is worked too much, with a sliding motion instead of just pressing, the
butter is apt to become greasy. If there seems to be any danger of
greasiness, it is better to stop and put the butter in a cool place for
a few hours to recover its elasticity. The working can then be finished
safely.
=Salting.=—During this working process salt is added and thoroughly
distributed and worked in. About half an ounce of salt is used for a
pound of butter.
=Composition of Butter.=—When finished, the butter ought not to contain
more than 12% to 15% of water, and there should be at least 80% of
butter-fat. If all the butter-fat originally in the milk could be taken
out in the butter, 100 lbs. of 4% milk should yield 4.88% (4.88 lbs.) of
butter with 82% butter-fat. But a little is lost in the skim milk and
more in the buttermilk, which usually contains ½% fat, so that about 4½
lbs. is all the butter that can be expected from 100 lbs. of milk.
=Overrun.=—Creamery men are much interested in the “Overrun” which means
the increase from the churn over the amount of fat in the milk. For
instance, if a quantity of milk containing 100 lbs. butter-fat as shown
by the Babcock Test produces 114 lbs. of finished butter, the overrun is
14%. The buttermaker who gets the largest overrun by reducing the loss
of butter-fat in the skim milk and the buttermilk to a minimum, keeping
the percentage of water in the butter just below 16%, and yet producing
high scoring butter, is considered most efficient.
=Packing.=—For the market, butter is packed in tubs or stone jars. Or it
is molded in neat one-pound bricks and wrapped in parchment paper.
=Sweet Butter.=—Real “sweet” butter is churned from fresh, sweet,
unsoured cream. But usually the name is given to the _unsalted_ and
_uncolored_ butter that many people relish. Without the salt it does not
keep as well as ordinary butter, and must be eaten quite fresh.
Well-made salted butter will keep for months with ordinary care, and in
cold storage it may be kept a year. But when it comes out of cold
storage it must be used within a few weeks, for butter, like other cold
storage foods, will soon spoil and become rancid when it is exposed to a
higher temperature for any length of time.
=Renovated Butter.=—Butter that has become old and rancid can be
“renovated.” The butter is melted and the butter-oil washed,—aërated in
the renovating plants,—and then churned with fine-flavored sour skim
milk. From the sour skim milk it gets back its old butter flavor. The
granular physical consistency of fresh butter is gained by pouring the
emulsified mixture over cracked ice or into ice water. By the time the
excess of “buttermilk” has been removed by working, and salt has been
mixed in, the renovated butter may be almost as good as fresh creamery
butter.
=Oleomargarine= or =Butterine= is made in much the same way. A mixture
of beef-fat (the soft part of beef-tallow) and lard and cottonseed oil
is churned with sour milk and worked and granulated like renovated
butter. For the better grades, some of the finest creamery butter is
mixed with it, so that the mixture can hardly be distinguished from real
butter.
=Coco-butter=, =Nut-butter=, etc., in great variety, are now also on the
market as substitutes for butter, all prepared in a similar way, but
lacking the vital unknown element that makes genuine butter so superior
to substitutes.
BUTTERMILK
If the cream has been carefully ripened, with or without a pure culture
starter, and it has shown the proper sourness when churned, the
buttermilk will be of a pleasing taste and flavor. Its thickness will of
course depend upon the amount of water, if any, added to the cream in
the churn during the buttermaking. If the buttermilk is to be used for
human food care must be taken not to dilute it too much.
=Cooling Essential.=—If buttermilk is left to stand for hours in a warm
room, fermentation goes on and may soon spoil the buttermilk by making
it sloppy or bitter. It should therefore be cooled at once when drawn
from the churn; if kept in ice water it may remain in fine flavor for
several days. Well taken care of it is not only a pleasing and
refreshing drink but eminently healthful. In cooking, too, it can be
used to advantage.
=Commercial Buttermilk= or =Cultured Milk= is simply carefully soured
milk. It can be made at home from fresh milk either whole or skimmed or
partly skimmed. Partially skimmed milk containing from 1% to 2%
butter-fat is plenty rich enough and even better for most purposes than
whole milk. The essential qualities of good buttermilk depend upon the
proper ripening of the cream or milk, the development of a pure “breed”
of healthful bacteria in a clean field free from weeds. Such a
plantation or “culture” may be grown in milk as well as in cream. Its
function is to turn the sugar of milk into lactic acid under the
development of pleasing flavors and whether the butter-fat is removed by
the separator or by churning makes little difference. In natural
buttermilk there is always a little butter-fat—at least ½%—left, mostly
in the form of fine granules, too small to be retained in the butter. If
the same amount of butter-fat is left in skim milk and that is ripened
and churned, the product will be identically the same as natural
buttermilk from ripened cream.
=Ripening.=—For best result the milk should be pasteurized, not
necessarily as thoroughly as for starters, but sufficiently so as to
destroy all obnoxious bacteria and give those introduced through a pure
culture starter a chance to grow. Buttermilk may, however, also be made
from good, clean, unpasteurized milk of good flavor. Whether pasteurized
or not the milk is set to ripen with from 5 to 10% starter at a
temperature of from 65 to 75°. The preparation of starters is described
under “Bacteria” and the ripening of the milk for “buttermilk” is
essentially the same process (see also under _Ripening_ of cream for
butter). When ripened to the desired acidity,—say .5% to .6% by the acid
test,—stop further fermentation by thorough cooling.
=Breaking up the Curd.=—After cooling, the ripened milk may be broken up
fine and if vigorously shaken or “churned” it will remain smooth and
creamy. Otherwise it may separate into curd and whey. If churned long
enough for the butter to form, it becomes absolutely identical with real
buttermilk. But, for all practical purposes, a vigorous shaking for a
few minutes is enough.
=Thick Milk.=—“Thick Milk” as eaten in Scandinavia is made in the same
way as commercial buttermilk, except that the milk—rich whole milk—is
set to ripen in the bowl in which it is to be served. Instead of being
churned or stirred, it is left thick, to be served as a pudding, like
Junket made from sweet milk. The rich layer of cream that forms on top
is excellent. “Thick Milk” is eaten plain with the oatmeal for
breakfast, or as a dessert with grated stale bread and sugar spread over
it.
The uses of buttermilk in making pancakes and for many other culinary
purposes are mentioned in the chapter on “Milk Cookery.”
[Illustration:
Dr. Elie Metchnikoff, author of “The Prolongation of Life”
]
=Yoghourt= or =Bulgarian Sour Milk= is prepared with a culture of
bacteria originally found in Bulgaria where Metchnikoff, the late
director of the Pasteur Institute of Paris, found people living to
exceptional old age which he ascribed to the fact that their principal
diet is sour milk of very high acidity.
The theory is that a luxurious growth of lactic acid bacilli, acting as
a germicide, destroys other fermentations in the lower intestines. The
bacilli active in Yoghourt require a somewhat higher temperature for
their best growth than the lactic acid bacilli predominant in sour cream
for the finest butter, a fact which must be taken into consideration in
preparing the various products.
FERMENTED MILK
In the preparation of Koumis, Kefir and other fermented milks of the
same class, Yeast plays an important part, changing some of the
milk-sugar into the alcohol which is found in these preparations in
quantities up to 2%.
[Illustration:
Baba Vasilka, 126 years old and her son, Tudor, 101;
Bulgarian peasants whose principal food has been sour milk all their
lives
]
=Koumis= was first made from mare’s milk by the Tartars, but is now
prepared in this country from cow’s milk by the addition of sugar and
yeast. As carbonic acid is developed in the process it is quite
effervescent and may be regarded both as a food and a stimulant. It is
sometimes prescribed by physicians in cases when the patient cannot
retain other food.
=Kefir= is a similar preparation originally made in the Caucasus by a
fermentation started by Kefir grains which contain both yeast and
various bacteria. The dry Kefir grains are soaked, first in lukewarm
water, later in lukewarm milk, for several days, until they develop so
much gas as to float on the top. A couple of tablespoonfuls of the
grains are then added to a quart of milk which is left to ferment at 70°
F. under frequent stirring or shaking. When the fermentation is fully
developed the grains are strained off and the milk is bottled and kept
for 1 to 2 days at 60°. The grains may be used at once again in fresh
milk, and when the manufacture is finished they may be dried and kept,
to be used again another time.
[Illustration:
Kefir grains of natural size; a, b and c dried; d, e and f soaked
(Orla Jensen, Milk Bacteriology)
]
------------------------------------------------------------------------
CHAPTER III
CHEESE
[Illustration:
Students making cheese in the University cheese factory, Madison, Wis.
]
Most of the following pages on _Cheese_ were published in 1918 as a
separate pamphlet to meet an urgent demand for brief directions along
this line during the Food Conservation campaign. The copy has, however,
been revised and new material has been added with the view of making
this chapter more useful to those who desire to study in detail the
manufacture of various fancy foreign types of cheese such as Edam,
Swiss, Brick, Roquefort, etc., which are now made in this country in
constantly increasing quantities.
For more complete directions in cheese making students are referred to
“A B C in Cheese Making” by J. H. Monrad, and other technical works.
Cheese of a thousand different kinds is made, varying in properties and
appearance from the solid, yet mellow and agreeable Cheddar cheese to
the semi-soft, malodorous Limburger, the delicious, soft Neufchatel and
Cream cheese, or the sweet Myseost of Norway. In India cheese was made
centuries ago; to-day it is produced the world over, in the caves of the
Swiss Alps and in the most modern and scientific American cheese
factories and laboratories. Of these myriad types we can here describe
only a few.
Cheese may be classified into that made with rennet and that made
without. Of cheese made with rennet some is what is called hard, some
soft.
The English and American _Cheddar_—the common _American cheese_—the
_Dutch Gouda_ and _Edam_, the Swiss _Gruyere_, and the Italian
_Parmesan_ are all hard cheese made with rennet. As examples of the soft
varieties may be mentioned the French _Camembert_ and _Brie_, _Cream_
and _Neufchatel_ cheese. In a class by themselves are such cheeses as
the French _Roquefort_, the English _Stilton_, and the Italian
_Gorgonzola_, their peculiar flavors being derived from molds implanted
in the curd.
[Illustration]
When cheese is made without rennet, the milk is allowed to curdle by
natural acidity or it is in some other way made acid. Among the
varieties made by this method the common _Cottage_ cheese is the best
known.
For many years imitations of foreign varieties such as Swiss and
Limburger have been made in Northern New York and Wisconsin. As a result
of the war and the cutting off of foreign cheese imports, the State of
Wisconsin has built up a large business in these fancy varieties. New
types have lately been added, as the _Romano_, _Riggiano_, and
_Myzethra_, which are of Italian and Greek origin. Some of these are
made of whole milk, some of partly-skimmed milk, and others of the
albumin of the whey.
Let us briefly review the characteristic features in the making of the
older types.
CHEDDAR CHEESE
For a hundred years or more this famous cheese has been made and
marketed at the village of Cheddar near Bristol, England.
In the middle of the nineteenth century a farmer in that neighborhood,
Joseph Harding of Marksbury Vale, systematized the manufacture and it
was his method that became the model for cheesemaking in America. In
this country it was first made in Herkimer County, N.Y., where Harry
Burrell not only made cheese for the home market, but also exported to
England, and his son, David H. Burrell, at Little Falls later developed
the machinery which became the standard for the American and Canadian
cheese factories.
The factory system by which cheese was made from milk brought together
from several farms, originated near Rome, N.Y., and soon cheesemaking
became an important industry throughout Central and Northern New York
whence it spread into Pennsylvania, Ohio and the West, as well as to
Canada. To-day Wisconsin makes more cheese than all the other states
together and Canada largely supplies England with Cheddar cheese of
excellent quality.
[Illustration:
Joseph Harding, who systematized the making of Cheddar cheese in
England
]
[Illustration:
David H. Burrell,
who introduced laborsaving machinery and supplies in the cheese
factories
]
[Illustration:
Jesse Williams, father of the American factory system
]
_The Factory System_
The milk is delivered in the morning by the farmers at the factory and
is weighed and strained through cheese-cloth into the cheese vat. When
it is all in the vat it is warmed to a temperature of 86° F. by letting
steam into the water surrounding the bottom and sides of the jacketed
vat.
[Illustration:
A measuring glass and an accurate thermometer are indispensable
]
[Illustration:
The Marschall rennet test
]
=Ripening.=—The milk should be slightly acid, not noticeably sour, yet
sufficiently ripened for the proper fermentation to take place in the
process that follows. The best cheesemakers regulate the ripening by
adding a starter to the sweet milk and allowing the lactic acid bacteria
to multiply in the milk until a _Rennet Test_[6] or _Acid Test_[7] shows
that the desired degree of acidity has been reached. The starter may be
sour whey or preferably prepared from sweet skim milk or whole milk with
a commercial lactic acid culture as described in Chapter I under
_Ferments_ and _Buttermilk_. From 1% to 2% starter is usually
sufficient. An acidity of .18% to .20% or 2½ degrees on the Rennet Test
is usually desired before the rennet is added.
[Illustration:
Christian D. A. Hansen, inventor of commercial rennet extract
]
[Illustration:
Blowing up the rennets to dry them
]
=Adding Color and Rennet.=[8]—If the cheese is to be colored, from 1 to
2 ounces of liquid cheese color (Annatto dissolved in an alkali) per
1,000 lbs. of milk is now added and thoroughly mixed into the milk which
is then set with rennet. Three ounces of a standard rennet extract to
1,000 lbs. of milk is usually sufficient. Enough should be used so that
the milk will show beginning coagulation in 10 to 15 minutes and be
ready to cut in 30 to 40 minutes.
The extract should be diluted with ten times as much water and is then
poured into the milk under vigorous stirring so as to be thoroughly
distributed and incorporated in the whole mass.
Owing to the scarcity of the raw material for rennet extract during the
war, pepsin extracted from hogs’ stomachs has been substituted in many
factories and is used either in dry form or as a liquid extract instead
of rennet extract.
With pepsin as the coagulant it is necessary to ripen the milk somewhat
further than if rennet is used, in fact to the danger-point where a
little more acidity is apt to do harm and produce a dry and crumbly
cheese and loss of butter-fat in the whey. Most cheesemakers therefore
prefer rennet when they can get it.
The rennet having been added, the milk is left undisturbed until a firm
curd has been formed. When the curd breaks or splits sharply before the
finger pushed slowly through it, it is ready to be “cut.”
[Illustration:
Curd knives
]
=Cutting.=—Two sets of curd knives are used, each consisting of a metal
frame in which tinned steel blades are hung, in one vertically and in
the other horizontally. The vertical knife is first carried slowly
through the curd lengthwise and crosswise; the horizontal set of blades
is then moved carefully through the length of the vat. When the cutting
is over, the entire mass should be in cubes about half an inch square.
The whey that begins to separate out should be clear and yellow. Milky
whey is a sign that the butter-fat is escaping in it; the curd has been
broken up too violently. In curdling, the casein encases the butter-fat
and the object of the breaking up of the curd in the vat is to expel the
whey but retain the fat in the cheese.
=“Cooking” the Curd.=—Gentle heat is now applied to raise the
temperature gradually to 98° or 100° in the course of about 30 minutes.
Meanwhile the small pieces of curd are kept floating in the whey by
gentle stirring with a rake and the hands, and are not allowed to pack
at the bottom of the vat. The heating is easily regulated by opening the
steam valve little by little. Through the “cooking” the pieces of curd
shrink to some extent and are hardened so that they will gradually stand
livelier stirring without losing butter-fat. After the cooking the curd
is left for an hour or so in the whey for a slight acidity to develop
and it is then shoved toward the sides of the vat and the whey is
drained off. Here again the “Acid Test” may assist in determining when
the whey should be drawn.
[Illustration:
Cutting the curd
]
=Cheddaring or Matting.=—After thorough draining, the curd is packed
together in the bottom of the vat or on a “sink” provided with a false
bottom covered with cheese-cloth. After fermenting for 10 or 15 minutes
it is cut into large pieces which are again packed together for further
matting. The exact condition to be attained can be determined only by
experience.
[Illustration:
“Cheddaring” or “Matting” the curd
]
A simple test, the “Hot Iron Test,” may, however, help the cheesemaker
to judge of this point. A handful of curd squeezed together and touched
to a hot steam pipe or an iron rod heated almost red-hot in the fire
under the boiler, and slowly withdrawn, will leave threads sticking to
the iron. Depending upon the maturity of the curd, the threads will
break at a length of from ½ to 2 inches. Usually fermentation is
considered sufficient when threads 1½ inches long are formed by this
test.
[Illustration:
Curd mill
]
=Salting.=—The matting is then interrupted by breaking up and salting
the curd. This can be done by hand or by a curd-mill which cuts or
breaks up the curd and permits a thorough mixing in of the salt. Two or
three pounds of salt to one hundred pounds of curd, or the curd from
1,000 lbs. of milk, is the usual ratio.
=Pressing.=—Stirring and cooling the salted curd to about 80° F. makes
it ready for packing into the hoops in which it is to be pressed. The
hoop is usually a cylinder of heavy tin with a “follower” of wood on
which the pressure is applied. Before the curd is put in, the hoop is
lined with cheese-cloth which remains on the cheese, when it is taken
out. The press mostly used in the factory is the continuous pressure
“gang-press” in which a number of cheeses can be pressed at the same
time.
=Curing.=—After 18 hours’ pressure the cheese is taken out of the press
and out of the hoop, weighed and placed on a shelf or table in the
curing room. For the first week or ten days it is kept at a temperature
of about 70°, later the cheese is removed to a cooler room and possibly
placed in cold storage. Usually it is paraffined to prevent too much
drying and cracking of the rind.
[Illustration:
Filling the curd into the hoops
]
To cure a first-class Cheddar cheese takes from three to six months, but
most of the American cheese is made to cure much more quickly and is
eaten two to four months old. Indeed, it is generally shipped from the
factory eight to ten days old and whatever further curing it gets is in
the warehouse of the commissionman or in the grocery store.
[Illustration:
The Gang press
]
=Form, Size and Packing.=—The old style American cheese is cylindrical,
about 14 inches in diameter, and varying in depth to weigh between 60
and 80 pounds. Various other forms are now often made, square and long
or in fancy shapes, such as a ball or a pineapple. Aside from such
freaks, which have never become very popular, other deviations from the
large, standard, American Cheddar, are also made to a considerable
extent. People who have visited the beautiful National Dairy Shows held
in turn in Chicago, Springfield, Mass., and Columbus, O., the National
Milk and Dairy Farm Expositions of New York City, the Ontario Provincial
Fair held each year at Toronto, or the annual State Fairs in New York,
Wisconsin, Michigan and other cheesemaking sections will have in mind
first the prominent exhibits of the regular Cheddar, showing a
uniformity in texture, form and taste that is really remarkable. But one
will also admire the variety of other forms. There are the _Flats_ or
_Twins_, packed two in a box and weighing together the same as one
_American_; the _Young Americas_ packed four in a box; the _Longhorns_
of six to eight inches in diameter; others made like a loaf of bread and
creased so that a pound or two may be cut off fairly accurately, etc.
[Illustration:
Taking the cheese out of the press
]
The _Giant Cheeses_, weighing five to six tons, occasionally exhibited
and cut up at World Fairs and on similar occasions are, like the
pineapple cheese, a curiosity rather than an industrial product.
One of the best forms, in the writer’s opinion, is the small 5-lb.
cheese, proportioned exactly like the large American. This makes a
suitable size for an average family, the members of which have learned
to appreciate a good cheese. If it is made smaller, too much is lost in
the rind; if larger it gets too old before it can be consumed by one
family.
[Illustration:
Curing room
]
The larger cheeses are usually packed in neat, snug-fitting elm-wood
boxes, with thin “Scale Boards” on the top and bottom of the cheese, the
smaller ones in paraffined pressed pulp or pasteboard boxes.
=Cleaning the Vats and Utensils.=—Like every other place where milk and
its products are handled, the cheese factory must be kept scrupulously
clean. Vats and utensils should be rinsed first with cold or lukewarm
water or whey, then scrubbed with boiling hot water and if necessary
with soda, soap, or washing powder. The surroundings should be kept neat
and attractive, and the cheesemaker must see that the transportation
cans are kept clean by the farmers and the milk delivered in good
condition.
[Illustration:
Cheese box
]
=Yield.=—The yield is around 10% of the milk. To make a pound of fresh
cheese takes from nine to eleven pounds of milk. In curing, a part of
the weight is lost by evaporation, but this loss is reduced to a minimum
by paraffining.
In some localities an increased yield is obtained by washing the curd
and making it absorb all the water it can hold. The process is not
commendable and while it may sell to some extent, in certain markets
where a soft, fresh cheese is liked, “washed” or “soaked” curd cheese
can never compare favorably in quality with a well-made, firm Cheddar
cheese that is mellowed down by long-time curing to a consistency so it
will fairly melt in your mouth.
=Composition.=—The American cheese contains almost all the casein and
the butter-fat of the milk, besides such portions of the milk-albumin,
milk-sugar, and mineral matter as are held in the water or whey which is
retained in the cheese. In round figures average American cheese
contains equal parts of casein, butter-fat and water, 30 to 35% of each.
In order to protect the honest maker and the consumer and prevent
“soaking” of the curd to an extent that may be considered fraudulent,
the dairy laws of the State of New York limit the contents of water
permissible to 40% and 42% respectively for certain classes of cheese.
=Qualities.=—A good Cheddar cheese should be mellow, yet solid, without
holes, and of an agreeable taste, neither sharp nor bitter. Cheese can
be made of skim milk, but it is hardly palatable. In the fall of the
year, when the average milk is rich in butter-fat, 1% or 2% butter-fat
may be taken from the milk and the resulting partly-skimmed milk will
still make a fairly good cheese, hardly distinguishable from full cream
cheese. Under the laws of the State of New York it must, however, be
marked “Skim Milk Cheese.”
Cheese Made from Pasteurized Milk
From time to time attempts have been made to make Cheddar cheese from
pasteurized milk. If the milk is heated to 145° only, and held for 30
minutes at such temperature, its property to form a firm curd with
rennet is not destroyed and it will make a fine cheese, but if it is
pasteurized at a higher temperature it will not curdle firmly until it
is ripened or otherwise brought back to the condition required for
satisfactory action of the rennet ferment. Thorough ripening with a pure
culture starter will do it, or an addition of muriatic acid will
accomplish the same in a shorter time, but care must be taken not to use
too much, which would make the cheese dry and crumbly. Dr. J. L. Sammis
and A. T. Bruhn of the Wisconsin Dairy School worked out the problem and
systematized a process which is described in Bulletin 165 of the U. S.
Department of Agriculture and by which it is claimed a first-class
cheese can be made regularly from thoroughly pasteurized milk.
Making Cheddar Cheese on the Farm
[Illustration:
American outfit for farm cheese making
]
[Illustration:
Plain wooden vat and curd mill
]
It takes quite a little experience to make a good Cheddar cheese and,
unless one has the time and opportunity to study it and make it an
every-day practice, it is not as a rule advisable to attempt making
Cheddar cheese in the home from the milk of one or a few cows.
The amateur will usually find it easier to make Neufchatel or Cream or
Cottage cheese for home use or for the home market.
[Illustration:
Danish kettle and cheese vat
]
If Cheddar cheese is to be made regularly it is best to get an outfit
consisting of a small boiler and a jacketed vat, although cheese may be
made in a plain wooden tub or any other convenient vessel. The double
bottomed vat generally used in American as well as in Danish dairies
facilitates both the heating of the milk before setting and the
“cooking” of the curd in the whey after cutting. Either low pressure
steam, or—better—water heated by steam, is introduced in the space
between the outer, wooden bottom and the inner, tinned steel or copper
bottom. If it is cool the milk should be warmed to 86° F. In the summer
it may be warm enough as it comes in, fresh from the cow. If not, heat
it by steam or by setting it in a “shot-gun” can in another vessel of
hot water, stirring frequently, until the thermometer shows 86°. It may
be well to add a little buttermilk or sour whey from the preceding day,
or a pure culture starter made with Buttermilk Tablets, not to exceed 1%
or 2%.
[Illustration:
Cutting the curd
]
If it is desired to make colored cheese add a teaspoonful of liquid
cheese color, or ½ cheese color tablet dissolved in warm water, to 100
pounds of milk, more or less according to season and the shade of color
desired in the cheese.
Next add the rennet. Where cheese is made from less than 500 lbs. of
milk Rennet Tablets are handy, one tablet to 80 or 100 lbs. For less
than 50 lbs. of milk, Junket Tablets may be used, one to a gallon.
Dissolve the tablet, or tablets, or fraction of a tablet, as the case
may be, in _cold_ water and stir the solution well into the milk, making
sure of thorough mixing. Let stand covered for half an hour until a firm
curd is formed. Cut or break the curd very carefully with a big knife or
spoon or home-made fork with wires across the prongs, imitating as far
as possible the operation with curd knives in the factory.
[Illustration:
Taking the temperature of the milk in a shot-gun can
]
[Illustration:
Curd fork
]
[Illustration:
Mold or “Hoop”
]
“Cook” the curd as in factory cheesemaking. If steam is not available,
allow the curd to settle and dip off some of the whey which is then
heated and poured back on the curd so as to raise the temperature of the
whole mass about 2 degrees. Repeat this several times, gradually raising
the temperature to 100°, a few degrees at a time.
Keep the curd gently stirred up and floating in the whey and do not
allow it to lie on the bottom of the vat long enough to pack firmly
together, stirring once in a while until by smell and taste (if not also
by acid or hot iron tests) it appears to be sufficiently fermented for
the whey to be drawn, a condition that can only be learned by
experience. This will be about two or three hours from the time the
rennet is added.
[Illustration:
Diagram of lever press
]
[Illustration:
Combined screw and lever press
]
Draw the whey and press more out of the curd with the hands. Let the
curd mat and break it up alternately several times; finally crumble and
pulverize it and keep it stirred with the hands, adding salt at the rate
of three to four ounces to the curd from 100 lbs. of milk and continuing
the stirring until the curd is cooled down to below 80°, when it should
be packed into the hoop and put to press. This salting and cooling may
take another hour. The hoop may be made of wood or heavy tin of any size
desired, with a loose follower of wood. The sides and bottom should be
perforated to allow the whey to escape. Or it may be a cylinder without
top or bottom, placed on a corrugated piece of board. Line the hoop with
cheese-cloth before putting in the curd.
[Illustration:
Upright factory and dairy cheese press
]
For pressing, a home-made lever-press, as outlined in the diagram, may
be made of a plank or bar, one end of which (_C_), is stuck under a
piece of a board nailed on the wall while at the other end a weight
(_K_) is applied which may be moved in and out to regulate the pressure.
The hoop is placed under the plank at the fulcrum (_K__{1}) near the
wall. If a compound lever-press or a screw-press is available it is
better. It is important that the pressure is applied straight so as to
make the cheese even and not one side lower than the other. Begin with
light pressure and increase it gradually every hour until at night the
full pressure is applied. After an hour take the cheese out and turn it
in the hoop, then return it to the press and at night apply full
pressure. The next morning take it out and weigh it and place it on the
shelf to cure in a room of moderate temperature, turning it every day.
After a couple of weeks it may be removed to a cool cellar and rubbed
with grease. In two to three months it should be sufficiently matured
for consumption.
OTHER TYPES OF HARD CHEESE MADE WITH RENNET
[Illustration:
A variety of domestic and foreign cheese made at the dairy school of
the University of Wisconsin
]
In the manufacture of the Dutch Gouda, the Danish Export, and other
similar types, the “cooking” and matting of the curd, characteristic of
the English and American Cheddar, are more or less omitted. Otherwise
the process and the result are not greatly different. They are all
“hard” or solid cheese of the same class, though there are hundreds of
varieties in different localities, each with some peculiarity of its
own.
[Illustration:
Gouda cheese
]
=Gouda Cheese.=—The _Gouda_, like the _Danish Export_ cheese, is made
from whole or partly-skimmed milk which is set with rennet at 90° F. and
is coagulated, ready for cutting, in fifteen to twenty minutes. The curd
is broken with the “lyre,” so called, a frame on which piano wires are
suspended. The curd is but slightly “cooked” and the whey is drawn while
still sweet. After being pressed with the hands in the vat to squeeze
out the whey the curd, still quite warm, is put into wooden molds and
worked and squeezed in them with the hands for half an hour to eliminate
more whey, when the mold is placed in a regular press for 12 to 18
hours. To salt it the cheese is placed in a strong brine where it
remains for several days. It is then put on the shelf in the curing room
where it is turned and rubbed daily and in four to six weeks it is
marketed. The cheese is about 10 inches in diameter by 4 to 5 inches
high.
[Illustration:
The Lyre
]