A Treatise on Baking

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Milk

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Chapter IX

MILK

MILK

I. FOREWORD

Milk is one of our oldest and best known natural foods.

Milk not only adds considerable nutritive value to the bakery products but definitely enhances their flavor, appearance and keeping qualities.

The single word “milk” unqualified, is generally understood to refer to liquid whole milk as secured from the cow.

However, in order to prolong its keeping qualities and to facilitate handling and shipping, milk is now available not only in its original liquid state, but also in various concentrated forms such as evaporated, sweetened condensed and dried milk, either whole, skimmed or partially skimmed. The fact thaJt excellent milk can be secured in these different forms is due to the conscientious research work and improved manufacturing methods developed by the dairy industry and undoubtedly is one reason for the increased use of milk by the modern progressive baker.

Any of these forms of milk can be used to advantage in bakery prod-ucts provided they are handled in the proper manner.

In view of the important part which milk plays in bakery products, it is essential to understand in a general way, the characteristics of each form of milk available so as to secure the best possible results.

II. FEDERAL DEFINITIONS AND STANDARDS FOR MILKS

The definitions and standards for milk and its products as stated below are quoted from a bulletin published by the U. S. Department of Agriculture and dated July 3, 1926.

(a) Milk is the whole, fresh, clean, lacteal secretion obtained by the complete milking of one or more healthy cows, properly fed and kept, excluding that obtained within 15 days before and 5 days after calving, or such longer period as may be necessary to render the milk practically colostrum-free.

(b) Skimmed Milk is milk from which substantially all of the milk fat has been removed.

(c) Buttermilk is the product that remains when fat is removed from milk or cream, sweet or sour, in the process of churning. It contains not less than eight and five-tenths percent (8.5%) of milk solids not fat.

(d) Evaporated Milk is the product resulting from the evaporation of a considerable portion of the water from milk, or from milk with adjustment, if necessary, of the ratio of fat to non-fat solids by the addition or by the abstraction of cream. It contains not less than seven and eight-tenths per cent (7.8%) of the milk fat, nor less than twenty-five and five-tenths per cent (25.5%) of total milk solids; provided, however, that the sum of the percentages of milk fat and total milk solids be not less than thirty-three and seven-tenths (33.7).

(e) Sweetened Condensed Milk is the product resulting from the evaporation of a considerable portion of the water from the whole, fresh, clean, lacteal secretion obtained by the complete milking of one or more healthy cows, properly fed and kept excluding that obtained within fifteen days before and ten days after calving, to which sugar (sucrose) has been added. It contains not less than twenty-eight per cent (28.0%) of total milk solids, and not less than eight per cent (8%) of milk fat.

(f) Evaporated Skimmed Milk is the product resulting from the evaporation of a considerable portion of the water from skimmed milk, and contains not less than twenty per cent (20.0 %) of milk solids.

(g) Sweetened Condensed Skimmed Milk is the product resulting from the evaporation of a considerable portion of the water from skimmed milk to which sugar (sucrose) has been added. It contains not less than twenty-four per cent (24.0%) of milk solids.

(h) Dried Milk is the product resulting from the removal of water from milk, and contains not less than twenty-six per cent (26.0%) of milk fat, and not more than five per cent (5.0%) moisture.

(i) Dried Skimmed Milk is the product resulting from the removal of water from skimmed milk, and contains not more than five per cent (5.0%) moisture.

III. COMPOSITION OF MILKS

A. GENERAL REMARKS

The composition of fresh liquid milk naturally varies quite widely, depending on the breed of cow, time of year, character of feed and completeness of milking. The federal definition of liquid whole milk therefore, does not include definitely fixed limits of composition. However, various states have their own legal standards and it is advisable for the purchaser of liquid milk to see that samples are analyzed occasionally, both from a chemical and bacteriological standpoint, in order to be sure that it conforms to the prevailing local standards.

For the other forms of milk defined above, such as evaporated, sweetened condensed and dried milks, certain minimum limits are specified concerning milk solids and milk fat.

Now while these other forms of milk are derived from fresh liquid milk which may vary in its composition, the manufacturers of the various concentrated forms of milk can regulate the extent to which the liquid milk is evaporated or dried as well as the amount of cane sugar which is added in the case of sweetened condensed milk.

In this way the manufacturers of dried, evaporated and condensed milk can control and standardize the percentages of water, milk fat and other milk solids in their final products sold to the trade. Of course, there are slight differences in the composition of various brands of these concentrated forms of milk depending on the method of manufacture employed. This information, however, can readily be secured from the manufacturers. __

Thus the purchaser is enabled to know that the milk product he is getting is at least up to the government standards. Claims that the milk is better than government standards should be required in writing or should be checked by chemical analysis.

B. TABLES SHOWING APPROXIMATE COMPOSITION OF VARIOUS FORMS OF MILK

1. Explanation

Inasmuch as the composition of liquid milk is not fixed and since the various brands of evaporated, sweetened, condensed and dried milks differ slightly one from another in composition, it is only possible in the diagrams which follow to show the approximate analysis of certain recognized good samples of these different forms of milk. While the particular samples shown in these tables all comply with the Government Standard requirements, it will be noticed that the composition of some of the samples indicate a higher content 01 milk solids than is actually required. These are so stated merely because many manufacturers put out milk products which are even better in milk solids than required to meet the specified U. S. Standards. The particular samples listed are merely chosen arbitrarily as examples so as to give the reader an idea of their relative composition. Furthermore, it will be noticed that the preceding tables show only forms of whole and completely skimmed milk. However, partially skimmed milks in both condensed and dried forms,—from which only a part of the normal milk fat has been removed,—are used quite extensively and to good advantage in bakery products today. Inasmuch as “milk fat” is the most costly part of the milk, the exact percentage of fat contained in any partially skimmed milk product should be clearly understood by the purchaser. The exact composition of such milks can be secured from the manufacturers.

APPROXIMATE COMPOSITION

TYPICAL SAMPLES OF WHOLE MILK PRODUCTS

APPROXIMATE COMPOSITION

TYPICAL SAMPLES OF SKIM MILK PRODUCTS

The subject of buttermilk is taken up at the end of this chapter.

C. DESCRIPTION OF THE VARIOUS CONSTITUENTS OF MILK

1.Division of Milk into Three Parts

In order to understand just what milk is made up of, it may be well to consider the composition of milk in three parts namely, “water,” “milk fat” and “solids not fat.”

Liquid whole milk is about seven-eighths water which acts as a carrier for the milk solids which are either dissolved or suspended in it.

2. Milk Solids

a. GENERAL EXPLANATION

If a sample of liquid whole milk were evaporated to dryness or in other words if all of the water were driven out of it, the remaining dry substance would be “milk solids.”

Because of the fact that milk fat is frequently separated from whole milk in the form of cream, leaving skim milk containing little or no fat,—milk solids are usually differentiated as “milk fat or butterfat” and “milk solids not fat.”

LIQUID WHOLE MILK

WHOLE MILK SOLIDS

Approximate Composition

Inasmuch as the solids of milk constitute the body or substance of milk, they represent the value of milk to the purchaser and therefore should be given primary consideration in the purchase of any form of milk. In view of the fact that the butter fat or cream is the most expensive part of milk many people are apt to underestimate the true value of the other milk solids which play an important part in the quality and nutritive properties of bakery products.

Both of the two classes of milk solids are worthy of serious attention to the user of milk, and therefore are explained separately:—

b. MILK FAT

Milk fat is often spoken of as butterfat. Cream as it occurs in fresh liquid milk is made up largely of extremely tiny droplets of milk fat. A drop of milk, the size of a pin-head is said to contain over a million of these tiny globules of milk fat. If milk is allowed to stand these tiny particles come to the top.

Cream can be separated from milk more or less crudely by skimming, —but in the modern dairy this is done by cream separators which are merely special forms of centrifugal machines or “whizzers” which cause a very efficient separation of the cream, leaving only about 1/10 % of fat in the skim milk.

If this cream is churned the fat droplets run together into a solid mass in the form of butter which is easily separated from the remaining fluid known as buttermilk.

Butter usually contains about 83% pure milk fat or butter fat, the remainder being mainly water together with a very small amount of other milk solids. Ordinary butter usually contains about 2% added salt.

c. MILK SOLIDS NOT FAT

LIQUID SKIM MILK

SKIM MILK SOLIDS

Approximate Composition

If the cream is removed from whole milk,—skim milk is left. If all the water is evaporated or driven off of this skim milk, the remaining dry substance is known as “milk solids not fat.”

These are frequently spoken of as skim milk solids and when combined with the milk-fat make up whole milk solids. “Milk solids not fat” are made up of protein, milk sugar or lactose and mineral matter or ash.

(1) Protein

If liquid skim milk is allowed to stand at room temperature, lactic acid bacteria develop and result in changing some of the milk sugar into lactic acid which causes the milk to sour. This souring of the milk causes it to separate into solid curds and liquid whey. The curd is made up of a very valuable milk protein known as “casein.” If the whey is boiled another white protein substance known as albumen will separate out. This albumen is very similar to egg white. About % of the protein of milk is casein and about % is albumen.

(2) Milk Sugar

The natural sugar of milk is known as lactose, and unlike other forms of sugar, it is very low in sweetening value and is not fermented by yeast. However, it is of value from a nutritional standpoint and imparts crust color to the loaf.

If the albumen were removed from the whey of milk as described above and the remaining liquid then boiled down to a thick syrup and allowed to cool, crystals of milk sugar would separate out.

(3) Mineral Matter

If all of the water is boiled off a sample of milk and the remaining solids then burned, the ash left would represent the mineral content of the milk. This consists of lime and phosphates together with other mineral constituents which are exceedingly important from a nutritive point of view.

IV. FACTORS INFLUENCING THE SELECTION AND VALUE OF MILK PRODUCTS FOR USE IN BAKERY PRODUCTS

In selecting and using any form of milk in bakery products, the following factors should be given primary consideration:—

1. The composition of milk, especially the solids contained.
2. The cost of milk on the basis of its butter fat,—milk solids not fat,—and any added sugar.
3. The uniformity of composition of the different lots of milk used.
4. The keeping qualities of the milk and storage conditions required.
5. The ease of handling the milk.
6. The readiness with which the form of milk used dissolves in water and mixes into the dough batch.
7. The increase in amount of water absorbed and retained by the dough due to the milk used.
8. The effect of the milk used on the quality of baked goods produced, i.e., taste, appearance and keeping qualities.
9. The effect of the milk used on the yield of baked goods secured. 10. The net cost of the milk used taking into consideration the original cost of -the milk and the increased yield of baked goods obtained.

V. EQUIVALENTS OF DIFFERENT FORMS OF MILK

A. THE MEANING OF MILK EQUIVALENTS

As explained previously, different forms of milk contain widely different percentages of milk solids and water. If it is desired to replace one form of milk by its equivalent in another form,—the quantity of the new form to be used should contain the same amount of milk solids as was contained in the form of milk previously used. Obviously the weight of the two forms of milk will be different but the actual weight of the milk solids contained in each should be the same.

For instance, 1 gallon of liquid milk weighs approximately 8^ lbs. and contains about the same amount of milk solids as 1 lb. of dried whole milk. Therefore, 8^ lbs. of liquid whole milk is approximately equivalent to 1 lb. of dried milk and 7*/2 lbs. of water.

B. NO ONE TABLE OF EQUIVALENTS WILL APPLY TO ALL BRANDS OF MILK

1. Difference in Composition of Various Brands of Milk Products Necessitates Special Factors

The composition of various brands of the same form of milk may vary within certain limits. In other words, two brands of sweetened condensed milk may have a slightly different percentage of milk solids. The same holds true with different brands of dried milk as well as evaporated and liquid milks,—although all may comply with the Federal Standards.

Therefore, it is impossible for any one table of conversion factors or “equivalents” to apply exactly to the various brands of the different forms of milk on the market. In each case, where one form of milk is to be replaced by another form,—the exact conversion factors or equivalents to be employed depends on the respective composition of the two particular forms of milk in question.

2. Table of Equivalents Should Be Secured From Manufacturers of Milk Products

In most cases, the manufacturers of the various forms of prepared milks on the market will supply the purchaser of milk with the necessary “conversion factors” or “equivalents” in the form of a chart or table together with the other necessary data showing just what quantity of their particular brand and form of milk will replace one pound of any other form of milk as well as instructions concerning any other changes to be made in the dough formula.

C. IF NO TABLE OF EQUIVALENTS IS AVAILABLE, SPECIAL CALCULATION IS NECESSARY

1. Method of Calculation Requires Knowledge of Composition of the Milk Products and Use of Decimals

In replacing one form of milk by another, the use of conversion factors or tables of equivalents supplied by the milk manufacturer will save some time and mental effort on the part of the baker by relieving him of the usual arithmetic and calculation necessary to determine the exact amount of one form of milk to be used in place of another form.

However, if such conversion factors are not at hand the baker can figure this out for himself. In order to calculate the amount of any one form of milk which should be used in order to replace a certain amount of any other form of milk and the corresponding adjustments which must be made in the dough formula when this is done,—it is first necessary to know the composition of the two forms of milk in question. Furthermore this calculation, involves the use of decimals and while the method of figuring this out is simple, it requires some thought and study in order to understand the same.

In view of the fact that some readers may be interested to know just how such calculations are made,—the system of figuring involved is explained at the end of this chapter under “XIV” together with examples illustrating the same and a table of equivalents based on the forms of milk having compositions shown under “III-B.”

D. APPROXIMATE MILK EQUIVALENTS FOR SAMPLES HAVING COMPOSITIONS SHOWN UNDER “III-B” OF THIS CHAPTER

For the benefit of those who do not wish to study the mathematical method of figuring out milk equivalents as explained later in this Chapter under “XIV” the following tables will show in a simple way, the approximate amounts of the various samples listed under III-B of this chapter which may be used to replace 1 lb. of any other particular sample:—

ONE POUND OF LIQUID WHOLE MILK
(Containing 2 oz. whole milk solids and 14 oz. water)

May be replaced by

ONE POUND EVAPORATED WHOLE MILK
(Containing 4 1/2 oz. whole milk solids and 11 1/2 oz. water)

May be replaced by

ONE POUND SWEETENED CONDENSED WHOLE MILK
(Containing 4 1/2 oz. whole milk solids, 6 1/2% oz. added cane sugar and 5 oz. water)

May be replaced by

ONE POUND DRIED WHOLE MILK
(Containing 15 3/4 ozs. whole milk solids and 1/4 oz. water)

May be replaced by

ONE POUND LIQUID SKIM MILK
(Containing1 1/2 ozs. skim milk solids and 14 1/2 ozs. water) May be replaced by

ONE POUND EVAPORATED SKIM MILK
(Containing 4 1/2 ozs. skim milk solids and 11 ½ ozs. water)

May be replaced by

ONE POUND OF SWEETENED CONDENSED SKIM MILK
(Containing 4 1/2 ozs. skim milk solids, 7 ozs. added cane sugar and 4 1/2 ozs. water)

May be replaced by

ONE POUND OF DRIED SKIM MILK
(Containing 15 1/2 ozs. skim milk solids and 1/2 oz. water)

May be replaced by

VI. GOVERNMENT STANDARD FOR MILK BREAD

A. GENERAL EXPLANATION

According to standards set by the U. S. government “Milk bread is the bread obtained by baking a wheat bread dough in which not less than one-third of the water ingredient has beeen replaced by milk or the constituents of milk solids in proportions normal for whole milk. It conforms to the moisture limitation for wheat bread.

From the above definition it is seen that in order to be labelled milk bread, the dough must contain whole milk solids equal in amount to those contained in at least enough whole milk to replace one-third of the “water ingredients.” In other words, if the normal amount of water used with 100 pounds of flour is 60 pounds, then at least 20 pounds of this will have to be replaced by whole milk or by a sufficient quantity of some other form of milk so that it will supply the same amount of milk solids as that contained in the 20 pounds of liquid whole milk. In using other forms of milk, however, the instructions listed under XIV of this chapter should be carefully observed.

B. SKIM MILK SUPPLEMENTED WITH SUFFICIENT BUTTER MAY BE USED

This milk requirement may be met by the use of proper amounts of whole milk, either liquid, evaporated, sweetened condensed or dried, or else by skim milk either evaporated, sweetened condensed or dried,—provided sufficient butter has been added to make up the necessary butter-fat needed to meet the specified requirements for whole milk.

VII. QUANTITIES OF DIFFERENT FORMS OF MILK TO MEET THE REQUIREMENT FOR MILK BREAD

As shown in the preceding paragraphs, the exact amount of milk needed to meet the government requirement depends on the normal amount of “water ingredients” in the dough.

Suppose, however, that we consider a typical case where 1 barrel (196 lbs.) of flour will take up 120 lbs. of water to form a dough of proper consistency for bread making. In such a case the requirements for milk bread would be complied with if any of the following quantities of the different forms of milk were used provided they had the composition stated in the diagrams shown under III-B of this chapter. The amount of butter shown below with the skim milk products is calculated on the basis of 80% butter fat.

40 lbs. raw liquid whole milk

or

37% lbs. liquid skim milk and 1 lb. 12 oz. butter

or

17 lbs. 4 oz. evaporated whole milk

or

17 lbs. 4 oz. sweetened condensed whole milk

or

12 lbs. 3 oz. sweetened condensed skim milk and 1 lb. 12 oz. butter

or

5 lbs. dried whole milk

or

3 lbs. 10 oz. dried skim milk and 1 lb 12 oz. butter.

The above stated amounts of the various forms of milk needed to meet the requirements of milk bread where the normal amount of water in the dough is 120 lbs.,—apply only for milks having the composition stated under III-B of this chapter. For milks of slightly different composition corresponding difference will have to be made. Furthermore, if a baker is aiming to make milk bread he should use a little more milk than the minimum called for. This is a safety measure and any extra milk over the minimum requirement will be reflected advantageously in the way of improved quality and increased yield.

VIII. “FULL MILK BREAD”

Full milk bread is generally considered to mean bread made from a dough in which all of the water used has been replaced by liquid whole milk or the constituents of milk solids in proportions normal for whole milk.

IX. USE OF SKIM MILKS IN BAKERY PRODUCTS

A. SKIM MILKS IN BREAD DOUGHS

While most everyone recognizes the value of whole milk, the majority of people are apt to underestimate the true value of skim milk as a food and as an “improver” for bread and other bakery products. In order to illustrate the true value of skim milk one authority on the use of milk in bakery products has very nicely compared milk to meat in the following manner:—

“Meat consists of a fat portion and a lean portion, both of them valuable food,—but of these two, the lean meat is the more valuable as human food than the fat. In the same way, milk consists of a fat portion and a lean portion (namely, skim milk). Of these two, the lean portion, that is the skim milk, has really the greater nutritive and other value, though its cost is actually less. Lean meat is that part which contains the protein, salts, etc. Skim milk, in a similar way, is that part of the milk which contains the protein and salts so that it is a fair comparison to refer to skim milk as the “lean meat of milk.”

Of course, butter is an excellent food possessing an exceptionally fine flavor, and whole milk carrying its normal proportion of butter fat is unexcelled for use in bakery products. However, butter fat is very expensive, and the cost involved, in many cases, limits the amount which is used for bread making.

Therefore, in order to secure the improved loaf characteristics afforded by the other milk constituents, various forms of skim milk are being used in increasing amounts by progressive bakers.

B. SKIM MILK SUPPLEMENTED WITH BUTTER TO MEET THE REQUIREMENTS OF WHOLE MILK

In the event that only some form of skim milk is on hand but it is desired to use whole milk,—the equivalent of whole milk can be secured by adding one pound of butter to every two pounds of skim milk solids contained.

C. PARTIALLY SKIM MILK

Partially skim milk, especially in its condensed and dried forms is excellent for use in bakery products. These forms of milk are produced from raw liquid milk from which only part of the cream has been removed. In some instances, one-half of the normal butter-fat content is retained in the partially skimmed product. The use of sufficient such partially skim milk to meet the butter fat requirement for milk bread is a very satisfactory way of producing a high quality milk loaf and at the same time, the many advantages resulting from the larger amount of skim milk solids,—will be secured.

X. ADJUSTMENTS TO BE MADE WHEN MILK IS ADDED TO FORMULAS PREVIOUSLY CONTAINING NO MILK

A previous section of this chapter has shown how to calculate the amount of any form of milk required to replace an equivalent amount of any other form of milk. In such calculation, it was made clear that the butter fat, milk solids not fat, and water in each case should be kept the same. However, in adding milk to a non-milk formula we have a different situation requiring a different system of calculation.

A. WATER ADJUSTMENT EXPLAINED

When milk is added to a non-milk dough, an adjustment in the amount of water called for in the formula will have to be made from two standpoints :

1. Water Content of the Milk

When either liquid, evaporated or condensed milk is employed the amount of water contained in the milk used will have to be taken into consideration. However, in the ordinary forms of dried milk, the water contained is nearly negligible.

2. Increased Absorption Due to Milk Solids

Milk solids are “essentially thirsty,”—or in other words the introduction of milk solids into the dough will enable it to hold or carry additional water. Experiments have shown that for each pound of milk solids,—1 lb. of extra water can be carried by the dough. When over 5 lbs. of milk solids for 100 lbs. of flour are used, this figure is slightly lower.

B. EXAMPLES SHOWING HOW THE WATER ADJUSTMENT IS CALCULATED

If a regular non-milk bread formula calls for 100 lbs. of flour and 60 lbs. of water and we wish to replace 1/3 of the water with milk, how much of the various forms would be required and how much water would be used:— (For convenience, the composition of the forms of milk used in the following examples are those shown under “III-B” of this chapter.)

1. Liquid Milk

Required amount liquid milk 20 lbs.

Total water in dough batch would then be:—

62.4 lbs.		40.0	lbs. normal amount not replaced by milk
		17.6	lbs. introduced by 20 lbs. milk
		2.4	lbs. to make up the normal absorption deficiency
		2.4	lbs to take care of 2.4 milk solids at the rate of 1 lb. of added water for each lb. of milk solids.

Answer:— Use:— liquid whole milk 20 lbs., and 44.8 lbs. water in dough.

2. Dried Whole Milk

Suppose the Composition to be		2½%	water
		97½%	solids

Required amount of milk solids to be equivalent to 20 lbs. liquid milk = 2.4.

Amount of dried whole milk required to supply 2.4 lbs. solids would be 2.4 ÷ 0.975 or 2.5 lbs.

Answer:— Use: 2.5 lbs. Dried whole milk and 62.4 lbs. water.

3. Evaporated Milk

Suppose the Composition to be		72%	water
		28%	milk solids

Required milk solids to equal 20 lbs. liquid milk = 2.4 lbs.

Amount of evaporated milk to supply 2.4 lbs. solids would be 2.4 ÷ 0.28 or 8.57 lbs.

Now 8.57 lbs. evaporated milk would carry 72% water or 6.17 lbs.

Total water in dough batch would then be:—

62.4 lbs.		40.00	lbs. normal amount not replaced by milk
		6.17	lbs. introduced by 8.57 lbs. evap. milk
		13.83	lbs. to make up normal absorption deficiency
		2.4	lbs to take care of 2.4 milk solids

Answer:—Use 8.6 lbs. Evap. Whole Milk and 56.2 lbs. Water.

4. Sweetened Condensed Milk

Suppose the Composition to be		31%	Water
		28%	Milk Solids
		41%	Cane Sugar

Required milk solids to equal 20 lbs. liquid milk = 2.4 lbs.

Amount of condensed milk to supply 2.4 lbs. solids would be 2.4 ÷ 0.28 or 8.57 lbs.

Now 8.57 lbs. condensed milk carries 31% water or 2.66 lbs.

Total water in dough batch would then be:—

62.4 lbs.		40.00	lbs. normal amount not replaced by milk
		2.66	lbs. introduced by 8.57 lbs. condensed milk
		17.34	lbs. to make up normal absorption deficiency
		2.4	lbs to take care of 2.4 milk solids

Answer:—Use 8.6 lbs. Sweetened Condensed Whole Milk and 59.7 lbs. water.

C. SHORTENING ADJUSTMENT

This applies only where an appreciable quantity of some form of whole milk or partially skim milk is used. The normal fat content of such forms of milk enables the baker to make a corresponding- reduction in the amount of shortening used in this dough formula.

D. SUGAR ADJUSTMENT

This adjustment only applies where sweetened condensed milk is used. In such cases, it must be remembered that most brands of sweetened condensed milk contain about 40% of added cane sugar, and the normal amount of sugar in the dough should be reduced according to that carried by the condensed milk. In estimating the cost of sweetened condensed milk, this is a factor to be considered.

XI. GENERAL INFORMATION REGARDING VARIOUS FORMS OF MILK AVAILABLE

The definition and composition of various forms of milk as well as the calculations and adjustments required in regard to their use in the dough batch have been explained previously in this chapter. It may be well to repeat here that no matter what form of milk is purchased by the baker it should be of high quality. While the more concentrated forms of milk will keep better than liquid milk it should be remembered that all forms of milk are perishable and should be purchased as frequently as practically possible. Unless the forms of milk used are of high quality and

stored under proper conditions they can not be expected to produce satisfactory results. For instance without proper storage liquid and evaporated milk will become sour, sweetened condensed milk may deteriorate, and dried milk may cake or become insoluble.

The following paragraphs contain general comments of interest to the baker concerning each form of milk, including advice concerning the proper storage and handling of the same.

A. LIQUID MILK

1. General Explanation and Remarks

Some bakers still prefer to use liquid milk in its original form. However, inasmuch as this form of milk is bulky to handle and transport, and requires constant refrigeration, it has been largely replaced in the bakery by the more concentrated forms of milk which are easier to store and ship and which are more uniform in composition. Very satisfactory results can be secured from the use of raw liquid milk provided only that it is secured fresh from a neighborhood dairy which is operated under sanitary scientific conditions. Inasmuch as it is rather difficult to secure liquid milk having the same composition, the purchaser should occasionally check up on its percentage of butter fat and milk solids as well as its bacterial content. Raw liquid milk contains certain organisms which bring about the production of lactic acid. Now lactic acid in the dough batch hastens fermentation and conditioning of the dough and is beneficial only when supplied in definitely small regulated amounts such as that carried by certain types of malt extract. However, it is practically impossible to control the amount of acidity developed in milk on standing and therefore difficult to control its effect on the dough batch. Hence, in order to make uniform bread with liquid milk it is essential that the milk possess the same degree of sweetness each day.

In order to make this possible, liquid milk should be used as promptly as possible and always kept in clean cans carefully refrigerated. A baker using liquid milk should taste each batch before using to be sure it has not soured.

One gallon of liquid milk weighs about 8 1/2 pounds and is about 88% water. Liquid milk should be thoroughly stirred directly before use to insure a uniform distribution of the cream.

2. Pasteurized Milk

The pasteurization of milk aids in maintaining it in a fresh sweet condition.

Pasteurized milk is defined as “milk that has been subjected to a temperature not lower than 145 degrees Fahrenheit for not less than thirty minutes, after which it is promptly cooled to 50 degrees Fahrenheit, or lower.”

The main purpose of pasteurizing milk is to kill any harmful bacteria present and also to assist in delaying the normal souring of the milk.

B. SWEETENED CONDENSED MILK

1. History

During the civil war in this country, condensed milk became recognized as a novel and very desirable form of milk due to the fact that it was concentrated, less bulky than raw liquid milk, and could be easily shipped and stored. The method of manufacturing condensed milk has vastly improved since that time as well as its quality, and today condensed milk is well known to everyone.

2. Method of Manufacture

Briefly the “condensing” of milk takes place as follows: Fresh liquid milk is shipped under refrigerated conditions to the “condensery” as promptly as possible. It is then inspected and heated to kill any bacteria present. Enough cane sugar is added to the hot liquid milk so that the final condensed milk will contain about 40% sugar. The milk is then heated in “vacuum” pans where a large part of the water contained is quickly evaporated off, leaving the milk in the familiar condensed form. It is then gradually cooled, packed in barrels and is ready for shipment.

3. Purpose of Sugar in Sweetened Condensed Milk

The main purpose of incorporating the cane sugar in condensed milk is to preserve its keeping qualities and to greatly inhibit the bacterial action which causes sourness. As explained previously, the amount of sugar contained in sweetened condensed milk must be taken into consideration by the baker when using this form of milk in his doughs.

4. Storage and Handling

In view of the decreased amount of water and relatively high percentage of sugar, sweetened condensed milk keeps much better than raw liquid milk and also better than evaporated milk. However, if kept too long or in a warm room this form of milk will go bad in time, but if stored in a cool place in a tightly covered barrel, it may be safely kept for several weeks. It is advisable to examine and taste the sweetened condensed milk used from day to day especially in warm weather to be sure that it is in good condition before use in the dough batch.

Usually portions of the condensed milk are removed as needed by means of a gate valve set into the head of the barrel. Sometimes on standing, condensed milk becomes “grainy” and some of the sugar starts to settle out. Therefore, if possible, the condensed milk should be occasionally mixed or stirred to make sure that each sample removed is uniform in composition.

Due to the consistency of condensed milk some of it is quite likely to stick to the sides of the barrel. Therefore, all barrels should be carefully drained out and rinsed out with water so that none of the milk may be wasted.

5. Use of Sweetened Condensed Milk for Bread Making

The required amount of condensed milk should be weighed out carefully,—mixed with some of the water to be used in the dough and added with the rest of the water. The amount of sweetened condensed milk which can be used in a bread dough is usually limited by the amount of sugar which it carries. Seven pounds of this milk contains about 3 pounds of sugar, and together with 1% of malt extract in most cases will meet the total sugar requirements for a bread dough containing 100 pounds of flour.

C. EVAPORATED MILK

Evaporated milk is often called unsweetened condensed milk and sometimes merely “condensed” milk, but inasmuch as it is quite different from ordinary sweetened condensed milk,—we shall adhere to the name evaporated milk when referring to this type of milk from which part of the water has been evaporated off without the addition of sugar or any other substances.

1. Method of Manufacture

Raw liquid milk is first received at the evaporating plant and tested. It is then drawn into vacuum pans and heated. Thus part of the water is removed. When the proper degree of concentration is reached, the evaporated milk is put through an homogenizer, a machine in which the thick milk is forced through very fine openings under a high pressure. This breaks up the butter-fat into such very tiny particles that they will not come together and rise to the top in the form of cream. Thus the evaporated milk is uniform in composition throughout. It is then cooled, tested and canned. The sealed cans are then heated sufficiently to thoroughly sterilize the contents and the evaporated milk is ready for shipment. The temperature required for sterilization frequently coagulates the albumen of the milk to a certain extent, thickens the milk and also imparts a yellowish color and characteristic taste to the evaporated milk.

2. Storage and Handling

Evaporated milk will keep indefinitely if the cans are unopened. However, when once the cans are opened, the evaporated milk is quite perishable and should be promptly used.

3.  Bulk Evaporated Milk

In addition to the regular evaporated milk prepared as above described, there is another form often termed “bulk” evaporated milk, or merely “condensed milk” which may be slightly more concentrated and may contain about 40% milk solids. This bulk evaporated milk prepared from either whole or skim liquid milk is sometimes heated causing it to thicken and is sold in 10 gallon milk cans. Bulk evaporated milk is used mainly in cases where the bakery is located near the condensery and usually is not shipped any great distance due to the fact that it will sour on standing although not as rapidly as raw liquid milk. If properly refrigerated, it may be kept for several days. If this precaution is not adhered to there is some danger of the development of an uncertain acidity which,—not being definitely regulated in amount,—makes the production of uniform bread very difficult. Therefore, if this type of evaporated milk is employed it should be kept refrigerated and used as promptly as possible if the desired results are to be secured.

4. Use of Evaporated Milk for Bread Making

For breadmaking, this form of milk is handled in about the same manner as sweetened condensed milk,—but it contains no added sugar and may be used in amounts sufficient for “full” milk bread.

D. DRIED MILK

1. General Information Regarding Dried Milks

As the name implies, dried milk is milk from which practically all of the water has been removed leaving the dry milk solids intact. The federal standards specify that dried milk sold as such, shall not contain more than 5% moisture. The main purpose in removing the water from liquid milk were naturally as follows:

1. To produce milk in its most concentrated form.
2. To facilitate handling and transportation.
3. To facilitate storage and to eliminate the necessity for refrigeration.

The aim of the modern manufacturer of dried milk is to produce a dried milk which will dissolve readily in water, and when dissolved in the proper amount of water will yield a liquid milk which is practically identical with the raw liquid milk from which the dried milk was originally secured.

As a result of years of research work and study, modern drying processes have been developed which makes possible the production of the excellent forms of dried whole milk, partially skimmed or skim milk which are now available for bakers’ use.

While dried milk generally speaking is termed powdered milk, it must be remembered that some brands of dried milk are in the form of tiny flakes.

2. Method of Producing Dried Milk

a. HANDLING OF MILK PRELIMINARY TO DRYING

In the manufacture of dried milk, utmost care, sanitation and scientific control are necessary in order to insure a product of the highest quality. Usually the dried milk manufacturing plants are located in the center of dairy districts so that the raw liquid milk can be received at the drying plant with as little delay as possible. Reliable manufacturers secure the raw liquid milk from sanitary farms and make sure that it is handled and transported in a clean manner. Preliminary to the actual drying process the milk is inspected and tested, so as to make sure that it is in good condition. Usually it is also pasteurized although care

is taken to avoid heating to an extent that will coagulate the albumen for this would prevent the final dried milk from dissolving readily when used and also tend to alter its natural flavor and other characteristics.

There are several different drying methods now employed, but it will be sufficient here to describe briefly only two of them.

b. ROLLER PROCESS

According to this method the liquid milk is slowly run or sprayed on the revolving drums which have been heated and which are sometimes enclosed in a vacuum chamber. The milk is thus dried in very thin films and is removed from the drums by means of a scraper. The dried milk thus secured is usually in the form of tiny thin flakes. These are usually ground up so that the finished product has the appearance of a somewhat coarse powder.

c. SPRAY PROCESS

According to this method the milk is forced under pressure through a tiny opening thus forming a fine spray into a chamber or room thru which hot air is circulated. The water contained in the milk is thereby removed almost instantly and is carried away in the form of a vapor by the current of hot air. The milk solids fall to the bottom of the chamber in the form of a dry fluffy powder which is removed and packed.

In some spray drying processes, part of the water contained in the original liquid milk is first removed by a special condensing process and the “pre-condensed” milk then sprayed into the drying chamber described above.

d. STORAGE OF DRIED MILK

While it is not necessary to refrigerate dried milk, it is advisable to store it in a cool, dry place, free from contamination. Due to the dryness of such milk, it possesses excellent keeping qualities, although in time some rancidity of the butter-fat may take place. In view of this, the keeping qualities of dried skim milk are superior to those of dried whole milk.

e. MIXING AND HANDLING DRIED MILK

1. General Advice

The manner of mixing and handling dried milk is highly important and cannot be emphasized too strongly. When properly incorporated, dried milk of good quality should give the same excellent results which can be secured from the use of any other forms of milk in baked goods. If a baker has not obtained the expected results with dried milk, the reason is usually because he has not mixed the milk in the correct manner. It is a simple and easy matter to handle dried milk in the proper manner and no difficulty should be encountered provided the following points are adhered to: —

The dried milk purchased should be of high quality. It should possess a clean, sweet taste and be free from hard lumps. Proper storage conditions should be maintained.

The composition of the dried milk used should be understood and the amount employed calculated accordingly. Usually 1 pound of dried whole milk dissolved in 7½ pounds (or pints) of water will be equivalent to 1 gallon (8½ lbs.) of liquid whole milk and ¾ pounds dried skim milk dissolved in 7¾ pounds of water will be equivalent to 1 gallon of liquid skim milk.

The necessary adjustments in the dough formulas employed as described under section X of this Chapter should be made. It is of special importance to keep in mind that for each pound of whole milk solids, 1 pound of additional water should be used.

2. Method of Mixing Dried Milk Described

Before incorporating dried milk into the dough batch it should always be first thoroughly dissolved in water. This is done by setting aside part of the water to be used in the dough,—in a separate receptacle. The dried milk should then be added gradually on top of the water, and thoroughly beaten into the water with a baker’s whip until all of the lumps are broken and a uniform solution formed. Three pounds or more of water to every pound of dried milk should be used. It has often been found very satisfactory to first mix the malt extract or sugar and dried milk together before dissolving in the water.

When relatively large amounts of dried milk are used, it is desirable to employ a special mechanical agitator or mixer for dissolving the milk.

After the dried milk is thoroughly mixed into the water it is advisable, if possible, to let it stand fifteen or twenty minutes before mixing into the dough batch.

When handled properly, a milk solution thus prepared is practically identical with natural liquid milk with the exception that the cream will not rise to the top due to the fact that the butter-fat has been broken up into such small particles during the spraying process. This fact however, is an advantage in that, the milk solution will remain uniform in composition throughout.

XII. COMMENTS REGARDING THE HANDLING OF MILK DOUGHS

A. ABSORPTION

See that the necessary adjustments in the formula are made especially the absorption. This point has already been covered previously, but it should be kept in mind that a milk dough should come out of the mixer slightly slacker than a regular non-milk dough. This is necessary in view of the fact that a milk dough will tighten up during the fermentation period.

B. MIXING OF MILK DOUGHS

All milk doughs should be thoroughly mixed, but not over-mixed.

C. FERMENTATION AND CONDITIONING OF MILK DOUGHS

Experience has taught that it is especially important that doughs containing milk should be thoroughly conditioned during the fermentation period.  Under-fermentation is disastrous to a milk dough.

The maintenance of cool doughs and a short vigorous panary fermentation made possible by the use of liberal quantities of yeast and malt extract will tend to prevent any excessive lactic fermentation in the milk dough and will therefore, produce a loaf of the finest quality with a maximum yield and saving of time and labor. Some recent work done at the American Institute of Baking has indicated that the presence of skim milk solids in the dough, not only improved the general quality of the resulting loaf,—but also increased the actual stability of the dough during fermentation.

D. SPONGE DOUGHS

In doughs made by the sponge method, the milk can be incorporated in either the sponge or the dough. Some recent work done in this connection shows that excellent results are secured by using the milk in the sponge.

E. AMOUNT OF MILK TO USE

The amount of milk to be used has been discussed under Government Standard for “milk bread” and also under the paragraph concerning “full milk bread.” The exact amount to be used of course, depends on the type of bread desired but the use of ten or more pounds of actual milk solids to the barrel of flour is usually to be recommended most highly. The increased yield secured and the superior eating and keeping qualities of the bread secured in most instances will prove that such a practice is real economy from the bakers’ standpoint.

F. USE OF MALT EXTRACT IN MILK DOUGHS

The many advantages of malt extract are especially noticeable in milk doughs. Not only does malt extract invigorate the fermentation process of such doughs but the flavor of malt combined with that of the milk results in a loaf which possesses an incomparable appeal to the appetite. Many authorities recommend that 1 ½% or more of malt extract be always used in a milk dough.

G. WRAPPING OF MILK BREAD

While all bread should be thoroughly cooled before being wrapped, this is especially true in the case of loaves rich in milk, particularly in the summer time. The moisture-holding power of milk is so great that mold may result if this elementary precaution is overlooked.

XIII. ADVANTAGES SECURED BY THE USE OF MILK

A. IMPROVED APPEARANCE OF LOAF

1. Crust Color

While the lactose or natural sugar contained in milk is not fermented by yeast and is of low sweetening- value, it nevertheless carmelizes readily in the oven and produces a beautiful crust color which is very appealing to the eye.

2. Grain and Texture

Due to the tightening effect of milk on the dough batch, the grain and texture of a milk loaf is superior to that of a loaf containing no milk. A soft velvety texture is characteristic of milk bread.

3. Color of Crumb

The use of milk imparts a very desirable creamy whiteness and luster to the interior of the loaf.

B. IMPROVED EATING QUALITIES

One of the greatest advantages of milk in bakery products is the very delightful taste and flavor which it imparts to the finished baked goods. The soft, tender crust and silky texture of the crumb which characterize milk bread definitely indicates that the use of milk materially enhances the eating qualities of the loaf, thus stimulating the appetite and making bread eating a pleasure.

C. INCREASED NUTRITIVE VALUE

1. Why Milk Adds to the Food Value of Bakery Products

Practically everyone realizes in a general way, the importance of milk as a food, but many do not appreciate the extent to which the nutritive value of bread is enhanced through the use of liberal quantities of milk. Bread, the Staff of Life, becomes very nearly a completely balanced diet in itself when milk is used in making up the dough. Hundreds of feeding tests conducted with experimental animals show definitely that better growth and health are secured from eating bread made with milk than from bread containing no milk.

In this day and age, people are watching and studying their diet more closely than ever before and school children are being taught the importance of food values and proper nutrition. Therefore, at the present time the established nutritive value of any food commodity should be utilized as an advertising claim which will lead to increased sales.

A baker making a milk and diamalt loaf is neglecting a real opportunity to build up his business if he fails to bring this important fact to the attention of the public through proper advertising.        In considering this matter, it should be kept in mind that the “milk solids” are the only real nutritive portion of the milk. It is a very fortunate fact that these milk solids supply just the important nutrient substances which the ordinary non-milk loaf lacks and for this reason, the use of milk in bread is to be very highly recommended. Therefore, it will be well to point out the peculiar food value contributed by each constituent of the milk solids.

2. Butter Fat

The butter-fat content of whole milk is naturally the most expensive part of the milk. Butter-fat for ages past has been recognized as one of nature’s ideal foods, furnishing heat and warmth to the body, and also Vitamin A. Because of its peculiar composition and low melting point, butter is ihore easily digestible than most other fats. One pound of butter-fat represents a fuel value of about 4,000 Calories. Nature has blended into butter in properly balanced proportions those complex substances which impart to it that delightful, unmistakable “butter” flavor found in no other fat. From a nutritive and taste standpoint, butter-fat is desirable in bakery products but its use in bread doughs is necessarily limited from a cost standpoint. However, it is very gratifying to know that the use of skim milk is a very convenient and economical means of incorporating the other valuable milk solids into the loaf, and because of this increasing amounts of skim milk are being employed for bread making.

3. Milk Protein

While the protein of flour is excellent and necessary to normal health and growth, we must remember that in addition to the proper quantity of protein, the body requires a variety of different kinds of protein in order to build up and replace the body tissues properly. The protein of milk which is made up of casein and albumen,—together with the protein of malt extract and yeast supplements that furnished by the flour and because of this,—makes bread a more nearly perfect food.

4. Mineral Salts

The natural mineral salts or “ash” of milk are very essential and necessary for the proper growth of the bones and teeth. Milk contains a variety of mineral salts but is especially rich in calcium and phosphorous and because of this milk is an excellent source of these mineral salts.

5. Milk Sugar

The natural sugar of milk known as lactose is an excellent sugar from a nutritive standpoint and represents another source of energy food when contained in bread or other bakery products.

6. Vitamins

Milk is especially rich in Vitamin A which is necessary for the maintenance of a normal healthy bodily condition.

D. IMPROVED KEEPING QUALITIES

Many tests show definitely that a milk dough not only will carry more moisture,—but that it retains this moisture in such a manner that the freshness of a milk loaf is distinctly prolonged. In other words, the use of milk delays staling and a milk loaf will stay fresh considerably longer than a loaf containing no milk.

E INCREASED YIELD

The use of milk brings about a definite increase in the yield of bread secured.  This is due mainly to the following reasons:—

1. When milk is used,—the milk solids contained naturally add a certain definite weight to the dough batch.
2. As explained previously, each pound of milk solids require an addition of 1 to 11/4 pounds of extra water which is tightly retained in the dough and adds still further to its weight.
3. Milk doughs tend to bake out less in the oven than doughs containing no milk. This means that a portion of the added water is retained in the finished baked bread, thereby increasing the yield obtained.

XIV. METHOD OF CALCULATING EQUIVALENTS OF THE VARIOUS FORMS OF MILK

A. PRELIMINARY REMARKS

1. Calculation of Equivalents is Based on Milk Solids

In view of the fact that the percentage of milk solids and water are so widely different in the various forms of prepared milks,—it can be readily seen that such a calculation must be based strictly on the relative amount of milk solids contained in each case.

In order to replace one form of milk with an equivalent quantity of another, it should be kept in mind that the amount of the new form to be used, must supply exactly the same weight of milk solids as was contained in the type of milk previously used.

2. Other Necessary Adjustments in Formulas

After the required amount of the form of milk to replace another form has been calculated, of course, necessary adjustment will have to be made in the amount of water added to the dough, so that the total water content in each case will be kept the same. Furthermore, in the case of sweetened condensed milk, the amount of cane sugar contained will have to be taken into consideration and corresponding adjustment made so that the total amount of sugar incorporated into the dough through the condensed milk or as added sugar will be kept the same.

In the event that some form of skim milk is used to replace whole milk, the amount of the skim milk used should be such that it will contain the same amount of solids as the content of “milk solids not fat” in the whole milk. Then sufficient butter must be added to supply the exact amount of butter fat contained in the whole milk previously used.

B. INSTRUCTIONS, RULES AND EXAMPLES FOR CALCULATING EQUIVALENT AMOUNTS OF VARIOUS FORMS OF MILK

1. First secure the exact analysis or composition of the two forms of milk in question.
2. Then divide the figure representing the percentage of milk solids in the form of milk being used by the percentage figure for the milk solids in the form of milk to be used. This result will represent the amount of the new form of milk expressed in pounds which will be equivalent to one pound of the old.
3. Multiply this result by the weight of milk being used.   This will give you the weight of the new form of milk to be used.
4. Then make necessary deduction or addition of water or sugar to the dough batch.

It will be much easier to understand the methods of calculation described above by studying certain typical examples,—stated in the following paragraphs:—

EXAMPLES

1. How much powdered whole milk should be used to replace 8% lbs. of sweetened condensed whole milk and what adjustment will this require in the amount of water and sugar used in the dough formula ?

(a) Suppose the composition of the two milks are as follows:—

(b) Then:—

28 ÷ 98.5 = 0.285 lbs. of powdered whole milk, contains the same amount of milk solids as 1 lb. of sweetened condensed milk.

(c) 8.75 x 0.285 = 2.5 lbs. of Powdered Milk equivalent to 8.75 lbs. sweetened condensed milk.

(d) Adjustment for Sugar

Dried milk contains no added cane sugar but 8.75 lbs. of sweetened condensed milk of the above composition contains (8.75 x .41) or 3.6 lbs. of added cane sugar. Therefore, in replacing 8.75 lbs. of sweetened condensed milk with 2.5 lbs. of powdered milk of the above composition, the amount of sugar normally added as such to the dough formula will have to be increased by 3.6 pounds.

(e) Adjustment for Water

From the composition shown above, 8.75 lbs. of sweetened condensed milk contains (8.75 x 0.31) or 2.7 lbs. of water. Therefore, in replacing 8.75 lbs. of sweetened condensed milk with 2.5 lbs. of powdered milk, 2.7 lbs. of extra water should be added to the dough formula to compensate for the amount carried by the sweetened condensed milk.

(f) Conclusion Summarized

In order to replace 8.75 lbs. of sweetened condensed whole milk with powdered whole milk of the compositions stated herein, use:—

2.5 lbs. powdered whole milk

3.6 lbs. sugar

2.7 lbs. water

EXAMPLE NUMBER 2

How much sweetened condensed whole milk should be used to replace 2.5 pounds of dried whole milk, and what adjustment will this require in the amount of water and sugar used in the dough formula ?

(a)   Suppose the composition of the two milks are as follows:—

(b) Then 98.5 ÷ 28 or 3.5 lbs. of Swt. Cond. Milk Contains the same

amount of milk solids as 1 lb. of dried whole milk.

(c) 3.5 x 2.5 = 8.75 lbs. of Swt. Cond. Milk equivalent to 2.5 lbs. dried whole milk.

(d) Adjustment for Sugar Contained in the Sweetened Condensed Milk

8.75 lbs. of sweetened Cond. Milk of the above composition contains (8.75 x 41) or 3.6 lbs. sugar. Dried whole milk contains no cane sugar. Therefore, in replacing 2.5 lbs. of dried milk with 8.75 lbs. of sweetened condensed milk of the above composition, the amount of added sugar normally employed in the dough will have to be reduced by 3.6 lbs.

(e) Adjustment for Water

From the composition shown above, 8.75 lbs. of Swt. Condensed Milk will contain (8.75 x 0.31) or 2.7 lbs. water, while the water content of 1 lb. of the dried milk is practically nil. Therefore, in replacing 2.5 lbs. of powdered milk with 8.75 lbs. of sweetened condensed milk of the above composition, the amount of added water employed in the dough formula will have to be reduced by 2.7 lbs.

(f) Conclusion Summarized

In order to replace 2.5 lbs. of dried whole milk by sweetened condensed whole milk of the compositions stated herein, use:

8.75 lbs. sweetened condensed whole milk but reduce the sugar added to the dough formula as such by 3.6 lbs. and the water by 2.7 lbs. to compensate for the amount of sugar and water carried into the dough by the condensed milk.

EXAMPLE NUMBER 3

How much dried skim milk and added butter must be used to replace 8.75 lbs. sweetened condensed whole milk, and what adjustments will this require in the amount of water and sugar used in the dough formula?

(a) Suppose the composition of the two milks are as follows:—

(b) 20 ÷ 97.5 = 0.21 lbs. of dried skim milk,—contains the same amount of “milk solids not fat” as 1 lb. of sweetened condensed whole milk.

(c) 8.75 x 0.21 = 1.8 lbs. of dried skim milk contains the same amount of “milk solids not fat” as 8.75 lbs. of sweetened condensed whole milk.

(d) Adjustment for Butter Fat

8.75 lbs. of sweetened condensed whole milk contains (8.75 x .08) or 0.7 lbs. butter fat, while the amount of butter fat in the dried skim milk is practically negligible.

Therefore, in replacing 8.75 lbs. of sweetened condensed whole milk with 1.8 lbs. of dried milk,—0.70 lbs. of butter fat must be added in the form of butter. Inasmuch as butter contains at least 80% butter fat, it will require,0.70 ÷ 0.80 or 0.875 lbs. of added butter.

(e) Adjustment for Sugar

Powdered milk contains no added cane sugar but 8.75 lbs. of sweetened condensed milk of the above composition contains (8.75 x .41) or 3.6 lbs. of added cane sugar. Therefore, in replacing 8.75 lbs. of sweetened condensed milk with 1.8 lbs. of dried skim milk of the above composition, the amount of sugar normally added as such to the dough formula will have to be increased by 3.6 pounds.

(f) Adjustment for Water

From the composition shown above the 8.75 lbs. of sweetened condensed milk will contain 2.7 lbs. water while 1.8 lbs. of dried skim milk contains practically no water. Therefore, in replacing 8.75 lbs. of sweetened condensed whole milk with 1.8 lbs. of dried skim milk, 2.7 lbs. of extra water should be added to the dough formula to compensate for the amount carried by the sweetened condensed milk.

(g) Conclusion Summarized

In order to replace 8.75 lbs. of sweetened condensed milk by dried skim milk and butter of the compositions stated herein, use:—

C. TABLES OF EQUIVALENTS OF MILK PRODUCTS HAVING COMPOSITIONS AS SHOWN UNDER III-B.

1. Explanation

As explained previously the exact conversion factors or “equivalents” to be used in replacing any one form of milk by another depends on the relative compositions of each. However, the preceding paragraphs have explained the method of calculating these equivalents in any given case.

Therefore, with milks of a known composition a table of equivalents can be figured out. The following tables have been calculated in this manner on the basis of the composition of the various samples of milk shown in the diagrams entitled “Approximate Composition—Typical Forms of Milk” as illustrated under “III-B” of this chapter.

Hence the following tables show the respective amounts of these various forms of milk which will supply the same amount of milk solids as that contained in one pound of the other forms. In other words the following tables represent the “equivalents” of the various forms of milk of the particular composition stated in the preceding diagrams, on the basis of the actual milk solids contained in each. Furthermore, the extra amounts of water to be added or deducted from the amount normally used is also indicated. This is done so that the total water content of the dough will be kept the same when one form of milk is replaced by an equivalent amount of another. A similar adjustment of cane sugar is indicated in the case of sweetened condensed milk so as to compensate for the cane sugar which it contains. In the following tables the form of milk which it may be desired to replace by other forms is shown in the left hand column. Then under the proper headings will be found the corresponding amount of any of the other forms equivalent to 1 1b. of the form of milk stated in the first column. Furthermore, the amount of water or sugar to be added or deducted from the formula is indicated by plus (+) or minus (–) signs.

2. Illustration of a Typical Table of Milk Equivalents. (Whole Milk Products)

These tables hold true only for milks of the compositions stated under III-B of this chapter.

Examples Shown by Above Chart

1 lb. of liquid whole milk can be replaced by 0.43 lbs. of Sweetened Condensed Milk provided 0.75 lbs. additional water is also used and the added sugar in the dough is reduced 0.18 lbs.

1 lb. of Sweetened Condensed Milk can be replaced by 0.28 lbs. of dried whole milk provided 0.3 lbs. extra sugar and 0.41 lbs. additional water is employed.

Illustration of a Table of Milk Equivalents (Skim Milk Products)

Note:— Similar equivalents can be worked out for Partially Skim Milk products depending on their exact composition.

This table holds true only for milks of the composition stated under III-B of this chapter.

Examples Shown by Above Chart

1 lb. of liquid skim milk can be replaced by .09 lbs. dried skim milk provided 0.91 lbs. of extra water is also used.

1 lb. sweetened condensed skim milk can be replaced by 0.29 lbs. dried skim milk provided 0.28 lbs. extra water and 0.43 lbs. extra sugar is also used.

XV. BUTTERMILK

A. LIQUID BUTTERMILK

Buttermilk is the liquid product remaining when cream is churned into butter. The approximate composition of an average sample of such buttermilk is as follows:—

From the above it is seen that liquid buttermilk is similar in composition to liquid skim milk with the exception that it contains a greater amount of butterfat and contains more acidity.

While buttermilk deserves consideration by the baker as a valuable ingredient together with other milk products,—it must be kept in mind that through the use of any appreciable amount of buttermilk,—considerable lactic acid is carried into the dough, thereby accelerating the fermentation and condition process to a marked degree.

B. CONDENSED BUTTERMILK

In order to facilitate handling, storing and shipping as well as to standardize its composition, buttermilk has been made available to the baker in dried as well as condensed and so-called semi-solid forms. The composition of condensed buttermilk naturally depends on the amount of water which has been evaporated from the liquid buttermilk as well as the composition of the original buttermilk from which it was prepared. Quite frequently buttermilk is condensed to a point where it will contain about 30% buttermilk solids and 70% water.

C. DRIED BUTTERMILK

The approximate composition of a sample of dried buttermilk would be as follows:

However, as in the case of other forms of milk, various brands of condensed and dried buttermilk will differ somewhat in composition and information concerning the exact composition of these different brands can be secured from the manufacturer so that the baker may be guided accordingly.

D. STORAGE AND HANDLING BUTTERMILK

Liquid buttermilk should only be used just as soon as possible after being produced. It should be refrigerated until used in the dough batch. Condensed buttermilk should be kept in a cool place and should be used as fresh as possible. Dried buttermilk can be kept for a longer period of time but should also be stored in a cool, dry place and kept tightly covered. Dried buttermilk should be dissolved in water before use in the dough batch,—in much the same manner as ordinary dried milk is handled preliminary to mixing into the dough.

E. USE OF BUTTERMILK IN BREAD MAKING

The amount of buttermilk which can be employed in bread doughs is limited by the amount of lactic acid which it contains. While a small regulated amount of lactic acid hastens dough fermentation and conditioning, an excess of lactic acid has too pronounced an effect on the dough and makes it quite difficult and often impossible to produce the uniform, high quality bread which might otherwise be secured. Therefore, a limited amount of buttermilk is generally used, and frequently in conjunction with the other forms of milk. It is usually advisable to use liquid buttermilk in amounts not exceeding 20 pounds to 100 pounds of flour, which is about equivalent to 6 pounds of condensed buttermilk or from 2 to 3 pounds of dried buttermilk. Thus the advantages of buttermilk may be safely secured provided the fermentation period and proof period are materially reduced, and the doughs taken on the young side. The additional advantages of the use of larger amounts of milk solids can be easily secured by supplementing the buttermilk with other forms of whole or skim milk.