SUMMARY SHOWING RELATION OF FAT IN MILK TO YIELD OF CHEESE

==============================================================

AVERAGE PER

POUNDS OF GREEN CHEESE

POUNDS OF GROUP

CENT OF FAT

MADE FROM 100 LB. OF

GREEN CHEESE

IN MILK

MILK

MADE FOR 1 LB.

OF FAT IN MILK ------+-------------+------------------------+---------------- I

3.35

9.14

2.73 II

3.72

10.04

2.73 III

4.15

11.34

2.70 IV

4.74

12.85

2.71 V

5.13

13.62

2.66 ==============================================================

Table X shows that as the fat in the milk increases, the pounds of cheese made from 100 pounds of that milk increases; but the amount of cheese made for each pound of fat in the milk does not increase. This is due to the fact pointed out in Table IX, namely, that as the fat increases in the milk the casein does not increase in the rich milk in proportion to the fat. From Tables IX and X this conclusion may be drawn: that as the percentage of fat increases in the milk the more cheese can be made from 100 pounds of that milk, but after the increase in fat gets above 4 per cent the amount of cheese that can be made for each pound of fat in the milk is decreased because the casein does not increase in proportion to the fat. No exact statement of yield can be made without first stating the moisture-content of the cheese. The losses also must be considered.

Van Slyke[95] in the following Table XI shows the effect of the fat-content of normal milk on the yield of cheese.

The moisture-content of all the cheeses is reduced to a uniform basis of 37 per cent. (See cut showing yield of cheese, Fig. 52.)

[Ill.u.s.tration: FIG. 52.--The figures represent the relative yield of cheese containing different percentages of fat, but all have a uniform content of 37 per cent water.]

TABLE XI

TABLE SHOWING THE EFFECT OF THE FAT-CONTENT OF NORMAL MILK ON THE YIELD OF CHEESE

----------------+-------------+--------------+------------------- PER CENT OF FAT

PER CENT OF

AMOUNT OF

AMOUNT OF CHEESE IN THE MILK

CASEIN IN

CHEESE MADE

MADE FOR EACH

THE MILK

FROM 100 LB.

POUND OF FAT

OF MILK

IN THE MILK ----------------+-------------+--------------+------------------- 3.00

2.10

8.30

2.77 3.25

2.20

8.88

2.73 3.50

2.30

9.45

2.70 3.75

2.40

10.03

2.67 4.00

2.50

10.60

2.65 4.25

2.60

11.17

2.63 4.50

2.70

11.74

2.61 4.75

2.80

12.31

2.59 5.00

2.90

12.90

2.58 ----------------+-------------+--------------+-------------------

+213. Fat loss in cheese-making.+--The amount of solids lost in the whey also affects the yield. The following table gives the amount of fat lost in whey with normal milk containing different percentages of fat:

TABLE XII

SUMMARY SHOWING AMOUNT OF FAT IN MILK LOST IN CHEESE-MAKING

================================================================= GROUP

POUNDS OF FAT IN

POUNDS OF FAT LOST

PER CENT OF FAT

100 LB OF MILK

IN WHEY FOR 100

IN MILK LOST

LB. OF MILK

IN WHEY ------+------------------+--------------------+------------------ I

3 to 3.5

0.32

9.55 II

3.5 to 4

0.33

8.33 III

4 to 4.5

0.32

7.70 IV

4.5 to 5

0.28

5.90 V

5 to 5.25

0.31

6.00 =================================================================

Table XII shows that the percentage of fat in the whey is approximately the same for milk high or low in fat. But the milk low in fat loses a higher percentage of the total milk-fat in each 100 pounds of whey.

+214. Effect of bacterial-content of milk on yield of cheese.+--The bacterial-content[96] of the milk influences the yield by affecting both the moisture-content and the losses. If the milk is sour or has bad fermentation, the losses will be increased because the curd cannot be carefully handled, and the moisture cannot be incorporated to the extent that it can in clean milk, without injury to the quality. The proper-cooling of the milk in one instance increased the yield 0.3 pound of cheese for each 100 pounds of milk. The more moisture that can be incorporated into the cheese up to the legal limit, the greater the yield.

+215. Factors affecting the moisture-content of Cheddar.+--The amount of moisture that can be incorporated in a curd depends on several factors.[97] The following increase the moisture-content control of the cheese:

1. Cutting the curd coa.r.s.e.

2. High setting temperature.

3. Low acid in the curd at time of removing whey.

4. Not stirring the curd with the hand as the last of the whey is removed.

5. Slow pressure.

6. High piling of the curd in the cheddaring process.

7. Small amount of salt.

8. Holding the curd at low temperature after the whey is removed.

9. Large amount of rennet.

10. Cutting the curd hard.

The following factors decrease the moisture-content of the cheese:

1. Fine cutting.

2. Low setting temperature.

3. High acid in the curd at time of removing the whey.

4. Stirring the curd with the hand as the last of the whey is removed.

5. Fast pressure.

6. Low piling of the curd in the cheddaring process.

7. Large amount of salt.

8. Holding the curd at high temperature after the whey is removed.

9. Small amount of rennet.

10. Cutting the curd soft.

From this discussion, it is evident that the yield of cheese from 100 pounds of milk increases with higher percentages of fat and casein in the milk, with reduced losses of solids during manufacture, with the absence of undesirable fermentations, and with the incorporation of large amounts of water.

+216. Variations of the Cheddar process.+--The Cheddar process, as already described, is widely employed in cheese factories. Many varieties are found, however, and varietal names are used for such products. A whole series of these forms are either locally or widely made in England and taught in the English dairy schools. Some of these varieties resemble the factory Cheddar product fairly closely; others are clearly different products. A typical series of the variations as developed in America will be considered.

In the commercial trade Cheddar cheese is usually designated by some name which indicates its size. The size of the cheese is determined by that of the hoops. The hoops vary both in diameter and height. The table on the following page shows the usual sizes of the hoops and the weight and name applied to the cheese.

+217. Cheddar-type cheese from pasteurized milk.+--Sammis and Bruhn[98]

have described a variation of the Cheddar process to overcome the difficulties of making cheese from pasteurized milk. Such milk curdles in very unsatisfactory manner unless some chemical is added to compensate for the salts lost and to offset the other changes resulting from heat.

For this purpose, they found the use of hydrochloric acid satisfactory.

TABLE XIII

SIZE OF CHEESE HOOPS, WEIGHT, AND TERM APPLIED TO CHEESE

======================================================================== DIAMETER OF

HEIGHT OF

WEIGHT OF

TERM APPLIED TO HOOP

CHEESE

CHEESE

CHEESE

POUNDS

---------------+-------------------+------------+----------------------- 6-7 in.

7-8 in.

9-11

Young America Tapers 5-7 in.

10-14 in.

10-16

Long Horn 12-14 in.

3-4 in.

18-24

Daisy or Picnic 14-15 in.

4-6 in.

30-40

Twin (two in same box) 14-16 in.

4-7 in.

35-40

Flat 13-15 in.

10-12 in.

40-50

Cheddar 14-16 in.

12-15 in.

75-90

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"The acidulation of milk with hydrochloric acid after pasteurization is accomplished without difficulty or danger of curdling by running a small stream of the acid, of normal concentration, into the cooled milk as it flows from the continuous pasteurizer into the cheese vat. One pound of normal-strength acid is sufficient to raise 100 pounds of milk from 0.16 percent to 0.25 percent acidity (calculated as per cent of lactic acid).

The amount of acid needed each day to bring the milk up to 0.25 per cent acidity is read from a table or calculated from the weight of the milk and its acidity, determined by the use of Manns's acid test (t.i.tration with tenth-normal sodium hydrate and phenolphthalein). The preparation of standard-strength acid in carboy lots for this work and the acidulation of milk present no great difficulty to any one who is able to handle Manns's acid test correctly.

"After the milk is pasteurized and acidulated three-fourths per cent of first-cla.s.s starter is added and the vat is heated to 85. It is set with rennet, using 2 ounces of rennet per thousand pounds of milk, so that the milk begins to curdle in 7 minutes and is cut with three-eighth inch knives in 25 minutes. All portions of the work after adding rennet are carried out in an unvarying routine manner, according to a fixed-time schedule every day. As soon as the rennet has been added the cheese maker is able to calculate the exact time of day when each of the succeeding operations should be performed, and the work of making the cheese is thus simplified and systematized. It is possible that the routine process here described may be varied somewhat with advantage at different factories."

This cheese usually lacks characteristic Cheddar flavor or contains it in very mild form. It therefore satisfies only those who seek very mild flavored products. Efforts are now being made to find a flavor producing substance or organism which will bring the flavor of this product more nearly to that of typical Cheddar.