82 RePorRT OF THE CHEMIST OF THE 
3. Yield and Composition of Cottage Cheese.—(1) Yield of 
cheese from 20.5 pounds of milk varied from 3.56 to 4.63 pounds 
under the conditions tried. (2) Moisture in cheese varied from 
below 70 to over 80 per ct. The variation in moisture accounts 
largely for the variation in yield. The amount of moisture in 
cheese is dependent upon the temperature used in curdling the 
milk and in heating the curd to expel moisture and also on the 
length of time the curd is heated. Cottage cheese of the best tex- 
ture should contain 70 to 75 per ct. of moisture. Best success 
was attained when milk was soured and curdled not much above 
70° F. (21° C.) and the subsequent heating was not carried above 
90° F. (82° ©.) (8) Milk-sugar in the cheese varied from 3.28 to 
4.08 per ct., which is equivalent to 10 to 16 per ct. of the sugar 
originally present in the milk. Of the sugar in the milk, 23 to 27 
per ct. was decomposed in the souring. (4) Nitrogen in cheese 
is mostly in the form of casein dilactate, equivalent to 2 to 2.5 
per ct. of nitrogen. 
4. Manufacture of Cottage Cheese by Direct Addition of an 
Artificial Acid to Milk.—Milk was coagulated by addition of 
lactic acid and hydrochloric acid and the curd made into cottage 
cheese. Satisfactory results in every respect were secured. For 
example, hydrochloric acid (sp. gr. 1.20), diluted with 10 times 
its volume of water, was added to milk in the proportion of 8 
ounces for 100 pounds of milk at 75° F. (24° C.) and stirred 
vigorously. The curd separated at once in flocculent form and was 
strained from the whey without further heating. Any absence 
of sour-milk flavor can be supplied by mixing with the cheese 
some ripened cream. Cheese made in this way contains more 
milk-sugar and more nitrogen than cheese made by the ordinary 
method of souring milk. 
5. Slight Change of Insoluble into Soluble Nitrogen Compounds 
in Cottage Cheese. Cottage cheeses were made by ordinary sour- 
ing method from whole milk and from pasteurized and unpasteur- 
ized skim-milk, with and without rennet, and were examined at 
intervals to ascertain to what extent insoluble nitrogen com- 
pounds change into soluble ones, as in the case of cheddar cheese. 
Such proteolytic changes as occurred in 2 to 3 weeks were in- 
Significant. 
