2. Select several pint samples of fresh milk, put into the jars or bottles, cool to 75° F., cover and keep at that temperature until curdling occurs.
3. The curdling or coagulation should take place in about 30 hours. An ideal curd should be firm, smooth, marblelike, free from holes or gas bubbles, and should show little separation of the whey. To be a good starter the curd should have a clean, sharp, sour or acid flavor.
4. Select the sample that most closely meets these conditions and propagate it. This is done as follows:
a. Prepare, shortly before using, a quart jar or bottle and a teaspoon according to the method described in paragraph 1.
b. Fill the jar or bottle with fresh skim milk and pasteurize by heating to 175° F. and keeping at that temperature for 30 minutes.
c. Cool to 75° F. and add a teaspoonful of curdled milk or starter described in paragraph 3, and set away to curdle.
d. Propagate the starter from day to day until one is found with desirable qualities. In doing this repeat steps a, b, and c, but in the last use the starter of the day before instead of that originally mentioned in paragraph 3.
Pasteurization
While for small-scale operations the pasteurization of milk may not always be practicable, it permits a better control of the fermentations, increases the yield of cheese, and renders the product safe from disease-producing organisms. If milk is pasteurized it is absolutely necessary to use a vigorous starter for ripening. Otherwise, great difficulty is found in draining the curd, and as a result the cheese probably is spoiled.
Skim milk is pasteurized for making cottage cheese by heating it in a pail, can, or vat to a temperature of 145° F. and holding it at that temperature for 30 minutes. The milk then is cooled quickly to 75° F., when it is ready for adding the starter.