The Use of Starters
The first step in the making of cottage cheese is to sour or ripen the milk. If care has been used in the production and handling of milk, a good grade of cheese may be made by allowing the milk to sour naturally. Uncertainty of results and lack of uniformity in the cheese, however, have caused many to resort to a more definite means of controlling fermentation or souring by the use of starters. Some of the dangers and disadvantages of natural souring are—
1. Slow coagulation or curdling.
2. Glassy and undesirable fermentations, causing loss of curd in whey.
3. Bitter and other undesirable flavors.
4. Lack of uniformity in the cheese.
Fig. 1.—Bottles of Starter.
When cottage cheese is to be produced in large quantities it is advisable to use a starter. Starters aid and hasten acid fermentation and tend to suppress and eliminate undesirable fermentation. A starter, in brief, is a quantity of milk in which the acid-forming bacteria have grown until the milk contains a great number of them. There are two kinds of starters, commercial and homemade.
Fig. 2.—Stirring in starter and rennet and taking temperature.
Commercial Starters
When cottage cheese is to be made on a large scale it is advisable to use a commercial starter, obtainable from a reliable starter company or through a dairy-supply house. The small package of starter, which may be either liquid or solid, is added to a pint of pasteurized skim milk and the milk covered and set away at 75° F. to sour. This is called a “mother starter.” After curdling or coagulation, a teaspoonful of the “mother starter” is added to a quart of pasteurized skim milk, which, when coagulated, is used to ripen the milk for cheesemaking. In pasteurizing milk for starters, it is heated to 175° F. and held at that temperature for 30 minutes, after which it is cooled to 75° F. before the starter is added.
Homemade Starters
Homemade starters are made as follows:
1. Clean thoroughly and boil for five minutes several pint fruit jars or wide-mouthed bottles, together with tops or tumblers for covering them. ([Fig. 1].) After boiling, keep the jars or bottles covered to prevent the entrance of bacteria.
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.