20 SCIENCE AND PRACTICE OF CHEESE-MAKING 



Propagation of starter. — In a can that has been 

 thoroughly cleaned and sterilized, place two gallons of 

 clean, fresh skim-milk. Heat the milk to 185° F. for 

 one hour by setting the can in boiling water. Stir 

 the milk frequently to insure even heating. After the 

 milk has been held at this temperature for one hour, 

 it may be cooled immediately to 70° F. by placing 

 the can in cold water. Then add the contents of the 

 small vessel that was prepared on the previous day, 

 stirring it in with a sterilized spoon. Hold the tem- 



FIG. 6 — THIS STYLE OF DIPPER HAS A SOLID HANDLE 

 AND IS EASY TO KEEP CLEAN IN EVERY PART 



perature at 70° F. for 18 hours. At the end of this 

 period the milk should be sour and firmly coagulated. 

 A uniform starter can thus be prepared from day to 

 day, always adding enough of the coagulated starter 

 to the amount of pasteurized skim-milk necessary for 

 the cheese-making process. 



Precautions. — All vessels, pails, dippers, thermome- 

 ters and everything with which the starter-milk comes 

 in contact should be sterilized before being used. 

 Starters should not be prepared from the milk mixed 

 in the vat or from whey. A good starter is an in- 

 valuable aid in cheese-making, while a bad one is a 

 sure source of trouble. As soon as the starter loses 



