DAIRYING 151 



long. Place the thermometer in the glass, and 

 pourin all the milk. Stir rapidly for ten seconds, 

 then remove the thermometer. Directly the 

 milk coagulates the straws should stop and 

 reverse, usually at the end of about twenty- 

 two seconds, which is then called a twenty-two 

 second rennet test. The milk for cheese- 

 making should give an acid test of from .21% 

 to .22%, and a rennet test of twenty-two or 

 twenty-three seconds. 



If the milk is too sweet acidity must be Starter 

 promoted by adding sour milk or whey. 

 Milk which gives as much as a twenty-eight 

 second rennet test is sweet, and should have 

 about 2% of starter added. With a twenty- 

 four second rennet test i% is sufficient. 



Rennet acts best at a temperature of about Setting 

 95 F., but the best results are obtained 

 between 84 and 86. If milk is set at a 

 high temperature, the fat has a tendency to 

 separate, but at 85 (the usual temperature), 

 we obtain a fairly rapid coagulation without 

 injuring the fat. The setting temperature 



