A DAIRY LABORATORY GUIDE 73 



EXERCISE XIV 

 BABCOCK TEST AND USE OF RENNET 



1. Test by the Babcock method a sample of butter- 



milk and a sample of skimmed milk cheese 

 and whole milk cheese. Compare the results 

 of the cheese tests. 



2. Boil a sample of milk for about two minutes and 



then cool. Add some rennet and see if the 

 milk will coagulate. 



3. Boil 25 cc. of milk for about two minutes and 



then cool. Add one-half cc. of sulphuric acid 

 and see if the milk will coagulate. 



4. Add to 25 cc. of milk six drops of rennet. Have 



the temperature of the milk at ioo° F. Note 

 the time it takes the milk to coagulate. Test 

 25 cc. of the same lot of milk for acid. Com- 

 pute the amount of n/io alkali necessary to 

 neutralize the acid in 50 grams of the milk. 

 Divide the milk into two portions of 25 cc. 

 each and bring the temperature of each to 

 100° F. and add to each six drops of rennet. 

 Note the time it takes the samples to co- 

 agfulate. Compare with the length of time 

 required to coagulate the milk before the 

 alkali was added. 



