6o A DAIRY LABORATORY GUIDE 



EXERCISE XI 

 BABCOCK TEST AND ACID TEST 



1. Make up an alkali tablet solution as directed. 



Shake frequently, and set aside for use later 

 in the exercise. 



2. (a) Test by the Babcock method a sample of 



whole milk and a sample of butter. 

 (b) Place a piece of butter in your acid measure 

 and allow it to stand in a cup of hot 

 water for about fifteen minutes. Then 

 with a pipette draw the fat from the sur- 

 face of the liquid. Weigh out the proper 

 amount and test by the Babcock method. 

 What conclusions do you draw from this 

 experiment ? 



3. Test for acid a sample of starter, using the 



alkali tablet solution furnished and n/io 

 alkali solution. Use 3 cc. of starter. 



4. Pour back and forth from one vessel to another 



about 100 cc. of skimmed milk. Do this for 

 about three minutes. Test 25 cc. of it for 

 acid, using the alkali tablet solution which 

 you made up at the beginning of the exer- 

 cise. Then boil about 35 cc. of the milk for 

 about one minute ; cool ; keep covered while 

 cooling, and retest 25 cc. for acid. Compare 

 with first test and see if you get lower re- 

 sults. 



Explain fully why lower results may be ex- 

 pected with boiled milk. 



The alkali tablet solution was made by dissolv- 

 ing ID alkali tablets in 115 cc. of water. 



