34 
LABORATORY MANUAL 
EXERCISE NO. 26 
Object: To become acquainted with the Babcock test for fat in buttermilk. 
Procedure: The general opinion among creamery operators has been that 
the loss of fat in buttermilk did not exceed .2%. Recent inves¬ 
tigations, however, have disclosed the fact that the loss rarely 
is less than .4%. The amount lost depends greatly on the 
methods of handling the cream and the churns. 
A. Thoroughly mix a sample of butter milk. Rapidly pipette 
17.6 cc. into a double necked bottle and add 20 cc. of acid. 
Mix well. Whirl a total of 10 minutes in three steps. 
B. Measure out 17.6 cc, of buttermilk into a second double necked 
bottle and add at least 22-25 cc. of sulfuric acid in two portions, 
mixing carefully after each addition. Whirl in a hot tester as 
follows: 15-3-2. 
C. Repeat “A” above by using an 8.8 cc. sample of buttermilk 
and 10 cc. of sulfuric acid. 
D. Repeat “B” above by using an 8.8 cc. sample and at least 11- 
13 cc. of acid and whirling in a hot tester 15-3-2. 
E. Test one 17.6 cc. sample of buttermilk in a whole milk test 
bottle. Use 20 cc. of acid and whirl a total of 20 minutes. 
Note: Method “A” is the old recommended method by which 
results below .2% were usually obtained, while method “B” 
and “D” are the improved methods by which results within 
.1% of actual gravimetric analysis are obtained. 
Observations: 
Sample 
cc. 
Butter 
milk 
cc. acid 
Length 
whirling 
% fat 
Color Condition 
1 
17.6 
10 
2 
17.6 
20 
3 
8.8 
10 
4 
8.8 
20 
5 
17.6 
20 
Conclusions: 
Questions: (l)The fat test of 150 pounds of whole milk is 3.4%, and 
the fat test of 128 pounds of skimmilk from this milk is .04%. 
What should be the approximate test of the cream? 
(2) Briefly describe the Association test for fat in buttermilk. 
