DATRY HUSBANDRY 
33 
SERIES D. 
Testing Skimmilk, Buttermilk, ami Whey for Fat. 
Materials necessary for 10 students: 
20—Double necked test bottles graduated in .01 % up to .5%. 
5 —25 cc. graduated cylinders. 
EXERCISE NO. 25 
Object: To lest skimmilk for fat using two different quantities of acid and 
varying whirling time. 
Procedure: It has been found that if a sample ot skimmilk is tested for 
fat as whole milk is tested, the result will be much less than 
the actual amount of fat present. 
A. After thoroughly mixing the sample of skimmilk, measure out 
17.6 cc. into a double necked bottle, add 17.5 cc. of sulfuric 
acid, mix, and whirl as for whole milk. Read without a water 
hath. « 
B. Obtain a 17.6 cc. sample as above, but add at least 22 cc. of 
sulfuric acid in two portions, mixing thoroughly after each 
addition. Whirl at the usual speed as follows: 15-3-2. 
C. Use whole milk test bottles and add 17.5 cc. of acid to 17.6 cc. 
of skimmilk and complete the test as for whole milk. 
Observations: 
Sam 
iple 
cc. acid 
Time of 
Whirling 
% fat 
Color 
Condition 
1 
a 
b 
2 
a 
b 
3 
a 
b 
Conclusion: 
Questions: (1) Why are double necked bottles to be placed with the 
fdling tube toward the center of the tester? 
(2) What reason can be given for the fact that not all of the fat 
gathers in the neck of the bottle when skimmilk is tested for 
fat? 
(3) If a separator leaves .2% fat in the skimmilk, how much fat 
would be lost in 2855 pounds of skimmilk? 
(4) Why should a sample of skimmilk not be pipetted into the 
test bottle immediately after separating? 
References: F. & W. f 97, 98, 99, 100; Van S. pp. 93-95; Jud p. 85; St. 
pp. 129-130. 
