70 
LABORATORY MANUAL 
EXERCISE NO. 53 
Object: To become acquainted with the alcohol test for quality of milk. 
Procedure: It has been claimed that the alcohol test is a better indication 
of the suitability of milk for condensing than the acidity test. 
A. The alcohol solution is prepared by using ethyl alcohol, diluted 
with distilled water so that it contains 60% by weight or 68% 
by volume of ethyl (grain) alcohol. 
B. The test is made by using a clean small test tube and tilling 
about one-third of the milk to be tested. An equal quan¬ 
tity of the above alcohol solution is added and mixed. After 
mixing, the tube should be slowly raised to a vertical position. 
White flakes on the glass indicate a strong degree of acidity. 
A slight film indicates a slight degree of acidity. A clear glass 
indicates a low degree of acidity. 
C. Test the milk provided by means of Mann’s acidity test and 
compare with tests of the same milk made with the alcohol 
solution. 
Observations: 
Sample 
% Acidity 
Condition with alcohol test 
1 
2 
3 
Conclusions: 
Questions: (1) How much light and ventilation should be provided for 
each cow when a stable is being constructed? 
(2) How should a milk house be constructed and where should it 
be located? 
(3) Why are partly covered pails superior to the open top pail? 
(4) Why should turnips, ruta-bagas, silage, etc., not be fed during 
the milking period? 
References: F. & W. ^ 152-158; Van S. pp. 153-154. 
