194 BUTTER-MAKING. 
dency of the desirable. When such overripened cream is 
churned, these undesirable germs are transmitted to the butter, 
and cause deterioration. If the butter is churned from properly 
ripened cream, and at the proper ripening stage, and the butter 
washed in purified water, very few undesirable germs are trans- 
mitted to the butter, and, as a consequence, it keeps better. 
Ripening Temperature of Cream.—In practice, the ripening 
temperature of cream varies within wide limits. Some makers 
prefer to ripen cream at a temperature of about 80° F., others 
ripen at about 70° F., and still others prefer to ripen at a tem- 
perature between 60° and 70° F. Undoubtedly, the conditions. 
in the creamery will to some extent govern the ripening tem-- 
perature. Up to a certain limit the higher the temperature, 
the quicker the ripening process. In some instances, it is. 
desirable to ripen and cool cream in a few hours, and then 
churn the same day. Under such conditions a comparatively 
high ripening temperature is undoubtedly preferable, as the 
cream will sour more quickly at such a temperature. Un- 
doubtedly good butter can be made at any of the temperatures 
mentioned above, but when we are to decide which temperature 
is the best, we are, through experimental evidence, forced to 
come to the conclusion that a ripening temperature between 
60° and 70° F. gives the best results. 
When cream is ripened at a high temperature it needs to be 
cooled very little previous to ripening. Milk is usually sepa- 
rated at a little above 80° F., and if the starter is added imme- 
diately after separation, it will ripen in a very short time. 
If ripened at a lower temperature, a longer time will be re- 
quired to develop the same amount of acid, and hence with a 
prolonged ripening period more attention is necessary. The 
Danish butter-makers ripen their cream at a comparatively 
low temperature, usually between 60° and 65° F., and obtain 
the best results. 
The germs producing lactic acid grow within a wide range 
of temperature; viz.: from about 50° to 100° F. The extreme 
temperatures are not favorable to the greatest possible growth. 
