Temperature of Ripening. 127 
On the other hand, a considerable number of fac- 
tories in this country have secured an increased flavor 
and quality in them product from ripening their 
eream with the aid of either Hansen’s ferment or B. 41. 
The present status of the whole matter seems 
to be that the various commercial artificial ferments 
are now prepared in such form that they are readily 
transported, they retain their vitality for a consider- 
able length of time, and are practically free from 
any undesirable germs. Their use in careful hands 
is likely to be followed with uniformly good results. 
Still, where all of the surroundings are cleanly and 
the atmosphere pure, the use of such artificial germs is 
not necessary to produce butter of the highest quality. 
Temperature of ripening.—The various germs of 
lactic fermentations find their optimum growth point 
at from 80° to 90° F., and milk or cream kept at those 
temperatures will most rapidly become sour. The 
effect of such high temperatures, while favorable to 
the production of lactic acid, is less favorable to 
the texture of the butter, and on this account it is 
desirable to ripen the cream at as low a tempera- 
ture as will insure a fairly rapid growth of the lactic 
germs. <A temperature of from 60° to 70° F. will 
ordinarily bring this about. The amount of acid de- 
veloped in any given length of time will depend not 
only upon the temperature at which the cream has 
been kept, but also upon the number and activity of 
the germs originally present, so that if we have a 
thorough inoeulation to start with, a lower temper- 
ature will be sufficient to cause the development of 
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