132 Milk and Its Products. 
stopped before the churning is completed, and much 
fat is lost in the buttermilk. It is a matter of 
considerable practical importance, so far as loss of 
fat is concerned, and to some extent also upon the 
flavor of the butter, that all of the cream churned 
at one time should be ripened together, evenly and 
uniformly. If creams of different ages are to be 
churned together they should be mixed together at 
least twelve hours before churning, so that the con- 
dition of acidity shall be the same throughout the 
whole mass. 
Bad effects of over-ripening.—When too much lactic 
acid is developed in the cream the casein is firmly 
coagulated, and in the process of churning is broken 
up into minute granules, which become ineorpo- 
rated into the butter in the form of white specks or 
flakes of casein. Such white specks, besides injur- 
ing the appearance of the butter, greatly detract 
from its keeping qualities, as the putrefactive fer- 
mentations soon set up in them and give rise to 
disagreeable flavors. Danger from this source is 
Hable to be present if the coagulation of the cream 
has gone so far that any whey has separated. The 
eream should in all cases be churned before the ripen- 
ing process has reached this pomt. It was formerly 
supposed, and is still generally believed, that the pro- 
duction of an excess of lactic acid in ripening tends 
to a loss of butter, from the fact that the aeid 
dissolved or “eut” the fat, causing it to disappear. 
This has been shown, both theoretically and practi- 
eally, not to be the case. Lactic acid has no appre- 
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