138 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 incorpo- 

 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 

 liable to be present if the coagulation of the cream 

 has gone so far that any whey has separated. The 

 cream should in all cases be churned before the ripen- 

 ing process has reached this point. 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 acid 

 dissolved or "cut" the fat, causing it to disappear. 

 This has been shown, both theoretically and practi- 

 cally, not to be the case. Lactic acid has no appre- 



