DAIRYING 



open than either that from the sweet or the pasteurized cream- 

 butter, and considerable brine showed in drops on the surface, 

 making the appearance as well as the flavor of this butter 

 decidedly different from that of the others. 



CREAM RIPENING STARTERS. 



525. The use of a starter in cream ripening is becoming 

 more common among butter makers every year. It is nearly 

 always made of skim milk which has been carefully soured 

 and in which the butter maker has attempted to propagate a 

 more or less pure culture of bacteria. 



526. The purpose of a starter is to supply cream with a 

 large excess of the ferments or bacteria which will control the 

 souring process and thus aid in developing good flavors in the 

 butter. Butter fat absorbs odors or flavors produced by the sour- 

 of cream and it is therefore essential that only such fermenta- 

 tions as will give butter its peculiar flavor are permitted to 

 grow in cream while it is ripening. Butter fat absorbs objec- 

 tionable as well as desirable products formed during the souring 

 process and the flavor of the butter is therefore influenced by 

 the kind of fermentation that takes place in the cream. 



527. The addition of selected sour milk to sweet cream 

 is something like adding yeast to bread, it "starts" the desired 

 fermentation in the cream. There are many becteria in milk 

 and cream, but the starter is used to control and to multiply the 

 good ones whose growth forms products that give butter a de- 

 sirable flavor. Milk and cream usually contain a great many 

 kinds of bacteria ; some of them are beneficial, others are in- 

 different, and still others are positively detrimental to the good 

 qualities of butter. 



528. It is generally believed that the lactic acid bacteria 

 are among the most desirable germs* for cream ripening, as 

 they convert milk sugar into lactic acid and produce the normal 

 sourmg of milk and cream. If there were no other kinds of 

 bacteria in cream, the butter made from day to day would 



* As a rule, the words bacteria and germs have the same meaning, and 

 they are therefore here used synonymously. 



