CREAM-RIPENING 219 



sible for the high flavor and aroma of butter. Conn claims that 

 the germs which act upon the nitrogenous matter of milk are 

 associated with the lactic-acid-producing bacteria in the pro- 

 duction of desirable butter flavors. Weigman asserts that 

 the best results are obtained when a variety of species work 

 together in the cream. He has isolated a single species of germ 

 which produces alcohol and lactic acid as by-products, and which 

 according to experimental evidence deduced by him, is capable 

 of producing the delicate butter flavors. Freudenreich also 

 studied a species of germ which produced alcohol and lactic acid 

 as by-products, and which he claimed was able to produce the 



FIG. 73. Cherry vat pasteurizer and cream-ripener. (J. G. Cherry Co.) 



characteristic butter flavors. Eckles studied the question of 

 flavor production during cream-ripening. He came to the con- 

 clusion that the flavor and aroma substances developed during 

 cream-ripening may be produced by a variety of acid-producing 

 bacteria. He asserts that of the species tried the most common 

 milk-souring organism (Bacterium lactarii) gave the most satis- 

 factory results as a culture for ripening cream. Storch, who has 

 perhaps studied this question to as great an extent as any of the 

 investigators, maintains that the germs producing lactic acid are 

 essential to good cream-ripening, and that the flavor and aroma 

 products are the results of the joint action of a great many 

 species of lactic-acid-producing germs. Tiemann finds that an 

 addition of a small amount of hydrochloric acid to the cream does 



