CREAM RIPENING. 189 



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 lac- 

 tarii) gave the most satisfactory results as a culture for ripen- 

 ing cream. Storch, who has perhaps studied this question 

 more than any one else, 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 not produce the characteristic flavor, and in- 



FIG. 124. The Wizard cream-ripening vat. 



dicates that the process of fermentation is necessary to get 

 the proper flavors. Dean, of the Ontario Agricultural College, 

 has recently reported that the flavoring substances can be 

 developed in the starter, then added to the cream. The re- 

 sulting butter has as good or a trifle better flavor than that 

 which undergoes a process of fermentation by ripening in the 

 usual way. 



From the investigations quoted above it will be seen that 

 there is some doubt yet as to the specific origin of the flavor 

 and aroma substances developed during cream-ripening. It 

 is also not known for certain just what those flavoring sub- 



* Milch-Zeitung, Vol. 13, p. 701. 



