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. 
