Origin of Btttter Flavors, 129 



lactic acid in ripening-, Tiemann''^' fonnd that in cream 

 to which a small amount of hydrochloric acid had 

 been added there was no difficulty in churning the 

 butter, that the general flavor of the butter was 

 good, but that it lacked in aroma and had a some- 

 what oily texture. 



There is some doubt as to the origin of the 

 characteristic flavors which are developed in the cream 

 during the ripening process. These flavors are un- 

 doubtedly due to the presence of certain volatile sub- 

 stances — fats, bacterial products, or ether- like com- 

 pounds — which are formed during the ripening pro- 

 cess. It was formerly supposed that the production 

 of the characteristic flavors was almost wholly a pro- 

 cess of oxidation, and that cream, in order to be prop- 

 erly ripened, and to develop the best flavors, must be 

 supplied with an abundance of oxygen in pure air 

 during the process. Our knowledge of the presence of 

 germs in milk and cream and the effect of their 

 growth upon the various constituents of the milk, has 

 led us to modify these views. At the present time it 

 seems probable that the growth of germs which pro- 

 duce lactic acid has much to do with the production 

 of the characteristic flavors of ripened cream. It has 

 been asserted by some, notably Conn, that the produc- 

 tion of the flavors is due to the growth of specific 

 flavor -producing germs that are largely independent of 

 the formation of lactic acid, but this view does not 

 seem to explain all of the phenomena of the appear- 



*Milch Zeitung, xxiii p. 701. 

 I 



