AERATING OR BLOWING CREAM 223 



This fan draws the air from the outside of the factory and 

 pumps it through the cream. In order to insure pure air 

 for this purpose, the air is drawn through absorbent cotton, 

 canvas or other filtering material, usually placed in a funnel 

 at the suction end of the air pipe on top of the roof. This 

 filter removes the dust, soot, flies and other impurities in the 

 air. From this funnel the air is generally drawn through a 

 water bath, preferably lime water, for additional cleansing. The 

 lime water not only removes dirt, etc., but also absorbs car- 

 bon dioxide and other gases, some of which may contain objec- 

 tionable odors. 



From the lime water bath the air is blown through the 

 cream in the vat, or fore warmer, or both, through perforated 

 pipes installed in the bottom of the vat. In some of these 

 blowing systems, the vat is closed during the blowing opera- 

 tion and a second pump or fan draws the air escaping from 

 the cream to the outside. The blowing generally occupies 

 from 20 to 30 minutes. In some creameries the cold cream is 

 blown, in others the air is blown through the hot cream. 



In the third method of aeration the cream is enclosed in 

 a nearly air-tight chamber, to which suction is applied, sucking 

 the air and gases present in the cream out of it. This method 

 represents a partial evacuation of the air in the cream. 



Effect of Aeration on Flavor of Cream and Butter. There 

 can be no question that any form of aeration, assists in removing 

 objectionable gases, odors and flavors, that may be present, and 

 therefore, improves the flavor of the cream and butter to that 

 extent. The more intimate the contact of the cream with the 

 air, the more complete is the removal of odors. In this 

 respect, therefore, the blowing of cream is a more effective 

 method of aeration than the mere surface exposure of the 

 cream to the air. 



Effect of Aeration on the Keeping Quality of Butter. 

 From, the standpoint of the keeping quality of the butter, any 

 method of aeration, that mixes air into the cream, is positively 

 objectionable. The newer knowledge of butter deterioration is 

 demonstrating conclusively, that the fundamental agencies that 

 shorten the life of butter, that cause it to deteriorate and to 

 develop flavor defects with age, are intimately associated with 



