CHAPTER VI. 



CREAMING. 



Cause. Creaming is due to the difference in the speci- 

 fic gravity of the fat and the milk serum. The fat being 

 light and insoluble rises, carrying with it some of the 

 other constituents of the milk. The result is a layer of 

 cream at the surface. 



Processes of Creaming:. The processes by which milk 

 is creamed may be divided into two general classes : ( i ) 

 That in which milk is placed in shallow pans or long 

 narrow cans and allowed to set for about twenty- four 

 hours, a process known as natural or gravity creaming; 

 (2) that in which gravity is aided by subjecting the milk 

 to centrifugal force, a process known as centrifugal 

 creaming, The centrifugal force has the effect of increas- 

 ing the force of gravity many thousands of times, thus 

 causing an almost instantaneous creaming. This force 

 is generated in the cream separator. 



Shallow=Pan Method. The best results with this 

 method are_ secured by straining the milk directly after 

 milking into tin pans about twelve inches in diameter 

 and two to four inches deep. It is then allowed to remain 

 undisturbed at room temperature (60° to 65° F.) for 

 twenty-four to thirty-six hours, after which the cream is 

 removed either with a nearly flat, perforated skimmer, or 

 by allowing it to glide over the edge of the pan after it 

 has been carefully loosened along the sides. The aver- 

 age loss of fat in the skim milk by this method is 0.7%. 



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