86 



BUTTER-MAKING. 



free the fat. The contents of the bottle should be well shaken 

 at once after the acid has been added. 



The bottle with its contents is then whirled about five 

 minutes in a centrifugal machine at a rate depending upon the 

 diameter of the machine, usually about 850 to 1000 revolutions 



Fig. 33. 

 Skim-milk 

 test-bottle. 



Fig. 34. 

 Whole-milk 

 test-bottle. 



Fig. 35. 

 Cream test- 

 bottle 



Fig. 36. 



9-gram cream 



test-bottle. 



Fig. 37. 



Cream 



test-bottle. 



Babcock Test-bottles. 



per minute. The machine is then stopped and filled to the 

 neck of the bottle with pure hot water. Distilled water is 

 preferred. The bottles are then whirled two minutes, and 

 hot water added again until the fat rises in the neck where it 

 can be read. The bottles are then whirled againJor about one 

 minute. The machine is then stopped and the fat read in 

 percentage direct from the bottle. By using a pair of dividers 



