54 



THE BOOK OF BUTTER 



FIG. 15. The water-dilution 

 method of cream separation. 



This loss of milk-fat from the milk of a single cow 

 giving 5000 pounds of milk each year, is shown in Fig. 16. 

 The skimmed-milk usually amounts to about 85 per cent 



of the whole milk, which 

 in this case would mean 85 

 per cent of 5000 pounds of 

 whole milk, or 4250 pounds 

 of skimmed-milk. In the 

 manufacture of butter, cer- 

 tain amounts of moisture, 

 salt, and casein are incor- 

 porated. Thus it is possible 

 to make more butter from 

 a certain amount of milk-fat 

 than there was original fat. 

 This increase is known as 

 over-run. In the computation in Fig. 16, allowance 

 was made for an over-run of one-sixth of the original 

 amount of milk-fat. 



According to the statements given, if the price of 

 butter were 30 cents a pound, there would be an annual 

 loss of $9.60 on each cow by the use of the water-dilution 

 method, and $2.25 on each cow by the use of the deep- 

 setting method. These losses are computed on the basis 

 of the amount of milk-fat lost through the use of these 

 methods as compared with the amount lost if a modern 

 centrifugal separator were employed. 



SEPARATION BY CENTRIFUGAL FORCE 



The centrifugal cream separator has meant very much 

 to the dairy industry. It would not be possible, with 

 the old gravity methods, to separate the cream in some of 

 the modern creameries where 50,000 to 75,000 pounds of 



