THE CUEMISTET OF BUTTER MAKING 67 



being due to impurities. The salt crystals should 

 be clear and of medium granulation. If the crystals 

 are too large in size, overworking of the butter may 

 be necessary in order to incorporate the salt. If the 

 butter is worked too dry and too much fine salt is 

 used, the salt will separate and form a crust on the 

 surface of the butter. A pure salt will not become 

 very moist when stored in a reasonably dry room, 

 neither will it form hard cakes which crush with 

 difficulty. Salts that are not pure may impart an 

 undesirable taste and flavor to the butter. 



67. Buttermilk. — Buttermilk has about the same 

 general composition as skim milk. It is practically 

 the skim milk of cream and varies in fat content 

 with the exhaustiveness of churning. Buttermilk 

 may contain a high per cent of fat, but ordinarily 

 it contains .2 of a per cent or less. The composi- 

 tion of buttermilk is generally about as follows : — 



Water 90.50 



Fat 0.20 



Casein and albumin 3.30 



Sugar ........ 5.30 



Ash 0.70 



If not overdiluted with wash water, buttermilk has 

 practically the same feeding value as skim milk. 



68. Losses of Fat in Butter Making. — When 100 

 pounds of milk are creamed, about 80 pounds of skim 

 milk and 20 pounds of cream are obtained. If the 

 milk tests 4 per cent fat, and the cream is care- 

 fully churned, it will make about 4.6 pounds of 



