THE DAIRY. 121 



0"2 to O'o. The two latter processes are thus the most 

 effective for the removal of cream. Ordinary skim-milk 

 will contain about as follows : — Water, 90-0 ; albuminoids, 

 37 ; fat, 0*8 ; sugar, 4-8 ; ash, O'T. Its specific gravity is 

 generally 1*034 to 1-037. Skim-milk is a very nitrogenous 

 food, the albuminoid ratio being as high as 1 : 1*7. 



Butter. — The object of butter-making is to bring about 

 the union of the fat globules which in milk and cream 

 have existed separate from each other. The skilled butter- 

 maker is not, however, satisfied with producing a solid 

 mass of butter-fat ; for butter to be of good quality it 

 must possess a certain texture and grain, and be neither 

 hard nor greasy ; this desired result can only be attained 

 by churning at a favourable temperature. If the tem- 

 perature of the cream is too low, the butter will be long 

 in coming, and will be hard in texture. If the tempe- 

 rature is too high the butter will come very speedily, but 

 the product will be greasy, destitute of grain, and de- 

 ficient in quantity. No temperature can be fixed as the 

 best at which churning should always take place. The 

 proportion of solid and fluid fats in the milk varies some- 

 what with the diet of the cow^s, and this necessitates a 

 change in the temperature. A rather higher temperature 

 will be required in winter than summer ; the temperature 

 must also be higher for sour cream than for sweet cream. 

 Generally speaking, perfectly sweet cream should be placed 

 in the churn at 50° to 55° Fahr., and sour cream at 52° 

 to 60°. When sour milk is churned for butter the tempe- 

 rature must be about 65°. The exact temperature most 

 suitable for churning may be ascertained by recording 

 every day the temperature employed, with the length of 



