198 Testing Milk and Its Products. 



There is, on the other hand, an increase in weight in the but- 

 ter made, owing to the admixture .of non-fatty components 

 therein, principally water and salt. Butter packed and ready 

 for the market will contain in the neighborhood of 84 per cent, 

 of fat (214), so that the fat recovered in the butter must be in 

 creased by ^rril.lQ. If B therefore designate the yield of but- 

 ter from 100 Ibs. of milk, the following formula will express the 

 relation between yield and fat content, provided there are no 

 other factors entering into the problem, viz.: 

 B=(f .20.) 1.19 



From this value for B, should be deducted the loss due to 

 wastes in the manufacturing processes, amounting to 3 per cent, 

 of the total fat in the milk handled, and we therefore have: 

 B=:(f .20) 1.16 



Since this table is based on a fat content of .2 per 

 cent, in the skim milk, the figures for the overrun are 

 slightly lower than may be obtained in creameries pro- 

 vided with up-to-date cream separators. 



221. Table XI in the Appendix, founded on this 

 formula, may be used to determine the number of 

 pounds of butter which milk containing 3 to 5.3 per 

 cent, fat will be likely to make. It presupposes good 

 and careful work in separating and churning and under 

 such conditions will generally show yields of butter 

 varying but little from those actually obtained. It may 

 be conveniently used by the butter maker or the manager 

 to check up the work in the creamery; the average test 

 of the milk received during a certain period is found 

 by dividing the total butter fat received, by the total 

 milk, and multiplying the quotient by ICO; the amount 

 of butter which the total milk of this average fat con- 

 tent will make, according to the table, is then compared 

 with the actual churn yield. 



