MECHANICAL LOSSES 183 



milk from which was produced 35 per cent cream. The loss of 



butter fat in skim milk was .1 per cent. The cream was made 



into butter containing 80 per cent of butter fat. 



Answer: 



20,000 (4 — .1) . , 



c = = 2,234.96 pounds. 



35 — -I 



The amount of butter fat used for making the butter is the 

 amount contained in the cream or 



2234.96 X -35 = 782.236 pounds. 



The overrun is determined on amount of butter fat pur- 

 chased as whole milk. This overrun is therefore equal to 



(782.236 X 100/80 — 20,000 X 4/100) ^ . 



— ; ■ X 100 = 22.224. 



20,000 — 4/100 



Had no butter fat been lost in the skim milk then the over- 

 run obtained would have been equal to 



100 — 80 



X 100 or 25 per cent. 



80 



Therefore the overrun due to the loss of .1 of a per cent fat 

 in the skim milk has been reduced 2.776 per cent. It will be 

 noted from Table X that this reduction in overrun is decreased 

 slightly as the fat content of the butter increases. It is in- 

 creased as the fat content of the whole milk is decreased 

 (Table XI), and is decreased as the richness of cream decreases 

 (Table XII). 



