186 Testing Milk and Its Products. 



butter which milk containing 3 to 5.3 per cent, fat will 

 be likely to make. It presupposes good and careful work 

 at the separator, churn and butter worker, and under such 

 conditions will generally show yields of butter varying 

 but little from those actually obtained. It may be con- 

 veniently used by the butter maker or the manager to 

 check the work in the creamery; the average test of the 

 milk received during a certain period is found by divid- 

 ing the total butter fat received, by the total milk, and 

 multiplying the quotient by 100; the amount of butter 

 which the total milk of this average fat content will 

 make, according to the table, is then compared with the 

 actual churn yield. 



Example: A creamery receives 200,000 Ibs. of milk during 

 a month; the milk of each patron is tested and the fat con- 

 tained therein calculated. The sum of these amounts of fat 

 may be 7583 Ibs.; the average test of the milk is then 3.79 

 per cent. According to table XI, 10,000 Ibs. of milk, testing 3.8, 

 will make 418 Ibs. of butter, and 200, 000 Ibs., therefore, 8360 Ibs. 

 of butter. The total quantity of butter made during the month 

 will not vary appreciably from this figure if the work in the 

 creamery has been properly done. 



221. b. Use of overrun table. The table referred to 

 above gives a definite calculated butter yield for each 

 grade of milk, according to average creamery conditions. 

 As it may be found that this table will give uniformly 

 either too low or too high results, table XII in Appen- 

 dix is included, by means of which the butter yield cor- 

 responding to overruns from 10-20 per cent, may be 

 ascertained in a similar way as above described. 



The total yield of butter is divided by the total num- 

 ber of pounds of fat delivered; the quotient will give the 



