.. 



Calculation of Butti^and Cheese Yield. 



of butter made from it, and iindmg ^fiat^ter. cent, this 

 difference is of the amount of butter fat in the milk. 



Example 1 : 8000 Ibs. of milk is received at the creamery on 

 a certain day; the average test of the milk is 3.8 per cent. By 

 a simple multiplication we find that thd milk contained 8000 X 

 .038=304 Ibs. of butter fat. 340 Ibs. of butter was made from 

 this milk, as shown by the weights of the packed tubs. The dif- 

 ference between the weight of butter and butter fat is, therefore, 

 36 Ibs.; 36 is 36 t X100 =11.8 per cent, of the quantity of butter 

 fat in the milk; that is, the overrun for the day considered was 

 11.8 per cent. 



The formula for the overrun is as follows : 

 v _(b f) 100 



~T~ -r.aaa 



b and / designating the quantities of butter and butter 



fat, respectively, made from or contained in a certain 

 quantity of milk. In the preceding example, the calcu- 

 lation would be as follows: (340-aoi)xioo = ii < 8 per cent. 



804 



Example 2: 1000 Ibs. of cream testing 25 per cent, fat con- 

 tains 1000 X. 25=250 Ibs. butter fat. If 304 Ibs. of butter is 

 made, the overrun may be calcullated by subtracting the butter 

 fat from the butter, 304250=54 Ibs., 'then divide this by the 



fat in the cream and multiply by 100; or ^2^=18 per cent., 



oOO 



which is the cream overrun. 



219. Conversion factor for butter fat. A committee 

 of the Association of American Agricultural Colleges 

 and Experiment Stations at the ninth annual convention 

 of the Association reported that "in the ninety-day 

 Columbian Dairy Test, 96.67 per cent, of the fat in the 

 whole milk was recovered in the butter. This butter, on 

 the average, contained 82.37 per cent, butter fat; in 

 other words, 117.3 pounds of butter were made from 

 each 100 pounds of butter fat in the whole milk. 1 The 



1 When 82.37 Ibs. of butter fat will make 100 lt>s. of butter, how much 

 butter will 96.7 tt>s. of butter fat make? 82.37:96.67: : 100 :x, x= 117.3. 



