WHY CREAM TESTS VARY us 



cream that too much care cannot be exercised in 

 order to maintain a uniform and correct speed, 

 as by doing so less variations in the cream will 

 occur. 



Fig. 1 1 above shows the percentages of butter 

 fat contained in the various milks which were used 

 throughout these trials (with the exception of the 

 first), and it will be observed that these percentages 

 vary from 2*9 % to 4*8 %. Table I. gives purely 

 the result of working a separator at varying speeds. 

 It will be noticed from the figures given that turn- 

 ing the handle at the correct speed, viz. 60 revolu- 

 tions per minute, gave a cream containing 54 % of 

 butter fat, but when the speed was reduced to 45 

 revolutions, using the same machine and the same 

 milk, the percentage of butter fat in the resulting 

 cream was immediately reduced to 26 %, whilst 

 irregular turning, such as turning the handle some- 

 times too fast and then too slow, produced a cream 

 containing 44 % of butter fat. All these factors go 

 to show how very easily cream tests can fluctuate 

 from day to day simply through varying the speed 

 of the separator. I fear that cream suppliers do 

 not realise sufficiently how important a matter speed 

 is in connection with cream separating, as they have 

 so frequently assured me that their separators are 

 always turned at the correct speed, whereas I know 

 from experience that this cannot be the case, espe- 

 cially with the class of labour usually employed in 



