2 Testing Milk and Its Products. 



from different sources, or even from the same sources 

 at different times, varies greatly in butter-producing 

 capacity, as will be shown under the subject of cream 

 testing (203 1 ). The system of paying for the number 

 of creamery inches delivered could not therefore long 

 give satisfaction. 



The proposition to take out a small portion, a pint or 

 half a pint, of the cream furnished by each patron, and 

 determine the amount of butter which these samples 

 would make on being churned in so-called test churns, 

 found but a very limited acceptance, on account 'of the 

 labor involved and the difficulty of producing a first-class 

 article from all the small batches of butter thus ob- 

 tained. 



2. The introduction of the so-called oil test churn in 

 creameries, which followed the creamery-inch system, 

 marked a decided step in advance, and it soon came 

 into general use in gathered-cream factories (202). In 

 this test, glass tubes of about % inch internal diameter 

 and nine inches long, are filled with cream to a depth 

 of five inches, and the cream is churned ; the tubes are 

 then placed in hot water, and the column of melted 

 butter formed at the top is read off by means of a scale 

 showing the number of pounds of butter per creamery 

 inch corresponding to different depths of melted but- 

 ter. While the oil test is capable of showing the differ- 

 ence between good and poor cream, it is not sufficiently 

 accurate to make satisfactory distinctions between dif- 

 ferent grades of good and poor cream. 2 As a result, 



1 Refers to paragraph numbers. 



9 Wlscon-in experiment station, bulletin 12. (Soonlso umlor203.) 



