378 



EXPERIMENT STATION RECORD. 



[Vol. 40 



observations were made during 43 working days at the Minnesota State 

 creamery. 



Preliminary studies, some detail* of which are given, convinced the authors 

 that the Babcock test for milk and cream, carried out with care, gave results 

 sufficiently accurate for their purpose. Deviations from standard practice, 

 however, in conducting the test were not found wise. Errors in sampling 

 the sweet and not very rich cream handled in the creamery were found to be a 

 far greater source of inaccuracy than the trifling errors of the Babcock 

 method. 



An endeavor was made to determine accurately the fat loss at every stag 

 manufacture under normal operating conditions. The weight cans, vats, flash 

 pasteuriser, pipes, pump, etc., after the usual rinsing, were thoroughly scrul 

 with hot water, which was then weighed and quickly sampled. The butter 

 wash-water and the hot churn wash-water were both weighed into the churn 

 and sampled as sunn as used. Wash-waters were all tested by the Bab 

 method (skim milk bottles). Roth gravimetric Mid Babcock tests were ap- 

 plied to the skim milk and buttermilk. I •• samples were taken from at 

 least 10 different places in the churn and given gravimetric analyses. Tlu? 

 details of the unavoidable are given in the subjoined tab 



Loss of butter fat in tin mechanical proceat of the manufacture of buti 



Source of loss. 



daily 

 Ums. 



Milk woiRh can, vat.heater 



Cream forewarmer, flash pasteurizer, and cooler 



Cream ripener 



Butter wash-water 



Churn wash-water 



Total for whnle-miik rro:imrrv 



Total for hand-separator creamery 



Pound'. 



.1.". 

 .14 



Total fat 



in milk 



used. 



Per cent. 

 0.13 



.» 



.03 



.14 





.47 



As this mechanical lo radically Independent of tin' volume of product 



handled, the percentage loss in a large creamery is small, but careless work 

 would greatly increase it. 



The chief can--.' of unaccountable losses of butter fat was the fact that the 

 Babcock method gave only about one-third of the true amount of fat in skim 

 milk and buttermilk, as is shown in the following tabulation: 



Failure of Babeork test to account satisfactorily for fat losses in skim milk 



and buttermilk. 



Disposition of fat. 



I 



Babcock 

 method. 



Gravi- 

 metric 

 method. 



Fat lost in skim milk... 

 Fat lost in buttermilk.. 

 Fat lost mechanicallv. . 

 Fat recovered in butter 

 Fat not accounted for. . 



Per crnt. 

 0.49 



Ptr cm!. 

 .60 



96. 72 



.ii 



Percentage loss< 9 in skim milk and buttermilk would not be affected by the 

 size of the creamery, in a whole-milk creamery the losses from all sources 



are estimated as 3.17 per cent, and in a band-separator creamery (losses in 



