228 CRUAMURY BUTTER M/IKING 



sweet cream, the other for that which has more or less 

 soured. 



After all the cream has been sampled and weighed, the 

 tubes containing the samples for testing are placed in a 

 water bath at a temperature of 120 where the cream is 

 warmed preparatory to testing. A suitable rack, made 

 to fit the water bath, should be provided for the cream 

 tubes. When the cream has become sufficiently warmed 

 in the tubes, it is poured and repoured a few times and a 

 sample weighed out by transferring the cream to the test 

 bottle by means of an automatic pipette like that shown 

 in Fig. 70. This consists essentially of a pipette with a 

 rubber bulb at one end by means of which the cream 

 is sucked into the pipette and again forced out of it. This 

 method of forcing permits a rapid delivery of the cream. 



Testing. Accurate tests of cream can not be secured 

 by measuring the sample into the bottle as is done in the 

 case of milk. The reason for this is that the weight of 

 cream varies with its richness. The richer the cream the 

 less it weighs per unit volume. This is illustrated in the 

 following table by Farrington and Woll : 



Weight of fresh separator cream delivered by a 17.6 c.c. 



pipette. 



Per cent of fat Specific gravity Weight of cream 



in cream. (weighed). in grams. 



10 1.023 17.9 



15 1.012 17.7 



20 1.008 17.3 



25 1.002 17.2 



30 .996 17.0 



35 .980 16.4 



40 .966 16.3 



45 .950 16.2 



50 .947 15.8 



