Cream Testing. 



83 



and dividing the product by the weight of the cream 

 taken. 



Example: Weight of cream tested, 5.2 grams; reading of 

 columns of fat tH.S, 2 '4. 7, average 4.75; percent, of fat in the 



cream 



5.2 



b- 



c - 



The weighing of cream and the reading of the fat col- 

 umn must be made very carefully; a division of one- 

 tenth on the neck of the test bottle has a 

 value of over three-tenths of one per cent. 

 of fat when 5 grams of cream are tested, 

 _ r and six-tenths of one per cent, if only 3 

 grams of cream are weighed out. The 

 reading is rendered more accurate and 

 certain if a number of tests of a sample 

 are made, at least two or three, and the 

 results averaged. 



The accompanying illustration (fig. 

 35), shows the proper method of reading 

 the fat column in cream tests; readings 

 are taken from a to &, not to d or to c. 1 



95. No special precautions other than 

 FIG. 35. Measur- those required in testing milk have been 



ing the fat column 



in the neck of a found necessary in testing cream, except 



cream bottle. Read- 



a. 



or to c - 



^^ ^ * s some ^ mes advisable not to whirl 

 the test bottles in the centrifuge at once 

 after mixing, but to let the cream-acid mixture stand for 

 awhile, until it turns dark colored. At first, the mix- 

 ture of cream and acid is much lighter colored than that 

 of milk and acid, owing to the smaller amount of solids 

 not fat contained in the cream. 



iThe size of the meniscus is magnified in the cut. 



