Dairying 



381 



whey differ in a few details from that of testing 

 whole milk. When testing cream, the sample 

 is weighed, 18 grams being the quantity used. 

 About 17.5 c.c. of acid is added to each sample, 

 but the quantity is varied slightly with the rich- 

 ness of the cream, rich cream requiring slightly 

 less acid than thinner cream. Experience will 

 aid in determining the exact quantity to be used. 

 Be careful when rotating the bottles after adding 

 the acid ; the fat will burn if the rotating is too 

 vigorous. After the acid is added let the sample 

 stand four minutes before placing it in the 

 tester. The other operations are the same as 

 for whole milk. In reading the percentage of 

 fat, read as shown in Fig. 163. When testing 





FIG. 161. 

 Method of read- 

 ing fat column 

 in milk testing. 

 Read from a to 

 b, not from a 

 to c, nor a to d. 



skim-milk, 

 buttermilk, 

 or whey, use 

 20 c.c. of acid. Place each 

 bottle in the tester with the 

 filling tube toward the cen- 

 ter. This is to prevent any 

 fat from being caught be- 

 tween the tube and the 

 sides of the bottles after 

 the whirling in the tester. 

 Turn the tester a little faster 

 than for whole milk. If 

 there is a layer of curd at 

 the bottom of the fat column 

 do not include it in the read- 

 ing. Read the fat column 

 as for whole milk. A pair 



FIG. 162. - Dividers for measuring length f dividerS is especially US6- 



of fat column. 



ful for these readings. 



