RECEIVING, SAMPLING, AND GRADING. 



87 



the reading may be facilitated. The temperature at the time of 

 reading should be between 120° and 140° F. 



There are three very common defects in the clearness of fat 

 reading: (1) The fat contains black, charred, flocculent matter 

 at the bottom of the fat column. This is commonly caused by 



frl 



Fig. 38. _ Fig. 39. Fig. 40. Fig. 41. 



Wagner's skim- Ohlson's skim- Butter test-bott!e, and Russian Babcock 



milk bottle. milk bottle. funnel which holds test-bottle and 



(Both with pneumatic fat- about 9 grams of reading-tube, 



indicator (pat.).) butter. 



using too much or too strong acid or mixing milk and acid at too 

 high a temperature. The remedy is to use less acid or to 

 cool milk and acid before mixing. The black charred matter 

 may also be due to allowing the acid to stand in contact with 

 the milk too long a time before mixing or by pouring acid 

 through the center of the milk. (2) There may be a layer of 

 white flocculent matter at the bottom of the fat column. This 

 is due to not having used enough acid or to the temperature of 

 milk and acid being too low or to not mixing the acid and milk 



