608* DETERMINATION OF TOTAI, SOLIDS 



serum conform to the above assumptions. The actual weights found 

 in most cases will be somewhat less than the weights given in the 

 table because of the varying amounts of air in the cream. They are 

 calculated on the bases of a temperature of approximately 60 F. 

 Cream at a higher temperature will weigh slightly less and cream at 

 a lower temperature will weigh slightly more. 



DETERMINATION OF TOTAL SOLIDS IN MILK, SKIM 

 MILK, CREAM AND BUTTERMILK 



By Means of the Babcock Formula. For rapid and reason- 

 ably accurate work the total sglids of milk may be determined by 

 the use of the Babcock formula, which is as follows : 



Total solids -^ + 1.2 X f. 

 L = Quevenne lactometer reading, 

 f = per cent of fat. 



Example : Lactometer reading is 32 ; per cent fat is 4. 



32 

 Total solids =-j-+ 1.2 X 4= 12.8 per cent. 



For the determination of the solids not fat use the formula : 



-^+.2xf. = per cent solids not fat. 

 or deduct the per cent fat from the per cent total solids. 



The Babcock formula for the determination of total solids and 

 solids not fat is applicable only to milk and skim milk. For cream 

 and buttermilk the gravimetric method is recommended. See also 

 Table 103, showing per cent total solids in milk and skim milk when 

 per cent fat and lactometer reading are known. 



Gravimetric Method. "Heat from three to five grams of milk, 

 skim milk or buttermilk at the temperature of boiling water until it 

 ceases to lose weight, using a tared flat dish of not less than 5 c.c. 

 diameter. If desired, from fifteen to twenty grams of pure, dry 

 sand may be previously placed in the dish. Cool in a desiccator 

 and weigh rapidly to avoid absorption of hygroscopic moisture. In 

 the case of cream use only two to three grams of sample." 





