Chemical Analysis of Milk and its Products. 213 



first dried on water bath and then ignited in a muffle oven 



at a low red heat. Direct heat should not be applied in 



determining the ash of milk, since alkali chlorids are 



likely to be lost at the temperature to which milk solids 



have to be heated to ignite all organic carbon. 



Example: Weight of porcelain dish+milk ..... 49.0907 grams. 



Weight of porcelain dish ............... 28.3538 grams. 



Weight of milk .............. 20.7369 grams. 



Weight of dish +milk,after ignition 28.5037 grams. 

 Weight of dish ................. ! ............. 28.3538 grams. 



Weight of milk ash ......... 1499 



.1499X100 

 Per cent, of ash = =.72 per cent. 



The residue from the determination of solids (251) 

 may also be used for the ash determination. 



258. Acidity of milk. The acidity of milk is conven- 

 iently determined by means of Farrington's alkaline 

 tablets (seep. 120), or by one-tenth normal soda solu- 

 tion. In the latter case, 20 cc. of milk are measured into 

 a porcelain casserole; a few drops of an alcoholic phe- 

 nolphtalein solution are added, and soda solution is drop- 

 ped in slowly from a burette until the color of the milk 

 remains uniformly pinkish on agitation. 1 cc. of N alkali 

 corresponds to .009 grams lactic acid, or to .045 per cent., 

 when 20 cc. of milk are taken (see p. 112). 



B. CREAM, SKIM MILK, BUTTERMILK, WHEY, CON- 

 DENSED MILK. 



259. The analysis of these products is conducted in 

 the same manner as in case of whole milk, and the same 

 constituents are determined, when a complete analysis is 

 wanted. Skim milk, butter milk, and whey generally 



