344 CREAMERY BUTTER MAKING 



been washed out, put the jar down and allow to remain 

 quite a few minutes, or until all the fat floats on top of 

 the water. The salt contained in the butter is in the 

 clear liquid below the fat. 



Now remove 17.6 c.c. of the clear liquid by inserting 

 a pipette through the layer of fat, blowing through it 

 as the point passes through the fat to keep the latter out 

 of the pipette. Put the sample thus selected in a white 

 tea cup and add one drop of "indicator" prepared as 

 directed below. Next add, from a burette "silver nitrate 

 solution" prepared as explained later on. Shake the cup 

 after each addition of the nitrate solution. Continue add- 

 ing small quantities of silver nitrate solution until a faint 

 red color is produced, which remains after shaking. 

 Every c.c. of silver nitrate solution added represents I 

 per cent of salt in the butter. For example, if 3.5 c.c. 

 of solution are required to produce the faint red color, 

 the butter contains 3.5 per cent salt. 



Silver Nitrate Solution. This is prepared by dissolv- 

 ing 5.1 grams of chemically pure silver nitrate crystals 

 in 250 c.c. of pure water. The silver nitrate solution 

 should be preserved in a brown, glass stoppered bottle. 

 The brown glass protects the solution from light which 

 decomposes it. Keep the solution in a dark place when 

 not in use. Owing to the tendency of the solution to lose 

 strength, it is best to make up a new solution at least 

 once in two months. 



Indicator. The indicator is prepared by dissolving 

 one ounce of chemically pure potassium chromate in lOO 

 c.c. of water. 



