TESTING BUTTER 647 



mate. A solution of silver nitrate containing 29.06 grams per liter, 

 is then added slowly from a burette, the mixture containing the 

 butter being thoroughly shaken or stirred. After the first 

 appearance of a brick-red coloration, the silver nitrate solution is 

 added, a drop at a time, until a brick color develops which is perma- 

 nent for several minutes after thorough stirring or shaking. 



If 10 grams of butter have been taken, each cc. of silver nitrate 

 solution used represents .1 per cent of salt in the butter ; thus, if the 

 burette reading showed 29 cc. of silver nitrate solution had been 

 used, the butter under examination contained 2.9 per cent salt. If 

 only a 5 gram sample is taken, each cc. of silver nitrate solution used 

 will represent .2 per cent of salt in the butter. 



The residue from any of the moisture tests can be used by add- 

 ing a little water to replace that driven off by drying, and the chem- 

 icals as directed above. (The titration can be made in the same cup 

 used for the moisture determination.) 



If the commercial acetone is not available a mixture of equal 

 parts of alcohol and ether may be substituted with equally good 

 results. (Denatured alcohol such as is sold for fuel purposes, and 

 the cheaper grades of ether are entirely satisfactory.) 



SALT TEST FOR FACTORY USE 



By Hunziker and Hosman. 1 



Equipment. One salt tester. This is a copper container, 3| 

 inches deep, 2y 2 inches in diameter, and holding about 250 c.c. It 

 is equipped at its top edge with a heavy rubber ring on which the 

 moisture evaporating dish is inverted, and with a lightning jar 

 wire clamp for pressing the evaporating dish down on the rubber 

 ring. 



One 100 c.c. glass cylinder (low style). 



One 25 c.c. pipette. 



One or more 150 c.c. flasks (cone shape) for titrating. 



One 50 c.c. burette with stand. 



One large bottle, with glass tubing and clamps to connect with 

 burette, for standard silver nitrate solution. 



One small bottle for potassium chromate solution. 



Chemicals. Silver nitrate solution containing- 7.265 grams 

 silver nitrate in 1000 c.c. water. 



Potassium chromate solution. 



1 Hunziker and Hosman, Blue Valley Research Laboratory, 1918. 



