TESTING BUTTER 649 



(7). If the sample of butter is not exactly 10 grams, but some- 

 what more or less, the per cent of salt is readily calculated by divid- 

 ing the c.c. silver nitrate solution required, by the exact weight of 

 the sample of butter. Say the sample weighed 10.5 grams and re- 

 quired 35 c.c. of silver nitrate solution, the butter then contained 



i =3.3% salt, p^ltfe" i "^ :.:;;;.:: 



(8). This salt test occupies about five minutes. It is exceed- 

 ingly simple and accurate, when made in accordance with the above 

 directions. It eliminates the weighing of the sample for the salt 

 determination and it automatically washes the moisture evaporating 

 cup. For uniformly reliable results the following precautions must 

 be observed : 



(a). Do not slobber the melted butterfat in the evaporating 

 dish, over the outside of the salt tester. The butter must stay inside 

 of the periphery of the evaporating dish, when the latter is inverted 

 over the tester. 



(b). Do not use water at a temperature lower, nor much 

 higher than 100 F. Water must be warm enough to melt the fat. 

 If too warm it will generate pressure when shaking the tester, caus- 

 ing loss of contents. 



(c). Strap the evaporating dish down to the tester so that 

 there is no leak around the rubber ring. 



(d). Shake vigorously thirty (30) times. 



(e). Give the titrating flask the proper rotating movement for 

 vigorous and continuous agitation, while the silver nitrate solution 

 runs from the burette. 



(/). Stop titration when the desired color has been reached 

 (brick-red). 



(g). It is necessary to give the fat time to rise in the tester 

 after shaking. This requires about one minute. For this reason, 

 the tester should be set down after shaking, and the aluminum cup 

 taken off and wiped dry and gotten ready for the next weighing of 

 butter. While this is done, the fat in the tester automatically rises 

 to the surface. 



(h). If the edges of the evaporating dish become uneven, due 

 to wear, causing the cup to leak when inverted over the rubber ring 

 of the tester, invert the cup over a piece of fine emery cloth, and 

 wear down the edges until even. 



