TESTS NECESSARY IN CREAMERIES 365 



dividing the number of cubic centimeters of lime water re- 

 quired for neutralization by 5. Thus : 



c.c. lime water w 1 , , ., 

 X 77C = per cent of acid. 



Thus, if a cream be so sour as to require 30 c.c. of saturated 

 lime water to neutralize the acid in 17.6 c.c. of cream, we have 



30 



_ =: 6, or 0.60 per cent acid. The lime water test will not work 



on sweet milk or cheese making, but is of value in farm or 

 creamery butter making. 



The moisture test is used to determine the amount of 

 moisture in finished butter and its use is highly important, espe- 

 cially in preventing the incorporation of an illegal quantity of 

 water. Butter must contain some water to dissolve the salt and 

 to prevent an oily taste. This is accomplished by about 14 or 

 15 per cent moisture. The law in many states and a ruling of 

 the Internal Revenue Department of the Federal Government 

 make a butter illegal if it contains 16 per cent or more of 

 moisture. 



The test is made by warming a carefully taken sample and 

 mixing it into a paste and then carefully weighing out into an 

 aluminum cup 10 grams or 20 grams, according to test used. 

 The sample is then heated slowly over an alcohol lamp or 

 other flame until the water is entirely expelled from the sample. 

 The complete absence of moisture is indicated by a slight brown- 

 ing of the sample. The sample is then re-weighed. The per- 

 centage amount of water originally present is shown by the 

 percentage amount of loss occasioned by drying. The apparatus 

 for making this test is not expensive and it is highly important 

 that it be used regularly in creamery butter-making. 



Salt Test. — The salt test now usually employed is that de- 

 vised by Mr. Gray of the Federal Dairy Division. The 

 solution used is one made by dissolving 5.81 grams silver 

 nitrate in 2000 cc. pure water. The indicator used is potassium 

 chromate. Ten grams of butter to be tested are weighed 

 into a flask, dissolved in hot water and made up to 500 c.c, 

 50 cc. of this solution is then pipetted out and discharged into 



