CHAPTER VII. 



Testing Cream for Acidity 



THE acid test tells when the cream is "ripe" or 

 sour enough to churn. This device should be 

 used with the Minnetonna Home Creamery. 

 It is simple. Anyone can quickly learn to use it. 



We will explain the Nafis acidity-testing outfit 

 here. We believe it to be the best outfit made for 

 home creamery use because of its simplicity and small 

 cost. You can procure it from the Minnetonna Com- 

 pany. It is listed in their dairy supply catalog. 



The idea of the test is simply this : The acid in 

 the cream when mixed with an alkali becomes neutral 

 that is, it changes into a substance that is known 

 among chemists as a salt. (There are different kinds 

 of salts. Table salt or the salt used for seasoning 

 food is only one of the many kinds of salts.) 



The alkali which we use to neutralize the acid in 

 sour cream we call neutralizer. 



The amount of neutralizer it takes to neutralize 

 the acid in a given quantity of sour cream gives us 

 a basis for figuring the percentage of acidity in the 

 cream we are testing. 



"But can you tell when the acid in sour cream 

 has become neutralized?" you ask. 



We put a few drops of a solution called indicator 

 into the sample of sour cream we are testing. Then, 

 when enough neutralizer has been added to the sour 

 cream to neutralize the acid, the cream will turn 



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