272 DAIRYING. 



Cream is often ripened so far that the quality of the but- 

 ter is injured. The usual method of the butter-maker for 

 testing the sourness of the cream is by the sense of smell 

 and taste. A tablet test shows exactly what per cent of 

 acid each lot of cream contains, so that the butter-maker 

 is better able to manufacture a uniform grade of butter by 

 ripening his cream to the same point before it is churned. 

 Sweet cream contains about 0.15^ acid. Cream has reached 

 the proper point for churning when it contains about six- 

 tenths per cent acid. As the souring of cream is largely 

 influenced by the temperature at which it is held, the but- 

 ter-maker is able to know from an acid test of the cream 

 whether it should be warmed or cooled in order to have it 

 ready for churning at a given time and just sour enough 

 for making butter of good flavor (see page 275-^). 



DIRECTIONS FOR THE USE OF MANNS' TEST 



FOR ASCERTAINING THE ACIDITY OF 



CREAM. 



1. Stir the cream thoroughly; insert small end of pipette 

 in cream and draw until nearly full; then put the finger over 

 upper end of pipette and allow cream to escape slowly (by 

 admitting air) until mark on neck of pipette is reached. 

 Transfer to a tumbler, rinse the pipette three times with 

 lukewarm water, adding the rinsing water to the cream in 

 the tumbler. Now add to contents of the tumbler three 

 drops of the solution marked " Indicator" (phenolphtalein). 



2. Fill the burette up to the o mark with the solution 

 marked " Neutralizer" (alkali solution). 



3. While constantly stirring the cream with the glass rod, 

 allow the liquid to flow from the burette into the tumbler 

 until the entire contents of the tumbler shows a pink tinge. 

 Stop adding the solution from the burette the moment the 

 color is permanent. 



4. Read the level of the liquid remaining in the burette. 

 The reading shows the amount of acid present. 



The experience of those using the test indicates tha'. 

 where the acidity of the cream is right, to secure the bes'> 

 results in yield and flavor of butter, from 38 to 42 cc. of the 

 jieutralizer will be required for the test. It is a simple 



