206 Milk and Its Products 
therefore neutralize .38 of .009 grams, or .0034 
grams, of lactic acid. 
To determine the percentage of acid in any 
given sample of milk or cream, any convenient 
amount, as 20 c. c., of the sample to be tested 
is measured out, and the tablet solution ‘is 
added from a burette or graduated cylinder till 
the milk retains a pinkish tinge. If this occurs 
when 1 ec. ec. of the tablet solution has been 
added, the 20 ec. c. of milk contain .0034 grams 
of lactic acid; but 20 c. c. of milk weigh 20.64 
grams (sp. gr. milk, 1.032), therefore the per- 
centage of lactic acid is .00384--20.64—.00017, 
or .017 per cent. If more than 1 ec. c. of 
the tablet solution is required to neutralize 
the acid, or if more or less than 20 ¢. ec. of 
- milk or cream are taken, the percentage of 
acid will be found by multiplying the number 
of cubic centimeters of tablet solution 7 
required by .0034 and dividing by the I 
9 number of grams of milk taken (grams err, 
A of milk=e. ¢. X 1.032). me 
| Further effects of ripening.—Besides — fe 
affecting the flavor, it is believed that ee 
ripening aids in the ease of churning, in the 
completeness of churning, and in improving bog, 
the keeping quality of the resulting butter. It ?» 
was formerly supposed that sweet cream could 
not be churned into butter,'and, in fact, with 
but a moderate percentage of fat (15 to 20 *i%;422: 
per. cent) it does churn with much more diffi- « S4eiass 
TTA] 
Eh 
=| 
