178 Testing Milk and Its Products. 



particles, which, when the butter is re-melted, will set- 

 tle to the bottom. The butter is melted after the sec- 

 ond churning by placing the tubes in water at 150-175 

 F., allowing them to remain therein for at least twenty 

 minutes. 'Some samples must be churned three or four 

 times before a gcod separation of oil is obtained. A 

 clear separation of oil is often facilitated by adding a 

 little sulfuric acid to the tubes. 



The length of the column of liquid butter fat is de- 

 termined by means of a special rule for measuring the 

 butter oil ; this rule shows the number of pounds and 

 tenths of a pound of butter which an inch of cream will 

 make; the first tenth of a pound on the rule is divided 

 into five equal parts, so that measurements may be made 

 to two-hundredths of a pound. The melted fat is meas- 

 ured with the rule, by raising the tin card holding the 

 bottles, to about the height of the eye ; the reading is 

 recorded on the driver's tablet under Test per incli, op- 

 posite the number of the particular patron. The test 

 per inch multiplied by the inches and tenths of an inch 

 of cream supplied will give the butter yield in pounds, 

 with which the patron will be credited on the books of 

 the creamery. 



203. The objection to this system of ascertaining the 

 quality cf cream delivered by different patrons lies in 

 the fact that it determines the churnable fat, and n<>1 

 the total fat of the cream; the amount of the former 

 obtained depends on many conditions beyond the con- 

 trol of the patron, viz., the consistency, acidity and tem- 

 perature of the cream, the size of the churn or churn 



