28 



CREAMERY BUTTER MAKING 



many tests are made a graduate of this kind saves time 

 in rilling, but should be made to hold twenty-five charges. 



H. A cream scales commonly used is illustrated in 

 Fig. 8. 



Acid. The acid used in the test is commercial sul- 



Fig. g. Cream Scales. (See pp. 167 and 168.) 



phuric acid having a specific gravity of 1.82 

 to 1.83. When the specific gravity of the 

 acid falls below 1.82 the milk solids are not 

 properly burned and particles of curd may 

 appear in the fat. On the other hand, an 

 acid with a specific gravity above 1.83 has 

 a tendency to blacken or char the fat. 



The sulphuric acid, besides burning the 

 solids not fat, facilitates the separation of 

 the fat by raising the specific gravity of the 

 medium in which it floats. 



Sulphuric acid must be kept in glass bot- 

 tles provided with glass stoppers. Exposure 

 to the air materially weakens it. 



Making a Babcock Test. The different 

 indicated as follows : 



1. Thoroughly mix the sample. 



2. Immediately after mixing insert the pipette into 

 the milk and suck until the milk has gone above the mark 

 on the pipette, then quickly place the fore finger over the 



Fig. 9. Show- 

 ing manner of 

 emptying pi- 

 pette. 



steps are 



