MILK 239 



from skim milk generally fills less than one division on the scale, 

 and therefore cannot be read. The skim milk test bottles have a 

 double neck, with a wide tube for pouring in the milk and acid 

 and a narrow tube in which the fat column rises. The scale reads 

 up to one-fourth or one-half of one per cent. 



These bottles are also used for testing buttermilk and whey. 

 Only about three-fourths of a cylinder full of sulphuric acid should 

 be added to each test bottle of whey. The test is then completed in 

 the usual way. (111. Circ. of Inf. 27.) 



BUTTER MAKING ON THE FARM. 



Ripening the Cream. Up to the point of ripening the cream 

 the dairyman has been trying to keep his cream as free as possible 

 from bacteria and to check the growth of all that may get into it, 

 but from this point on the work will be quite different Cream 

 should be perfectly sweet, and if cooled properly will remain so for 

 a number of hours. In fact, it can be preserved four or five days if 

 kept at a temperature below 50 F. It might be churned in this 

 condition and a quality of butter made that is in demand in a limited 

 way, but, practically speaking, nearly all butter used in this country 

 is churned from sour cream. Sweet cream butter to most users tastes 

 flat and insipid. 



The Starter and Its Use. The dairyman may think, if it is 

 necessary to sour the cream, why is all this pains taken up to this 

 point to keep it sweet. The trouble with ordinary souring is, it may 

 not be the desirable kind. It must be handled in such a way that 

 desirable flavors will be developed and the undesirable ones kept in 

 check. This can only be done by starting with a perfectly sweet 

 cream and afterwards controlling the souring process. This control 

 is secured by introducing into the cream what is known as a starter. 

 A starter is nothing more nor less than nicely soured milk, either 

 whole or skimmed. It will contain those kinds of bacteria that will 

 develop the good flavors wanted and not those that cause putrefac- 

 tion, gassy fermentations, and similar undesirable changes. To 

 secure a starter containing desirable bacteria, the dairyman has sim- 

 ply to set away a portion of skim milk as it comes from the separator 

 and await developments. If the milk is kept at a temperature be- 

 tween 70 and 80 F., it should sour inside of twenty-four hours and 

 form a solid curd. A test of this curd shows whether or not the 

 dairyman has kept his milk clean. If the taste is found pleasant 

 and mildly acid and the curd readily breaks up when poured from 

 one vessel to another, becoming creamy, showing no hard lumps 

 that will not break down, he has a good starter. On the other hand, 

 if the curd is stringy or will not break with a square, sharp cleavage, 

 but seems to be granular, or if a clear whey is formed on the surface, 

 it shows that bacteria of a harmful species are present. The forma- 

 tion of this curd is caused by the development of acid in the milk. 

 If the souring continues too long and too much acid is formed, the 

 starter becomes sharp and unfit for use. After a certain amount of 

 acid is formed its further development is checked, but this does not 

 occur until the milk is too sour for a good starter. 



