PRODUCTS OF MILK. 151 



milk itself. These work changes in the milk and milk pro- 

 ducts when the conditions are favorable. 



BUTTER. We have referred to the use of the separator for 

 obtaining sweet cream from the fresh, warm milk. A machine 

 made on a similar plan is capable of so throwing the particles 

 of fat together that they come out, not in the form of cream, 

 but of fine butter. This machine is called an "extractor." 

 The butter made from it will, of course, be sweet cream butter. 

 Ordinarily, however, the cream is obtained either by the 

 separator, by setting in shallow pans, or by setting in deep 

 cans placed in ice water. Then the cream is allowed to ripen. 

 This ripening is caused by some of the little ferments that 

 were referred to before. These get in from the air, or they 

 may be placed there by taking a little cream from some that 

 has already ripened, just as we may take some dough that has 

 already worked and place in a fresh lot of dough to start it 

 working. At once these ferments begin work, and produce 

 changes that give a new taste or flavor and a new odor to the 

 cream. If we allow the cream to stand too long, or in a foul 

 atmosphere, some ferments will get in that will produce 

 unpleasant taste and foul odors. These little ferments, then, 

 help us in our work, or they can spoil our work. We must, 

 therefore, learn the methods which will give us the best 

 ferments to assist us and keep out the bad ferments that will 

 hinder us. If the milk or the cream is first warmed for a few 

 minutes the ferments in the milk will be killed the milk will 

 be "pasteurized," as we say. Then the right kind of ferment 

 is added, and the ripening of the cream takes place. By this 

 method the making of butter is under the perfect control of 

 the dairyman, and butter of uniform quality is produced. 



The cream, well-ripened, is placed in the churn, and the 

 action of the churn throws the little particles of fat together, 

 until soon we have them gathered into little masses ; the butter 

 begins to come in little grains ; these grains gather into large 



