THE MANUFACTURE AND HANDLING OF BUTTER. 239 



the keeping quality and flavor of the butter. The buttermilk 

 is nothing but the cream minus the butter, and the maker 

 who secures cream of a good quality at the same time 

 gains good means of transferring this quality to the butter. 



Influence of Air and Light. But the keeping quality 

 of the butter also depends on other conditions than the 

 quality and the amount of buttermilk in it. Duclaux has 

 shown through numerous experiments that the butter 

 must be protected from the influence of air (oxygen) and 

 light. Precautions in this direction should, he says, be 

 taken even in the churn e.g., by washing the butter with 

 water poor in oxygen ; well-water or spring water should 

 be used for washing and not lake or rain water. Duclaux 

 considers the latter injurious both on account of their 

 larger content of oxygen, as well as the probable presence 

 of numerous micro-organisms in them. The advantage 

 of the application of ice-water for this purpose has already 

 been dwelt on (see p. 136). The butter must farther be 

 protected from direct sunlight. 



Some dairymen advocate washing the butter with skim- 

 milk; but this practice cannot be recommended, as the 

 casein of the skim-milk will be coagulated by the acid 

 buttermilk, and cannot be completely removed by subse- 

 quent washing and working of the butter. The butter 

 may advantageously be washed with ice-water (about 4 C.), 

 as is done in the making of "Paris butter." The cold 

 water will harden the butter granules and favor the ex- 

 pulsion of the buttermilk; the butter as a result will con- 

 tain less water and less buttermilk. Warmer wash-water 

 does not seem to produce the same effect. It is objected 

 that the butter is apt to be too hard by this method, but 

 this shortcoming can *be remedied in the workim 



