SAI/UNG THE BUTTER 



345 



iments conducted by Rahn, Brown and Smith. 1 This loss of 

 moisture in storage was formerly attributed to evaporation, 

 and such is in fact the case to a limited extent with butter, 

 stored at ordinary temperature. In commercial cold storage, 

 however, moisture does not evaporate to any noticeable extent. 



Table 54. Showing Loss of Moisture in Butter in Cold Storage. 



If here the loss of moisture were due to evaporation, this de- 

 crease of moisture would necessarily have to be accompanied 

 by a material increase in the per cent of salt. This is not the 

 case, as shown in the results of Hunziker, Mills and Spitzer in 

 table 55. 



The loss of moisture in butter in storage is apparently 

 due to leakage, caused partly by the precipitation and contrac- 

 tion of the casein, rendering the buttermilk less viscous and 

 giving the butter a more open texture, and partly to the fact 

 that in heavily salted butter the brine is so concentrated that its 

 freezing point is near that of the cold storage temperature. 

 This leaves the moisture in butter in liquid form during a con- 

 siderable part of its storage period and gives it an opportunity 

 to leak out. In the case of unsalted and lightly salted butter 

 the moisture freezes at the usual cold storage temperature, pre- 

 venting further leakage. In butter stored at ordinary temperatures 

 and not far below the freezing point of water, the leakage of 

 moisture in both salted and unsalted butter would be more nearly 

 the same. 



1 Rahn, Brown and Smith, Keeping Qualities of Butter, Michigan Technical 

 Bulletin 2, 1909. 



