STORAGE 193 



Temperatures of 60 degrees F. or above are too high for satis- 

 factory storage for a prolonged period of time and the higher 

 the temperature the greater the resulting defect. 



Temperatures below the freezing point of water are also 

 undesirable. The evaporated milk freezes and while so doing it 

 expands sufficiently to swell the cans. Although this swelling 

 disappears when the contents of the cans dissolve again, yet 

 the swelling action tends to weaken the cans and may give rise 

 to subsequent leakers. Again, the melted evaporated milk is 

 prone to be grainy as the result of freezing. This is due to the 

 fact that when freezing, the watery portion separates from the 

 curd and the latter contracts. When the milk thaws up the curd 

 remains contracted and fails to form a smooth emulsion with 

 the remainder of the milk. 



The sweetened condensed milk does not freeze, because it 

 contains so concentrated a sugar solution that its freezing point 

 is usually far below the refrigerating temperature. If it is packed 

 in solder-sealed cans there is usually no bad effect from cold 

 storage. However, when packed in cans sealed with the friction 

 cap or the burr cap, difficulties may arise. These seals are not 

 air-tight. Excessively low storage temperatures cause the con- 

 tents to shrink appreciably. Suction is formed and air is drawn 

 in through the seal. When these cans again warm up, the vis- 

 cous milk in the cans seals the microscopic openings, the air and 

 the liquid expand but the air finds no exit. This causes the cans 

 to swell. While the quality of the milk in these cans is not im- 

 paired in the least, the swelled cans suggest gaseous fermenta- 

 tion, which means spoiled milk and which is invariably rejected 

 on the market. 



The temperatures at which condensed milk can be stored 

 with least objectionable results, range between 32 arid 50 de- 

 grees F. 



Advisability of Storing. A heavy stock of condensed milk 

 is a severe drain on the working capital of the condensery, in- 

 volving the cost of the fresh milk, cane sugar, tinplate, boxes, 

 solder, labels, coal and labor. 



Unless the manufacturer has successfully overcome and 

 mastered all of the principal condensed milk defects, and, unless 

 his experience justifies him in believing that his goods will stand 



