228 UNSWEETENED CONDENSED MILK DEFECTS 



swell, while the check cans, containing distilled water only, 

 remained normal. 



Brown Evaporated Milk 



General Description. It is the aim of the processor to so 

 govern the sterilizing process as to give the evaporated milk a 

 rich, yellow, creamy color. Frequently, this color limit is over- 

 stepped to the extent of imparting to the evaporated milk a brown 

 color, suggesting coffee with milk in it. In this condition evap- 

 orated milk fails to appeal to the consumer. 



Causes and Prevention. The dark color in evaporated milk 

 is due to the oxidizing action of excessive heat on the milk sugar, 

 causing the milk sugar to caramelize. This can be avoided by 

 reducing the sterilizing temperature, or shortening the sterilizing 

 process, or both. The storing of evaporated milk at high temper- 

 atures (summer heat) also tends to deepen its color with age. 



Gritty Plain Condensed Bulk Milk 



General Description. Grittiness in the unsweetened goods 

 appears usually only in the plain condensed bulk milk. It is a 

 defect which renders the product undesirable for ice cream 

 making. 



Causes and Prevention. The chief cause of this defect is 

 too great concentration. Plain condensed bulk milk which is not 

 condensed over 3.5 parts of fresh milk to 1 part of condensed milk 

 does not become gritty. When the concentration exceeds 4:1, 

 the milk sugar begins to crystallize out, making the product 

 gritty. Milk sugar requires about six times its weight of water 

 for complete solution in cold w r ater. When condensed at the 

 ratio of 4:1 or over, the plain condensed bulk milk contains con- 

 siderably less than five parts, by weight, of water to one part 

 of milk sugar. This high concentration, together with the prac- 

 tice of storing this product at refrigerating temperatures in order 

 to preserve it, is responsible for the grittiness. This trouble can, 

 therefore, easily be prevented by not condensing to quite as high 

 a degree of concentration. 



Metallic Evaporated Milk and Plain Condensed Bulk Milk. 



General Description. Both evaporated and plain condensed 

 bulk milk may show a metallic and puckery flavor, though this 

 defect is rather rare. 



