Condensed Mjlk and Milk Powder 143 



Cane Sugar Content. — It has been argued that the large amount 

 of sucrose which sweetened condensed milk contains, is the principal 

 cause of sandy milk and of sugar sediment in the bottom of the tin- 

 cans, and that a reduction in the amount of sucrose lessens the 

 tendency of the sugar to crystallize and the milk to become sandy. 

 This line of reasoning is erroneous. The presence, in water, of 

 sucrose in solution does not materially lessen the power of the 

 water to dissolve milk sugar, provided that the sucrose solution is 

 not a saturated one. Sweetened condensed milk, contains about 35 

 to 45 per cent, sucrose and 24 to 28 per cent, water. Sucrose dis- 

 solves in one half its weight of water. The sweetened condensed 

 milk does not, therefore, contain a saturated solution of sucrose. 



The chief factors causing milk sugar crystallization and sandy 

 condensed milk are: incomplete solution of the sucrose, excessive 

 chilling in the vacuum pan, superheating in the vacuum pan, im- 

 proper cooling, excessive stirring, and warming up too cold con- 

 densed milk with the help of agitation. 



Incomplete Solution of Sucrose. — If the finished product is to 

 be smooth and free from sandiness, it is essential that the' sucrose 

 which is added to the hot, fresh milk be thoroughly dissolved before 

 the mixture reaches the vacuum pan. Undissolved sugar crystals 

 in a medium as highly concentrated as sweetened condensed milk 

 have much the same effect in a physical way, as have bacteria in 

 fresh milk in a biological way ; they multiply rapidly. Therefore, 

 if all the sugar added to the fluid milk is not completely dissolved, 

 the undissolved sugar crystals give rise to- wholesale precipitation of 

 the milk sugar in this product after manufacture. Complete solu- 

 tion of the cane sugar can best be accomplished by heating the 

 liquid, milk or water, in which the sugar is to be dissolved, to the 

 boiling point and by boiling the mixture for several minutes ; or by 

 placing the sugar on a large wire mesh strainer (about eighty 

 meshes to the inch) which stretches across the sugar well and 

 allows hot milk to run over this sugar into the well below. In this 

 way the sugar crystals must dissolve before they can reach the 

 sugar well. 



One of the safest methods of insuring complete solution of the 

 cane sugar is to dissolve it in a separate kettle in a sufficient quan- 

 tity of boiling water (preferably distilled water) and boiling the 

 syrup for five to fifteen minutes. If the syrup thus made is given, 



