224 SWEETENED CONDENSED Mik DEFECTS 
24 to 28 per cent water. Sucrose dissolves in one half its weight 
of water. The sweetened condensed milk does not, therefore, 
contain a saturated solution of sucrose. 
Incomplete Solution of Sucrose.—lIf the finished product is 
to be smooth and free from sandiness, it 1s essential that the 
sucrose which is added to the hot, fresh milk be thoroughly dis- 
solved 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, and since the crystals of undissolved cane sugar 
are relatively large, their presence also gives rise to the formation 
of milk sugar crystals of large size. Hence the sandy condition of 
the condensed milk. Complete solution 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 allowing 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 
quantity of boiling water (preferably distilled water) and_ boil- 
ing the syrup for five to fifteen minutes. If the svrup thus made 
is given a few minutes rest it should become perfectly clear; 
by its clearness, the purity of the sugar can also be observed. 
If a scum forms at the top it should be removed; then the hot 
sugar syrup is drawn into the pan. Care should be taken that 
the milk already condensing in the pan has not become too con- 
centrated, otherwise sugar crystallization may set in. It is ad- 
visable to inject the sugar syrup gradually, rather than to wait 
until nearly all the milk is in the pan. 
Excessive Chilling in the Pan.—The cause of grittiness of 
condensed milk may lie in the pan itself. Where the water used 
for condensing is very cold, and where one end of the spray 
