SWEETENED CONDENSED MILK DEFECTS 229 



can be removed and mixed into the milk with difficulty only. 

 Like gritty milk, settled milk is a very common condensed milk 

 defect. Though it does not render the product less wholesome, 

 it is an undesirable characteristic. Such milk is usually rejected 

 on the market and results in a partial loss to the manufacturer. 



Causes and Prevention. It is obvious, for reasons above 

 referred to, that the conditions leading up .to the production of 

 settled milk, are closely related to those that cause milk to 

 become gritty. Condensed milk cannot drop its milk sugar, 

 unless the latter is present in the form of crystals. The absence 

 of crystals then, means that condensed milk will not settle but 

 experience has shown that it is a practical impossibility to manu- 

 facture sweetened condensed milk which contains no sugar crys- 

 tals. Sugar crystals are always present in it, and the fact that 

 the milk is not sandy or gritty, does not necessarily mean that 

 it will not settle. Nevertheless, the removal of conditions con- 

 ducive of sandy or gritty milk, diminishes the tendency of the 

 formation of sugar sedim,ent. The successful and uniform pro- 

 duction of condensed milk that does not settle, however, involves 

 additional conditions that are not controlled by the factors 

 causing gritty milk. 



Effect of Density on Sugar Sediment. One of the chief of 

 these conditions is the density of the condensed milk. The thin- 

 ner the condensed milk, the greater the difference between the 

 specific gravity of the liquid portion and that of the sugar crys- 

 tals; therefore, the more readily will the crystals sink to the 

 bottom. The viscosity of thin condensed milk, also, is less than 

 that of thick milk, offering less resistance to the force of gravity 

 of the crystals. In the manufacture of sweetened condensed 

 milk that has the proper density, about 2.5 parts of fresh 

 milk are condensed into one part of condensed milk. If the 

 evaporation is stopped sooner, so that the ratio is much less than 

 2.5 to 1, the condensed milk is usually too thin to hold its sugar 

 crystals in suspension unless its specific gravity and viscosity 

 are increased by the addition of more sucrose. 



Effect of Fat Content on Sugar Sediment. The per cent of 

 fat in milk, also, influences the specific gravity of the condensed 

 mtilk, and therefore, has some effect on the settling of the sugar 



