Sweetened Condensed Milk — Striking 89 



The degree of concentration may be more accurately determ- 

 ined by taking a sample from the pan and testing it by various 

 methods, such as by weighing a definite quantity of condensed milk 

 on a sensitive scale, by the use of a resistance apparatus, or by the 

 use of a specially constructed hydrometer. Of these the Beaume 

 hydrometer has been found the most suitable to use under average 

 factory conditions. 



Mechanical devices and methods, such as the above, can be de- 

 pended upon, when all the conditions influencing the specific gravity 

 of the liquid are under control, and when there is plenty of time 

 for their manipulation. When the boiling and rapidly evaporating 

 milk in the retort is approaching the proper density, however, quick 

 action is essential. One minute over- or under-condensing may 

 cause the milk to be either too thick or too thin for the market and 

 may necessitate the "re-running" of the entire batch. These instru- 

 ments are, therefore, often inadequate at the time they are needed 

 most. There is not time to carefully measure and weigh out a 

 sample of sweetened condensed milk, nor can the processor al- 

 ways wait until the hydrometer has found its equilibrium in as 

 viscous a fluid as sweetened condensed milk. Again, the density or 

 specific gravity of the finished product depends, outside of the de- 

 gree of concentration, on many and fluctuating conditions, such as 

 amount of heat applied toward the end of the process, the tem- 

 perature of the sample when drawn and the per cent of fat and 

 cane sugar in the condensed milk. It is for these reasons that arbi- 

 trary mechanical instruments and methods are not uniformly satis- 

 factory and are liable to yield misleading results ; while they are very 

 desirable to use as a check, the experienced eye and good judgment 

 of the processor are all essential. The following factory methods 

 have been found satisfactory and reasonably reliable: 



Draw a sample from the pan into a tin dipper, lower the dipper 

 into a pail of ice water or snow. Stir the condensed milk with a 

 metal-back thermometer until the condensed milk is cooled to 70 

 degrees F. Note the thickness of it. ■ Or, finish the batch at a con- 

 stant temperature, say 120 degrees F. Draw a sample into a tin 

 cup and note the thickness by examining the milk when pouring 



