98 SWEETENED CONDENSED MILK STRIKING 



processors are easily deceived by the mere appearance of the con- 

 densed milk through the sight glass. 



The degree of concentration may be more accurately deter- 

 mined 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 viscosimeter, or by the use of a specially constructed hydrom- 

 eter. Of these the Beaume hydrometer has been found the 

 most suitable to use under average factory conditions. 



Mechanical devices and instruments, such as above enumer- 

 ated can be depended upon, when all conditions influencing the 

 specific gravity of the product, such as chemical composition 

 and temperature, are under control. Their successful use ren- 

 ders careful and accurate standardization of the milk for butter- 

 fat, solids not fat, and sucrose indispensable. Without standardi- 

 zation of the component ingredients of milk the result of the 

 use of these devices may prove erroneous and misleading. 



The operation of these devices must also be simple and rapid, 

 for when the boiling and rapidly evaporating milk in the pan 

 approaches the proper density, 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 "rerunning" of the entire batch. 



In the absence of a satisfactory instrument for rapid deter- 

 mination of the concentration, and particularly in the absence of 

 a carefully standardized product, the experienced eye and the 

 good judgment of the processor are all essential. The following 

 factory methods have been found applicable and reasonably 

 reliable. 



Determination by Appearance to the Eye. 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 constant tem- 

 perature, say 120 degrees F. Draw a sample into a tin cup and 

 note the thickness by examining the milk when pouring from 



