SWEETENED CONDENSED MILK DEFECTS 227 



tion to details in the cooling process of sweetened condensed 

 milk, it should be understood, that the formation of large sugar 

 crystals in concentrated solutions is enhanced by sudden chilling 

 and by excessive agitation of these solutions. In the case of 

 cooling in 10 gallon cans as described under "Cooling of Sweet- 

 ened Condensed Milk," Chapter VI., the sudden and irregular 

 chilling of a part or all of the sweetened condensed milk in 

 the cooling cans is the result of the use of badly dented cans, 

 poorly fitting paddles, a warped condition of the pivots on which 

 the cog wheels in the bottom of the cooling vat revolve, too cold 

 water, and the application of too much cold water. 



The paddles must scrape all parts of the sides of the cans, 

 from top to bottom. This is possible only when the cans are 

 intact and their sides are smooth and free from indentations. 

 The paddles must be adjusted properly so that their edges fit 

 snugly against the sides of the cans, they must be firmly fastened 

 to the cross bars and forced against the sides of the cans by 

 springs. In order that the cans may run true they must properly 

 fit into the rim of the cog wheels in the bottom of the cooling 

 vat and the pivots on which the cog wheels revolve must be per- 

 pendicular. If the pivots are warped, the cog wheels cannot 

 run true and the cans wobble; this causes uneven and incom- 

 plete scraping of the sides of cans by the paddles. 



The water in the cooling vat should not be cold, but have 

 a temperature of about 90 degrees F. when the cans, filled with 

 the hot condensed milk, are set into the vat. The cold water 

 should flow into the vat slowly and be evenly distributed 

 throughout the vat. This is best accomplished by the installa- 

 tion of a perforated pipe running the entire length of the vat. 

 The cooling must be gradual. See also "Excessive Stirring." 



Excessive Stirring. The cans should revolve slowly. Rapid 

 revolution causes excessive agitation of the condensed milk, 

 which stimulates the formation of crystals. About five revolu- 

 tions per minute is satisfactory. In order to make more effective 

 the proper scraping of the cans by the paddles when the cans 

 revolve slowly, it is advisable to install two paddles in each can, 

 touching the periphery of the can on opposite sides. 



When the milk has been cooled to between 60 and 70 de- 



