104 SWEETENED CONDENSED Mi1,K—COooLInc 
This was a very crude method, it involved much hard work 
and time, and the quality of the product was poor. It was soon 
found that the imperfect hand stirring caused excessive sugar 
crystallization, which made the milk sandy. The sudden chilling 
and irregular stirring of a saturated sugar solution like sweet- 
ened condensed milk are favorable to the formation of sugar 
crystals. \Where the stirring is imperfect and irregular, all the 
milk is not kept in sufficient motion to insure uniform and gradual 
cooling. ‘The milk next to the side of the cans is chilled too 
abruptly, favoring the formation of crystals. Vigorous stirring 
in itself is conducive of sugar crystallization. 
Later the hand stirring was completely superseded by 
mechanical stirring, paddles closely scraping the sides of the 
cans being used. Instead of setting the paddles in motion, they 
are stationary and the cans revolve. The principle is similar 
to that of the vertical ice cream freezer. Heavy iron tanks, with 
a capacity of twelve to forty-eight 40-quart cans, are used for 
this purpose. The bottoms of these tanks are equipped with a 
system of cog wheels, set in motion by means of a gear at one 
end of the tank. The wheels have a diameter large enough to 
carry one can each. The cans are set on these wheels, the paddles 
are inserted and fastened to cross-bars and the power started. 
The cans should be heavily constructed to stand rough usage, 
without suffering indentations. Cans with irregular, depressed. 
or bulged sides cause the paddles to do poor work. Such cans 
should be slipped over a wooden horn, or other contrivance, and 
the indentations hammered out with a mallet. The paddles are 
held stationary by cross-bars and are forced against the periphery 
of the cans by springs. Attention should also be paid to the 
pivots on which the cog wheels rest. If they are warped, the 
wheels do not run true, so that it is not possible for the paddles 
te scrape the sides of the cans properly. 
The sweetened condensed milk should be cooled gradually. 
Sudden chilling should be avoided. This is best accomplished 
by warming the water in the cooling tank to about 90 degrees F., 
before the cans are set in. ‘The cans are then allowed to revolve 
for fifteen to twenty minutes before any cold water is turned 
into the tank. After that, cold water is turned in slowly until 
the temperature of the milk has fallen to about 70 degrees F. The 
