318 Milk and Its Products 
8 to 20 ounces, and retailing at from 5 to 20 cents 
per can; and partly in barrels holding from 300 to 
600 pounds of condensed milk. The barrel goods are 
sold to bakeries and confectioners. They are generally 
made from partly or wholly skimmed milk. 
Sweetened condensed milk is not sterile, but is 
preserved by the sucrose it contains; it will keep for 
a considerable length of time, but is best when fresh. 
Unsweetened condensed milk.—There are three kinds 
of unsweetened condensed milk, namely, evaporated 
milk, plain condensed bulk milk, and concentrated milk. 
Evaporated milk.—In the manufacture of this prod- 
uct, cows’ fresh milk is heated to near the boiling 
point, then condensed in vacuo at 180° F. to 150° F. 
The ratio of concentration is about 2274: 1 (2%4 parts 
of fresh milk are condensed to 1 part of evaporated 
milk). The evaporated milk is then filled and sealed 
in tin cans varying in size from 8 ounces to 1 gallon. 
The hermetically sealed cans are sterilized at tempera- 
tures ranging from 226° F. to 240° F. for from 30 to 
60 minutes. From the sterilizer the cans are trans- 
ferred to the shaker, where they are subjected to vio- 
lent agitation, to completely break up the coagulum 
that may have formed during sterilization. The fin- 
ished product has the consistency of cream of medium 
richness, and has a specific gravity of about 1.065. It 
sells at from 5 to 50 cents per can. 
Evaporated milk is sterile, it keeps indefinitely, but 
is best when fresh. 
Plain condensed bulk milk.—This kind of condensed 
milk is made from whole milk, partly skimmed, or 
