Unsweetened condensed milk

Goulden, J. D. S. 1963. Determination of SNF in milk and unsweetened condensed milk from refractive index measurements. J. Dairy Res. 30, 411-417. 

The two main types of condensed milk are unsweetened and sweetened. The unsweetened condensed milk contains about twenty per cent of sugar due to concentration of milk constituents. Sweetened condensed, milk contains about forty per cent of sugar, cane sugar having been added. 

The sterilization of unsweetened condensed milk is a much harder problem than the sterilization of sweetened condensed milk. Also the danger of coagulation and caramelization during sterilization is much greater. 

MILK. In laboratory tests, alloys 1100 and 3003 were resistant to sweet milk at ambient and boiling temperatures. Aluminum alloys have not affected the ta.ste of milk.. Aluminum alloy equipment has been used for handling whole milk and sweetened or unsweetened condensed milk. Powdered milk has been dried in aluminum alloy towers. Foil hoods have been used to protect and seal bottles. Fresh milk has been transported in aluminum alloy equipment. See also Ref (Dp. 137. (2) p. 463, (3) p. 204, (4) pp. 78. 84. 98. 100. 101, 102, 106, 109, (6) p. 11, (7) p, 127. 

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