Evaporated milk is a milk product, usually sold in cans, that is made by removing about 60 percent of the water from ordinary milk.
Evaporated milk can be made from both whole milk or skim milk. In either case, the milk is homogenized and then the water is removed by gently heating it. The evaporated milk product is sealed in cans which are then heated to kill any bacteria in the milk. Thus evaporated milk is actually sterile, which, combined with the fact that it is stored in airtight cans, gives it an extremely long shelf life. Evaporated milk is enriched with vitamin D. The process of heating the evaporated milk in the cans imparts a slightly sweet flavor to the milk, and it's also just a bit darker in color than ordinary milk. Note that evaporated milk is not the same thing as condensed milk. Condensed milk is also reduced by 60 percent, but it is heavily sweetened and usually used in baking and desserts.