Powdered milk, also called dried milk, or milk powder is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content.
Milk powder is made from fresh, pasteurized skim milk. First, the milk is concentrated in an evaporator until 50 percent of the milk solids remain. Next, the concentrated milk is sprayed into a heated chamber where the water almost instantly evaporates, leaving behind tiny dry milk particles.