Powdered milk, also called milk powder, dried milk, or dry milk, 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. Another purpose is to reduce its bulk for the economy of transportation. Powdered milk and dairy products include such items as dry whole milk, nonfat (skimmed) dry milk, dry buttermilk, dry whey products, and dry dairy blends.
Powdered milk is frequently used in the manufacture of infant formula, confectionery such as chocolate and caramel candy, and in recipes for baked goods where adding liquid milk would render the product too thin. Many no-cook recipes that use nut butter use powdered milk to prevent the nut butter from turning liquid by absorbing the oil.
Milk powders contain all 21 standard amino acids, the building blocks of proteins, and are high in soluble vitamins and minerals. According to USAID, the typical average amounts of major nutrients in the reconstituted nonfat dry milk are (by weight) 36% protein, 52% carbohydrates (predominantly lactose), calcium 1.3%, and potassium 1.8%. Whole milk powder, on the other hand, contains on average 25-27% protein, 36-38% carbohydrates, 26-40% fat, and 5-7% ash (minerals). In Canada, powdered milk must contain added vitamin D in an amount such that a reasonable daily intake of the milk will provide between 300 and 400 International units (IU) of vitamin D. However, inappropriate storage conditions, such as high relative humidity and high ambient temperature, can significantly degrade the nutritive value of milk powder.