dried milk

Dried milk, also known as milk powder or powdered milk, is milk that has been dehydrated to approximately 5 percent moisture content. This process is done to reduce weight, facilitate shipping, extend shelf life, and create a useful ingredient for other food products.1234

Various dairy products can be dried, including skim milk, whole milk, buttermilk, and cheese whey. Most products are dried to less than 4 percent moisture to prevent bacterial growth and spoilage. However, products containing fat can become rancid due to the oxidation of fatty acids.34

Two main types of dryers are used: drum dryers and spray dryers. Drum dryers produce a flakelike powder that dissolves poorly, while spray dryers, which are more common, produce more soluble products. An "instantizing" process can be used to make spray-dried milk more soluble by rewetting and re-drying the powder into granules.34