Non-fat dry milk or powdered milk is a dairy product from which all liquids and fats have been removed. It was developed in Russia in the early 19th century, and since then, it’s become a staple in many households, and is used in a variety of ways.
In some countries, particularly where shipping costs are prohibitive or few dairy cows exist, non-fat dry milk may be more common that standard liquid milk. In developing countries where access to refrigeration is limited, powdered milk can last much longer and tends to be much less expensive, since it is easier to transport. Even in developed countries, city dwellers may turn to using dry instead of liquid milk because it tends to be significantly less expensive.
This product is also used for medical reasons. The powder can be added to standard milk or other liquid drinks to boost its protein and calories for those who need calorie fortification in their diets. It can be used in a variety of smoothies, and it’s also used in place of liquid milk in a number of baked goods because it reduces the price of ingredients. Some people keep the powder on hand for home baking or to add to their own homemade smoothies for extra protein. Campers and hikers may also bring along dry milk on trips because it weighs less and is more easily transported.
The standard manufacturing process for non-fat dry milk is called dry spraying. Skim milk, which has already been defatted, first goes through an evaporation process, where the milk concentrates and becomes denser. It is then sprayed in fine bursts into a heating chamber, which causes the rest of the liquid to evaporate, leaving behind milk powder.
Two other methods in use are drum drying and freeze-drying. Drum drying is less common because the powder has a “cooked” taste that people often find undesirable. Freeze drying is fairly uncommon.
Shoppers can purchase powdered milk that isn’t non-fat, but it tends to be more difficult to reconstitute because of its fat content. Non-fat dry milk is usually the easiest to mix, although some people still report difficulty getting the milk solids to blend with water. It won’t taste the same as fresh milk, especially to those used to getting their milk from cartons, but the difference is negligible when the milk is used as an additive in baked goods or to bulk up smoothies. It certainly does have the advantage of long storage time, since when stored in a cool, dry place, it will usually last 18 months.