Nonfat dry milk: storing, mixing, and cooking with powdered milk

Powdered milk is the cow in "Dehydrated Cow". It is a pantry staple for camping, emergency kits, baking, and anyone who goes through milk slowly. It is also easy to store badly.

What it is

Commercial nonfat dry milk is pasteurized skim milk with almost all of its water removed, usually by spray drying. Instant versions are processed to dissolve more easily in cold water. Dry whole milk keeps its fat, which gives a richer taste but a much shorter shelf life because milk fat oxidizes and turns rancid.

Why not make it at home?

Home dehydrators cannot dry milk evenly or quickly enough to make a safe, good-quality powder, and food-preservation authorities do not provide tested home methods for drying milk or eggs. Buy commercial powdered milk and use your dehydrator for fruit, vegetables, and jerky.

Storage

• Keep it cool, dry, and dark. Heat, humidity, and light all speed loss of flavour and nutrients.
• Move opened powder to an airtight container such as a glass jar or a food-grade bucket with a tight lid. Powder absorbs moisture and odours from the air.
• Use the package date as your guide for best quality, and use an opened package within a few months for best flavour.

Signs it has gone off: yellowing or browning, a stale, sour, or rancid smell, or hard lumps that will not break up because the powder has absorbed moisture. Discard it if in doubt.

Mixing

Always follow your package, because the ratio differs between instant and regular powders.

Add the powder to water, not the other way round, and whisk or shake. Chilling it for a few hours improves the taste.

Reconstituted milk is perishable. Refrigerate it at 40°F (4°C) or below and use it within the time you would use fresh milk.

Cooking and baking

• Baking: add the powder with the dry ingredients and the matching amount of water with the wet ones.
• Richer results: an extra spoonful of powder in yoghurt, bread dough, or mashed potatoes adds protein and body.
• Travel and camping: pre-mix with oats, cocoa, or pancake mix so you only need to add water.

Emergency storage

Powdered milk is a common part of emergency food supplies. Rotate it: use the oldest package in everyday cooking and replace it, so your stored supply stays fresh.

For drying other foods, see Drying fruit and vegetables and Jerky safety.