Powdered Milk for Food Storage: Nonfat Keeps 20 Years, and How to Mix It so It Tastes Right

Nonfat dry milk sealed in Mylar or a #10 can with an oxygen absorber, kept cool, is a 20 year food; storage studies found it still acceptable after two decades, with flavor fading before nutrition does. In the store bag or tub it is good for 18 to 24 months and usable well past that if it stays dry. Whole milk powder is a different product: the fat goes rancid in 6 to 12 months no matter how you pack it, so it is a rotate-through item, not storage. Once mixed, it is milk: refrigerate and drink within 3 to 5 days.

Put the powder in the jar first, add a cup of warm water, cap it and shake until there are no lumps, then fill the rest of the way with cold water, shake again, and put it in the refrigerator overnight. Cold and rested is the whole trick; powdered milk mixed and drunk warm tastes like the box, and the same jar after a night in the fridge tastes like milk. A pinch of salt or a drop of vanilla helps the people who still notice.

Instant nonfat: 1 1/3 cups of powder to a quart of water, or a third of a cup per cup. Regular non-instant nonfat, which is denser: about 3/4 cup per quart. Brands vary a little, so read the bag once and write the ratio on the lid. A pound of powder makes about 5 quarts; a 50 pound bag makes about 60 gallons.

Dry, no; that is the point of it. Keep the powder sealed, cool and dry and it needs nothing. Mixed, yes: reconstituted milk spoils exactly like fresh milk and goes in the refrigerator within two hours of mixing, to be finished in 3 to 5 days. With no refrigerator, mix only what you will drink at that sitting.

Buy the bag with one ingredient: nonfat dry milk, with vitamins A and D as the only additions. Skip anything with added vegetable oil, which is how cheap whole milk substitutes and coffee creamers are made and which goes rancid; anti-caking agents and flow agents; sugar; and milk drink mixes that are mostly whey, corn syrup and oil. If the label reads like a chemistry set it is not milk and it will not keep.

Fresh milk is separated to pull the fat off, pasteurized, then evaporated under vacuum to about half its volume and spray-dried: sprayed as a mist into a tower of hot air, where the water flashes off in seconds and the solids fall as powder. Instant milk is that powder wetted and re-dried so the particles clump into porous granules that dissolve in cold water. Nothing is added; the powder is the milk with the water and fat gone.

Instant has been agglomerated into fluffy granules that dissolve in cold water with a stir; it is what the grocery store sells and it takes more cups per quart because it is airy. Regular or non-instant is the dense, fine powder the food-storage companies and bakeries sell; it is cheaper per quart and packs denser, but it wants warm water and a whisk or a shake to dissolve. Same milk, same nutrition. For storage I buy regular; for the kitchen shelf, instant.

A cup of milk a day per person is about 2 pounds of powder a month, so a year for one person is about 25 pounds and a family of four is around 100, which is two 50 pound bags packed into Mylar. Less if milk is mostly for cooking, more with small children. Store what you will actually use: it goes into bread, oatmeal, pudding, yogurt and sauces as well as the glass, and the calcium and protein are hard to replace from a pantry.