Powdered milk can be stored without refrigeration until it's converted to liquid, and it costs about half as much as liquid milk. Converting powdered milk to liquid milk is a simple process.
Fill the pitcher with 2 cups of water. Add 1-1/3 cups of powdered milk. Stir vigorously until all the powder dissolves. Add the remaining water and stir again. Refrigerate until chilled.
Stir the milk again, allow it to sit and then repeat. The protein in the milk blends more efficiently if you allow it to stand for a while before mixing again. You can use the milk directly after mixing, but it tastes best after four hours of chilling.
Store your milk in a refrigerator and stir the milk vigorously before each time you use it. Some brands of milk powder have a tendency to sink to the bottom of the pitcher when left standing in the fridge. If you don't stir it, you'll end up with a watery beverage.