How to Freeze-Dry Things

Freeze-drying is used to preserve food for later use, such as in emergency situations or when camping.

The process of freeze-drying involves sublimation, which is when food’s moisture transforms from solid to gas without turning into liquid.

It gives edibles a longer shelf life, makes them more portable by shedding water weight and retains their flavor.

Things You’ll Need:

  1. Freezer
  2. Perforated tray
  3. cake-cooling rack
  4. metal mesh tray
  5. cookie sheet or plate
  6. Knife
  7. Food


Step 1

Pick something to freeze-dry. According to the website for The Farm, a self-sufficient commune in Tennessee, apples, potatoes and carrots work best for first-time freeze-dryers.

Step 2

Cut the food into paper-thin slices. The thickness determines how long it will take to freeze-dry it.

Step 3

Place the food on a perforated tray, cake-cooling rack, metal mesh tray, cookie sheet or plate, and put it in the freezer. Do this quickly after slicing the food, before discoloration sets in.

Step 4

Wait about a week before removing the food from the freezer. At this point, the moisture will have turned into ice, removing virtually all of the water from the food. According to The Farm, you can test whether the food is dry by removing one piece and allowing it to thaw. If it is not completely dry, it will turn black right away.

Step 5

Store freeze-dried food at room temperature in a cool, dry location. They can last last years without refrigeration. To reconstitute freeze-dried food, put it in a bowl and pour boiling water over it. You can also pour on cold water and use a microwave to heat up the water.