What is freeze-dried food?

What is freeze-dried food?

Freeze-dried food is fresh or cooked foods that have been frozen then had the water removed. The result is a light-weight, fresh appearing and tasting preserved food that can be rehydrated with a minimum amount of water: making them a great option for backpackers.

The process involves freezing a fresh food (fruit, dairy, vegetable, cooked meat or fish) in a special "freeze drying chamber", then removing the water by quickly changing the chamber's pressure and temperature. This causes the water in the food to change from a solid to a gas without ever changing back into a liquid. This "quick change" preserves the cell structure of the food without compromising vitamins, nutrients, color or aroma. Because the freeze-drying process requires specialized equipment, it is not something the average backpacker can do themselves at home; however, freeze-dried ingredients and meals are readily available in a variety of retail stores.


What are the advantages of freeze-dried food?


Since the water and oxygen have been removed from freeze-dried food it does not require refrigeration when stored and is, therefore, considered to be "shelf stable" or safe to store at room temperature for long periods of time. Although all food is best when eaten as soon as possible after being packaged, freeze-dried food will last several years when stored in a cool dry location.


The main source of weight in food is the water it contains. All fresh foods contain water; however, once the water has been removed, the weight can be reduced by as much as 70% - 90%. For example: a package containing one-half pound of frozen cooked chicken will weight a mere 2 ounces once freeze-dried. Now that's a significant reduction in weight!

Fast Rehydration Time

Freeze-dried foods are very moisture sensitive; therefore, they will rehydrate in a matter of minutes when added to boiling water. Many freeze-dried items can be reconstituted with cold water as well, but may take longer to achieve their full moisture level. Unlike dehydrated food, most freeze-dried fruits and vegetables can be eaten 'raw' (without adding any water) and usually have the crispy texture of a chip. This makes them a good choice for a tasty and healthy trail mix in addition to using them for in-camp recipes.

Cooking Tip: Freeze-dried foods are pre-cooked; therefore, due to the quick rehydration time, freeze-dried food may be incorporated into the recipe toward the end of the cooking cycle to lend a more "fresh crunch" texture to the dish or to retain a more "fresh food" flavor.


Freeze-drying uses very low levels of heat so most food closely retains the taste, texture and aroma of it's fresh counterpart. Most people believe that the flavor of freeze-dried foods are superior to dehydrated especially when added to entre at the last minute.