How Are Freeze-Dried Foods Made?

How Are Freeze-Dried Foods Made?
Freeze-dried foods are a good backcountry camping staple as they are lightweight and easily transportable. Look for freeze-dried food options at the grocery store as well as specialty outdoor stores.

Quality Check

Before food is processed in a freeze-dry facility it is carefully checked for spoilage and bacteria. High-quality foods are cut into small, homogenous pieces and cooked if necessary.



Foods are spread uniformly onto chilled metal trays and placed in cold rooms until frozen. Freezing chambers may be kept as cold as -40 C to ensure quick, complete and consistent freezing.

Drying Part 1

Trays are wheeled into a vacuum drying room and dried using a process called sublimination. Food is quickly exposed to tempratures as high as 38 C, forcing the water particles in the food from their solid state directly into their gaseous state.

Drying Part 2

The water vapor is drawn out of the food and evaporated in the chamber leaving dried, dehydrated food behind.


Food is packaged in vacuum-sealed, airtight containers so particles will not be exposed to any moisture until the product is ready to be prepared.


Article Written By Caroline Schley

Based in New York City, Caroline Schley has been writing articles on fitness, social interaction and politics since 2008. Her articles have appeared in "The Tahoe Weekly," "Second Line News" and websites, including Schley graduated from CU Boulder in 2005 with a degree in environmental science.

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