Hot water, equal volume, five to ten minutes. Freeze-dried food takes water back far faster than dehydrated food, and oversoaking is the main way to ruin it.
The method
Add hot water at roughly the same volume as the food, stir once, cover and wait five to ten minutes. Meals with sauce may want a little more water; fruit usually wants less.
Because the internal structure survived drying, water moves straight back into the cells. There is no need for the long cold soak that dehydrated vegetables benefit from.
Food by food
Cooked meals: hot water, cover, 8 to 10 minutes, stir before serving.
Meat: hot water or broth, 10 to 15 minutes. Broth returns flavour that plain water dilutes.
Fruit: cool water for 5 minutes, or eat it dry. Most freeze-dried fruit is better as a crisp snack than rehydrated.
Powdered dairy and eggs: whisk cold water in gradually to avoid lumps, then let it stand for a few minutes.
Common mistakes
Too much water is the usual one. Freeze-dried food absorbs quickly, so excess sits in the bowl and dilutes flavour.
Leaving it too long is the second. Ten minutes gives a good texture, thirty gives mush, particularly with vegetables and pasta.
How it compares
Dehydrated food needs longer and never quite returns to its original texture. Freeze-dried food comes back close to fresh, which is what makes full meals practical.
If a batch stays hard in the middle after fifteen minutes, it was probably not fully dry when packaged, and you should check the rest of that batch.
Safety note. Use water at drinking temperature or hotter, and treat rehydrated meat and eggs like fresh food: eat promptly or refrigerate. Do not leave a rehydrated meal at room temperature for more than two hours.
What this is based on
- Manufacturer rehydration guidance supplied with home freeze dryers
- USDA guidance on safe holding of prepared food
- National Center for Home Food Preservation, using dried foods