Oven Dried vs. Freeze Dried- The Differences
The process of freezing food such as freeze-dried mushroom involves exposing it to very low temperatures, often -40F or below. A vacuum is created around the meal once it is frozen, and then the temperature is gradually increased. Sublimation is the process by which frozen liquids are transformed into vapor without first going through a liquid phase, and the heat energy is what causes the water to sublime. Commercial kitchens, not residential kitchens, usually use freeze-drying since it's a more involved procedure than dehydrating.