Are freeze dryers the same as dehydrators?

Similarity

Dehydrators and freeze dryers are both used to remove moisture from food. Both extend the shelf life of food and reduce its weight and bulk, making it easier to store and carry.

Difference

Freeze-drying and dehydration are two different food processing methods. There are also some distinct differences between freeze dryers and dehydrators. Here are the main differences between them:

Working principle:

Freeze dryer: A freeze dryer achieves dehydration by freezing food and then converting water from ice to steam in a vacuum environment. This process is called freeze-drying or lyophilization.
Dehydrator: A dehydrator dehydrates food by heating it to evaporate and drain away the water. This process is called hot air dehydration.

Time and temperature:

Freeze Dryer: The freeze-drying process usually takes longer because it occurs at a lower temperature to maintain the texture and nutrients of the food.
Dehydrator: The dehydration process is relatively quick because high temperatures help evaporate water faster.

Appearance,Taste and nutrition:

Appearance:Freeze-dried foods generally retain the color and appearance of the original food. Because it is done under vacuum, freeze-dried food can maintain its natural color.Some dehydrated foods may change in color because heat processing may affect the pigments in the food.
Taste: Freeze-dried food usually maintains its original texture and tastes relatively close to fresh food. Dehydrated foods may in some cases become more crumbly or hard or have a change in texture.
Nutrition: Because the freeze-drying process is relatively gentle, it helps preserve the nutrients in your food. During dehydration, some nutrients may be lost due to high temperature.

Applicable food:

Freeze-drying machine: It is suitable for producing food that can be stored for a long time, is portable, and has relatively complete nutrition, such as freeze-dried fruits, vegetables, meals, etc.
Dehydrator: More suitable for relatively fast dehydration of foods with less demanding texture requirements, such as dehydrated fruits, crispy skins, etc.

Freeze dryers are more suitable for foods that require a longer shelf life and retain more nutrients.
Dehydrators are more suitable for food dehydration that requires faster speed and relative economy.

Therefore freeze dryers and dehydrators are not exactly the same.