The Difference between Freeze-Drying and Dehydrating
Freeze-dried food refers to the food preserved by rapidly freezing and then subjecting to a high vacuum which removes up to 99% of moisture. Dehydrated food refers to the food dried in order to remove a considerable amount of moisture but much less than freeze-drying.
Therefore, the shelf life of freeze-dried food can be longer, up to 25 years (unopened and properly stored) while the shelf life of dehydrated food is much less and best kept refrigerated. Furthermore, 97% of the original nutrients are retained in the freeze-dried food while only 5-60% of nutrients are retained in the dehydrated food.
More importantly, freeze-drying results in a high-quality product due to the involvement of a lower temperature. Therefore, the quality of the rehydrated product is excellent.
Also, both methods prevent the growth of microorganisms including mold, yeast, and bacteria on the food by removing water.
Freeze-Dried treats weigh less than dehydrated treats due to a lower amount of moisture.
Freeze-drying is a modern industrial technique of food preservation while dehydration is an ancient technique used since 12,000 BC.