What's Freeze Drying?

freeze drying is the process of removing all moisture from a substance without damaging its basic composition. Moisture not only adds weight but also provides an environment for microorganisms to grow and cause spoilage. For this reason, Removing moisture greatly increases the shelf life of a substance, as well as reducing its size and weight.

​

​

​

​

​

​

​

​

​

Unlike preserving foods by only dehydration, Freeze drying skips the liquid water phase all together. Substances are frozen and then de-pressurized to induce sublimation. Sublimation is different from evaporation because the water will transition directly from a solid ice state to a gaseous state. This process prevents the substance from breaking down on a cellular level and helps retain its composition until it can be re-hydrated.

​

​

​

​

​

​

​

​

​

Freeze drying removes almost all moisture, typically around 99% depending upon the substance. Because of this, freeze dried materials have a much longer shelf life than dehydrated materials. The process also helps preserve its original color, appearance, and molecular composition. Freeze dried materials also retain almost all of their nutritional content. 

(https://northslopechillers.com/blog/how-do-freeze-dryers-work/)