Freeze-drying
 

Freeze drying, also known as lyophilisation or cryodesiccation, is a low temperature dehydration process [1] which involves freezing the product, lowering pressure, then removing the ice by sublimation.[2] This is in contrast to dehydration by most conventional methods that evaporate water using heat.[3]

Freeze drying results in a high quality product because of the low temperature used in processing.[1] The original shape of the product is maintained and quality of the rehydrated product is excellent.[4] Primary applications of freeze drying include biological (e.g. bacteria and yeasts), biomedical (e.g. surgical transplants), and food processing (e.g. coffee).[1]

(C) wiki

good to know :)