What is "freeze-drying"

Freeze-dry \Freeze"-dry`\ (fr[=e]z"-dr[imac]`), v. t. [imp. & p. p. Freeze-dried; p. pr. & vb. n. Freeze-drying.] to remove the moisture from (e.g. food) by first freezing and then subjecting to a high vacuum; -- used as a mild method for drying foods or chemicals while causing little decomposition, in contrast to heat-drying.

Note: This is a relatively gently drying process used to preserve food or sensitive biological materials. For biochemical materials, the term {lyophilize} is often used.

n. The process of dehydration by sublimation for preservation or convenience.

n. a method of drying food or blood plasma or pharmaceuticals or tissue without destroying their physical structure; material is frozen and then warmed in a vacuum so that the ice sublimes [syn: lyophilization, lyophilisation]

Freeze-drying—technically known as lyophilisation, lyophilization, or cryodesiccation—is a dehydration process typically used to preserve a perishable material or make the material more convenient for transport. Freeze-drying works by freezing the material and then reducing the surrounding pressure to allow the frozen water in the material to sublimate directly from the solid phase to the gas phase.