Freeze-drying is a process in which the product is frozen and subsequently introduced into a vacuum chamber to perform the separation of water by sublimation. In this way, water from the solid to the gaseous state is removed from the environment without going through the liquid state. To speed up the process, freeze-sublimation cycles are used to practically eliminate all the free water contained in the original product, while preserving the molecular structure of the lyophilised substance.

Preparation of solid matrices (soils, sediments, food) to be subjected without alteration to a long preservation.