Freeze drying of a vacuum freeze dryer refers to the process of removing moisture or other solvent from a frozen biological product by sublimation. Sublimation refers to the process of solvents, such as water, like dry ice, which change from a solid to a gaseous state without going through a liquid state. The product obtained by freeze drying in a vacuum freeze dryer is referred to as a lyophilizate, and the process of vacuum freeze dryer is referred to as lyophilization. Traditional drying can cause the material to shrink and damage the cells. The structure of the sample is not destroyed during the freeze drying process because the solid component is supported by the firm ice at its location. When the ice sublimes, it leaves pores in the dry remaining material.

This preserves the biological and chemical structure of the product and the integrity of its activity. In the laboratory, lyophilization has many different uses and is indispensable in many biochemical and pharmaceutical applications. Vacuum freeze dryers are used to obtain biomaterials that can be preserved for long periods of time, such as microbial cultures, enzymes, blood, and pharmaceuticals, retaining their inherent biological activity and structure in addition to long-term storage stability.

To this end, lyophilization is used to prepare tissue samples for structural studies (eg, electron microscopy studies). Vacuum freeze dryers are also used in chemical analysis to obtain dried samples or to concentrate samples to increase analytical sensitivity. Freeze-drying stabilizes the sample components without changing the chemical composition, making it an ideal analytical aid. Freeze drying can occur naturally. In the natural case, this process is slow and unpredictable. Through the vacuum freeze dryer system, people have improved and subdivided many steps to speed up the process.