冷冻干燥是一个利用冷冻方式干燥食材的方法，常用来保存易腐坏的食物，或是使得食物更容易运送。冷冻干燥会先冷冻食物，再将周围压力降低，使得食物中冻结的冰直接升华，由固态变为气态。

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.