Freeze-drying is a dehydration process typically used to preserve perishable material or make it more convenient to transport. The process involves freezing a substance, reducing the surrounding pressure, and adding enough heat to allow the frozen water in the material to sublimate, or change directly from the solid to gas state. Properly sealed freeze-dried substances can be stored at room temperature for years without spoiling. How is freeze-drying often used by pharmaceutical companies? Discuss
Source: The Free Dictionary