Freeze drying, or lyophilization, is a sophisticated dehydration process that takes place entirely within a freeze dryer. This process is designed to preserve perishable materials while maintaining their structure and nutritional content. Here’s how the process works inside a freeze dryer, broken down into the key steps:

1. Freezing: The material is frozen at extremely low temperatures (-40℉ or lower). This preserves the material’s structure and nutrient content.
2. Primary Drying (Sublimation): Once frozen, the material remains in the freeze dryer which creates a vacuum. This reduces the surrounding pressure, enabling the frozen water in the material to sublimate – meaning it converts directly from a solid to a gas, skipping the liquid phase.
3. Secondary Drying: The material undergoes a further drying process to remove any remaining water molecules.