Freeze drying is a dehydration process used to preserve food, biological samples, and other materials. It works by freezing the material and then reducing the surrounding pressure and adding heat to allow the frozen water in the material to sublimate directly from the solid phase to the gas phase. During this process, the food or material is kept at a low enough temperature so that the molecules don‘t break down. Freeze drying can be used to preserve a wide variety of products, including fruits, vegetables, meats, dairy products, and even pharmaceuticals. Freeze drying is often preferred over other methods of food preservation because it preserves the structure, color, flavor, and nutritional content of the food.