What is freeze-drying?

The freeze-drying process begins with freezing the item. Next, the product is placed under vacuum pressure to evaporate the ice in a process known as sublimation. This allows the ice to directly transform from a solid to a gas, bypassing the liquid phase. Heat is then applied to aid in the sublimation process. Finally, low temperature condenser plates remove the vaporized solvent to complete the freeze-drying process. For most items, the finished product that can be brought back to its original state by just adding water, while other items are transformed into a more effective end product in the dry form.