Freeze-drying quickly removes moisture from foods through sublimation, the process of turning liquid directly into vapor. Foods retain their nutritional value and much of their taste during the freezing process. Freeze-drying is less common than pickling or canning but it produces healthy, lightweight meals that store well. Although it is usually performed in a lab, you can freeze-dry at home using some special ingredients and techniques.
Prepare your food for preserving by slicing it thinly. Foods with high water concentration work best for freeze-drying. Fruits such as strawberries, apples, pears and bananas are particularly good when preserved in this manner.
Place the freezer bag full of food into the cooler and place it evenly on top of the dry-ice layer. You can add several layers of bagged food, one on top of the other.