How to Freeze-Dry Food

Freeze-dry berries for delicious snacks.

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.

Things You'll Need

• Paper plates
• Large freezer bags
• 5-gal. Styrofoam cooler
• 1/4 lb. dry ice
• Gloves
• Fruits and vegetables

Instructions

1. 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.

2. Place the food onto a paper plate and insert into a freezer bag. Seal the bag securely.

3. Pour the dry ice into the cooler. Be sure to always wear gloves while handling dry ice, as exposure to skin can cause frostbite quickly.

4. 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.

5. Place the lid on top of the cooler. Do not seal it tightly for the first five to six hours. The dry ice will sublimate, replacing the oxygen in the cooler with carbon dioxide.

6. Snap the lid so it closes tightly after approximately five hours. Your food will be preserved and, without oxygen, will not spoil or attract insects. Before serving, rehydrate the food with a little water and heat if desired.

Tips & Warnings

• Always be careful when handling dry ice. Use gloves to protect skin from exposure.

References

• "Happy Living Magazine": How To Freeze Chilies For Storage
• Ifood.tv: Food Preservation Techniques

Resources

• Read this Article in Spanish