How does Drying Preserve Food?
The process of drying/dehydrating removes moisture from food, which prevents bacteria, yeasts and molds from growing. In addition, drying inhibits the action of enzymes within the food, but does not inactivate them. Therefor, when the food is ready to be consumed, it can be re-hydrated and regain its original shape.
Methods of Drying:
- Dehydrators: Food dehydrators are electrical appliances that usually have a thermostat to control the temperature
- Dehydrofreezing: this method uses a combination of drying and freezing. This method removes only 70% of the moisture, which results in a tastier product. This method is not to be confused with freeze drying- which is a commercial technique that cannot be reproduced in the home.
- Indoor Air Drying (Room Drying) - this method is most effective for herbs or hot peppers. These items can be tied into small bundles and suspended from racks or string. Nuts can be effectively dried by spreading them into single layers on newspapers or parchment paper.
- Oven Drying: Before using this method to dehydrate foods, be sure that you can set the temperature to 140F. Food must be dried at this temperature, it the oven is set higher, the food will actually cook, rather than dry. Although it may appear to be dried, the inside may retain too much moisture, allowing mold to form, spoiling your food. To use the oven, set the temp to 140F, prop the door open slightly to allow for air circulation. Cooling racks placed upon cookie trays work quite well for foods such as jerky or fruits. The cookie tray will catch any drips and prevent a mess on the bottom of your oven.
- Solar/Sun Drying: this method uses the sun as the heat source, but in a specially designed dehydrating box which results in shorter drying times
- Vine Drying: Usually reserved for vegetables and legumes, this method is to leave the item (beans, for example) on the vine until the pods are shriveled and rattle when moved. This method is effective for several types of beans, navy, kidney,butter,great northern, lima, lentils, and soybeans. However, if the beans are dried in this manner, pasteurization is required to kill insects and their eggs.
- Pasteurization Freezer Method: Seal foods and place in freezer (0F or colder) for 48 hours.
- Pasteurization Oven Method: Place food in a shallow pan or cookie sheet in an oven that has been preheated to 160F. Bake at 160F for 30 minutes.
Dried foods must be stored in a cool dry place away from moisture and heat. Overly warm storage conditions will cause the food to sweat, thereby creating enough moisture for mold to grow.
Store the dried food in clean, dry containers in quantities necessary for the preparation of your favorite recipes.
Do not store any sulfured fruits in metal containers, as the fumes will react with the metals and cause changes in color.
Recommended Storage Times:
- Dried fruits stored below 60F will last for 12 months, safely.
- Dried Fruits stored at 80F will last for 6 months
- Vegetables stored at 60 F will last approximately 6 months
- Vegetables stored at 80F will last approximately 3 months
Please note that it is possible for Stored Foods to reabsorb some moisture during storage. It is important to choose proper containers and maintain proper storage temperatures to prevent spoilage.