This information is taken from the University of Illinois at Urbana-Champaign, College of Agriculture, Cooperative Extension Service, Circular 1227. For even more detailed information please visit their website.
Drying is the oldest method of preserving food. The early American settlers dried foods such as corn, apple slices, currants, grapes, and meat. Compared with other methods, drying is quite simple. In fact, you may already have most of the equipment on hand. Dried foods keep well because the moisture content is so low that spoilage organisms cannot grow.
Drying will never replace canning and freezing because these methods do a better job of retaining the taste, appearance, and nutritive value of fresh food. But drying is an excellent way to preserve foods that can add variety to meals and provide delicious, nutritious snacks. One of the biggest advantages of dried foods is that they take much less storage space than canned or frozen foods.
Recommended methods for canning and freezing have been determined by research and widespread experience. Home drying, however, does not have firmly established procedures. Food can be dried several ways, for example, by the sun if the air is hot and dry enough, or in an oven or dryer if the climate is humid.
With the renewed interest in gardening and natural foods and because of the high cost of commercially dried products, drying foods at home is becoming popular again. Drying is not difficult, but it does take time and a lot of attention. Although there are different drying methods, the guidelines remain the same.
Although solar drying is a popular and very inexpensive method, some areas do not have a suitable climate for it. Dependable solar dehydration of foods requires 3 to 5 consecutive days when the temperature is 95 degrees F. and the humidity is very low.
Drying food in the oven of a kitchen range, on the other hand, can be very expensive. In an electric oven, drying food has been found to be nine to twelve times as costly as canning it. Food dehydrators are less expensive to operate but are only useful for a few months of the year. A convection oven can be the most economical investment if the proper model is chosen. A convection oven that has a controllable temperature starting at 120 degrees F. and a continuous operation feature rather than a timer-controlled one will function quite well as a dehydrator during the gardening months. For the rest of the year it can be used as a tabletop oven.
Dehydrating foods is still one of those things that is a little intimidating to us, but we are researching it and getting ready to attempt some things soon. We will post our progress as we learn!