The Dictionary defines dehydrating as “ To remove water or moisture from vegetables, fruits and other foods”. This might sound like a modern invention, but actually has been around for thousands of years, for as long as man has known how to hunt and cook his meals. Game was hung out to dry to preserve it as well as Grains dried to store for winter months.
Canning, freezing and dehydrating are three ways to preserve fresh fruits and vegetables and enjoy your garden surplus all winter. Plus, you may discover that you enjoy preserving your harvest as much as you do growing it. When you have bushels of extra tomatoes, canning is usually your first choice. You can can lots of tomato ketchup and soup, and delicious salsas. Also cucumbers, peppers, zucchini and strawberries, Some things are even better when frozen or dried (dehydrated). Zucchini turns to mush when canned as a vegetable unless it's pickled or transformed into a tasty relish. Peppers somehow keep their magical crunch when diced and then quickly frozen (no blanching necessary) into convenient servings just right for a steaming pot of chili or sizzling stirfry. Knowing which variety you're growing will also help you decide on which method of preserving to use. Canning, freezing and drying your garden surplus also gives you lots of choices. If you don't like frozen green beans, then can them instead with a nice sprig of fresh basil added to each jar. After all, it depends on what you and your family want or enjoy the most.
The oldest method of food preservation is also one of the most convenient. Since 80 to 95 percent of the moisture is removed, dehydrated foods take less storage space than frozen or canned foods. Flavors also become concentrated, so use your fresh, vine-ripened and mature produce for drying.
Sun drying is free, though not always readily available. Other factors such as heat, dry air and air circulation are also variable outdoors. That's why a good dehydrator is well worth the investment -- then these factors are easily controlled. Celery leaves, onions and parsley season soups and stews. You can dehydrate corn and sweet peppers or even make your own fruit leather. Dehydrated tomatoes create a thick sauce in a snap, and thinly sliced and seasoned zucchini make tasty chips.
There are several ways to dehydrate, low tech and more advanced high tech. It all depends on your individual needs and preferances. From one site I found this information http://syndication.getoutdoors.com/go/golearn/304
1. Sun-drying - the original solar technology. Prepare food as for any dehydrator and lay it on screens. Place the screens at least 8 inches off the ground in direct sunlight (south-facing exposure) where air can circulate freely around the food. Keep an eye out for insects, birds, and neighborhood pets. (Netting may be required.) Turn the food 2 or 3 times during the day. If the food isn't dry by nightfall, bring it inside to protect it from dew.
2. Oven-drying. Nothing wrong with using the same oven you bake in as a food dryer. The racks are already there, and you can use cookie sheets for liquids. Most ovens can be set as low as 140 degrees F, which is a little too warm for fruits and veggies, but okay for liquids, meats, and dairy. Use an oven thermometer to check the setting. Prop the oven door open several inches to encourage some air circulation and moisture release, place the tray of food in the center, and you're in business.
3. Room-drying. Some things, such as herbs, chilis, snow peas, and green beans, will dry nicely if you simply hang them in the open air indoors. A fan to circulate air is helpful, but not essential.
4. Buying a Dryer. Over the long haul, the advantages of a store-bought dehydrator make the burden of its initial expense seem pretty puny. For $50 to $300 you can purchase a dehydrator with all the hardware to handle years of food processing, and bypass many of the shortcomings inherent with other methods.
Advantages of (high tech) Commercial Dryers.
Tips and tricks
Home-food dehydrators fall into two categories: those with stackable trays, and those constructed of a rigid box with removable shelves. Size is a factor; most fit on a countertop, but larger models are freestanding and require more space. Some models have base-mounted fans that move hot air vertically; one has a rear-mounted fan for moving air horizontally; yet another uses convection drying, with no fan at all. Uneven heat distribution in the stack means that the trays closest to the heat element and fan dry much faster than those at the top of the stack. Diligent tray rotation is critical, especially if very fleshy foods are being dried. If you're considering drying speciality items, investigate which models can accommodate your needs. Stick-proof fruitleather sheets, tray screens, jerky spices or kits. Living Foods markets a heavy-duty tray to support weightier jobs like yogurt-making; a grow box for starting seeds; a sprouting tube kit; and their food dehydrating handbook, Dry It—You'll Like It!
In My personal experience with dehydrating I have found cheaper units do not have temperature control and so they are limited on their uses. I like to dry herbs, parsley, onions, bell peppers, mint, I don’t make leathers, though my meat cutting husband does like his jerky. Maybe someday I will experiment with dried fruit granola type mixes. I feel it is better to invest with a good unit you can do several different things with, than buy a cheap unit you are limited with and have to turn around and buy another one down the road,.