Drying is the oldest method to preserve food. Ancient peoples didn't have a refrigerator/freezer, pressure canners or canning jars.
They simply used the sun.
The results were dried berries and meat jerky, and other items that could be easily transported or stored.
Today, drying still has advantages. If you have a garden full of tomatoes or a tree loaded with fruit, you can shrink down most of that inventory into a few containers. As the food dries, its natural sugars become concentrated and the flavors are often more intense.
Kim Irvine of Ogden says adding chopped dried tomatoes to her spaghetti sauce is a shortcut to slow-simmered flavor.
"My grandmother used to cook it all day to get it to cook down," she said. "The dried tomatoes absorb some of the moisture and adds a richer flavor dimension. It cuts off a lot of time."
Although today's dehydrating techniques have become more sophisticated, the basics remain the same.
1. Controlled heat that's high enough to force moisture from the food.
2. Dry air to absorb the moisture as it's released.
3. Air circulation to carry the moisture away.
When food is dehydrated, 80 percent to 95 percent of the moisture is removed, so bacteria and other spoilage micro-organisms can't grow. But drying doesn't kill the micro-organisms already present. The food can still spoil if not enough moisture is removed.
There are several ways to dry foods:
The sun. You can go low-cost by using the sun, but you need bright, hot sunshine, low humidity and low air pollution. The "Ball Blue Book of Preserving" (Jarden Home Brands, $5.95) advises daytime temperatures of at least 90 degrees. The hotter the weather, the faster, and more safely, your foods will dry. Also, you need a screen or netting to protect the food from insects.
Yes, there are people who dry food in a hot car with the windows rolled down. But one slam on the brakes, and there goes the upholstery.
Oven. The energy costs are higher in an oven, and it takes longer because there's less air circulation. You'll want to put your oven on the lowest setting (usually 145), and leave the door open a few inches for air circulation. Obviously, this isn't a good method if you've got young children around who could get burned. It also heats up your kitchen, something you don't want when it's already hot outside.
Electric dehydrators. These provide the most reliable and consistent results because of the controlled temperature and air flow. You can use it anytime, whether it's raining or even snowing outside.
Kent Teichert, owner of the For Your Kitchen store in Ogden, recently taught a class on dehydrating.
Growing up, his family owned seven apple trees, "so we had plenty of fruit leather and apple chips," he said.
As a newlywed, he asked his wife to get him a dehydrator for his birthday. Unfortunately, it was a low-budget one and didn't dry foods evenly or efficiently because it lacked a fan.
During the class, he recommended the L'Equip Filter Pro Dehydrator, which filters dust and pollens so they don't end up in the food. It costs about $139. He also likes a square-shaped dehydrator, because it's easier to store in a cabinet than a round one.
"Remember that a lot of the time, you'll be storing it," he said.
In the class, Teichert dehydrated bananas, cherries, tomatoes, apples, apricots, nectarines, fruit leather and beef jerky.
If you have a dehydrator, follow your manufacturer's instructions for best results. But here are some basics, in case you're using the sun, the oven, or if you bought your dehydrator at a garage sale and the instructions are missing.
Fruits and vegetables
Teichert's method for preparing fruits and vegetables was simple and straightforward: Peel or pit, cut or slice in uniform pieces, and dip the pieces in pineapple juice to keep the fruits, such as apples, bananas and peaches, from oxidizing and turning brown; then place on the dehydrator.
Citrus and pineapple juices contain ascorbic acid; you can also use a commercial solution, such as Fruit Fresh. Teichert said he prefers pineapple juice because it doesn't make the food sour or bitter as lemon juice does.
The "Ball Blue Book" advises blanching vegetables and some fruits before drying to stop the ripening action of their enzymes. Blanching also sets the color, kills many spoilage microorganisms and shortens the drying time.
To blanch, heat the food in steam, boiling water or the microwave for a few minutes, then cool quickly in ice water.
Choose produce that's in prime condition. Peel tough-skinned fruits or vegetables.
Peaches, plums and apricots benefit from pushing the peel-side inward to expose more of the pulp surface to dry, known as "popping the backs."
Cut the slices or pieces uniformly, so they will dry evenly.
The thicker the slices, the longer they take to dry.
Dried fruit should retain only about 15 percent to 20 percent moisture. Cut a piece in half; no visible moisture should be present. Most fruits can still be pliable and leathery; but bananas and strawberries should be almost crisp for best protection against mold.
Finished vegetables should contain only about 5 percent moisture. They should look and feel crisp or brittle.
Roma tomatoes take less time to dry than regular tomatoes because they have more solids.
When drying tomatoes, you can add seasonings such as basil from your herb garden, Teichert pointed out.
Generally, vegetables should be dried at 125 degrees and fruits at 135 degrees, according to the "Ball Blue Book."
Drying times can vary from 3 hours to 14 hours, depending on the amount of moisture in the food, the size and thickness of the food, the air temperature and humidity, and the dehydrating method.
Don't get impatient and turn up the oven heat. If it's too high, the food will harden on the outside while trapping moisture on the inside. This will result in spoilage.
If you're planning on long-term storage, the Utah State University Extension advises the final steps of conditioning and pasteurizing.
Conditioning ensures an even distribution of moisture and reduces the chance of spoilage.
Place cooled dried fruit loosely in large plastic or glass containers, about two-thirds full. Cover with a cloth and store in a warm, dry, well-ventilated place. Stir and feel the food every day for a week. If there's evidence of moisture, return the food to the dryer. The food can be left in this way for one to two weeks (that is, unless your family eats it all first).
Pasteurizing destroys any insect eggs that might be in the food, especially if it was sun-dried. The easiest way is to seal the food in protective bags or containers, and freeze for 48 hours.
Dried products will keep for a year if sealed in moisture-proof containers and stored in a cool, dark, dry place. They need to be protected from moisture and insects
Glass jars, tin cans with tight-fitting lids and plastic containers will work. During his class, Teichert showed how to use vacuum-sealing equipment, such as the Food Saver ($122).
Fruit leather is pureed fruit that's dried into chewy strips.
Kids who shy away from dried fruit will often go for fruit leather, especially if you call it by its more popular term, "fruit roll-ups."
It's great for lunch boxes, hiking and on-the-go snacking. Apples, apricots, berries, cherries, grapes, melons, nectarines, peaches, pears, pineapple and plums make good fruit leathers. Bananas can be blended in to the mixture for sweetening.
Puree fruit in a blender until smooth. Add a little pineapple or citrus juice, or ascorbic acid to protect the color. If too thick, thin with a little fruit juice. Add 1 tablespoon honey or sugar if fruit is too tart. You can add other spices or flavorings if you want.
Teresa Hunsaker of the Weber County USU Extension likes to add a little commercial pectin to her fruit leather to make it more pliable.
Cover drying trays with heavy plastic wrap, or spray a cookie sheet with vegetable spray.
Spread puree evenly, about 1?8-inch thick in the center to ¼ inch thick at the edges. Two cups of puree is enough to cover a 12-by-17-inch cookie sheet.
Oven drying: Set oven at the lowest setting (about 145 degrees). Place the trays of puree on the oven rack and leave the door open 2-6 inches to allow steam to escape. Check every hour to make sure the leather doesn't scorch.
Sun drying: Start by heating the puree in the oven for about a half-hour. This kills bacteria and helps speed the drying process. Then transfer outdoors to a hot, sunny spot. Place a screen or net over the trays to keep insects out.
To attract more heat, set the tray on a sheet of black plastic, such as a new garbage bag. To add air circulation, you can place a small fan near the trays.
The leather is done when it isn't sticky and is pliable enough to peel off the plastic wrap in a long sheet. The leather is overcooked when it's brittle or browned.
Store in jars or plastic bags or containers. Fruit leather will retain good quality for up to one year in the freezer, several months in the refrigerator, or one to two months at room temperature, according to USU Extension.
If you like commercial beef jerky, you can save a lot of money making your own, said Teichert.
"The less expensive the meat, the better," he said. "You won't really taste the meat as much as the spices that you're putting in it."
Avoid fatty meats because they can become rancid, according to the "Ball Blue Book."
First the meat must be treated with curing salts or marinades, or use enough heat in an oven or dehydrator to kill microorganisms.
"Home Drying of Food" recommends starting at 160 degrees and decreasing to 140 degrees halfway through the process. Teichert said he dries his jerky at a continuous 158 degrees, "Because I like to be safe."
Teichert showed how to turn ground beef into long strips of jerky by using a "jerky gun," which can cost anywhere from $13-$50. It's similar to a cookie press or caulking gun. You mix the ground beef with the curing salt and seasonings, put the mixture in one end of the tube, and squirt it out in long ribbons.
If you're drying both meat and other foods in your dehydrator at the same time, Teichert advises placing the jerky on the bottom tray so it won't drip on the other foods.