written by: Lindsay Evans•edited by: Niki Fears•updated: 4/15/2010
Use the all-natural power of the sun to preserve summer-fresh foods to enjoy throughout the year. All you need is some basic equipment, sunshine, and time to dry foods at home using solar power.
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The Sun: An All-Natural Food Preserver
Since the beginning of our species, humans have used the dehydrating power of the summer sun to preserve foods. Herbs, fruits, vegetables, and meat can be dried successfully using the heat of the sun and some basic equipment. Depending on your location (basically the humidity of your area in the summer) you can sun-dry foods on trays in the sunshine or by using a solar dehydrator.
Always bring your drying food inside during the night or if the humidity rises suddenly (as in a summer storm). Continue drying your food the next morning outside in the sun.
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The Basic Tray Method
If you live in a hot, dry area you can sun-dry foods by placing the food on screen trays and draping the trays with cheesecloth to deter pests. This method works best in weather conditions with temperatures around 100 degrees F and low humidity for several days. Only sun-dry foods if you live in an area without problem air pollution and away from busy roads. Particulate matter from the air can settle on the food you dry.
Purchase window screens at the hardware store to use as drying trays. Thoroughly wash the trays and line them with cheesecloth. Place the food you want to dry on the lined trays, leaving room for airflow around each piece. Drape another layer of cheesecloth over the food so insects and small pests cannot get to the food. Secure the cheesecloth to the tray with clothespins. Place the trays outside on a table in the sun. Allow for airflow underneath the trays by elevating them with wooden boards or books.
To dry herbs, thoroughly wash the herbs and let the water evaporate until dry. Herbs dry quickly in the heat of summer and dry best out of intense sunlight if the humidity is very low. Check the herbs for dryness after 3-5 hours. Herbs that are properly dry should crumble easily.
Fruits and vegetables can take several days to dry, so check the weather forecast to be sure temperatures stay high and humidity stays low. Thoroughly wash the food and cut into even slices about 1/4" to 3/8" thick. Make your own sun-dried tomatoes, dried apricots, dried plums and more. The food is dry when it is leather-like and pliable and free of moist spots.
If your food is not getting fully dry in the sun, avoid spoilage by using your oven. Fruits and vegetables dry best at about 130 - 140 degrees F. Check your oven thermometer to see if your oven light or gas oven pilot light keeps the oven within this range. Turn the oven on if the temperature can be kept under 150 degrees F, or turn to the lowest setting and keep the door propped open.
Since you cannot control the temperature when sun-drying food on trays, do not attempt to sun-dry meats without the use of a solar dehydrator (see below).
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Solar dehydrators get a little help from science to increase and maintain the temperature inside the dryer. A solar dehydrator is easy to make at home. You can find plans online to create an easy, basic solar dehydrator or a sturdy dehydrator to last for years to come. A variety of plans can be accessed through builditsolar.com, or check out The Solar Food Dryer: How to Make and Use Your Own Low-Cost, High Performance, Sun-Powered Food Dehydrator, by Eben V. Fodor.
A solar dehydrator is a must if you want to use the power of the sun to dehydrate foods but live in a humid or mild-weather area. Drying food outside in less than ideal conditions will do nothing but produce a big batch of mold! Using a solar dehydrator will greatly reduce the time it takes to dry foods in the sun.
You also must use a solar dehydrator to safely sun-dry meats. Since meat dries best at about 155 degrees F, only a solar dehydrator can produce and maintain a temperature to safely dry meats outside. For more information about sun-drying foods and instructions to make a simple solar dehydrator, see Food Drying by Marcella Shaffer.