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College of Agriculture and Home Economics

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Drying Foods
Guide E-322
Martha Archuleta Extension Food and Nutrition Specialist

Cooperative Extension Service

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This publication is scheduled to be updated and reissued 9/04.

Drying or dehydration, the oldest method of food preservation, is particularly successful in the hot, dry climates found in muchof New Mexico. Quite simply, drying reduces moisture necessary for bacterial growth that eventually causes deterioration. Successful dehydration depends upon a slow steady heat supply to assure that food is dried from the inside to the outside. Drying is also an inexact art. Size of pieces, relative moisture, and the method selected all affect the time required to dehydrate a food adequately.METHODS OF DRYING Foods may be sun dried with or without a solar dehydrator, in a gas or electric oven, or with a portable electric dehydrator. Dehydrators with thermostats provide better control over poor weather conditions and food quality than sun drying. An effective solar dehydrator is the shelf above the back seat of a car. Clotheslines are another popular drying rack for ears of corn. Colorfulred chile ristras hung from vigas are practical as well as decorative. Sun drying. Prepared foods are placed on drying trays. Stainless steel screening and thin wood lath are good materials for home-constructed drying trays. As aluminum screening reacts with acids in the fruit, it is less desirable. Do not use galvanized, copper, fiberglass, or vinyl screening. Trays measuring about 14"✕24"✕1"are an easy size to handle. If trays are to be used in an oven, they should be 1-1/2" smaller in length and width than oven shelves to allow air circulation. Place trays of food away from dusty roads and yards. Elevate them at least 1" above the table with spools or bricks to allow good air circulation below the food. Cover the food with a muslin or cheesecloth tent to protect it from insects. Dryfruits in direct sunlight; move trays periodically to assure direct sun exposure. Place vegetables in the shade to prevent excessive color loss.

If weather turns rainy, you will have to complete the drying process using another method. To destroy insects or their eggs that may be on sundried foods and to remove additional moisture in thicker pieces, heat foods in a 150° oven for 30 min. Ovendrying. Either build trays as described for sun drying or convert oven racks to drying racks by stretching muslin or cheesecloth across the oven rack. Secure with toothpicks or long sewn stitches. Alternate trays in the oven periodically to assure even drying. Set oven control at its lowest setting, but not below 140–150°. If using an electric oven, wedge a potholder between oven and door to allow a1" opening. Moisture from the drying food will vent through this opening. Close the door on a gas oven, as vent will permit moisture to escape. Dehydrator. There are two types of dehydrators: solar and electric. For each type of dehydrator, prepare food and place on racks. If using a solar dehydrator, adjust the position of the food throughout daylight hours to keep in direct sunlight. Followmanufacturer’s instructions for the electric dehydrators. When purchasing an electric dehydrator, select one that has a thermostat to regulate temperature and a fan to circulate air. General Directions for Preparing Foods for Drying. Refer to the tables at the end of this guide for instructions for specific foods. Vegetables. Choose tender vegetables. Wash, remove any damaged areas, and cut into evenpieces. Blanch, then chill as though preparing for the freezer. Note: Do not blanch mushrooms, onions, or sweet peppers. To blanch in boiling water, use one pound of food for each gallon of boiling water. Immerse vegetable into the boiling water using a wire basket or mesh bag, cover kettle, and boil the recommended time (see table). Blanching water may be reused until it becomes cloudy. Drain...