Back to Basics: Drying Vegetables 2
Drying in the kitchen oven or in a dehydrator is recommended; however, you can use sun drying under proper conditions. Arrange the pre-treated vegetable pieces on drying trays in a thin layer, leaving a little space between pieces for air circulation. Dry pieces of similar size on the same tray.
Successful drying depends on the following conditions:
• Enough heat to draw out moisture but not so much to cook the food. Hot sunny days are best for sun drying. Low heat, about 140 °F, dries it even faster. Do not let the heat go above 165 °F.
• Dry air to absorb the released moisture. Rainy, humid weather is a bad time to dry food unless you are using heat.
• Air circulation to carry the moisture off. A light breeze, a fan, or a draft supplies moving air. Try to interrupt the drying process as little as possible. Prolonged drying at low temperatures or interrupting the drying process may cause mold or spoilage.
Drying vegetables in the sun is unpredictable unless temperatures are above 100 °F and the relative humidity is low. If the temperature is too low, humidity too high, or both, souring or molding may occur. Place trays of pre-treated vegetables in direct sun in a flat or tilted position so that air can circulate underneath them. To keep out insects, cover trays with netting. Raise trays off the ground to protect them from dust, dirt, and animals. Stir the vegetables occasionally to help them dry evenly. Bring trays indoors at night to protect the food from dew or rain.
Oven drying is faster than sun drying. However, oven drying is done on a smaller scale and is more expensive. Limit oven load to 4 to 6 pounds of prepared vegetables. Trays should be at least 1 1⁄2 inches smaller than the width and depth of the oven. Separate trays by about 2 1⁄2 inches. Allow a 3-inch clearance from the top and bottom of the oven. An oven temperature of 140 °F is desirable for drying. Disengage the top heating element of an electric oven. Preheat the oven at its lowest setting. Place the trays of vegetables in the oven. Prop open the door of an electric oven 1 inch, a gas oven, 8 inches. This helps control heat and lets out moist air. A fan can help circulate the air and speed the drying. Use an oven thermometer to check the temperature throughout the drying process. As food dries it takes less heat to keep the oven at the specified temperature. Stir the vegetables occasionally from the outside to the center and shift the trays from top to bottom every 1 to 2 hours. Foods dried in the oven must be watched closely. It is easy to scorch vegetables that overheat near the edges of trays. When drying is almost completed, turn off the oven and open the door wide. Most vegetables will oven dry in 4 to 12 hours. Times will vary according to the kind of vegetable, size of the pieces, and the tray load.
Prepare foods and load trays as for oven drying. Preheat the dehydrator to 160 °F. After much of the water has been removed, lower the temperature to 130 °F to 140 °F.
Testing for Dryness
Cool the food before testing for desired dryness. Foods that are warm or hot seem softer, more moist, and more pliable than they will when cooled. Foods should be dry enough to prevent microbial growth and subsequent spoilage. Dried vegetables should be hard and brittle.
Conditioning & Pasteurizing
When drying is completed, small pieces will be drier than large pieces, even on the same tray. When dried in the oven or dehydrator, some food dries faster in some spots on the tray. To condition or equalize the moisture, place the dried vegetables in a glass or plastic container or crock. Cover tightly and let stand for a week. Stir or shake the vegetables everyday. If there is evidence of moisture, return them to the drying trays and heat in a 150 °F oven for 30 minutes. Cool and package.
Pasteurizing is recommended when vegetables are sun dried. Insects may have gotten on foods dried outdoors and may cause spoilage. To pasteurize, spread the dried vegetables on trays in a single layer. Place in a preheated oven, 175 °F for 15 minutes or at 160 °F for 30 minutes. Remove and cool. You may also pasteurize vegetables by sealing them in heavy plastic bags and placing the bags in the freezer at 0 °F for at least 48hours.
Cool vegetables before packaging. Package dried vegetables in small quantities you can use within one week after opening. Every time you open the container, the food is exposed to air and humidity and the quality deteriorates. Small glass jars, metal cans with tight lids, plastic freezer cartons, and plastic freezer bags that you can seal with heat, twist tapes, string, or rubberbands all make good containers. Scald and dry them thoroughly. Pack the dried food into the container as tightly as possible without crushing and seal to keep out moisture.