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The surface on which the food is placed should permit air to enter from below and pass through to the food. A surface made of wires with small square openings works very well. You should use wire with the largest openings or squares that do not allow the food to fall through. Air that comes in from below the wire surface will also carry away water evaporated from the food as it dries.
A direct dryer will dry most vegetables in two-and-one-half to four hours at temperatures from forty-three to sixty-three degrees Celsius. Fruits take longer, from four to six hours at the same temperatures.
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