The time necessary for drying fruit depends upon several factors: The type and construction of the drier; the depth to which the fruit is spread; the method of preparing, whether sliced, quartered or whole; the temperature maintained; and weather conditions, whether bright and sunny or cloudy and damp.
If the atmosphere is heavy and damp the drying is retarded. Under some conditions it is hardly possible thoroughly to dry fruit.
There is possibly no step in the entire drying process that requires better-trained judgment than the matter of knowing when the fruit is sufficiently dried. A little experience will soon teach this.
The fruit should be so dry that when a handful of slices is pressed together firmly into a ball the slices will be "springy" enough to separate at once upon being released from the hand. No fruit should have any visible moisture on the surface. As the dried apples, pears, peaches and apricots are handled they should feel soft and velvety to the touch and have a pliable texture. You do not want fruit so dry that it will rattle. If fruits are brittle you have dried them too much.
After the apples and all other fruits are dried they must go through another process, called "conditioning." The best way to "condition" fruits is to place them in boxes or cans and pour them from one container into another once a day for three or four successive days. By doing this you mix the fruit thoroughly and give to the whole mass an even degree of moisture. Pieces that are too dry will absorb moisture from those that are too moist.
You may lose a whole bag or jar of dried products if you neglect the conditioning, for if one moist piece goes into that bag all is lost. Moisture breeds mold and mold means decay.
Ask yourself these questions: "Do I ever lose any dried products? Are my dried products when soaked and cooked as near like the original fruit as possible?" If you lose products and if your dried fruits are tasteless you had better start the conditioning process. For with this one step added to your drying you need lose no dried products, and you need not dry the fruits to the brittle stage, as you must of necessity do when you put them away immediately.
After you have poured the dried products back and forth every day for three or four days as an additional precaution, reheat the dried fruit to 140 degrees just long enough—about thirty minutes—to allow the heat to penetrate throughout the product.
Two kinds of moths stand out prominently among insects that attack dried fruits and vegetables. They are much more likely to get into the fruit during the process of drying than to find their way through boxes into the stored products. This applies particularly to drying in the sun. The Indian-meal moth is the most destructive of these insects. It is about three-eighths of an inch long and has a cloaked appearance, one-third gray and the rest copper-brown. The fig moth is about the same size, but dark, neutral gray. A minute, flattened chocolate-brown beetle usually accompanies these moths and does considerable damage. Both of the moths deposit their eggs on fruit when it is on the drying racks—usually at dusk or after dark, for these insects are not fond of daylight.
It takes from three to ten days for the eggs to hatch into whitish or pinkish grublike caterpillars, and from five to ten weeks from the laying of the eggs before more moths appear to lay another lot of eggs. A number of "broods" or generations are produced yearly, so if a few of these moth eggs are stored away on dried fruits or vegetables hundreds of caterpillars are produced and many pounds of valuable material may be destroyed during the winter if the products are stored in a warm room. Dried fruits stored in warm, dark bins or in sacks offer especially favorable places for the development of these destructive moths.