Putting Food By - Janet Greene [173]
Drying Indoors
Here you’re increasing the speed of drying by use of temperatures higher than those reached outdoors in the sun, so be prepared to regulate heaters and shift trays around if you want the best results.
Rules of Thumb for Indoor Drying Times
If you are using a commercial dehydrator, the instructions for individual foods will say to start at a relatively lower temperature (this, to avoid case-hardening), then raise the heat after an hour or so, and lower it again during the last one-third of drying time to prevent any “cooked” flavor, caramelizing, or scorching.
For drying in a conventional oven, it’s best simply to set its thermostat at 140 F/60 C, and not change the heat unless the food may be tending to caramelize or cook toward the end of the drying time; then the temperature is lowered by 10 F/5.6 C by turning down the thermostat or by briefly turning the oven off. The convection oven may also be set initially at 140 F/60 C and let to carry on; with its fan, its times will be shorter than for the regular range oven.
This 140 F/60 C is the best across-the-board temperature if your dryer cannot be fine-tuned to changes, because it results in a safe product if not always a thrilling one.
The How of drying by artificial heat is simple if you keep in mind a few Whys:
When drying indoors always keep track of the temperature at the lowest tray, so you can use this heat as the base for judging the temperature higher up. And rotate the trays up or down every ½ hour to correct this difference and ensure even drying. (This is less necessary if using a dehydrator whose heating element and fan are built into the side of the unit rather than the bottom.)
Fresh food won’t dry well if it is exposed to too much heat too soon. But for the majority of its total drying time the food must have enough heat to kill the growth cells of some spoilers, as well as to remove moisture that lets other ones thrive. This means that, no matter how low the temperature at which you start food in order to prevent case-hardening, etc., you have to raise the heat to a killing level and hold it there long enough to make it effective.
When the food has reached the ⅔-dry stage, tend it with extra care to make sure it won’t scorch. Keep rotating trays away from the heat source. (Again, this is less critical if using a dehydrator with a side-mounted heating element and fan.) If you need to, during the last hour reduce the heat by 10 degrees or so.
Handling Food in a Dehydrator or Indoor Dryer
Line or oil the trays—see the earlier comments on tray bottoms under Equipment for Drying; spread prepared food on them one layer deep if it’s in large pieces, not more than ½-inch deep if it’s small. Place halved, pitted fruit with the cut side up (rich juice will have collected in the hollows if it was sulfured).
Stagger the trays on the slides: one pushed as far back as possible, the next one as far forward as possible, etc., as in the sketch earlier. (Staggering may not be necessary if using a dehydrator with a side-mounted heating element and fan.)
Check the food every half hour, stirring it with your fingers, separating bits that are stuck together. Turn over large pieces halfway through the drying time—but wait until any juice in the hollows has disappeared before turning apricots, peaches, pears, etc. Pieces near the front and back ends of the trays usually start to dry first: move them to the center of the trays.
If you add fresh food to a load already in progress, put the new tray at the top of the stack.
Make needed room for fresh food by combining nearly dry material in deeper layers on trays in the center of the dryer; it can be finished here without worry, but keep stirring it.
Using an Oven
As far as you can, use an oven as you would a dryer, following general procedures and the specific instructions for each food.
Leave the upper (broiling) element of an electric oven turned off, and use only a low-temperature Bake setting for