Now, I never used a dehydrator so I can't really say anything about that and reamin proffesional, but
I've got some experiance in let's say "rigged" drying techniques.
There are basically two methods i know. Oven drying and sun drying. Now for sun drying you need sun.
What you do is put the drying ingredient in a net tent(to avoid insects, I've even on some occasions built water barriers to keep of ants) preferbly on a rack and let the sun do the work : Mediterenian sun - 1 to 2 days, anything else up to 3 or 4.
Oven dryng is simple. You need to put the ingredients in a cool oven(75-100 C, 165 - 260 f). You need to keep the inside of the oven dry. So either use a turbo/convention oven or keep the door ajar(wooden spoon is great although gourmands claim a newspaper gives a better arome.) again put the food on a rack so the moisture can fall down. I guess that's what the dehydrator does.
How long? according to your product/oven
/newspaper brand. I'll say between 6 to 8 hours for most stuff.
Some foods will benefit with preliminety salting to extract moisture. or just sprinkle salt during the dryng process itself.
You wouldn't want always to dry stuff all the way(unless you plan to keep them for a long while). Semidried tomatoes are heavenly. And try to give half drying to figs that wern't sweet enough to concentrate what ever they got.
About mushrooms - I come from israel where our variaty isn't as good. But you shold want a firm textute musroom that's pretty dry already - shitaky for exemple. Otherwise cut it up before drying - for example cremini or portebello.
If you dry all the way you can powder them for a speciel spice(try it in pasta dough, or a sprinkle in a veal stock reduction)
You should remember that some mushroom,which are considered edible, do contains trace amounts of poison(that's why it's advised to eat most mushrooms cooked). Drying concentrate those poisons and can make the raw dried mushroom, not deadly but very discomforting to an eater.
That's my five pennies on the subject hoped it helped. Sorry it's long, but hey not my problem.
PS. Another tip - In a restaurant kitchen you can use some tricks for drying -
1. Put something on a high shelf, the warmth of the kitchen will do the work(maybe, I did it by mistake in a few and actually got god results.
2. Utilize the plate warmer if you have one. Put the dryng subject over night in an operating plate warmer closet and see what happend. It worked for me(at least in one brand).
[ April 12, 2001: Message edited by: shahar ]
