[CH] Home Built Dehydrator Tips
Dave Burrows (quail@cobweb.net)
Thu, 16 Jul 1998 00:26:38 -0400
Hi, All;
I've been using a dehydrator I built, mostly from plywood, quite
successfully for a number of years. All edges and corners of each
plywood piece are planed and sanded so to prevent splinters and make the
unit look a little more finished. It has no fan and therefore is
silent. It is heated with a light bulb. It resides in the basement;
with a little paint, it could be brought into the house but there's
really no need. It works fine where it is.
The base unit is essentially a topless box about 6" (15 cm) high and 14"
x 18" (37 x 48 cm). On the back side, a long opening was cut into the
plywood.. about 2" H (5 or 6 cm) x 10" (27cm) and this is covered from
the inside with regular window fiberglass or nylon screening to keep the
insects out of the dehydrator. In the center of the base, I attached a
porcelain light fixture of the kind meant for outdoor use. An aluminum
pie pan is added between the box bottom and the insulated socket
fixture; a rubber gasket separates the fixture from the reflector. I
wired a switch into the side of the box, but this is not necessary. One
could also be added in line to your electrical cord.
Each tray (I built 7) fits onto pegs that protrude from the bottom's 4
corners; each tray has corresponding pegs (1/4" [60 or 70 mm]) to accept
the next tray. The trays are 3" (8 cm) deep and have a piece of
hardware cloth which is 1/2" galvanized mesh for each tray's bottom. It
is sturdy and does not sag under the weight of the fresh material to be
dehydrated.
The lid of the dehydrator has almost no lip but does have the holes in
the corners' underside to accommodate the pegs in the tray below it. In
the center of the lid is an opening about 4" x 5" (10 cm x 13 cm) (but
the same 20 square inches as the slot in the bottom back) with more
window screening attached from the inside. I used a staple gun to
attach this and the hardware cloth to the bottom of the trays.
Finding the right light bulb to heat the dehydrator is not difficult.
You will need 2 thermometers to calibrate it. One should be placed on
the bottom tray (and I never put food directly above the light bulb on
the lower couple of trays), the other on the top. Do not place a
thermometer directly over or even very near the lightbulb; you could
loose your instrument. Later, even if you only have enough food to fill
one tray, all the trays you used for your callibration should be
employed when you dehydrate something. Fill the bottom tray, the one
closes to the lightbulb, last.
It then just becomes a matter of finding the right wattage bulb (and the
clear ones get hotter than the frosted ones of the same wattage) to
maintain your dehydrator at 100 - 105 F (37 - 41 C). Even without a
fan, the temp is remarkably consistent once the unit gets warm inside.
Peppers, maters, shrooms, herbs and so forth all dry evenly and
relatively quickly in this thing. I am using a clear 150 W bulb. Yours
will surely differ, but it is a place to start.
Because of convection and the principal that heat rises, fresh air is
drawn in through the bottom back and heated. It rises through the
various layers of trays and exits the vent in the lid. The air at the
'chimney' is noticeably moist when some materials are dried; shrooms,
especially. One can always feel the air rising here.
While I have not done this, I have considered using an old power supply
unit from a dead computer to power a small fan (the same one from the
power supply unit would do well enough) built into the side of the box
instead of the vent slot that's back there to draw air into the box.
Alternatively, but with some wiring issues, the fan could be installed
into the lid. Drawing cool air in or blowing hot air out; I imagine
it's all the same.
I don't see why you couldn't use whatever materials you have available
to you to build your own. Cardboard would not likely be the best choice
of materials, but then, I bet that could be challenged, too. You need
only concern yourself with the heat the bulb generates, but with the
porcelain socket and care in the placement of the food materials you are
drying so they are not directly above the heat source, you should have a
very low cost, energy efficient dehydrator. Mine cost nothing to build
as I had the materials on hand, but I should think it could be built
from new materials for under $25. While this gadget I built is plenty
big. I don't see why it could not be bigger.
Drying peppers is the way I put up almost all my peppers. When I have
sufficient quantity of the smae variety, I place the dried pods in a
freshly dishwashered qt canning jar, screw on the band with lid in place
but only loosly. After another 12 hrs and the pods are crispy dry, the
band is screwed tightly. It isn't sealed in the traditional sense, but
because of the partial vacuum formed as the air inside cools, the lid's
center stays down for years. So long as it does, I know the contents
are safe from humidity and subsequent fungal growth. Preserve color by
protecting from light. I like looking at the jars full of peppers and
don't care much about the fading I can't even detect.
Dried peppers are easily rehydrated, flaked, or powdered as you like.
They are easily made into sauces and for flavoring other foods. It will
flavor salsas, but fresh peppers are best for these, I think. Hope this
helps someone.
--
Dave Burrows (StoneBear)
10 Burkett Lane
Washington, PA 15301
USA
http://www.cobweb.net/~quail/Dave1.htm