Putting Food By - Janet Greene [169]
However, those who are handy may want to construct their own indoor dryer and/or a cold-frame dryer for use outdoors. If you build both, you should construct a single set of trays that will fit either, so that, if the weather becomes inclement, you can finish sun-dried foods in the indoor dryer. If you build only a cold-frame dryer, the trays should fit your oven, so that you can finish sun-dried foods there if need be. Aside from saving money, the advantage of constructing your own equipment is that it’s a lot of fun in this hypertechnical age to return to elementals. Here’s how to do it.
Trays First
Let’s start with the frames. Shallow wooden tray frames are necessary whether you dry outdoors in sun or shade, or indoors in a dryer or an oven. Never use aluminum, copper, or galvanized metal, or plastic that is not food-grade. Don’t make them of green wood—which weeps and warps; and don’t use pine, which imparts a resinous taste to the food; and don’t use oak or redwood, which can stain the food. The simplest frames to make would be those cut from wooden crates that produce comes in: saw the crates in several sections horizontally, rather as you’d split a biscuit.
Each 1 square foot of tray space will dry around 1½ to 2½ pounds of prepared food.
Loaded trays shouldn’t be too large to handle easily, and they should be uniform in size so they stack evenly. The flimsier the construction, the smaller they should be; but even well-built ones for sun-drying are better if they’re not more than 2 feet by 2 feet.
However, since you can have an emergency that means you will need to finish off in an oven or indoor dryer a batch you’ve started outdoors, it makes sense to have the trays smaller, and rectangular. Make the trays narrow enough for clearance when you slide them inside an oven, and 3 to 4 inches shorter than the oven or indoor dryer is from front to back: you’ll want to stagger the trays to allow air to zigzag its drying way up and over each tray as it rises from the intake at the bottom to the venting at the top.
Consider having the trays 1 to 2 inches deep, 12 to 16 inches wide, 16 to 20 inches long—but first having found the inner dimensions of the oven or indoor dryer (less the fore-and-aft leeway for staggering the trays).
The trays should have slatted, perforated, or woven bottoms to let the air get at the underside of the food. Don’t use metal screening for the bottom. Steer clear of fiberglass mesh: minute splinters of fiberglass can be freed easily and impregnate the food. Vinyl-coated screen in beguiling ¼-inch and ½-inch mesh looks like the answer at first glance, BUT be sure that it is food-grade and can withstand 140 F/60 C, the average heat in an indoor dryer or oven.
Any cloth netting will do if its mesh isn’t larger than ½-inch; nylon net is the easiest to keep clean. Two layers of cheesecloth work, as does mosquito net, etc.—but they’re hard to clean without getting frazzled. Old clean sheets let less air up through, but they’re stouter. (In a pinch you can dry food on sheets laid flat in the direct sun.) When cutting cloth for tray bottoms, allow 2 inches more all around so you can fold it over itself on the outside of the frame; then staple it in place.
We’ve seen good trays with bottoms of twine or strong cord strung back and forth and then cross-hatched the other way. Draw the twine tight and flat, staple each loop to the outside of the frame-strip before you turn around and go back, keeping the strands