Putting Food By - Janet Greene [176]
Alteratively, fruits can be treated by burning dry sulfur, or sulfur-fuming. Sulfur first melts—at around 240 F/116 C—becoming a brown goo before it ignites and burns with a clear blue flame that produces the acrid sulfur dioxide that penetrates evenly and is easy to judge the effect of. The usual amount to use is 1 level teaspoon burned for each 1 pound of prepared fruit.
Drugstores and other supply outlets offer several kinds of dry sulfur. We prefer the “sublimed” variety—99½ percent pure, to be taken internally mixed with molasses (the classic folk tonic); it’s a soft yellow powder with no taste and the faintest of scents that’s nothing like the rotten-egg odor of hydrogen sulfide. Two ounces are enough to do 16 to 18 pounds of prepared fruit.
How long to sulfur? Specific times are given in the instructions for individual fruits. Start to count sulfuring time after the sulfur has finished burning, which will take about 15 minutes. With the sulfuring box made airtight except for the intake of air (see drawing), you simply leave it inverted over the stacked trays for the required period to allow the sulfur dioxide fumes to reach all surfaces of the food.
For a sulfuring box you can use a stout, large carton of the sort that household appliances are shipped in. The box should be tall enough to cover an adequately spaced stack of up to 6 trays, and be about 12 inches longer than the trays from front to back so there’ll be room for the sulfuring dish beside the stack of trays and away from the side of the box, which might otherwise catch fire. (See drawing.)
Sulfuring box in action: air-intake notch at bottom; small chimney hole at top to make a draft. The dish contains 1 teaspoon of powdered pure sulfur for each pound of prepared fruit.
(Drawing by Norman Rogers)
To unload the sulfur box; remove the trays from the top, being careful not to spill any juice that has collected in the hollows of the fruit.
ALWAYS SULFUR-FUME FRUITS OUTDOORS AWAY FROM CLOSE CONTACT WITH PLANTS, SHRUBS, AND TREES.
Tests for Dryness In Produce
We rely on appearance and feel to judge dryness. Fruits generally can be considered adequately dry when no wetness can be squeezed from a piece of it when cut; and when it has become rather tough and pliable; and when a few pieces squeezed together separate readily when the pressure is released. “Leathery”—“suede-like”—“springy”—these are descriptions you’ll see in the individual instructions. Several, such as figs and cherries, also are slightly “sticky.”
Vegetables are generally “brittle” or “tough to brittle” when they’re dry enough; an occasional one is “crisp.” Again, instructions for specific vegetables will tell you what to look for.
Finally, foods still warm from the sun or hot from the dryer will seem softer, more pliable, more moist than they actually are. So cool a test handful a few minutes before deciding it’s done.
Post-drying Treatments for Produce
Even after a sample from each tray of food has shown no moisture when cut and pressed, and feels the way its test says it should, you can’t take for granted that the whole batch is uniformly dry. And especially if it’s been dried outdoors you need to get rid of any spoilers—air-borne micro-organisms or bugs you can see—that may have gotten to it somewhere along the line.
Conditioning
Conditioning is a wise precaution because it equalizes the moisture content between under- and overdried pieces.
Cool the food on the trays, then pour it all into a large, open, nonporous container that’s not aluminum—a big crock, enameled, or graniteware canner, even a washtub lined first with food-grade plastic and then with clean sheeting (washtubs are generally galvanized). Have the containers raised on trestles or tables, and in a warm, dry, airy, well-screened, animal-proof room.
Stir the food once a day—twice if you can manage to—for 10 days or 2 weeks,