DRYING FOODS at HOME by Penny Ross Extension Food and Nutrition Specialist
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DRYING FOODS AT HOME by Penny Ross Extension Food and Nutrition Specialist Drying is one of the oldest methods of highest quality possible-fresh, sound and Pretreating Vegetables food preservation--dating back thousands fully ripened. Wilted or inferior produce Most vegetables can be dried of years. Preserving seasonal foods by will not make a satisfactory dried product. successfully. Table 1 fists vegetables that drying is still useful and convenient. Immature produce lacks flavor and color. do not dry well, although they will still be Drying reduces the weight and bulk of Over-mature produce may be tough and safe to consume if drying is attempted. food, making it possible to store large fibrous or soft and mushy. Blanching is the recommended quantities in a small space. Dried foods are Prepare the produce immediately after pretreatment for vegetables. The steam easily prepared and add variety to the diet. gathering, and begin drying at once. Wash blanching method is preferred over the How does drying preserve foods? or clean all fresh produce thoroughly to boiling water method because it retains Successful drying depends upon the remove all dirt or spray residues. Sort and more of the water soluble nutrients. removal of enough moisture from a food to discard any defective food. Decay, bruises Blanching before drying helps save some prevent the growth of spoilage organisms. or mold on any piece may affect an entire of the vitamin content, sets the color, The water content of properly dried food batch of food being dried. Peel, pit and/or hastens drying by relaxing the tissues, varies from 5 to 25 percent. cut the food into uniform sized pieces. helps prevent undesirable changes in flavor Home drying, if done properly, can work Most fruits and vegetables will require during storage and helps insure satisfactory well for many fruits and vegetables. They pretreating prior to drying. Antioxidant restoration during cooking. can be dried: coating, blanching and/or sulfuring may be recommended. C in your kitchen oven. You will need Proper pretreatment is necessary to drying trays, an oven thermometer and a retard or destroy the enzymes in foods small fan. that are responsible for color and flavor C in a food dehydrator. Food dehydra- changes during ripening. Unless a food is tors can be constructed with rather simple pretreated, enzymatic changes will building materials or purchased from a continue during drying and storage and commercial outlet. eventually spoil the food. There are, however, varying recommendations for treatment before drying, methods of drying, temperatures and length of drying time and for Table 1. Foods Not Recommended For Drying. conditioning foods prior to storage. You Fruits Vegetables Jerky may have to use the "trial and error" Avocados Asparagus Lamb approach in finding out which drying Berries with seeds Broccoli Pork technique works best for your situation. Citrus fruits Brussels sprouts Fish with a high fat content Whatever method you use, remember that Crabapples Cauliflower Chicken - the size of most a quality dried product depends on quality Cranberries Eggplant chicken makes it fresh products. Melons Greens impractical for Pomegranates Lettuce making jerky Preparing Foods for Quince Radishes Drying Winter Squash Foods selected for drying should be of the With Steam preventing color and flavor losses. The Make a steamer out of a kettle with a sulfuring process requires some special tight-fitting lid. Use a vegetable steamer, equipment and extra time and work, but colander or sieve to hold the food. Layer the results are well worth it. Unsulfured the vegetables loosely in the basket, no fruit is less attractive but safe to eat. more than 2 1/2 inches deep. Add several inches of water to the kettle and bring to a Materials Needed Clean metal container to hold sulfur. boil. Place the basket of prepared • Trays, slatted, wood. Do not use For small amount of fruits, a flat tuna can vegetables in the kettle, making sure the aluminum or galvanized screening or an aluminum pie tin will be large enough. food is above the water level. Steam the materials because sulfur fumes corrode Heavy aluminum foil, molded around a vegetables until each piece is heated these metals. If slatted wooden trays are shallow dish, makes an excellent disposable through and is thoroughly wilted. See not available, wooden lids from lug boxes container in which to bum sulfur. Table 2 for recommended blanching times. may be used. Test food by cutting through a piece. If • Thread spools, wood or plastic (but How to Sulfur sufficiently blanched, it should appear not styrofoam), or small wooden blocks. Always sulfur outdoors in the open air cooked (translucent) nearly to the center. Place at comers of trays to separate the since sulfur fumes will irritate eyes and trays at least 1 1/2 inches apart when breathing passages. Choose a spot that is With Water stacked. away from close contact with plants, Use enough water to cover the product. • Box, heavy cardboard or wood with no shrubs and trees. Sulfuring times will Bring the water to a boil and gradually stir cracks or openings. It must be large differ depending on the fruit. See Table 3 in the vegetables. Begin to count blanching enough to place over stacked trays with 1 for recommended sulfuring times. time immediately. Follow the times given to 1 1/2 inches to spare between the trays 1. Spread fruits in a single layer on in Table 2. Re-use the same water for and the inside of the box. The box should trays, pit cavity side or cut surfaces additional lots when blanching the same also be large enough to accommodate the up. Pieces should not touch each vegetable, adding more water as necessary. container of burning sulfur under the other. Keep the lid on the kettle while blanching. stacked trays. 2. Stack trays 1 1/2 inches apart, • Firebricks to raise the stack of trays separated by spools or wooden blocks Pretreating Fruits high enough off the ground to placed at the corners. Unlike vegetables, pretreatment of fruits accommodate the container of burning 3. Make a 6 x 2 inch flap at the bottom of is optional. Fruits will make a better sulfur. the box and a small slash or hole at the product, however, if they undergo one of • Sulfur Use elemental sulfur, also called upper edge of the opposite side (as shown the treatment methods given below. Each sulfur flowers or flowers of sulfur. Use in the drawing). Cover the stacked trays method will differ with respect to its U.S.P. (food grade) quality, which is free with the box. The flap can be opened when effectiveness. of impurities and burns readily. It may be necessary to facilitate sulfur burning. purchased at most pharmacies. 4. Measure the sulfur and place it in the Sulfuring container. The amount used varies with the Many fruits, especially apples, apricots, length of time the fruit is to be sulfured, peaches, nectarines and pears, tend to the weight of the fruit, and the dimensions darken during drying and storage. Sulfuring of the box. Generally, if you are using a fruit (exposing it to sulfur fumes) cardboard box to cover the trays, you will preserves color, prevents souring, and also need 1 to 2 teaspoons of sulfur per pound decreases loss of vitamins A and C during of fruit. If you have constructed a more drying and storage. Commercially airtight sulfuring box from wood, you need produced fruits are usually sulfured, since no more than 1 teaspoon of sulfur per pound of fruit. Sulfur spread 1/2 inch deep bums better than that 1 inch or more deep. Sulfur fumes do the work, not the burning sulfur, so it is important that the box be tight. this is the most effective means of 5. Place can of sulfur under the box near inhibit the oxidation and enzymatic brown- but it will produce a softer textured and the lower opening and light the sulfur. It ing reactions that cause a fruit to ripen. sweeter flavored fruit than other methods. melts before it ignites, but soon burns with Sodium bisulfite is preferred for sulfiting Prepare a sugar syrup by mixing 1 cup a clear blue flame that produces the acrid because of its strength, but sodium sulfite sugar, 1 cup light corn syrup and 2 cups sulfur dioxide fumes. Do not leave burned or sodium metabisulfite may also be used. water. Bring the mixture to a boil. Add the matches in the container; they impede the The strength ratio is: 1 tablespoon bisulfite prepared fruit and simmer for 10 minutes. burning of the sulfur. = 2 tablespoons sodium sulfite = 4 Remove fruit from heat and let it stand in 6. Immediately lower the box over the tablespoons metabisulfite. You will need the hot syrup for an additional 15 minutes. stack and seal the bottom edges with soil, to use 2 times as much sodium sulfate or 4 Drain fruit well and proceed with drying. leaving the flap open. times as much metabisulfite to achieve the 7. When sulfur is burning well, close the same results as one part bisulfite. Sodium Salt Water Dip flap and start timing. sulfate and metabisulfite can be purchased Dissolve 4 tablespoons of table salt in 1 8. The proper burning time of sulfur at wine-making supply stores or gallon of lukewarm water. Slice or chop the varies with ventilation, shape of container, pharmacies. fruit directly into the water. Allow it to and weather conditions. Sulfuring is Prepare a solution of 1 to 2 tablespoons soak no more than 10 minutes or fruit will complete when fruit appears bright and bisulfite per gallon of water.