Drying/dehydrating Foods

[Kitchen Witch]

Drying is the oldest method of preserving food. The early American settlers dried foods such as corn, apple slices, currants, grapes, and meat. Compared with other methods, drying is quite simple. In fact, you may already have most of the equipment on hand. Dried foods keep well because the moisture content is so low that spoilage organisms cannot grow.

Drying will never replace canning and freezing because these methods do a better job of retaining the taste, appearance, and nutritive value of fresh food. But drying is an excellent way to preserve foods that can add variety to meals and provide delicious, nutritious snacks. One of the biggest advantages of dried foods is that they take much less storage space than canned or frozen foods.

Recommended methods for canning and freezing have been determined by research and widespread experience. Home drying, however, does not have firmly established procedures. Food can be dried several ways, for example, by the sun if the air is hot and dry enough, or in an oven or dryer if the climate is humid.

With the renewed interest in gardening and natural foods and because of the high cost of commercially dried products, drying foods at home is becoming popular again. Drying is not difficult, but it does take time and a lot of attention. Although there are different drying methods, the guidelines remain the same.

Although solar drying is a popular and very inexpensive method, Illinois does not have a suitable climate for it. Dependable solar dehydration of foods requires 3 to 5 consecutive days when the temperature is 95 degrees F. and the humidity is very low. The average relative humidity in central Illinois on days with 95 degrees F. temperatures is usually 86 percent. Solar drying is thus not feasible.

Drying food in the oven of a kitchen range, on the other hand, can be very expensive. In an electric oven, drying food has been found to be nine to twelve times as costly as canning it. Food dehydrators are less expensive to operate but are only useful for a few months of the year. A convection oven can be the most economical investment if the proper model is chosen. A convection oven that has a controllable temperature starting at 120 degrees F. and a continuous operation feature rather than a timer-controlled one will function quite well as a dehydrator during the gardening months. For the rest of the year it can be used as a tabletop oven.


GUIDELINES
Speed

For a good-quality product, vegetables and fruits must be prepared for drying as soon as possible after harvesting. They should be blanched, cooled, and laid out to dry without delay. Foods should be dried rapidly, but not so fast that the outside becomes hard before the moisture inside has a chance to evaporate.

Drying must not be interrupted. Once you start drying the food, don't let it cool down in order to start drying again later. Mold and other spoilage organisms can grow on partly dried food.


Temperature

During the first part of the drying process, the air temperature can be relatively high, that is, 150 degrees to 160 degrees F. (65 degrees to 70 degrees C.), so that moisture can evaporate quickly from the food. Because food loses heat during rapid evaporation, the air temperature can be high without increasing the temperature of the food. But as soon as surface moisture is lost (the outside begins to feel dry) and the rate of evaporation slows down, the food warms up. The air temperature must then be reduced to about 140 degrees F. (60 degrees C.).

Toward the end of the drying process the food can scorch easily, so you must watch it carefully. Each fruit and vegetable has a critical temperature above which a scorched taste develops. The temperature should be high enough to evaporate moisture from the food, but not high enough to cook the food. Carefully follow directions for regulating temperatures.


Humidity and Ventilation

Rapid dehydration is desirable. The higher the temperature and the lower the humidity, the more rapid the rate of dehydration will be. Humid air slows down evaporation. Keep this in mind if you plan to dry food on hot, muggy summer days. If drying takes place too fast, however, "case hardening" will occur. This means that the cells on the outside of the pieces of food give up moisture faster than the cells on the inside. The surface becomes hard, preventing the escape of moisture from the inside.

Moisture in the food escapes by evaporating into the air. Trapped air soon takes on as much moisture as it can hold, and then drying can no longer take place. For this reason, be sure the ventilation around your oven or in your food dryer is adequate.


Uniform Drying

Drying the food evenly takes a little extra effort and attention. Stirring the pieces of food frequently and shifting the racks in the oven or dryer are essential because heat is not the same in all parts of the dryer. For the best results, spread thin layers of uniformly-sized pieces of food on the drying racks.


NUTRITIVE VALUE

Dried fruits are a good source of energy because they contain concentrated fruit sugars. Fruits also contain a rather large amount of vitamins and minerals. The drying process, however, destroys some of the vitamins, especially A and C. Exposing fruit to sulfur before drying helps retain vitamins A and C. Sulfur destroys thiamine, one of the B vitamins, but fruit is not an important source of thiamine anyway. Many dried fruits are rich in riboflavin and iron.

Vegetables are a good source of minerals and the B vitamins thiamine, riboflavin, and niacin. Both fruits and vegetables provide useful amounts of the fiber (bulk) we need. Save the water used for soaking or cooking dried foods because this nutrient-rich water can be used in recipes to make soups, sauces, and gravy.


TYPES OF FOOD TO DRY

Many kinds of fresh fruits, vegetables, herbs, meat, and fish can be dried. If you have never tried drying food before, though, it's a good idea to experiment first by drying a small quantity in the oven. This way you can see if you like the taste and texture of dried food. At the same time, you can become familiar with the drying process.

]Fruits are easier to dry than vegetables because moisture evaporates wore easily, and not as much moisture must be removed for the product to keep. Ripe apples, berries, cherries, peaches, apricots, and pears are practical to dry.

Vegetables that are also practical to dry include peas, corn, peppers, zucchini, okra, onions, and green beans. Produce from the supermarket is usually more expensive and not as fresh as it should be for drying. It is a waste of time and energy to dry vegetables such as carrots that can be kept for several months in a cool, dry basement or cellar.

Fresh herbs of all types are suitable for drying. The parts of the plant to dry vary, but leaves, seeds, or blossoms usually give the best results.

Lean meats such as beef, lamb, and venison can be dried for jerky. Fish also is excellent when dried. Certain foods are not suitable for drying because of their high moisture content. Lettuce, melons, and cucumbers are a few foods that do not dry well.


SUCCESSFUL DRYING

Don't be surprised to find a variety of suggestions for drying methods, temperatures, and lengths of time. The drying process is simply not as precise as canning and freezing because it involves so many different factors. You may need to use a trial-and-error approach to find what suits you best. Whatever method you use, be sure to remove enough moisture from the final product so that spoilage organisms cannot grow.

When you dry foods, remember the following:

* Cleanliness and sanitation are essential.
* The flavor of dried fruits and vegetables will be somewhat different from that of their fresh, canned, or frozen counterparts.

[Kitchen Witch]

DRYING FRUITS

SELECTION AND CLEANING

For dried fruit that is naturally sweet and flavorful, be sure to start with good-quality fruit. Select fruit that is fresh, fully ripe, and sound -the same quality you would choose for table use.

Sort and wash the fruit thoroughly. Discard any bruised or overripe pieces. Decay on one piece may give a bad flavor to the whole batch. Sanitation during the handling and drying process is very important.


PRETREATMENT

Almost all kinds of fruit need some treatment before drying. Apples are peeled, cored, and sliced. Fruits with pits, such as peaches and apricots, are usually halved and pitted. Most fruits do not need to be peeled before drying. But the skins of some fruits such as cherries are tough and waxy, so you will have to "crack" the skins first. Fruit should be cut into uniform pieces or slices so that it will dry more evenly. Remember that thin pieces dry faster than thick ones.


Cracking Skins
Blueberries, cherries, grapes, plums, and a few other fruits have relatively tough skins with a waxlike coating.. The skin must be "cracked" or "checked" in many places to remove the waxy coating and to let the inside moisture come to the surface to evaporate. To crack the skin, put the fruit in-to boiling water for 30 to 60 seconds. Then dip in very cold water. Drain thoroughly on absorbent towelling.

We recommend cracking the skins in water rather than dipping the fruit in lye solutions because handling lye can be dangerous.


Protecting Light-Colored Fruits

When apples, peaches, pears, apricots, or other light-colored fruits are cut and exposed to the air, the flesh turns brown rapidly. This darkening is caused by a chemical change called oxidation. If oxidation is not stopped, it will injure the texture, flavor, aroma, and appearance of the fruit.

While you are working with light-colored fruits, treat them with an antioxidant to keep them from turning brown. Mix a small amount of ascorbic acid (2 teaspoons for apples and 1 teaspoon for other light-colored fruit) in I cup of water. Sprinkle the solution over the cut fruit as you are working. Stir lightly to coat all pieces. This amount is enough for about 5 quarts of fruit. Commercial antioxidants contain ascorbic acid plus other ingredients, but they are more expensive than pure ascorbic acid. You can buy ascorbic acid in most drugstores.

It's not a good idea to soak fruit in salt or vinegar water because this adds water to the fruit and lengthens the drying time. Soaking also dissolves out some of the water-soluble vitamins. The vinegar-salt solutions also tend to dull the color of the fruit.

The ascorbic acid coating is only a temporary treatment. For permanent, antidarkening action the fruit still needs to be specially treated before drying.


Sulfuring

Sulfuring is the best antioxidant treatment for preserving color. Without a permanent, antioxidant treatment, apples and other fruits with light-colored flesh will turn dark during drying and storage. Sulfur also helps prevent loss of vitamins A and C. Sulfur is not a preservative in itself, but it discourages insects and microbes, which can cause spoilage.

You don't need to worry about sulfur being harmful in the amounts used for treating fruits. Sulfur is a mineral that occurs naturally in foods and is necessary for life. Sulfur forms sulfurous acid when it combines with the water in the fruit, but the acid evaporates during drying. The residue is a harmless compound that the body easily excretes.

To keep fruit from discoloring, you should expose it to sulfur immediately after preparing it. There are two methods of sulfuring, each with its own advantages and disadvantages: using (1) sulfur fumes or (2) a sulfite solution.

Sulfur fumes are more effective than sulfur solutions, but this method takes more time and equipment. You need a wooden or cardboard box and wooden trays or screens covered with cheesecloth. Several of the recommended references describe methods for making a sulfur box. They also explain how to load and operate the box.

The sulfuring time for each type of fruit is different, so check your references. Fruits sulfured by this method should not be dried indoors because the odor of the fumes is unpleasant. And take care: sulfur f are irritating to the eyes and nose.

Soaking fruit in a sulfite solution is easy. The pieces of fruit are, however, less thoroughly sulfured than they are by fumes. Because of the soaking involved, the fruit absorbs some water, so the drying time is lengthened. Fruit that is sulfured by this method may be dried indoors or out.

To make a sulfite solution, add 1 to 2 tablespoons of sodium bisulfite to 1 gallon of water. Mix thoroughly. Soak the prepared fruit in the solution for 5 to 10 minutes. Soak lighter fruit longer. Use a weighted plate to keep the fruit submerged in the solution. Drain the pieces of fruit and then blot them dry on absorbent towelling. Do not rinse the fruit in water. Start the drying procedure immediately.

Sodium bisulfite is usually available at drugstores, winemakers' shops, and some health food stores. If not, check with your local Cooperative Extension Office. Use only pure reagent or food-grade bisulfite. Don't use practical-grade bisulfite because it is not pure enough for sulfuring fruit. Do not use garden-dusting sulfur either.


Steam Blanching

Steam blanching fruit is an alternative to sulfuring, but it is not as effective. More vitamins are lost and drying takes longer. For these reasons steam blanching is not recommended.


DRYING

You are now ready to begin drying. Arrange pretreated fruit in a single layer on the drying trays. Then place the trays in the oven or dryer. Be sure to stack the trays at least 1-1/2 inches apart. If you are drying juicy fruits such as apricots, cut them in half and remove the pits. Then set the pieces on the racks with the cut side up. This way the flavorful juices will not drain out and be lost.

If you are drying food in the oven, remember to leave the door open slightly. If you have an electric fan, place it in front of the oven to speed up the drying. A dryer comes equipped with a fan to provide ventilation, so you won't need to leave the door ajar.

The length of time needed for drying will depend on the size and number of pieces dried at one time. Drying fruit can take anywhere from 6 hours for very thin or small pieces such as apple slices or grapes to 10 hours for larger juicy fruits such as peach or apricot halves. Temperature and humidity will also affect the drying time. When the pieces are dry, they should be leathery. Cut a piece of fruit to be sure; there should be no moisture inside the fruit.


FRUIT LEATHERS

You might want to try making fruit "leathers," which are a tasty variation of dried fruits. They are made by pureeing almost any type of fruit, then spreading the puree on a cookie sheet or similar tray to dry. Cover the cookie sheet with plastic wrap and pour the thick puree onto the sheet. Spread it out to form a layer only 1/4-inch deep. The fruit puree can be sweetened with honey or corn syrup, and spices, nuts, or coconut flakes can be sprinkled on top. Start with very little because the drying process will concentrate the flavors. Dry the puree until it is leatherlike and pliable but has no sticky spots. Fruit leathers make delicious snacks, treats, or gifts. They can be eaten as is, or they can be reconstituted and used in many dishes. They will keep longest in the refrigerator or freezer.


USING DRIED FRUIT

Dried fruit may be eaten as is. It is great for children's lunches, after-school snacks, or parties. Dried fruit can also be used in cookie or granola recipes or with breakfast cereal.

To use dried fruit in prepared dishes, reconstitute it first by soaking it in cool water for about 2 hours, or until plump. Or pour boiling water over the fruit, just enough to cover, and simmer about 15 minutes, or until tender. Add more water if necessary. Do not overcook because the fruit will get mushy and lose flavor. After the fruit has been reconstituted, it can be used in any recipe that calls for fresh, canned, or frozen fruit.

[Kitchen Witch]

DRYING VEGETABLES

SELECTING, CLEANING, AND CUTTING

You may be surprised to learn that a great many vegetables can be dried successfully at home. Be sure start with fresh, mature produce. Harvest or buy on the amount you can dry at one time - 4 to 6 pounds if you plan to use your oven. Wash all dirt off the vegetables and cut out any bad spots.

Cut the vegetables into pieces of a suitable size. Keep in mind that thin pieces will dry faster than thick one. For example, french-cut green beans take less time dry than cross-cut beans.


BLANCHING

Almost all vegetables need to be blanched (scalded in boiling water a short time before drying. Blanching stops the enzyme action, which drying cannot stop. If vegetables are not blanched, enzymes will destroy the color and flavor during drying and storage. A few vegetables such as mushrooms, okra, and onions do n need to be blanched before drying.

Blanching also protects certain nutrients and bel reduce the drying time somewhat. Some nutrient however, are lost during blanching in boiling water b cause they dissolve into the water. Steam blanching takes more time, but fewer water-soluble nutrients a lost. To minimize the loss of nutrients, blanch only f the required length of time. But don't underblanch; the enzymes will not be inactivated, and the quality of the dried vegetables will be inferior.

Blanch the cut pieces of vegetables in a large amou of water. Follow the blanching times for freezing vegetable. Chill in ice wa ter or in cold running water the same length of time recommended for blanching. Drain well and blot the pieces dry on paper towelling to remove excess moisture. Save the water. It will add flavor and valuable nutrients to your soups, stews, and gravies.


DRYING

Spread the prepared vegetables in thin layers on the drying trays. Then stack the trays in the oven or dryer. Make sure to leave at least 1 inches between the trays so that the air can circulate freely around them. If the trays are too close together, drying will take longer.

If you are using an oven, keep the door open slightly and use an electric fan. A food dryer is equipped with a fan for ventilation, so close the door. Keep the oven temperature at 140 degrees F. (60 C.). Stir the pieces of vegetables about every half hour so that all surfaces are exposed to the air. Also, shift the trays around on the racks periodically because the temperature inside the oven varies somewhat from top to bottom and from front to back.

Vegetables take from 4 to 12 hours to dry. The length of time depends on the kind and amount of food being dried, the method you use (oven or food dryer), and the drying temperature. When sufficiently dry, the vegetables will be hard and brittle. You can test them by hitting a piece with a mallet; the piece should shatter.


SPECIAL HANDLING OF VEGETABLES

Mature beans, peas, and soybeans may be fully or partly dried on the vine.

Carrots, turnips, parsnips, rutabagas, and potatoes are better stored fresh than dried. They can be kept for several months in a cellar or basement.

Broccoli and asparagus are better frozen than dried because freezing helps preserve their fresh flavor and texture.

Combinations of vegetables can be dried at the same time. just remember that vegetables have different drying times, so some will be dry before others.

Vegetables with a strong odor should not be dried at the same time as other vegetables because those with a mild flavor may absorb the strong odor.

Salad seasoning ingredients should be dried separately, then mixed and stored together for delightful blends. A good mix for salads might include tiny bits of carrots, tomatoes, celery, onion, spinach, green peppers, and parsley.

Soup vegetables should always be dried separately. Then you can combine them in different ways so that you will have a vast variety of gourmet soups at your fingertips. You can blend the flavors to suit your own taste; just let your imagination be your guide. These home-prepared combinations will be much cheaper than those available commercially.


USING DRIED VEGETABLES

You don't need to soak dried vegetables before cooking them, but soaking will shorten the cooking time. Reconstitute by soaking I cup of dried vegetables in 2 cups of water for about 2 hours. Add more water if necessary. Vegetables will return to almost their original size and shape. Reconstituted vegetables are tasty additions to stews, casseroles, and soups. The water you use for soaking and cooking contains valuable nutrients, so use it in sauces and gravies.

Vegetable mixes for seasoning salads should not be soaked. Simply combine the dried vegetables with the other salad ingredients and add your favorite dressing.

[Kitchen Witch]

DRYING HERBS

Folklore often depicts the magical powers of herbs. But good cooks the world over have discovered another kind of power in the subtle flavors and aromas of herbs. If you grow and dry your own herbs, you will always have a fresh, inexpensive supply close at hand for making delicious foods.

Herbs do not add calories or nutritional value to foods, but they do add flavor. So if you want to cut down on calories, you can use herbs and spices to give zest to familiar, low-calorie foods. For someone on a salt-free diet, herbs can enhance the flavor of otherwise tasteless foods. A pinch of rosemary, for example, dropped into the water that potatoes or rice are boiled in will give a delightful taste to these vegetables.


SELECTION

You can grow and dry a wide variety of herbs. Some that are especially popular are thyme, tarragon, rosemary, mint, sage, sweet basil, bay leaf, parsley, marjoram, savory, oregano, chervil, chives, and dill. The foliage of these plants is attractive, and they give off a soft, pleasant fragrance. If you plant your herb garden near the kitchen, you can enjoy the plants and harvest the leaves easily as they reach the peak of quality. Young, tender leaves are more flavorful and aromatic than older leaves.


PREPARATION

Cut the stalks when the leaves are mature or the plants have just started to bloom. Use only the tender, leafy tops and flower clusters. Discard the leaves below 6 inches from the top of the stalk. They are not as pungent as the top leaves. Remove any dead or discolored leaves. Rinse with cold water to wash off dust and dirt. Blot off excess moisture with paper towelling. When drying dill, harvest the plant as soon as the seeds are ripe.


DRYING METHODS

Air
For air drying, tie six to eight stems together in a small bunch. Then tie a large brown paper bag around the bunch to protect the herbs from the light. Be sure the leaves do not touch the sides; otherwise, they may stick to the bag and not dry properly. Make several holes in the bag for ventilation. Hang it in a warm, dry, airy room or attic. Herbs will dry in 1 to 2 weeks.

If you like, you can remove the leaves from the stems before drying. Place the leaves on a tray in a warm, dry, airy place away from direct sunlight For best results, use a doth-covered rack or an open mesh screen. Turn or stir the leaves occasionally to assure even drying. Herbs should not be sun dried because light destroys the natural aroma. A poor-quality product will result if the herbs are exposed to direct sunlight.


Oven
For oven drying, place clean, fresh leaves in a single layer on racks. There should be at least 1 inches around the racks and between them so that the air can circulate freely. You can use blocks of wood to separate the trays. Set the oven on the very lowest setting and dry the herbs slowly. Keep the oven door propped open slightly for ventilation and to control the heat. Drying will be complete in 2 to 4 hours.


Microwave Oven
If you have a microwave oven, you can use it for drying herbs. Place the herbs between paper towels and set them on the rack. Close the door and turn the oven on a medium setting for 2 to 3 minutes. Then check for dryness; the leaves should feel brittle and should crumble easily. If they are not done, turn the oven on for 30 seconds longer. Although this process actually cooks the herbs, the end product is just about the same.


STORING

When the leaves are dry, shake them from the stems and discard the stems. Crush the leaves if desired. But keep in mind that whole herbs retain their flavor longer than crushed or ground herbs. Store dried herbs in small airtight containers away from the light. Containers such as metal cans or tinted glass that exclude light are best.

If stored in a cool, dry, dark place, whole dried herbs retain their flavor and aroma up to one year. A warm storage area may hasten the loss of flavor. A damp environment encourages caking, color change, and infestation. Close the containers tightly after each use so that the volatile oils are not lost.

Do not use old herbs. If you aren't sure an herb is fresh, rub a bit of it between your palms and breathe in the aroma. If there is little or no aroma, replace the herb with a fresh supply.


USING

To release the full flavor, cut or chop the dried leaves into fine bits before adding to food. Or crush the leaves by rubbing them between your palms or by grinding them with a mortar and pestle. For the best results, add herbs to the liquid in the recipe.

Keep seasoning blends subtle. When combining herbs, use one having a pronounced flavor with two to four others having a less pronounced flavor. All of the herbs in the following famous combinations can be grown and dried at home:

* bouquet garni, bunches of herbs and sometimes spices tied together or put into a cheesecloth bag. The usual combination is celery leaves, onion, parsley, and thyme. The combination varies for different dishes.
* fines herbes, a mixture of three or more herbs. Combinations used are (1) chervil, chives, and parsley; or (2) basil, sage, and savory.

The amount to use depends on your taste preferences, the piquancy of each herb, and the effect it has on different foods. If you do not have a recipe, start with 1/4 teaspoon of herb per pound of meat or pint of sauce, and increase as desired. If the recipe calls for fresh herbs, you can substitute dried herbs. Use a fourth of the recommended amount, for example, 1/4 teaspoon of dried herb instead of I teaspoon of fresh. Avoid using the same herbs in several dishes to be served at the same meal.

The flavor of an herb will be at its best if you add it to the recipe at the proper time. Add herbs as follows:

* to soups and stews during the last half hour of cooking. The delicate flavor and aroma of herbs can be lost by overcooking.
* to uncooked foods such as tomato juice cocktail 3 to 4 hours before serving, or even overnight, to release the full flavor of the herb.
* to quickly cooked dishes or sauces as soon as you begin cooking the food. To draw out more flavor, barely moisten herbs with a little lemon juice, water, cooking oil, or other liquid suitable for the food you are preparing, and let stand for 10 minutes or more before using.

Herbs may be used to flavor vinegar, mustard, and butter. Choose your favorite herbs to add variety to these everyday ingredients, following the recommended steps.

Use whole spices and herbs for beverages and pickles. Leaving whole spices in pickles can cause unsightly darkening. Tie herbs and whole spices in a small square of cheesecloth so that they can be removed easily before serving. This will also prevent seasoning specks in the finished product. The same method can be used when whole spices and herbs are added to other foods.