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GLOSSARY OF TERMS

Dry Time

The time listed is appropriate for a dehydrator. Drying times are approximate and depend on the initial moisture content of the product and particular dehydrator being used.

When drying fruit (especially large pieces), a dehydrator is suggested rather than an oven because of time needed to dry fruits. Range ovens can be used, but time and fuel expense will be great for the amount dried. Apples are the only fruit practical to dry in large pieces in the oven.

When drying vegetables, drying times in a conventional oven could be up to twice as long, depending on air circulation.


Prevent Browning

Fruits like peaches, apples, pears and apricots darken quickly when exposed to air and during freezing. They also may lose flavor when thawed. There are several ways to prevent darkening and flavor loss in frozen fruit. Crystalline (powdered) ascorbic acid, or vitamin C, is the most effective agent in preventing darkening of fruit. Not only does it preserve natural color and flavor of fruits, but it adds nutritive value as well. Ascorbic acid in crystalline or powdered form is available at some drugstores or where freezing supplies are sold. Check in advance as it may have to be special ordered. Ascorbic acid tablets are more readily available and less expensive, but are more difficult to dissolve. Also, fillers in the tablets may make the syrup cloudy. Three thousand milligrams of ascorbic acid in tablet form equal one teaspoon of crystalline ascorbic acid. To use, dissolve ascorbic acid in a little cold water. If using tablets, crush them so they will dissolve more easily. Use the amount specified for each fruit.


Ascorbic Acid

Commercial ascorbic acid mixtures are special anti-darkening preparations, usually made of ascorbic acid mixed with sugar or with sugar and citric acid. The important active ingredient in these mixtures usually is ascorbic acid. Follow manufacturer's directions for use. Do not confuse these mixtures with the ascorbic acid specified in directions for individual fruits found in this publication.

Citric acid or lemon juice are sometimes used in place of ascorbic acid. Neither, however, is as effective as ascorbic acid. When used in quantities high enough to prevent darkening, they often mask natural fruit flavors and make a tart-tasting product. To use, dissolve 1⁄4 teaspoon crystalline citric acid or 3 tablespoons of lemon juice in a quart of cold water. Place prepared fruit in the mixture for 1 to 2 minutes. Drain and pack the fruit.

More info on ascorbic acid.


Headspace (freezing)

Type of pack Pint Quart
Liquid pack (fruit packed in juice, sugar, syrup or water, crushed or pureed fruit and freezer jam) ½ inch 1 inch
Dry pack (fruits packed without added sugar or liquid) ½ inch ½ inch
Fruit juice 1 ½ inches 1 ½ inches

*Tray packed fruit does not need any headspace

CAUTION - Do not use narrow-mouth jars for freezing foods packed in liquid, as expansion of the liquid could cause the jars to break at the neck.


Syrup Pack

The sweetness of the fruit to be frozen depends upon the proportion of sugar to water used. A 40 percent syrup is recommended for most fruits. Lighter syrups are desirable for mild-flavored fruits to prevent masking the flavors. Heavier syrups may be needed for very sour fruits. See Table 3 for proportions of sugar and water to use for the different syrups. To make the syrup, dissolve sugar in lukewarm water, mix until the solution is clear. Chill syrup before using. Use just enough cold syrup to cover the prepared fruit after it has been placed in the container (about 1⁄2 to 2⁄ cup of syrup per pint). Leave appropriate headspace. To keep fruit under the syrup, place a small piece of crumpled, water-resistant paper, such as waxed paper, on top of the fruit and gently press fruit down into the syrup. Seal container tightly, label and freeze.

Type of syrup Sugar (cups) Water (cups) Yield of syrup (cups)
20% (very light) 1 1/4 4 4 ⅔
30% (light) 2 4 5
40% (medium) 3 4 5 ½
50% (heavy) 4 ⅔ 4 6 ½
60% (very heavy) 7 4 7 ¾

*In general, up to 1/4 of the sugar may be replaced by corn syrup or mild-flavored honey. A larger portion of corn syrup may be used if a very bland, light-colored type is selected.


Sugar pack

Sprinkle sugar over fruit and mix gently until the juice is drawn out and the sugar dissolved. Soft-sliced fruits such as peaches, strawberries, grapes, plums and cherries will yield sufficient syrup for covering if the fruit is layered with sugar and allowed to stand 15 minutes. Pack into containers, leaving appropriate headspace. To keep fruit under the syrup, place a small piece of crumpled, water-resistant paper, such as waxed paper, on top of the fruit and gently press fruit down into the syrup. Seal container tightly, label and freeze.


Unsweetened Pack

Most fruits have a better texture, color and flavor if packed in sugar or syrup. However, sugar is not necessary to safely preserve fruit. For those wishing to cut down on sugar, fruit can be packed dry without any sugar, or covered with water or unsweetened juice containing ascorbic acid. For a juice pack, use unsweetened, light-colored, complementary juices such as apple, pineapple, orange or white grape juice. For all unsweetened packs, leave appropriate headspace. When fruit is packed in unsweetened water or juice, keep fruit submerged by placing a small piece of crumpled, water-resistant paper, such as waxed paper, on top of the fruit and gently press fruit down into the juice or water. Seal container tightly, label and freeze. Raspberries, blueberries, blanched apples, gooseberries, cranberries and rhubarb can be frozen without sugar and still be a good quality product.


Tray Pack

The tray pack is a dry unsweetened pack that is good for small, whole fruits such as blueberries, raspberries and cranberries that give a good quality product without sugar. Spread a single layer of prepared fruit on shallow trays and freeze. Leave in the freezer just long enough to freeze firm. Longer exposure to dry freezer air will result in moisture loss and a decrease in quality. When frozen, promptly package, leaving no headspace, seal tightly, label and return to the freezer. The fruit pieces remain loose and can be poured from the container and the package reclosed.


Puree Pack

Puree fruit and add ascorbic acid. Sweetening is optional. Pack, leaving appropriate headspace, seal container tightly, label and freeze.


Sulfuring

Fruits such as apples, pears, peaches, nectarines and apricots require sulfur treatments to prevent browning during the drying process. Sulfur treatments protect vitamins A and C during drying and storage, help retain fresh fruit flavor and increase the shelf life of the fruit. Sulfur treatments destroy thiamin, but most fruits are not good sources of thiamin, so this is not a great concern.

Sulfuring is the most effective sulfur treatment and results in minimal loss of water-soluble nutrients; however it is not very practical. The fumes will irritate eyes and breathing passages, so it must be done outside. It is used primarily for fruits that are going to be sun dried, because sulfured fruits should not be dried inside. Sulfuring is more expensive, more time consuming and more complicated than using sulfite dips.


Sulfite dips

Sulfite dips can be prepared and used in the kitchen and sulfite-dipped fruits can be dried indoors. There are several disadvantages of sulfite dips. Penetration of sulfite may be uneven, resulting in uneven color retention. The loss of water-soluble nutrients is greater than in sulfured fruit. And, finally, the fruit may absorb water, which will result in a longer drying time.

Soaking times vary with the type of fruit and thickness of slices. Dissolve ¾ teaspoon to 1-½ teaspoons sodium bisulfate per quart of water. (If using sodium sulfite, use 1-½ teaspoons to 3 teaspoons. If using sodium meta-bisulfite, use 1 tablespoon to 2 tablespoons.) Place the prepared fruit in the mixture and soak 5 minutes for slices, 15 minutes for halves. Remove fruit, rinse lightly under cold water and place on drying trays. (This solution can be used only once. Make a new one for the next batch.) These chemicals must be of food-grade quality and usually are available at winemaking supply stores, natural foods stores or pharmacies. Prices vary considerably.

Recent research indicates that certain asthmatics may react adversely to sulfites. Persons who are sensitive to sulfites should avoid preparing or eating sulfite-treated foods. Sulfite fumes will be given off during the drying process; also, if sodium bisulfite is added to water for steam-blanching, fumes will escape with the steam.


Syrup Blanching

Blanching fruit in syrup helps it retain color fairly well during drying and storage. The resulting product is similar to candied fruit. Fruits that can be syrup blanched include: apples, apricots, figs, nectarines, peaches, pears, plums and prunes. Combine 1 cup sugar, 1 cup light corn syrup and 2 cups water in a pot. Bring to a boil. Add 1 pound of prepared fruit and simmer 10 minutes. Remove from heat and let fruit stand in hot syrup for 30 minutes. Lift fruit out of syrup, rinse lightly in cold water, drain on paper towels and place on dryer racks.


Steam Blanching (Drying)

Steam blanching also helps retain color and slow oxidation. However, the flavor and texture of the fruit are changed. Place several inches of water in a large pot with a tight-fitting lid. Heat to boiling. Place fruits or vegetables, not more than 2 inches deep, in a steamer pan or wire basket over boiling water. Cover tightly with lid and begin timing immediately. Check for even blanching halfway through the blanching time. Some fruits or vegetables may need to be stirred. Remove from heat and dip briefly in ice water only long enough to stop cooking. Cool until they feel only slightly hot to touch - about 120 degrees F. When done, remove excess moisture using paper towels.


Water Blanching (Drying)

Most vegetables need to be blanched before drying to stop enzyme activity. If enzymes are not destroyed, they will produce "off" flavors and the vegetables will turn brown during the drying process as well as during storage. Blanching kills some spoilage organisms, shortens the drying time of some foods and protects vitamins C and A during storage. But it also causes the loss of some water-soluble nutrients.

Blanching times vary with vegetables and thickness of slices. See specific blanch times listed for each vegetable. For boiling-water blanching, immerse no more than 1 pound of vegetables per gallon of boiling water. Place a lid on the pot. The water should return to boiling within 1 minute, or you are using too many vegetables for the amount of boiling water. Start counting blanching time as soon as the water returns to a boil. Remove from heat and dip briefly in ice water only long enough to stop cooking. Cool until they feel only slightly hot to touch - about 120 degrees F. When done, remove excess moisture using paper towels.


Steam Blanching (Freezing)

Steam blanching also helps retain color and slow oxidation. However, the flavor and texture of the fruit are changed. Place several inches of water in a large pot with a tight-fitting lid. Heat to boiling. Place fruits or vegetables, not more than 2 inches deep, in a steamer pan or wire basket over boiling water. Cover tightly with lid and begin timing immediately. Check for even blanching halfway through the blanching time. Some fruits or vegetables may need to be stirred. Remove from heat and dip in ice water for the same amount of time that the produce was blanched. For example, if the blanching is 3 minutes, leave in the ice water for 3 minutes. When done, remove excess moisture using paper towels.


Water Blanching (Freezing)

Most vegetables need to be blanched before drying to stop enzyme activity. If enzymes are not destroyed, they will produce "off" flavors and the vegetables will turn brown during the drying process as well as during storage. Blanching kills some spoilage organisms, shortens the drying time of some foods and protects vitamins C and A during storage. But it also causes the loss of some water-soluble nutrients.

Blanching times vary with vegetables and thickness of slices. See specific blanch times listed for each vegetable. For boiling-water blanching, immerse no more than 1 pound of vegetables per gallon of boiling water. Place a lid on the pot. The water should return to boiling within 1 minute, or you are using too many vegetables for the amount of boiling water. Start counting blanching time as soon as the water returns to a boil. Remove from heat and dip in ice water for the same amount of time that the produce was blanched. For example, if the blanching is 3 minutes, leave in the ice water for 3 minutes. When done, remove excess moisture using paper towels.


Checking

Cherries, grapes and small, dark plums that are dried whole may require a short heat treatment, called checking, to remove a naturally occurring waxy coating and to crack the skins. Checking speeds up drying by allowing interior moisture to evaporate. If checking is not done, there is a greater chance of case hardening, which is the formation of a hard shell on the outside with moisture trapped within the fruit. This may occur more readily when fruit is dried in an oven rather than a dehydrator. Fruit to be checked should be immersed in briskly boiling water for 30 to 60 seconds, then dunked in cold water and drained on paper towels. Treatment time depends on the thickness of skins. Checking can be done in a microwave oven by heating on high about 20 to 30 seconds, then chilling. Some flavor loss may result from the checking process.


Conditioning

  1. Cool food on trays.
  2. Pour into a large, nonporous container of food-grade material, fill to about ⅔ full.
  3. Cover container and place in a convenient, warm, dry place. Shake container daily or stir contents at least once a day for 10 to 14 days.
  4. Check for condensation on the lid and any signs of spoilage. If condensation occurs, return food to the dryer to finish the product.
  5. If any sign of mold growth occurs, discard the product.
  6. Cool thoroughly before packaging.

INSTRUCTIONAL VIDEOS

Acid levels in foods

Acid levels in foods affect processing method

There are two basic methods for canning foods at home, boiling water or pressure processing. The food's acid content, or pH, is a key factor in determining the minimally safe method. The boiling water canner method is used for acid foods and the pressure canning method is used for low acid foods.

Understanding altitude

Understanding altitude effects on processing

The amount of time that jars are held at a certain temperature during canning is important to producing a safe product. Because altitude affects the temperature of boiling water or steam inside a pressure canner, adjustments are needed in canning times based on your altitude.

Using jar filler

Using a canning funnel to fill jars

Using a canning funnel to fill jars makes the process neater and keeps the jar sealing surface (rim) cleaner. These funnels are also known and sold as "jar fillers."

Headspace

The importance of headspace in canning

Headspace is the completely empty space left in the jar underneath the lid and above the food. Headspace allows for food to expand during canning and not have food come out of the jars. Recommended amounts also allow for good vacuums to be formed for holding lids in place and good food quality to be maintained during storage.

Applying lids

Applying lids to jars

It is important to have a clean sealing surface when lids are applied to filled jars. Lids should be prepared according to manufacturer's instructions and then applied with ring bands tightened without too much or too little pressure.

Cooling jars

Cooling jars at end of process

Jars are placed on a protected surface after canning and allowed to air cool, undisturbed, until sealed. After boiling water canning, jars are removed from the canner at the end of the process. After pressure canning, the canner must be allowed to cool naturally to 0 pounds pressure after turning off the burner. The jars are removed after the pressure is gone from the canner.

Boiling water canning process

The boiling water canning process

Boiling water canning is recommended for processing acid foods such as fruits and properly acidified tomatoes, pickles, and relishes. This information covers most of the basic steps in managing the boiling water canning process.

Pressure canning process

The pressure canning process

Pressure canning is the only recommended method for canning low acid foods such as vegetables, meat, poultry and seafood. This information covers most of the basic steps in managing the pressure canning process, including venting air out of the pressure canner before it is brought to pressure.

Hot pack fruit

Hot pack for fruits

Prepared fruit is heated in water or syrup as described for specific foods prior to filling jars. This information demonstrates the hot pack process for filling jars with peaches.

Hot pack green beans

Hot pack for vegetables

Prepared vegetable pieces are heated in water or other liquid, as described for specific foods prior to filling jars. This information demonstrates the hot pack process for filling jars with green beans.

Raw pack green beans

Raw pack for vegetables

Raw prepared vegetable pieces are placed into jars without preheating. The vegetable pieces are then covered with hot or boiling liquid as described for specific foods. This information demonstrates the raw pack process for filling jars with green beans.

Using ascorbic acid

Preventing browning of cut fruits

Ascorbic acid is an effective anti-darkening agent when used as a pre-soak while peeling and cutting light-colored fruits and vegetables. It can also be added to syrups used in containers to pack fruits for freezer storage.

Freezing syrup pack

Syrup pack for freezing fruits

Sugar syrups are a good packing medium for many fruits being frozen. The syrup can result in maintaining a good texture for many frozen fruits during storage. This segment also discusses headspace for freezer containers and achieving a good seal on a plastic container for freezing peaches.

Freezing sugar pack

Sugar pack for freezing fruits

Some fruits can be frozen by mixing the cut pieces with dry sugar and allowing the sugar to draw out the juices from the fruit. This method can help maintain a good texture for many frozen fruits during storage compared to a water or plain pack without sugar. This segment covers the process of a sugar pack for sliced peaches.

Freezing dry pack fruit

Dry or tray pack for freezing fruits

Many fruits work well for an unsweetened pack of fruit pieces individually frozen on a tray before they are packed into containers. This segment demonstrates a tray pack for whole strawberries. Fruit pieces frozen in this manner are easily removed from packages without having to first thaw them.

Drying vegetables

Drying vegetables

Vegetables are easily dehydrated in an electric dehydrator and preparation steps for different vegetables will vary. Small, uniform pieces make the process easier to manage. This information shows drying for green beans and discusses blanching as well as a short freezing step prior to dehydrating that is specific for green beans.

Drying doneness of dried fruit

Determining doneness of dried fruit

Many fruits are good candidates for preservation by drying. Specific directions can be followed for preparing each fruit for the dehydrator. This segment discusses determining when fruit is dry enough to stop the process, and how to package dried fruits for storage.





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