Freezing fruits is the simplest, easiest and quickest method of preservation. Freezing costs more than canning or drying because of freezer purchase and operating costs, but it preserves more nutrients and fresh flavor, if done properly. Freezing does not completely destroy bacteria, molds and yeasts that cause food spoilage, but it does significantly retard their growth. As soon as food is thawed, microorganisms will continue to grow. Freezing also slows chemical changes that affect quality. Natural enzymes in fruits cause flavor, color, texture and nutritive value changes. Freezing slows enzyme activity but does not stop it. You can prevent enzyme-browning in light-colored fruits by treating them with ascorbic acid and other commercial products.
Selecting and Washing Fruits
Fully ripe fresh fruits lose quality rapidly after harvesting. Harvest only the amount you can preserve within a few hours; otherwise, refrigerate, then freeze as soon as possible. Choose fully ripe but firm fruit. Under-ripe fruits may be bitter. Freeze soft, very ripe fruits as purées. To thoroughly remove dirt, bacteria and pesticide residue, wash all fruits in cold water. Drain and rinse several times with cold water. Lift fruits from water to prevent redepositing of dirt and residues. Do not let fruits soak.
Packaging Materials
Air leads to flavor loss or off-flavors. If moisture evaporates, frozen food becomes dry, tough and might develop grayish spots called "freezer burn." To prevent air exposure and moisture loss, use only moisture-proof, vapor-proof packaging designed for freezing. Examples are "can or freeze" glass jars, plastic freezer containers, heavyweight aluminum foil, plastic-coated freezer paper, and heavy duty plastic wraps and bags. Only sealing tape designated for freezer use will adhere at freezing temperatures.
Rigid freezer containers are often reusable and have straight sides and flat lids to allow for easy stacking in the freezer. The straight sides also make it easier to remove frozen food. Place freezer bags in rigid containers for easy stacking.
Do not use cardboard cartons; they are not sufficiently moisture-resistant and vapor-resistant for long-term frozen food storage. Also, do not reuse plastic containers from cottage cheese, ice cream, whipped topping, margarine, etc. These containers are not designed to protect foods in long-term freezer storage. Pack fruit and syrup tightly in freezer bags or rigid containers. Squeeze air from bags before sealing. Leave ½ to 1 inch of headspace for expansion in rigid containers. Whole berries and cut fruit pieces may be frozen in a single layer on a tray until solid; package at once in freezer bags or freezer containers. Label and date product and return it to freezer.
Freezing
Because water in fruits expands during freezing and breaks cell walls, thawed fruits might leak juices and be soft. To retain quality, freeze fruits quickly at lowest possible freezer setting. Freeze only 2 to 3 pounds of food per cubic foot of available storage space in 24 hours.
Storing
Maintain freezer at 0°F or less to best protect the quality of foods, including fruits. If power fails, keep freezer closed; food should stay frozen 24 to 48 hours. If available, protect food with 25 pounds of dry ice per 10 cubic feet of freezer space. Food can safely be refrozen if it still contains ice crystals. Some loss of quality and food value will occur. Keep an inventory, and use oldest foods first. The more food you put into your freezer in a year, the less the operating cost per pound. Use frozen fruits within one year. Citrus fruit and juices should be used within 6 months.
Thawing
Defrost fruit in its original package in one of the following ways: (1) at room temperature in a pan of cool water—use only the thawing-in-water method if water can be kept cool (under 70°F) and the food can thaw in less than 2 hours; (2) in a microwave oven (only if fruit is to be used right away); or (3) in the refrigerator.
Allow 6 to 8 hours in the refrigerator for thawing a 1-pound package of fruit packed in syrup, or thaw slightly longer for unsweetened fruit. Allow one-half to 1 hour for fruit thawing in running, cool water. Serve fruit with a few ice crystals still remaining. Completely thawed fruits will be limp or mushy and may discolor.
Directions for Freezing Fruit
- Wash and sort fruit. Discard poor-quality pieces. Work with small quantities. Pare and remove pits, seeds and blemishes. Leave whole, slice or purée (see Table 2 or directions for individual fruits).
- Treat washed and sorted fruit with ascorbic acid (available at drugstores, 1 teaspoon = 3 grams) or some other treatment to prevent discoloration, particularly with apples, peaches and nectarines. Add crystalline ascorbic acid to chilled syrup just before using, or follow manufacturer's directions if using other anti-darkening products.
- Pack with sugar or syrup, or leave unsweetened (dry). Unsweetened fruits lose quality faster than sweetened fruits. Sugar helps fruit retain its flavor, color and texture, but it is not necessary to preserve fruit safely. Artificial sweetener can also be added to fruit prior to freezing. Artificial sweeteners give a sweet flavor but do not furnish the beneficial effects of sugar.
Types of Pack
The type of pack used will depend on the intended use. Fruits packed in syrup are generally best for uncooked dessert use; those packed in dry sugar or left unsweetened are best for most cooking purposes because there is less liquid in the product.
Sugar Pack
Sprinkle sugar over the fruit and mix gently. Allow to stand for 10 to 15 minutes to draw out juice—which will dissolve sugar—or freeze immediately.
Syrup Pack
Dissolve sugar in lukewarm water until the solution is clear. Cool, then add ascorbic acid and just enough syrup to cover fruit (about ½ to ⅔ cup per pint). To keep fruit under syrup, place a small, crumpled piece of plastic or freezer wrap on top and press fruit down into syrup before sealing the container. One-fourth of the sugar may be replaced by light corn syrup or mild-flavored honey.
Dry Pack
Pack fruit in container, seal and freeze. Good for small, whole fruits that taste good without sugar.
Tray Pack
Spread a single layer of fruit on shallow trays and freeze. When frozen, package promptly and return to freezer. This pack allows portions to be used when needed.
Other Unsweetened Packs
Unsweetened fruit may also be packed in water, unsweetened juice or pectin syrup. Pectin syrup is often used for fruits such as strawberries or peaches that retain their texture better than if frozen in water or juice. (To make pectin syrup, dissolve one package powdered pectin in 1 cup water, heat to boiling and boil for 1 minute. Add 1¾ cup water and cool.) To keep the fruit under liquid, follow directions for syrup pack.
Artificial Sweeteners
Sugar substitutes can be used in any of the unsweetened or dry packs, or they can be added to the fruits before serving. However, sugar substitutes do not offer the beneficial effects of sugar.
| Table 1. Syrups for Use in Freezing | ||||
| Type of Syrup | Percent Syrup* | Cups of Sugar** | Cups of Water | Yield of Syrup in Cups |
| Very light | 10 | ½ | 4 | 4½ |
| Light | 20 | 1 | 4 | 4¾ |
| Medium | 30 | 1¾ | 4 | 5 |
| Heavy | 40 | 2¾ | 4 | 5⅓ |
| Very heavy | 50 | 4 | 4 | 6 |
| *Approximate | ||||
| **In general, up to one-fourth of the sugar may be replaced by corn syrup or mild-flavored honey. A large proportion of corn syrup may be used if a very bland, light-colored type is selected. | ||||
| Table 2. How To Prepare Fruits for Freezing | |
| Fruits | Preparation |
| Apples | Wash, peel, core and slice. |
| Syrup pack: Use cold 40 percent syrup; add ½ teaspoon (1,500 mg) ascorbic acid per quart of syrup. Slice apples into syrup in container, seal and freeze. | |
| Sugar pack: To prevent darkening, dissolve ½ teaspoon (1,500 mg) ascorbic acid in 3 tablespoons water. Sprinkle over fruit or steam blanch 1½ to 2 minutes. Mix ½ cup sugar to 4 cups fruit. Pack, seal and freeze. | |
| Dry or tray pack: Treat with ½ teaspoon (1,500 mg) ascorbic acid in 3 tablespoons water to prevent browning. | |
| Applesauce | Wash, peel if desired, core and slice. Add ⅓ cup water to each quart of slices. Cook until tender. Cool and strain. Sweeten to taste with ¼ to ¾ cup sugar per quart of sauce. Pack into containers. |
| Apricots | Wash, halve and pit. Peel and slice if desired. If not peeled, heat in boiling water ½ minute to keep skins from toughening during freezing. Cool in cold water and drain. |
| Syrup pack: Use cold 40 percent syrup and add ¾ teaspoon (2,250 mg) ascorbic acid per quart of syrup. Seal and freeze. | |
| Sugar pack: Pretreat fruit by dissolving ¼ teaspoon (750 mg) ascorbic acid in 3 tablespoons cold water; sprinkle over 4 cups fruit. Mix ½ cup sugar per quart of fruit and stir until dissolved. Pack, seal and freeze. | |
| Avocados | Peel, cut in half, remove pit and purée. Add ¼ teaspoon ascorbic acid to each quart of purée, or add 1 tablespoon lemon juice for each 2 avocados. Pack, seal and freeze. |
| Bananas | Peel and mash thoroughly. Add ½ teaspoon (1,500 mg) ascorbic acid per cup of mashed banana. Pack, seal and freeze. |
| Blackberries | Wash carefully in cold water, discarding soft, under-ripe or defective fruit. Drain well. |
| Syrup pack: Pack berries into containers and cover with cold 40 to 50 percent syrup. Seal and freeze. | |
| Sugar pack: Gently mix ¾ cup sugar with 1 quart (4 cups) berries. Pack, seal and freeze. | |
| Dry pack: Pack, seal and freeze berries. Or, freeze first on a tray and then pack into containers, seal and return to freezer. | |
| Blueberries | Dry pack: Do not wash (washing results in a tougher-skinned product). Pack berries into container or freeze on a tray, then package. Wash before using while berries are still frozen. |
| Sugar pack: Wash first, then mix ⅔ cup sugar to 4 cups berries. Pack, seal and freeze. | |
| Cherries, red sour | Wash, stem and pit. |
| Syrup pack: Use cold 50 percent syrup. Pack, seal and freeze. | |
| Sugar pack: Mix ¾ cup sugar to 4 cups cherries, then pack, seal and freeze. | |
| Dry pack: Pack, seal and freeze. Or, freeze first on a tray and then pack into containers, seal and return to freezer. | |
| Cherries, sweet | Wash, stem and pit. |
| Syrup pack: Use cold 30 to 40 percent syrup with ½ teaspoon ascorbic acid per quart syrup. Pack, seal and freeze. | |
| Dry pack: Pack, seal and freeze. Or, freeze first on a tray and then pack into containers, seal and return to freezer. | |
| Cranberries | Stem and sort. Wash and drain. |
| Syrup pack: Use cold 50 percent syrup. | |
| Dry pack: Pack, seal and freeze. Or, freeze first on a tray, then pack into containers, seal and return to freezer. | |
| Grapes | Sort, stem and wash. Leave seedless grapes whole; cut grapes with seeds in half and remove seeds. |
| Syrup pack: Cover with 40 percent cold syrup, seal and freeze. | |
| Juice: Crush grapes. Add 1 cup water per gallon of grapes. Simmer for 10 minutes, then strain through a jelly bag. Let set overnight in refrigerator to remove tartrate crystals. Pour off clear juice for freezing and discard sediment. Pack, seal and freeze. | |
| Mangoes | Wash, peel and slice. |
| Syrup pack: Use 30 percent syrup. Pack, seal and freeze. | |
| Dry pack: Tray freeze, then pack into containers, seal and return to freezer. | |
| Purée: Mash slices thoroughly or chop in a food processor. Pack, seal and freeze. | |
| Melons (cantaloupe, honeydew or watermelon) | Scrub melon, peel and remove seeds. Then, cut melons into slices, cubes or balls. |
| Syrup pack: Put in containers and add cold 30 percent syrup. Seal and freeze. | |
| Dry pack: Pack into containers, seal and freeze. | |
| Peaches, nectarines | Sort, wash and peel. |
| Syrup pack: Use cold 40 percent syrup and add ½ teaspoon (1,500 mg) ascorbic acid per quart (4 cups) of syrup. Slice peaches directly into cold syrup in containers, press fruit down and add syrup to cover. | |
| Sugar pack: To retard darkening, sprinkle ascorbic acid solution (¼ teaspoon in 3 tablespoons cold water) on each quart fruit. Mix ⅔ cup sugar to 4 cups fruit. Pack, seal and freeze. | |
| Pineapple | Pare and remove core. Slice, dice crush or cut the pineapple into wedges or sticks. |
| Dry pack: Pack, seal and freeze. | |
| Plums, prunes | Wash, halve or quarter and pit. |
| Syrup pack: Cover with cold 40 to 50 percent syrup. To improve quality, add ½ teaspoon (1,500 mg) ascorbic acid to each quart syrup. Seal and freeze. | |
| Raspberries | Sort, wash, and drain well. |
| Syrup pack: Pack berries in containers and cover with cold 40 percent syrup. Seal and freeze. | |
| Sugar pack: To 1 quart berries, add ¾ cup sugar and mix carefully to avoid crushing. Pack, seal and freeze. | |
| Dry pack: Pack, seal and freeze berries. Or, freeze first on a tray and then pack into containers, seal and return to freezer. | |
| Rhubarb | Wash, trim and cut into 1-inch lengths. Heating rhubarb in boiling water 1 minute, then cooling promptly in cool water helps retain color and flavor. |
| Syrup pack: Pack into containers and cover with cold 40 percent syrup, seal and freeze. | |
| Dry pack: Pack tightly into containers without sugar. Seal and freeze. | |
| Strawberries | Wash and remove caps. |
| Syrup pack: Cover berries in container with a cold 50 percent syrup. Seal and freeze. | |
| Sugar pack: Mix ¾ cup sugar to 4 cups berries, stir and let stand 15 minutes. Pack, seal and freeze. | |
| Dry pack: Pack, seal and freeze berries. Or, freeze first on a tray and then pack into containers, seal and return to freezer. | |
References
Andress, E., and J. Harrison. So Easy to Preserve. 6th ed. Athens: University of Georgia Cooperative Extension Service, 2014.
Kuhn, G. D., and A. V. A. Resurricion. How to Freeze Food the Right Way. Pennsylvania State University Cooperative Extension Service.
Michigan State University Cooperative Extension Service. Preserving Food Safely. Version 3.0. Home Economics Library Program.
National Center for Home Food Preservation. "How Do I? ... Freeze." nchfp.uga.edu/how/freeze.html.
Previously revised by: Deb Angell, Extension Educator, Family and Consumer Sciences, retired