Home Freezing of Fruits and Vegetables
Reprinted (1994) by Alice Henneman, M.S., R.D., Extension Educator
This guide offers suggestions on containers for freezing, packing, loading the freezer, freezing fruits, preparation, preventing fruit from darkening, freezing vegetables, and heating and cooling vegetables.
Freezing is a simple and easy way to preserve foods. Properly frozen fruit and vegetables are much like fresh foods in color, flavor and nutritive value. They will keep up to a year without losing their high quality.
Some varieties of fruits and vegetables freeze better than others. If you are not sure how well a fruit or vegetable will freeze, test it first by freezing three or four packages. Then sample the food after freezing. This only shows the effect of freezing, however, not the effect of storage.
As a rule, all vegetables that need to be cooked freeze well. Vegetables such as cucumbers, lettuce, radishes and tomatoes lose their crispness when frozen and become limp. Most fruits can be frozen successfully.
Containers for Freezing
Good containers keep frozen foods from drying out and preserve food value, color, flavor and texture. A good quality wrapping material or container is moisture-vapor resistant to prevent loss of liquid and flavor. It does not give a flavor of its own and is clean and durable.
Tempered glass, plastic, and heavily-waxed cardboard containers are suitable cartons for liquid packs. Heavy plastic bags, specifically developed for use in the freezer are best for dry-packed vegetables and fruits. Overwrap thin plastic packages with another plastic bag to prevent tears.
Select a size that holds only enough fruit or vegetables for one family meal. Seal the carton by pressing or screwing on the lid. Most plastic bags can be scaled by twisting and folding back the top of the bag and securing it with a string, rubber band or other sealing device.
Pack food tightly to cut down on the amount of air in the package. Air draws moisture from the food, resulting in a poor quality product. Allow ample headspace (1/2 to 1 inch) because food expands as it freezes. Seal carefully.
Label packages plainly. Include the name of the food, the date it was packed and the type of pack if it is packed in more than one form. There are gummed labels, colored tape, crayons and stamps made especially for labeling frozen food packages.
Loading the Freezer
Freeze fruits and vegetables as soon as they are packed and store them at 0º F for best quality.
Put no more unfrozen food into a home freezer than will freeze within 24 hours. This is usually two to three pounds of food to each cubic foot of freezer capacity. Overloading slows the rate of freezing, so foods may lose quality or spoil.
If power is interrupted, keep the freezer closed. Otherwise transfer your food to a locker or use dry ice if the freezer will be stopped for more than a day. Food in a loaded freezer will usually stay frozen for two days, even in summer.
Both fruits and vegetables may be refrozen if they have not been completely thawed. However, thawing and refreezing will usually result in a lowered quality and loss of flavor.
Most fruits can be frozen successfully. Use only perfect, fully ripe, sound fruits of good flavor and attractive color to make the most satisfactory frozen products. The quality of the frozen product will vary with the kind of fruit, the stage of maturity and the type of pack. Generally, the flavor of frozen fruit is good, but the texture may be somewhat softer than that of fresh fruit.
All fruits need to be washed in cold water, a small quantity at a time. Do not let the fruit stand in water. Drain fruits thoroughly. Prepare enough fruit for only a few containers at one time.
The intended use helps decide whether to freeze the fruit whole, in pieces, juiced, crushed or pureed Small fruits and berries can be frozen whole. Large fruits are usually halved or sliced. Most fruits and berries can also be frozen crushed or as puree for use as fruit toppings or fillings. Good parts of less perfect fruits are suitable for purees. Juice pressed from fruit or berries can be sweetened slightly before freezing.
How To Pack
Most fruits have a better texture and flavor if they are packed in sugar or syrup. Some can be packed without sweetening. Fruits packed in syrup are generally best for dessert use; those packed in sugar or unsweetened are best for use in cooking.
Cut fruit into a bowl or shallow pan. Sprinkle sugar over the fruit. Use a large spoon or pancake turner to mix. Mix gently until the juice is drawn out and the sugar is dissolved. Put fruit and juice into containers, leaving 1/2-inch headspace.
A 40 percent syrup is recommended for most fruits (see chart). Lighter syrups are desirable for some mild flavored fruits; heavier syrups may be needed for very sour fruits. It takes 1/2 to 2/3 cup of syrup for each pint of fruit.
To make the syrup, dissolve the sugar in hot water
and chill before using. Place the prepared fruit in sturdy, leak-proof
containers and cover with syrup, leaving 1-inch headspace for expansion.
Fruit has a tendency to float to the top where it changes color when exposed
to the air. Therefore, to keep the fruit under the syrup, place a small
piece of crumbled freezer paper on top and press the fruit down into syrup
before closing the container.
Unsweetened PackóDry Pack
Some fruits such as raspberries, currants, figs, blueberries, gooseberries, cranberries, pineapple, rhubarb and strawberries freeze successfully without sugar. Crushed or sliced fruit can be packed in its own juice or covered with water containing ascorbic acid (vitamin C), available in pharmacies or grocery stores.
Fill containers to within 1 inch of the top. Fruit may also be dry packed--that is packed without added sugar or liquid. Fill containers to within 1/2 inch of the top.
How To Keep Fruit From Darkening
Ascorbic acid (vitamin C), available from drugstores or freezer-locker plants, can be added to prevent the darkening of light-colored fruits. Dissolve 1/4 to 1/2 teaspoon of crystalline ascorbic acid in a little cold water. In the syrup pack, add the dissolved ascorbic acid to 1 quart of cold syrup shortly before using. In the sugar pack, sprinkle the dissolved ascorbic acid over the fruit just before adding the sugar. In the unsweetened pack, sprinkle the dissolved ascorbic acid over the fruit and mix thoroughly just before packing. If fruit is packed in water, dissolve the ascorbic acid in the water. Six (6) vitamin C tablets of 500 mg each can be crushed (equal to 1 teaspoon) and added to 1 quart of water. Vitamin C is used most often with apples, apricots, nectarines, peaches and pears.
There are special anti-darkening preparations on
the market. If you use one of these, follow the manufacturer's directions
or steam-blanch for 3-5 minutes, depending on the size of pieces. Plain
lemon juice may also be used to prevent fruit from darkening, but is not
as effective as ascorbic acid and may add its own flavor to the fruit.
How to prepare fruits for freezing
Fresh, tender vegetables right from the garden are best for freezing. The fresher the vegetables when frozen, the more satisfactory your product.
As soon as possible after the vegetables are picked, wash them thoroughly in cold water and sort according to size. Freeze only prime and tender young vegetables. Peel, trim and cut into pieces as desired. Heat or blanch to stop or slow enzyme action. For some vegetables such as broccoli, Brussels sprouts and cauliflower, soak 1/2 hour in a solution of 1 tablespoon salt to 1 quart of water to draw out possible insects. Discard insects. Wash again in fresh water to get rid of salt.
For home freezing, the best way to heat nearly all vegetables is in boiling water. This process is usually called blanching. Use at least 1 gallon of boiling water for each pound of prepared vegetables. Put the vegetables in a wire basket and lower into the boiling water. Put a lid on the kettle and start counting the time immediately. Keep the heat high for the time given in the chart for the vegetable you are freezing. The length of time will vary according to the thickness of the stem or piece.
After vegetables are blanched, cool them quickly and thoroughly to stop the cooking. Plunge them immediately into a large quantity of cold water. Change water frequently, use cold running water or iced water. Cool the vegetables about the same amount of time used to blanch them. When the vegetables are cool, remove them from the water and drain.
Vegetables for freezing may be packed either dry or in brine. Dry pack is used most often.
Pack the vegetables immediately into a suitable container,
leaving 1/2-inch headspace, except for vegetables such as asparagus an
broccoli that pack loosely and require no headspace. Seal the packages,
label and store them in freezer.
How to prepare vegetables for freezing
At High Altitudes
Blanch vegetables by boiling rather than by steaming. Add 1 minutes of blanching time for every 1000 feet above 7000 feet. Refer to chartHow to prepare vegetables for freezing.
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