Bulletin #4047, Let’s Preserve Strawberries
Developed by Penn State Cooperative Extension with special project funds from Extension Service, U.S. Department of Agriculture.
Some Recommended Varieties
Allstar, Earliglow, Guardian, Sparkle, Tribute, and Tristar are usually excellent-quality berries for freezing. Most other varieties are suitable, especially for making jams and eating fresh.
A 24-quart crate weighs 36 pounds and yields 18 to 24 quarts. An average of 1 pound makes 1 pint of frozen berries.
Freeze strawberries or preserve them on the day they are harvested for best quality. They should be picked when they reach an ideal maturity for eating fresh. Select berries with fresh sweet flavor, deep uniform color, and firm texture. Smaller, misshapen, and seedy berries make good quality jams.
Remove caps. Wash 1 to 2 quarts at a time and drain. Do not soak berries.
Don’t freeze more than 2 pounds of food per cubic foot of freezer capacity per day. To make a syrup pack, mix and dissolve 3 cups of sugar in 4 cups of water. Add 1 cup of this syrup per quart of prepared fruit. To make a dry pack, mix 2/3 cup dry sugar per quart of prepared fruit. To package, fill pint or quart freezer bags to a level of 3 to 4 inches from top, carefully squeeze out air, leave 1 inch of headspace, seal, label, and freeze. Before freezing, bags may be inserted into reusable rigid freezer containers for added protection against punctures and leakage.
Wash and sterilize 4 half-pint or 2 pint jars. Prepare lids according to manufacturer’s instructions. Slice or crush prepared berries. To make jams with added pectin, follow the instructions of the pectin manufacturer to ensure obtaining a desirable texture. To make jam without added pectin, mix 4 cups sugar with 4 cups of berries. Bring to a boil while stirring rapidly and constantly. Continue to boil until done. Use a jelly or candy thermometer to determine when to put jam into jars. Boil until the temperature of the mixture reaches 220 degrees F if you live at an altitude between 0 to 500 feet; or 218 degrees F at altitudes between 501 and 1500 feet; or 216 degrees F at altitudes between 1501 and 2500 feet; or 214 degrees F at altitudes between 2501 and 3500 feet. If you do not have a thermometer, you may use a refrigerator test to determine doneness. Place 2 tablespoons on a cold plate (from the freezer), and chill the plate in the freezer for 2 minutes. If the mixture gels, it is ready to be put into jars.
Makes 7 half-pints. Wash and cut 1 1/2 pounds rhubarb into 1-inch pieces and blend or grind. Wash, stem, and crush 1 1/2 quarts strawberries, one layer at a time, in a saucepan. Place both fruits in a jelly bag or double layer of cheesecloth and gently squeeze out juice. Put 3 1/2 cups of juice into a large saucepan. Add 1/2 teaspoon butter and 6 cups sugar, thoroughly mixing into juice. Bring to a boil over high heat, stirring constantly. Immediately stir in 6 ounces of liquid pectin. Bring to a full rolling boil and boil hard for one minute.
Quickly skim off any foam and immediately place in sterile jars, leaving 1/4-inch headspace. Wipe sealing edge of jars with a clean, damp paper towel. Add lids, tighten screw bands, and process jars in boiling water.
|Process time at altitudes of|
|Jar size||0-1000 ft.||1001-6000 ft.||Above 6000 ft.|
|Half pints or pints||5 min||10 min||15 min|
After processing is completed, remove jars from canner with a jar lifter and place on a towel or rack. Do not retighten screw bands. Air-cool jars 12 to 24 hours. Remove screw bands and check lid seals. If the center of the lid is indented, wash, dry, label, and store in a clean, cool, dark place. If the lid is unsealed, examine and replace jar if defective, use new lid, and reprocess as before. Wash bands and store separately. Fruits are best if consumed within a year and safe as long as lids remain vacuum-sealed.
*Expressed as percentage of the U.S. Recommended Daily Allowances (US RDA). Other vitamins contained at insignificant levels.
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