Brian Prechtel/USDepartment of Agriculture K9189-1
Freezing without Sugar
- Wash, cap and drain whole berries.
- Spread berries in a single layer on a baking sheet or jellyroll pan and freeze until solid—an hour or two. This is tray freezing and prevents berries from sticking together.
- Transfer them to plastic freezer bags, pressing out as much air as possible.
- For best taste, consume berries in a slightly thawed state with a few ice crystals remaining. The expansion of frozen water in the berry ruptures the cell walls causing the berry to soften when thawed.
Freezing with Sugar
- To freeze whole, sliced or crushed strawberries, add ¾ cup sugar to 1 quart (about 1⅓ pounds) strawberries.
- Stir until most of the sugar dissolves and let stand for 15 minutes before putting berries into containers.
- Soft sliced berries will yield sufficient syrup for covering if the fruit is layered with sugar and allowed to stand 15 minutes.
- When packaging, allow adequate headspace so that syrup does not expand and overflow the container when the berries freeze. Allow ½-inch headspace for berries packed without added sugar or liquid. Allow 1 inch headspace in wide top containers (¾ inch in narrow top pints and 1½ inches in narrow top quarts) when packing in juice, sugar, syrup or water, or the fruit is crushed or pureed.
Follow the manufacturer’s directions to determine the amount of artificial sweetener to use for freezing berries. Remember though, they do not provide the beneficial effects of sugar such as color protection and thickness of syrup. An alternative is to add these sweeteners after the berries thaw.
The more quickly berries freeze, the higher their quality will be and the smaller the ice crystals formed. The desirable temperature for storing frozen foods is 0°F or lower. To facilitate more rapid freezing, set the temperature control of the freezer at minus 10°F or lower about 24 hours in advance. Place packages in contact with freezer surfaces, in the coldest part of the freezer. Allow a space between packages so air can circulate freely until the berries are frozen; then store the packages close together. Never freeze more than 2 pounds of berries per cubic foot of freezer space.
For best results, plan ahead when using frozen strawberries to make jam. Unsweetened berries work well; all you need to do is thaw the fruit completely before crushing and then measure as usual. Do not drain off excess juice. If you sweetened the berries to freeze them, record the amount of sugar added and then subtract this amount from the total amount of sugar in the jam recipe.
The method of combining ingredients when using liquid and powdered pectin differs. Therefore, when using presweetened berries to make cooked jam, use liquid pectin in order for the jam to set properly. This is not a problem when making freezer or no-cook jams.
Slightly under-ripe fruit contains more natural pectin than ripe fruit. Freezing a combination of ripe and slightly under-ripe berries—about ¾ fully ripe and ¼ slightly under-ripe —will provide the best mixture for jam.
Penn State Extension’s Let’s Preserve Strawberries has recipes for uncooked Strawberry Jam and Strawberry-Rhubarb Jelly. Why not try them!