Quick-frozen and stored at 0 degrees F. or lower, blueberries keep perfectly for up to two years. Simply overwrap the baskets, as is, with freezer-weight plastic, seal, and freeze.
Or empty the fruit, without washing, into freezer containers or bags, expel air, seal, label, and freeze. In either case, rinse berries before thawing for use.
If you prefer to wash berries before freezing, rinse, then roll on towels to blot moisture.
Spread in one layer on jelly-roll pans and freeze until marble-hard, then tumble them into freezer boxes or bags, expel air, seal, label, and return to freezer.
Berries that have been frozen are best used in breads and cakes, or for crisps and cobblers, by themselves or combined with another fruit, such as peaches or apples.
To sweeten berries before freezing, use a sugar or a syrup pack.
SUGAR: in a wide bowl with a rubber spatula, gently mix about 3/4 cup fine sugar with each quart rinsed, and drained or blotted blueberries. Pack in boxes or bags, expel air, seal, label, and freeze.
SYRUP: Place rinsed, drained berries ion rigid containers, leaving about 1/4 inch headspace. Cover fruit with medium syrup (2 1/2 cups sugar boiled with 2 cups water, then cooled), leaving 1/2 inch headspace; expel air, seal, label, and freeze.