Michigan State University Extension
Preserving Food Safely - 01600416
Whole, halves or quarters. Frozen plums and prunes are very good for use in pies and jams, or in salads and desserts. The unsweetened pack is preferred for plums to be used for jams.
Choose firm tree-ripened fruit of deep color. Sort and wash. Leave whole or cut in halves or quarters. Pack in one of the following ways:
Unsweetened pack Pack whole fruit into containers, leaving 1/2 inch headspace. Seal, label and freeze.
Syrup pack Pack cut fruit into containers. Cover fruit with cold 50-percent syrup (1 cup sugar to 1 cup water). For improved quality, add 1/2 teaspoon ascorbic acid to a quart of syrup. Leave 1/2 inch headspace. Seal, label and freeze.
Puree Select fully ripe fruit. Wash, cut in halves and remove pits. Puree may be prepared from unheated or heated fruit, depending on the softness of the fruit. To prepare puree from unheated fruit, press raw fruit through a sieve. For better quality, add either 1/4 teaspoon ascorbic acid or 1/2 tablespoon citric acid to each quart (2 pounds) of puree. To prepare puree from heated fruit, add 1 cup water for each 4 quarts (4 pounds) of fruit. Bring to a boil, cook 2 minutes, cool, and press through a sieve. With each quart (2 pounds) of puree, mix 1/2 to 1 cup sugar, depending on tartness of fruit. Pack into containers, leaving 1/2-inch headspace. Seal, label and freeze. Juice For juice to be served in beverages, select plums as for puree. For juice to be used for jelly making, select as recommended in specific jelly recipe. Wash plums, then simmer until soft in enough water to barely cover. Strain through a jelly bag. Cool. If desired, sweeten with 1 to 2 cups sugar for each quart of juice, depending on tartness of fruit. Pour into containers, leaving 1/2 inch headspace. Seal, label and freeze.