This recipe, adapted from Pomona’s Pectin, comes from Kate McCarty, a food preservation educator at the University of Maine Cooperative Extension and author of “Portland Food: The Culinary Capital of Maine.” This jam can be frozen, she said, or scaled down for a smaller batch and kept in the refrigerator.

Yields about 7 8-ounce jars

8 cups chopped rhubarb

Zest of 1 orange

1 cup orange juice

2 sprigs rosemary

1 tablespoon calcium water (included with Pomona’s Pectin)

3 cups sugar

1 tablespoon Pomona’s Pectin powder

Prepare calcium water (included with Pomona’s Pectin) as instructed in pectin directions. Wash and rinse canning jars; keep warm until ready to use. Wash screw bands and lids; simmer lids in a small saucepot of water.

Combine rhubarb, orange zest, orange juice, rosemary and calcium water in a large saucepot. Stir well and bring to a boil over medium-high heat, stirring occasionally.

Meanwhile, measure sugar into separate bowl. Thoroughly mix proper amount of pectin powder into sugar.

When fruit mixture comes to a boil, add pectin and sugar mixture; stir vigorously 1 to 2 minutes while cooking to dissolve pectin. Return to a boil and remove from heat. Remove rosemary sprigs.

Pour hot jam into hot jars, leaving 1/4-inch headspace. Wipe rims of jars with a clean, damp paper towel; apply two-piece metal canning lids until fingertip tight.

Process in a boiling water canner for 10 minutes. Let cool, undisturbed, for 24 hours and check for seals.