Plum-Ginger Freezer Jam

Preparation

1. Step 1

   Using a potato masher or fork, gently crush the plums in a large bowl to release some pulp and juices while keeping the fruit chunky. Toss with the sugar, then add the ginger and lemon zest and juice. Stir until the sugar dissolves. Measure the volume of your fruit mixture; you should have about 6 cups.

2. Step 2

   If your package of pectin comes with calcium powder, stir ¼ teaspoon of the calcium powder into ¼ cup water to dissolve. Set aside. Place the 4½ teaspoons pectin in a stand blender, or have it measured and ready if using an immersion blender. Bring 1 cup water to a boil, then pour it into the stand blender and blend. (If using an immersion blender, add the pectin to the saucepan and blend.) The mixture should become very smooth and look like a soft gel. Stir the pectin mixture into the fruit until evenly combined, then stir in 4 teaspoons of the calcium water, if using. The jam should thicken and be softly set. Add the salt, stir and taste. Adjust after tasting with more teaspoons of lemon juice, if necessary, for a good balance of sweet and tart.

3. Step 3

   Transfer to clean airtight containers, cover and chill in the refrigerator for at least 24 hours and up to 2 weeks before serving. Or, store in the freezer for up to 3 months; defrost completely in the refrigerator before serving.