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jar of blubarb jam with a spoon in it, surrounded by rhubarb
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Blubarb Jam

Excerpted from Preserving with Pomona’s Pectin by Allison Carroll Duffy (Fair Winds Press, June 2013)
Allison says: “The combination of blueberries and rhubarb is less common than the typical strawberry-rhubarb pairing, but it really shouldn’t be—this lovely, deep blue jam is a delicious, tangy treat. This recipe was adapted from one by jam-maker Kirsten Jennings, who first tried it at a local restaurant and liked it so much that she figured out how to make it at home.”
Servings 5 cups

Ingredients

  • 1 pound blueberries
  • 1 pound trimmed rhubarb stalks
  • ½ cup water
  • ¼ cup lemon juice bottled
  • 2 teaspoons calcium water see step #1
  • 1¼ cups sugar
  • 2½ teaspoons Pomona’s Pectin mixed with sweetener

Instructions

  • Before you begin, prepare calcium water.
    To do this, combine ½ teaspoon calcium powder (in the small packet in your box of Pomona’s pectin) with ½ cup water in a small, clear jar with a lid. Shake well.
    Extra calcium water should be stored in the refrigerator for future use.
  • Prepare boiling water canner. Heat jars in simmering water until ready for use. Wash lids and bands and set aside.
  • Rinse blueberries, remove stems, and mash in a large bowl. Set aside.
  • Rinse rhubarb, slice stalks lengthwise into thin strips, and then dice. Combine diced rhubarb in a saucepan with the ½ cup (of water. Bring to a boil over high heat, reduce heat, and then simmer, covered, for 5 minutes, or until rhubarb is soft, stirring occasionally. Remove from heat and mash rhubarb.
  • Measure out 2 cups of the mashed blueberries and 2 cups of the mashed rhubarb (saving any extra for another use), and combine the measured quantities in a saucepan. Add lemon juice and the calcium water, and mix well.
  • In a separate bowl, combine sugar and pectin powder. Mix thoroughly and set aside.
  • Bring fruit mixture to a full boil over high heat. Slowly add pectin sugar mixture, stirring constantly. Continue to stir vigorously for 1 to 2 minutes to dissolve pectin while the jam comes back up to a boil. Once the jam returns to a full boil, remove it from the heat.
  • Remove hot jars from canner and fill jars with (marmalade/jam/jelly), leaving ¼ inch of headspace. Remove trapped air bubbles, wipe rims and put on lids and screw bands, tightening bands only to “fingertip tight” (until resistance is met, and then just the tiniest bit more).
  • Place jars in the hot water, on the rack inside the canner. (Make sure jars are upright, not touching each other or the sides of the canner, and are covered with at least 1-2 inches of water). Place the lid on the canner, bring the canner to a rolling boil, and boil for 10 minutes. (Add 1 minute additional processing time for every 1000 feet above sea level.)
  • Turn off heat and allow canner and jars to sit for 5 minutes. Then, remove jars from canner. Allow jars to cool undisturbed for 12-24 hours. Then, confirm that jars have sealed, then store properly. Eat within 1 year. Lasts 3 weeks once opened.

Notes

Tip: Frozen Ease!
You can substitute frozen berries for the fresh, and if you don’t have a lot of time, this is a good option. Simply defrost the berries, and then mash them as the recipe calls for. After defrosting, the berries will be in a lot of juice, but don’t drain them—simply incorporate all of the juice into the mashed berries.