Blubarb Jam

blubarbjamExcerpted 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.”

Yield: 4 to 5 cups

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.

Blubarb Jam Ingredients

1 pound blueberries
1 pound trimmed rhubarb stalks
½ cup water
¼ cup lemon juice
2 teaspoons calcium water
1¼ cups sugar
2½ teaspoons Pomona’s pectin powder

Blubarb Jam Directions

1. Wash your jars, lids, and bands. Place jars in canner, fill canner 2/3 full with water, bring canner to a rolling boil, and boil jars for 10 minutes to sterilize them. (Add 1 extra minute of sterilizing time for every 1000 feet above sea level.) Reduce heat and allow jars to remain in hot canner water until ready to use. Place lids in water in a small sauce pan, heat to a low simmer, and hold until ready to use.

2. Rinse blueberries, remove stems, and mash in a large bowl. Set aside.

3. 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.

4. 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.

5. In a separate bowl, combine sugar and pectin powder. Mix thoroughly and set aside.

6. 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.

7. Can Your Jam: Remove jars from canner and ladle jam into hot jars, leaving 1/4 inch of headspace. Remove trapped air bubbles, wipe rims with a damp cloth, put on lids and screw bands, and tighten to fingertip tight. Lower filled jars into canner, ensuring jars are not touching each other and are covered with at least 1 to 2 inches of water. Place lid on canner, return to a rolling boil, and process for 10 minutes. (Add 1 extra minute of processing time for every 1000 feet above sea level). Turn off heat and allow canner to sit untouched for 5 minutes, then remove jars and allow to cool undisturbed for 12 to 24 hours. Confirm that jars have sealed, then store properly.

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.

Enjoy these pictures from a satisfied Pomona’s Pectin Jam Maker.

blubarb jam and bread

Photo by Mel Fitzpatrick, Hobart, Tasmania, Australia. See her comment below.

blubarb jam with blueberries and rhubarb

Photo by Mel Fitzpatrick, Hobart, Tasmania, Australia. See her comment below.

For more inspiring recipe ideas, see Preserving with Pomona’s Pectin: The Revolutionary Low-Sugar, High-Flavor Method for Crafting and Canning Jams, Jellies, Conserves, and More by Allison Carroll Duffy and the Pomona’s Partners, published by Fair Winds Press, June 2013, and available in paper or ebook everywhere books are sold.

Pomona’s Pectin is available at your local natural food store, food co-op, and many farm stands. Find it also at Sur La Table and a growing number of more conventional grocery stores with natural food sections (Wegmans, Hy-Vee, Rosauers, Nugget Markets, Coborns, Fairway, and others). If you can’t find a store near you on our store locator, you can order from our website or many other online sellers.

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16 thoughts on “Blubarb Jam

  1. Can you eliminate the calcium water? I ask this because I cannot find the calcium powder anywhere.

    • Hello Christine,

      You may be able to get away with it for this recipe, because blueberries are higher in calcium…but the calcium water is an essential part of the jamming process with Pomona’s. The calcium is what tells the pectin to “activate”/jell.
      If you send us an email with your mailing address, we would be happy to send you more calcium powder!

    • Hello Charyl,
      You absolutely can double this recipe, and just about all of our other recipes, but keep in mind you will need a pot large enough to fit all of the ingredients at the same time AND a water bath canner large enough to fit all of your jars at the same time.

      Happy jamming!


  2. This looks amazing. Just picked some rhubarb and I have blueberies in the freezer so I’m going to get some pectin and make this. Any idea how long it will keep in the fridge once a jar has been opened? Ther are just 2 jam eaters in our house so I want to know what size jars to use. Thanks.

    • Hello Kim,

      Thanks so much for reaching out to Pomona’s Pectin.

      Doesn’t the Bluebarb Jam look delicious? We hope you have a wonderful experience with it. It should keep in the fridge for about 3 weeks once the jar is opened.

      Please let me know if there is anything else I can assist you with.

      Have a wonderful day!


  3. Love this recipe. Made with frozen saskatoons (June berries I think some call them) instead of blueberries, then 1/2 cup sugar; 1/2 cup stevia & 1/4 cup xylitol. A definite keeper!

    • Dear Linda,
      Thanks so much for sharing your substitution of saskatoons/June berries for the blueberries in the Blubarb recipe.

      Thanks for using Pomona’s Pectin — and happy jamming!

  4. This recipe is a clear winner! “Delicious” according to my brunch guests today. I used maple syrup for the sweetener — half of the sugar amount called for in the recipe — and it’s perfect with the tart rhubarb.

  5. This is a wonderful jam. We’ve gotten comments from people we’ve given it to that it’s the “best jam ever.” The rhubarb intensifies the blueberry flavor without being very obvious itself.

    • Hi Mary,
      Thanks so much for sharing how much you and your friends and family like this recipe, and your take on how the flavors work together.

      Thanks for using Pomona’s Pectin — and happy jamming!

  6. Would it be OK to substitute raspberries for blueberries?
    I have lots of gold raspberries at the moment.
    Thanks for a wonderful product!!

  7. I just used Pomona’s Pectin for the first time and made this recipe. It’s amazing and I can’t wait to try more! So glad the real fruit taste comes through but is still sweet enough to make everyone happy.

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