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Watermelon Jam

slices of watermelon on a white table
Print Recipe
Watermelon Jam is a low-sugar cooked jam made with Pomona’s Universal Pectin. Pomona’s Pectin contains no sugar or preservatives and jells reliably with low amounts of any sweetener.

Notes

If you want to make jelly with only the juice of the watermelon, see our Watermelon Jelly recipe.
Servings 5 cups

Ingredients

  • 4 cups watermelon puree use a seedless watermelon or see Step 3 below
  • 4 teaspoons calcium water see step #1
  • ½ cup lemon juice bottled
  • ¾ cup up to 2 cups sugar
  • 3½ 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.
  • If watermelon is seedless, puree fruit to a pulp in blender or food processor. If watermelon has seeds, remove the seeds prior to pureeing.
  • Measure puree into sauce pan.
  • Add calcium water and lemon juice, and mix well.
  • Measure sugar into a bowl. Thoroughly mix pectin powder into sugar. Set aside.
  • Bring fruit to a full boil. Add pectin-sugar mixture, stirring vigorously for 1 to 2 minutes to dissolve the 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.

26 Comments

  2. I made this last summer but I’m just now posting about it. This was the only fail I’ve had with the Pomona’s pectin. My watermelon Jam came out like a thick syrup. I don’t know what I did wrong, but I was thinking of using it as a margarita mix. Do you think that would be okay? I did do watermelon-strawberry 50/50 and that came out fine. I also tried a watermelon-rhubarb combo 50/50 and that was absolutely delicious! Pomona’s pectin is the best!

    Reply

    1. Thanks so much for the review Jonni! Yes, that sounds delicious as a margarita mix, enjoy!

      Reply

    2. We do not have a ton of information about jamming with monk fruit, xylitol or a number of other alternative sweeteners that are new-er to the market.

      Reply

  4. Delicious! And came out wonderful. We got an overload of watermelon from the garden all at once this year. The jam is the perfect way to preserve some of it.

    Reply

  5. With pomonas it says you don’t have to add sugar and all.
    Is this possible with watermelon?

    With watermelon could I reduce the watermelon to a thicker consistency before?

    How would you then approach putting pectin / calcium water in recipe?

    Reply

    1. *We don’t recommend making jam or jelly with absolutely no sweetener. The final product is likely to be tart and bland. Sweetener, even in a small amount, brings out the flavor of the fruit.

      If you want to try it, however, this is what you do: For 4 cups of mashed fruit or juice, use either ½ cup water or unsweetened fruit juice (if you’re using 2 or 3 teaspoons of pectin) or ¾ cup water or unsweetened fruit juice (if you’re using 4 teaspoons of pectin).

      Make liquid pectin by measuring the correct amount of water or juice into a small sauce pan and bringing it to a boil. Put boiling liquid in cup for immersion blender, or in food processor, or in blender. Add pectin. It is very important to vent the lid (if there is one) to let steam out. Don’t use an enclosed blender that can’t be vented. Blend for 10 seconds, then stop and scrape down the sides so all pectin clumps are in or on the liquid. Blend for a full minute until all powder is totally dissolved.

      Add the liquid pectin to the boiling fruit or juice mixture, which should already contain the calcium water and lemon juice (or lime juice or vinegar) if called for in the recipe. Stir while mixture returns to a full boil. If you taste your jam before jarring and it isn’t sweet enough, you can add however much sweetener you want at this point. Stir well and return mixture to a boil, remove from heat, jar and process according to the recipe sheet that comes with Pomona’s Pectin.

      These instructions are also on the recipe sheet that comes with your box of Pomona’s Pectin.

      Reply

    1. We cannot say for sure that that would work, as we have never tried it. We believe you would miss a lot of flavor and the texture may be off.

      Reply

    2. I would like to make a watermelon/sweet cherry combo. Can I sub in some pureed cherries for watermelon? And lime juice for lemon and/or add lime zest?

      Reply

      1. Hello Heidi,

        You sure can! Yes, bottled lime juice can be substituted for bottled lemon juice, and lime zest can be added.

        Reply

  10. How can I add strawberry to this recipe or is there another recipe I can follow for this specific combination?

    Reply

    1. You can certainly add mashed strawberries to this recipe. We would recommend 25/75 or 50/50.

      Happy jamming!

      Reply

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