Blackberry Port Jam

Photo by Mia Valcarcel

Photo by Mia Valcarcel

Blackberry Port Jam is a low-sugar cooked jam made with Pomona’s Pectin. Pomona’s Pectin contains no sugar or preservatives and jells reliably with low amounts of any sweetener. See below for where to buy.

This recipe was adapted from Better Homes & Gardens Special Interest Publication Canning Magazine by Mia Valcarcel, who wanted to make it with Pomona’s Pectin.

Yield: about 4 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.

Blackberry Port Jam Ingredients

2 cups mashed blackberries (about 4 cups whole berries)
1 ½ teaspoons calcium water
1 cup port wine
2 tablespoons lemon juice
½ cup sugar
1 ½ teaspoons Pomona’s Pectin powder
Additional sugar if needed (depends on how tart your blackberries are)
¼ teaspoon ground cinnamon (optional, depends on your port flavors)

Blackberry Port Jam Directions

1. Wash jars, lids, and bands. Place jars in canner, fill canner 2/3 full with water, bring to a boil. Turn off heat, cover, and keep jars in hot canner water until ready to use. Place lids in water in a small sauce pan; cover and heat to a low boil. Turn off heat and keep lids in hot water until ready to use.

2. Measure mashed blackberries into sauce pan.

3. Add calcium water, port wine, and lemon juice, and mix well.

4. Measure sugar into a bowl. Thoroughly mix pectin powder into sugar. Set aside.

5. Bring fruit mixture 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. Taste the mixture to see if you need to add more sugar. This will depend on how sweet or tart your blackberries are. If adding more sugar, turn the heat back on, stir well while mixture returns to a full boil, then remove from heat. Add cinnamon now if desired to help boost the flavors.

6. Fill hot jars to ¼” of top. Wipe rims clean. Screw on 2-piece lids. Put filled jars in boiling water to cover. Boil 10 minutes (add 1 minute more for every 1,000 ft. above sea level). Remove from water. Let jars cool. Check seals; lids should be sucked down. Eat within 1 year. Lasts 3 weeks once opened.

Note from Mia: The port I used is from a local Maryland vineyard and contained overtones of chocolate and raspberry. The original recipe called for cloves, but I used cinnamon instead. I think it boosted the flavors more than cloves would have.

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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15 thoughts on “Blackberry Port Jam

  1. Thank you very much for posting this fabulous recipe! The jam came out great.

    Reading the discussion on the site about reducing the amount of pectin for more of a sauce consistency, my question is would you also reduce the amount of calcium water in proportion with reducing pectin?


    • Hello Alex,

      Wonderful! Great question, you would not reduce the amount of calcium water in a recipe, just the amount of pectin.


    • Hello Nancy,

      You will need to strain your mashed berries in a fine sieve to remove all of the seeds. Then proceed with the Blackberry Port recipe.
      I have also used my high power blender to emulsify my blackberries and that worked quite well for my liking…but was not entirely seedless.
      Happy jamming!


  2. I used this recipe as a base to make Strawberry Port Sauce. I added extra strawberries and used 1/4 of the pectin called for. I was hoping it would turn out more like a syrup, but it thickened up to more of a pourable sauce consistency. It was still very delicious!

    • Dear Debra,
      Thanks for writing to us about your experience with Strawberry Port Sauce. It is interesting that even with that small of an amount of pectin, it was more like a sauce than a syrup. If you were to make it again, you could reduce the amount of pectin even more and hopefully then you would get the syrup consistency you are looking for.

      I’m glad it was still delicious! Thanks for using Pomona’s Pectin — and happy jamming.

  3. Made this Blackberry Port Jam. It is absolutely wonderful. I was not as
    fortunate as the recipe author by having local port, but I used a Tawny Port, and this jam turned out wonderfully!

  4. If using honey instead of the sugar in this recipe, would you still mix the pectin with the honey and add it together? Or would you add the honey with the port and berries and add just the pectin at boil?

    • Hi Alyssa,
      Whenever you are using honey or sugar, or sweeteners that measure like honey or sugar, in a Pomona’s Pectin cooked jam or jelly recipe, you always stir the pectin into the sweetener before adding it to the boiling fruit mixture. This is because Pomona’s Pectin is pure pectin powder and will clump and not dissolve properly if added directly to the hot fruit mixture.

      For this recipe, the maximum amount of honey you would want to use is 1/2 cup. That is the top of the sweetener range for 2 cups of mashed blackberries. If your blackberries are sweet, you could stir the pectin into as little as 1/4 cup honey. If your blackberries are sour, you could start with 3/8 cup honey and go up to 1/2 cup if needed.

      Also because of the additional liquid in this recipe (the port wine), you may get a softer jell using honey as your sweetener. Since we haven’t made this recipe with honey, we can’t guarantee how it would turn out.

      I hope this is helpful — if you do make it with honey, we would love to know how much you use and how it comes out.

      Thanks for using Pomona’s — and happy jamming!

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