Homemade Blackberry Jam Recipe (Low-Sugar+ Canning Instructions)

3.86 from 21 votes

Make my easy low-sugar blackberry jam recipe with step-by-step water bath canning instructions. Delicious homemade jam without loads of sugar!

Cook Time15

Canning Time20

Total Time35

Course: Condiment

Cuisine: American

Keyword: blackberry jam recipe, homemade blackberry jam, how to make blackberry jam, low-sugar blackberry jam

Servings: servings

Calories: 32kcal

Cost: varies

3 cups blackberries freshly picked, or frozen and thawed
1 box Pomona's Pectin
1/4 cup lemon juice
1 cup white grape juice from concentrate You can use any juice from concentrate you like for different flavor profiles

If canning, wash jars in hot soapy water, rinse, and place them in your prepared water bath canner. Fill the canner with water so jars are completely covered by 1 inch. Turn the heat to medium, so the water is roughly 180 degrees F.

In a large stainless steel or enamelware pot, add your washed berries (I like to slightly crush mine with a potato masher).
Turn the heat to medium and add grape juice to the pot.
Follow the instructions that came with your Pomona's Pectin to make the calcium water. Then, add two teaspoons of calcium water to the berries and stir until combined.
Sprinkle two teaspoons of powdered pectin over the berries, then use an immersion blender to blend until the pectin until it's fully dissolved.
Bring to a boil, stirring frequently, until the jam is slightly thickened.
At this point, the jam can be spooned into a jar and placed in the refrigerator to be enjoyed immediately, stored in a freezer-safe container as freezer jam, or follow the canning instructions below. Pro-Tip: If freezing in glass jars, make sure to use wide-mouth, straight-sided jars with at least one-inch headspace so they don't crack when the jam expands.

Carefully remove the jars from the canner and dump the water out into the canner. Then, ladle the jam into jars, leaving 1/4 inch headspace.
Remove air bubbles with a bubble wand or chopstick, adding more jam if needed to stay at the 1/4 inch headspace. Wipe the rims clean (and check with a clean finger for any nicks or chips), put the lid in place and fasten the ring down to fingertip tight.
Place the jar into the canner and repeat until all jars are filled.
Bring the water to a full boil and process for 15 minutes. When the timer goes off, turn off the burner and remove the lid for 5 minutes. Then, using a jar lifter, carefully remove the jars and set them on a towel-lined draft-free counter to cool for 24 hours.
After 24 hours, check seals, remove bands, wipe down the jars, label lids and put them on the pantry shelf.

Recipe yields, on average, two pints (or four half-pints) of finished jam.

Blackberry Jelly - For a smoother jelly (that doesn't contain seeds), you can strain the jam through a food mill before adding it to your jars for canning.
Freezer Jam - If you'd rather not go through the canning process, you can make the jam, allow it to cool at room temperature for 24 hours, then transfer it to the refrigerator (for up to one month) or the freezer (for up to a year). If freezing in glass, be sure to use a straight-sided Mason jar, leaving at least 1 inch headspace to allow for expansion.
Pectin-Free Option - I share how to use a grated apple for your pectin source in my blueberry jam recipe. If you don't have any Pomona's Pectin, you can use 1/4 cup grated apple. If you'd like to leave the pectin out altogether, you'll just need to cook your jam longer until it thickens up to a gel stage (around 220°F). You can test if your jam is done by placing a spoon in the freezer, then dipping the cold spoon into the jam. If the jam comes off in a sheet, it's ready to can, but if it drips off in multiple drips, it needs to cook down further.