6 cups gently crushed blackberries, fresh or frozen (if frozen, thaw before crushing)*
1 1/2 cups pure maple syrup**
zest and juice of one large lemon (or two small)
Add all ingredients to a 6-quart stockpot.
Bring to a boil, turn heat to medium-low and simmer until berry mixture is slightly thickened, 45 to 50 minutes. TIP: Smash berries as needed with a potato masher to get a smoother, more consistent jam, especially when using fresh berries.
Test jam for gel point using one of the tests: -Use an instant read thermometer and check for 221 degrees F (105 degrees C) which is the fruit setting point for jam. OR -Dip a cold spoon into the jam and tip it gently. If it runs off in a sheet instead of liquid drips, it’s ready. OR -Place a small plate into the freezer for 10-15 minutes before testing. Add a spoonful of jam to the center of the plate. Leave it to cool a minute. Tilt it a bit and see if it runs off slowly; push jam with a spoon to see if it wrinkles.
If not gelled, return to pot and continue cooking at a simmer for another 5 minutes. Repeat gel test as needed until gelling occurs.
Let jam cool until just warm.
Ladle into freezer-safe containers and attach lids.
Label with contents and date. Use within a year to year and a half.
Prepare water bath canner, 6 half-pint jars and lids.
While fruit is still hot, fill jars one at a time with 1/4-inch headspace, wipe rims, attach 2-piece lids, and add to canner rack.
Process the jars for 10 minutes (start timing when the canner comes to a boil). Turn off heat, remove lid, and let the jars sit in the canner for 5 minutes.
Remove the jars to a towel-lined counter and let sit for 24 hours.
Remove rings, test seals, and label with contents and date. Store in a cool, dark place.
*6-7 pints or 3-4 pounds should get you 6 cups crushed berries. I strongly suggest buying more than you’ll need – you can always freeze the berries you don’t use.
**This makes a sweet-tart jam. You can increase to 2 cups if you’d like it sweeter (or you know your berries are really tart).
You can halve the recipe to make a small batch, which also will take less time to cook down and gel.