Blackberry Jam for 2 Pint Jars

Instructions:

1. Combine the blackberries, lemon juice, and salt in a heavy-bottomed pot. Use a potato masher or the back of a spoon to gently crush about half of the berries to release juices.
2. Stir in the granulated sugar (and powdered fruit pectin, if using). Set heat to medium-high and stir constantly.
3. Bring the mixture to a rolling boil—a state where the mixture continues to bubble vigorously even while stirring.
4. Continue to boil for 1–2 minutes if using pectin, or 10–15 minutes if not using pectin, stirring frequently to prevent scorching.
5. Perform the plate test: Drop a small spoonful of jam onto a frozen plate, let sit for 30 seconds, and push with a finger. If it wrinkles and holds its shape, the jam has reached the gel point.