Blackberry Jam with Lemon Juice

Instructions:

1. Place the cleaned blackberries in a heavy-bottomed stainless steel pot and use a potato masher to lightly crush about half of the berries to release natural pectin.
2. Stir in the granulated sugar and fresh lemon juice.
3. Heat the mixture over medium-high, stirring constantly until the sugar has completely dissolved, then increase the heat to a rolling boil.
4. Maintain the boil, stirring frequently to prevent scorching, until a digital candy thermometer reaches exactly 220°F (104°C).
5. Remove the pot from the heat and let the jam sit for 5 minutes to allow the fruit to distribute evenly.
6. Carefully ladle the hot jam into sterile canning jars, leaving ¼ inch of headspace, and seal tightly.