Instructions

1. Wash the blackberries thoroughly and remove any stems or leaves.
2. In a large pot, combine the blackberries, granulated sugar, and lemon juice. Stir gently to coat the blackberries.
3. Cook over medium heat, stirring occasionally, until the blackberries release their juices and the mixture comes to a boil, about 10-15 minutes.
4. Once boiling, reduce the heat to low and simmer for 15 minutes, stirring occasionally to prevent sticking.
5. Remove the pot from the heat and let the mixture cool slightly for about 5 minutes.
6. Using a fine-mesh sieve or cheesecloth, strain the mixture into another pot to remove any seeds or pulp, pressing down to extract as much juice as possible.
7. Return the strained liquid to the pot. Stir in the pectin until fully dissolved.
8. Bring the mixture to a rolling boil over high heat, stirring constantly to prevent scorching.
9. Once at a rolling boil, continue boiling for exactly 1 minute, then remove from heat.
10. Carefully pour the hot jelly into sterilized jars, leaving a 1/4-inch headspace at the top.
11. Seal the jars with lids and process in a boiling water bath for 10 minutes to ensure proper sealing.
12. Remove the jars from the water bath and let them cool completely at room temperature. Store in a cool, dark place.