Ingredients:

  • 6 cups (800g) fresh blackberries
  • 3 cups (600g) granulated sugar
  • 2 tbsp (30ml) fresh lemon juice
  • ½ tsp (3g) butter

Instructions:

  1. Place the fresh blackberries in a large bowl or the cooking pot. Using a potato masher, crush the berries until they reach your desired consistency.
  2. Combine the mashed blackberries, granulated sugar, and lemon juice in the pot. Stir in the butter. Set the heat to medium-high and stir constantly until the sugar completely dissolves, then bring the mixture to a full rolling boil.
  3. Maintain the boil, stirring frequently. Monitor the temperature with a thermometer until it reaches 220°F (104°C), or perform the plate test by dropping a spoonful of jam onto a frozen plate; if it wrinkles when pushed, it has reached the gel stage.
  4. Ladle the hot jam into sterilized jars, leaving ¼ inch (6mm) of headspace. Wipe rims clean, apply lids, and tighten rings. Process in a boiling water bath for 10 minutes to seal.