Ingredients:

  • 4 cups (approximately 600g) fresh blueberries, rinsed and picked over
  • 4 cups (800g) granulated sugar
  • 1/4 cup (60ml) lemon juice, freshly squeezed
  • 1 package (1.75 oz or 49g) powdered pectin (low-sugar pectin is also an option)
  • 1/2 cup (120ml) water (if using low-sugar pectin)

Instructions:

  1. Sterilize jars according to manufacturer's instructions or by boiling in water for 10 minutes. Keep jars hot. Simmer lids in a small saucepan of water.
  2. In the large pot, combine the blueberries and lemon juice.
  3. Whisk together water and pectin in a separate bowl until there are no more lumps. Add the pectin mix into blueberry mixture, stir until combined.
  4. Over medium-high heat, bring the blueberry mixture to a full rolling boil that cannot be stirred down, stirring constantly.
  5. Quickly add all the sugar at once. Stir vigorously to dissolve.
  6. Return to a full rolling boil, stirring constantly. Cook until the jam reaches the setting point (220°F / 104°C on a candy thermometer, or until a small spoonful placed on a chilled plate wrinkles when pushed). This usually takes about 1-2 minutes.
  7. Take the pot off the heat. Skim off any foam that forms on the surface using a metal spoon.
  8. Using a canning funnel (if using), carefully ladle the hot jam into the sterilized jars, leaving about 1/4 inch of headspace.
  9. Wipe the jar rims with a clean, damp cloth. Place the lids on the jars and screw on the rings finger-tight.
  10. If you plan to store the jam at room temperature for more than a few weeks, process the jars in a boiling water bath canner for 10 minutes (adjusting for altitude if necessary). Otherwise, let jars cool completely on the counter to seal.
  11. As the jars cool, you should hear a popping sound as the lids seal. Check the seals by pressing down on the center of the lid. If it doesn't flex, it's sealed.