Place blueberries in a large pot over medium high heat.

When they begin to boil stir in butter and pectin.

Once the Berries reach a rolling boil stir in 3 cups of sugar and allow to reach a boil again.

Boil for 1 minute and then place in sterile canning jars.

Process jars for 10 minutes in a boiling water canner.

Store unopened for up to 1 year in a cool dry place, or open for 3 weeks in the fridge.