Instructions

1. Place 1 cup of berries in an 8-quart heavy kettle or pot. Use a potato masher to crush berries. Continue adding berries and crushing them until you have 5 cups crushed berries. Stir in pectin and butter. Bring to a full rolling boil, stirring constantly.

2. Add sugar all at one. Return to a full rolling boil: boil for 1 minute, stirring constantly. Remove from heat, skim off foam with a metal spoon.

3. Ladle immediately into hot, sterilized half pint canning jars, leaving ¼ inch head-space. Wipe jar rims; adjust lids. Process filled jars in a boiling water canner for 5 minutes (start timer when water returns to boil). Remove jars from canner, cool on wire racks.

4. Note: As jam cools, turn jars occasionally, top to bottom, to help evenly distribute the fruit and prevent the fruit from floating to the top. Store upright to protect the seal.