Run the grapes through a food mill to quickly separate the grapes from their skins and seeds.

Pour the milled grapes and lemon juice into a large sauce pan. Bring to a boil and then let simmer, stirring frequently.

Prepare your canning supplies. Bring the temperature of the glass jars up by processing them in hot water for several minutes, and heat a few cups of water in a small saucepan for the lids.

Stir in the pectin until dissolved. Bring back to a boil, and then add in the sugar all at once. Boil hard for a minute longer.

Skim off any foam and ladle the hot jam into the hot jars, leaving 1/4″ headspace.

Place the lids and bands on top, screwing on the bands just until fingertip-tight. Place the full jars back into the boiling water and process 10 minutes.

Remove from the water and place the jars on a towel. Let the jars cool. The seals should suck down (you'll hear a popping noise as they do). Makes 5-6 eight-ounce jars.