These beautiful, blue Concord grapes are the best for jelly making. They must be picked when fully ripe, (for the best flavor and aroma) just before the birds discover them.
Wash, and gently pick the ripest ones.
Mash the grapes with a potato masher, careful not to press too hard to avoid the bitterness of broken grapeseeds.
Bring to a boil over high heat, stirring constantly, until the rich purple color comes out.
Layer cheesecloth into colander or sieve, tie, and let juice drip into large canning jar or bowl.
Take the strained grape juice, add one cup of water and 1 box of pectin, bring to a full rolling boil over high heat. Boil for one minute. Quickly add 7 cups of white granulated sugar to the juice, bring to a second boil, stirring constantly and until it cannot be boiled down, about one minute. Ladle into clean canning jars, lid and then band. Turn upside down for 30 seconds to make sure there are no leaks.
Put jars into a large water bath, and boil for 20 minutes. Lift out of bath and cool on towel.
