Measure the juice into a large pot (about 8- to 10-quart size). Mix the pectin with the juice and bring to a hard, rolling boil, stirring occasionally. Add all the sugar at one time. Stir until the sugar dissolves, and bring again to a full rolling boil (a boil that rises to the top and cannot be stirred down. Boil hard for 1 minute and 15 seconds, stirring constantly. † Remove from heat; skim off foam with a metal spoon. Pour at once into sterilized jelly jars, leaving one-fourth inch headspace. Wipe the jar edges with a damp towel, and seal with new lids according to manufacturer's instructions.
Yield: about 6 half-pint jars