The recipe yield is:
Place your grapes in a large enamelized pot and add sufficient water to cover. Bring slowly to a full boil. Reduce heat and let simmer until very tender, stirring frequently. Press through a coarse sieve, to remove skins and seeds, then turn pulp and juice into a jelly bag. Drain well but do not squeeze the bag or jully will be cloudy. Measure juice - for each 6 cups of juice add 4-1/2 cups sugar. Set over high heat and bring to a full boil, stirring constantly. Boil hard until jelly falls lazily from the spoon in "sheets" (220'F. on thermometer). Remove from heat and skim. Seal in hot sterilized jars.