Preparation / Directions:
Wash grapes and place in a large kettle. Mash slightly. Wash apple and cut into slices, but do not core or seed. Add apple to grapes, with 1/2 cup water. Quickly bring to a boil and boil until grapes soften, about ten minutes. Drain through a damp jelly bag, without pressing pulp. Refrigerate juice overnight. Strain again to remove tartrate crystals.
Measure juice into a large kettle. For every cup of juice, add 3/4 cup sugar (there should be about four cups of juice). Bring to a boil over medium high heat and cook until mixture reaches jelly stage, 220 degrees F on a candy thermometer. Skim foam off surface and pour jelly at once into sterilized, half-pint glasses. Seal with paraffin.