Crush grapes in an 8-quart stainless steel pot.
With Ribier grapes, which are quite firm, I do this by pinching each grape with my fingers to insure even crushing.
Core and slice apple thinly into pot.
Bring mixture to a simmer (there should be enough liquid, but, if not, add 1/2 cup water), cover, and cook for 20 minutes.
Strain mixture through three layers of dampened cheesecloth or a jelly bag; for a thicker consistency (the one I prefer), simply put mixture through a food mill twice.
Measure juice, pouring it back into pot.
Add one-third to one-half as much honey as you have juice.
Bring to a rolling boil, and then simmer over medium-high heat until it reaches jam consistency, about 30 minutes.
Toward the end of the cooking time, you have to be very careful to prevent the jam from sticking, stirring it often, and watching it carefully.
Test by placing 1 tablespoon jam on a cold plate and refrigerating for a few minutes.
It should not run when you tip plate; and when scooped up with a spoon, it should mound up.
Skim off foam.
Pour into hot sterilized jars.
If not refrigerating jam, follow directions for processing on page 262.
If refrigerating, cover and let stand at room temperature overnight before chilling in refrigerator.