Wash and stem two quarts of muscadine grapes. 

Separate the pulp from the skins and chop up the skins in a food blender or chopper.

Toss the skins in a pot and add just enough water (about half a cup) to prevent them from sticking. Cook them gently for 15 to 20 minutes.

Cook the pulp over medium heat without water until it's soft. Press the pulp through a sieve or food mill to remove the seeds. 

Combine the pulp, cooked skins, and the six cups of sugar in a large pot. Bring the mixture to a jellying point, which takes about 10 minutes of stirring frequently over medium heat.

Once the jam starts to thicken, get the jars ready. Carefully pour the hot jam into the hot jars, leaving about ¼ inch of headspace. 

Use a clean towel to wipe the jar rims and adjust the lids. Make sure they're tight, but not too tight - just fingertip tight is ideal. 

Load the jars into the canner. 

Process for 10 minutes in a boiling water bath (or 15 minutes if above 6,000 feet in elevation). After the time is up, carefully remove the jars with tongs and let them cool on a clean towel. 

Let the jars cool for 24 hours at room temperature. 

Label, check the seals, and store.