Thoroughly rinse the scuppernongs, remove the stems, and discard any blemished fruit.
Add the scuppernongs (plus a very small amount of water to prevent scorching) to a large pot, bring to a boil, reduce to simmer, and cook for 20 minutes. Use a potato masher to crush the scuppernongs as they cook.
Remove from heat and let cool.
Pour the mixture into a large jelly bag or cheesecloth, that you can suspend over your pot to let the juice strain back into the pot. Allow the mixture to drip at least 6 hours, or overnight.
To Make the Jelly
Bring 6 cups of the scuppernong juice to a rolling boil and stir occasionally.
Add in the sugar, stirring to dissolve.
Boil at high heat, reaching 220 degrees Fahrenheit, until jelly thickens.
Remove from heat and quickly skim the foam off the top if desired.
Ladle your jelly into clean jars and place in them in the fridge or freezer. OR, review the article section above called "To Jar The Jelly: Shelf-Stable Process" to make your jelly shelf-stable.
Notes
If you end up with extra juice, add 3/4 cup sugar for every additional 1 cup of juice.