Rinse the muscadines in a colander under cold water.
Transfer the muscadines to a large stock pot. Add enough water to the pot to cover the muscadines. You may need more or less than eight cups depending on the size of your pot.
Bring the water to a boil over medium heat. Reduce the heat to a simmer and boil the muscadines for about 20-25 minutes until they are soft.
Remove the muscadines from the heat. Mash the grapes with a potato masher.
Place a mesh colander or sieve over a stockpot. If using a colander, line the colander with three layers of cheesecloth.
Carefully pour the cooked muscadines into the cheesecloth. Allow the muscadines to strain for about 30 minutes, pushing on the grapes every few minutes with the potato masher or the back of a spoon to extract as much juice as possible. You should end up with about 10 cups of muscadine juice.
Remove and discard the cheesecloth with the muscadine solids.
Using the same stock pot, stir in the pectin until it dissolves. Bring the juice to a hard rolling boil.
Add the sugar and stir to dissolve. Continue to boil the juice for one more minute.
Remove the pot from the heat. Skim off any foam from the surface.
Transfer the hot jelly into clean sterilized jars, leaving 1/4 inch of headspace, and top with a lid.
Muscadine jelly will keep for up to three months in the refrigerator. It can also be preserved using the water bath canning method. Once canned, the jelly will last for up to 18 months if stored in a cool, dry place.