Wash the muscadines and make sure all stems are removed.
Add to a large stock pot, along with 2 cups of water. Bring to a boil and allow to cook down for about 20 minutes. Use a potato masher to mash the fruits as they cook.
Once the muscadines have softened and smushed, place them in a sieve over a large bowl to drain. Feel free to smush some more here if you don't mind that cooked pulp. If you want a super clear jelly, line the sieve with cheesecloth and let it drain through for several hours until you have a very clear juice. Toss the remainder of the hulls, seeds and pulp out to the wildlife or your compost pile.
To make the jelly using powdered pectin
In your large stock pot, add 5 cups of juice, lemon juice, butter, and powdered pectin. Bring to a rolling boil (stirring periodically), this should only take a few minutes. After it reaches a rolling boil that cannot be stirred down,
Add 7 cups of sugar, and return the mixture to a boil, and boil for 1 minute. Remove from heat, skim the foam and ladle into jars.
To make the jelly using liquid pectin
In your large stock pot, add 5 cups of juice, lemon juice, butter, and sugar. Bring this up to a full rolling boil, and boil for 1 minute, then add 1 pouch of certo liquid pectin. Boil for 1 minute more. Remove from heat, skim the foam and ladle into jars.
To Can:
Sterilize jars and lids, then ladle the hot jelly into the jars. Make sure to wipe the top and rim of the jars before adding the lid. Adjust rings to finger tight. Process in a water bath for 10 minutes. Remove to cool. You should hear the lids sealing. Test after 24 hours. If any lids haven't sealed, refrigerate those jars and enjoy your jelly!
Notes
You'll need 9 half pint jars (8 oz size); this recipe made about 8.5 half pint jars for me. You can use a small 4 oz jelly jar for the leftover and stick it in the fridge to use right away. If using powdered pectin, there will likely be a little more foaming than when using liquid pectin, even when adding 1 tsp butter to help reduce foaming.