When we moved onto this property several months ago, there were three sets of established grapevines. One set is growing up and over an arbor and has a mixture of muscadine (purple) and scuppernong (bronze) grapes. One is trellised and we think grows bronze grapes, but it is so overgrown that there are only a few grapes on it this year. Our plan is to cut it back later this year and allow it to come back out over time. The third is a single vine of Concord grapes left over from a trellis that the previous owner attempted to cut down. They weren't completely successful, and this lone vine remains. We got plenty of grapes off of it this year and made Concord grape jam with this recipe, and my in-laws took lots with them to make jam too.
Recently the muscadine and scuppernong grapes were ready to pick from the arbor. We went out on a Saturday morning and picked almost 25 pounds of grapes. As we picked them, we separated them into containers by color. We set aside two gallons in the freezer to reserve for pie filling which we will make a later date, and we made jam with the rest. We used the same recipe for the jam that we use with Concord grapes, the only difference being that the skins of the muscadines are thicker and don't break down as easily. Therefore, you end up with a less chunky jam with fewer pieces of skin. The pulp still gets used.
In all, we made 27 half-pints of jam that day (three batches). The grapes produce a lighter colored jam than Concord grapes and look like jewels in the sun. The only warning I would offer is that there are tiny specks of pulp that are browner in color and those show up more in the lighter jam. If you wanted to eliminate that, you could put the pulp in a jelly bag and let it drain, but then of course you would be making jelly and not jam. I personally prefer the texture of jam and the idea that I'm using the whole fruit rather than just the juice.
I'm not sure exactly what we plan to do with all this jam. I love peanut butter and jelly sandwiches but using this much jam (for us) would be a feat. We may sell it or give it as gifts. I'm sure we'll figure out something. :)
For the recipe, use the same recipe as for the Concord grape jam. You will still pulse the skins in the processor separately from the pulp, and you will push as much of the pulp and skins through the sieve as possible. You will probably find that not as much of the skins go through. Feed the rest to the chickens or compost them. The purple grapes produce a light pinkish lavender jam, and the bronze produce a golden yellow jam.