What color do they turn when they ripen and do you remember which month they ripen?

I am not sure what you mean by Possum Grape, because different wild grapes are called Possum Grapes in different areas.

One problem with using colloquial names for plants is that those names are used for different plants by different people in different areas.

If you are talking about the Possum Grape that is in the grape genus (Vitis)in the grape family (Vitaceae), then that one generally is Vitis cinerea var Baileyana, and it is widely referred to as possum grape in some areas (North Carolina, for example) and, then no, the one in your photo doesn't look like that one.

If you are talking about the member of the Ampelopsis genus (a genus in the Vitaceae family so they are related to grapes but they aren't grapes) which often is called Possum Grape here in OK (even the OK Biosurvey calls it Possum Grape), then that one is Ampelopsis cordata and yours looks somewhat similar to A. cordata. Another name for A. cordata is false grape.

So, if I had to guess, I'd bet yours is in the Ampelopsis genus, although it has a lot of members and I am not familiar with all of them. Some members of the Ampelopsis genus are referred to as peppervines. We have peppervines growing on the eastern edge of our woodland, but they are not the one in your photo.

And, if your plant is in the Ampelopsis genus, it isn't edible or fermentable, as far as I know.

Here is a link that might be useful: Ampelopsis cordata @ OK Biosurvey

Bah, it is indeed an Ampelopsis.... I am sooo disappointed. :(

lol

Sorry about crushing your dream.

There's more than one way to skin a cat, though. (Don't tell my cats I said that.)

Do you have other wild grapes around?

A couple of years ago, around Labor Day weekend (can't remember if it was before or after) we were down on the Red River in Love County in an area I'd never been to before on a search-and-rescue/recovery type fire call following a drowning. I think we were on Wildlife Management Area land that was adjacent to the river. We were down there for about a day and a half. Although it wasn't all that far from our place, I'd never been to that specific part of the county before. It was really rugged and wild. I admit that, having never been there before, I never really knew which land, if any, was private property and which was WMA land....because I was lost and confused the whole time. After we finally made it back up out of the valley and back to civilization, I realized that as the crow flies, we were just a couple of miles from our house.....but miles and miles away by dirt and gravel roads and by sandy footpaths down to the river. The fencelines and trees along one of the roads were covered by the vines of a wild grape that, I was told, people eagerly harvested every year and used to make wine. I don't remember if anyone ever told us its name, but I think it might have been fox grapes. Some old timer who was down there with us brought us a cluster of ugly, black grapes and wanted us to try one. They were the most awful, sour, astringent thing I've ever tasted in my life, and they were growing wild everywhere. He insisted they make a spectacular wine....said people would pick them like mad when they were fully ripe so they could make homemade wine. I can tell you right now that I wouldn't have wasted my time on them, but I am not a winemaker.

So, look around in late summer and early autumn and see what you find. Everyone here in our county who has fairly wild woodland has wild grapes of one sort or another. Unfortunately, in mature woodland like we have, the grapes climb so high up into very tall trees that you cannot reach them from the ground. I do have some sort of wild grape that keeps trying to grow on my garden fence and I keep hacking it back. I won't let the fruit ripen as I hack it off every spring, so cannot tell you what it is, but I am pretty sure I am stuck with it forever. I prune it back hard every couple of weeks and it grows like mad, and that goes on all summer long. Some day I will be an old woman with no garden, and a grape vine that covers all 14.4 acres....and then you can come over, and we will pick those grapes and make wine. The end. (grin)

Also, do you have other fruit like peaches or plums? My younger brother used to make peach wine with fruit from either his tree or a neighbor's tree.