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My wife brought back a few bottles of wine from a visit to Erie, PA, and one was a (Red) Concord wine. I frowned a little bit, looking at it, and it turned out to be a very palatable, enjoyable wine. A tad sweet perhaps, but a beautiful bouquet making it all work! It definitely had no resemblance to Welch's jam.
I don't know anything about Juniper grapes but I'm quite sure they'll make wine too.
That's what home brewing and home fermenting is about, and we don't have to make a living from it. It's fun and easy to make a few batches, experiment a little, and enjoy the fruits of our labor.
Keep good notes, so you know where to improve on your next run.