I don’t know anything about early alcohol making, but I doubt there was much distilling
or watering down. Wine occurs naturally, after all, so I would think it would just be the natural kind. That being said, we can’t really say if the yeast that fermented the juice was robust, providing more alcohol percentage, or easily killed by the alcohol. I’m not sure we really have any way of knowing that kind of detail.
Of course, I’m just shooting in the dark. Don’t take anything I say here as authoritative. I just drink the stuff