I thought that once any juice is bottled that you can’t really do fermentation out of it. Like Welch’s grape juice was designed to NOT ferment.
I’ve never tried it with Welch’s in a bottle, only frozen concentrate. But I’ve had great success with the “no sugar added” bottled juices, although I’ve never tried bottled grape. I’ve done apple, blueberry, peach, both red and white cranberry, and one other tat I don’t remember off the top of my head.