Two weeks ago I started an experiment: a half gallon of cheap Concord grape juice, 1/2 gallon of cheap Niagara (white) grape juice, 1 tsp of bread yeast, 1/2 tsp yeast nutrient. That's it; no sugar. I have wine yeast, but I wanted to try bread yeast to get a more "ale-like" character. The refractometer said the juice was almost 16 Brix, so about 8.5% ABV is the target. Something I can drink a pint or two without a buzz but probably not three.
After 10 days, the bubbling had almost stopped and the color started changing from an ugly mauve to a cloudy red wine color you could almost see through, and it had a generous 1/4" of sediment in the jug. I racked it to another gallon jug and added 1/4 tsp Knox gelatin dissolved in 1/2 cup of hot water. It started bubbling actively again and I thought I had screwed up, but a few hours later the bubbling stopped and the wine started to clear.
Today it is clear enough to read newsprint thru the jug. I can't believe how well the gelatin worked; I hope there's enough suspended yeast left to carbonate it. I plan to bottle it tomorrow night, in strong bottles with enough sugar to carbonate (about a teaspoon per 500 ml)
I'm excited by how fast this went.