You won't find any sulfites in any of my wines, I don't kill the yeast, I let it die of alcohol poisoning, like a wine yeast should. I will say, it takes a bit of extra sugar to feed the yeast to the point that it makes so much alcohol that it dies from it. I have some apple mead that has about 16-18 percent alcohol by natural fermentation. That's due to a specific wine yeast and a lot of honey in with the apple juice when you ferment it.
Also, I'm a barbarian, I almost never make wine from grapes, it turns out much too dry for my tastes.