Not wishing to be controversial or argumentative, but we need to be careful as a lot of newbie winemakers read these forums.....
Before it started it was at 0% you can only measure potential alcohol
what was your starting S.G?
To reach 19% alcohol (assuming you get it to ferment down to .990) you would need an S.G. drop of 140, that would mean a starting gravity of 1.130 or Brix 30.5...man thats a lot of sugar
if the grapes got that ripe then I suspect they will lack the required acid to make a balanced wine, did you need to adjust the TA?
What is the S.G. now?
it should have been finished by now I would have thought.....