I made some edelweiss a couple years ago. I suspect that the grapes may have been harvested a bit late or not stored properly. The juice seemed dark, a little oxidized and possibly had some VA. Sadly the wine followed the grapes and was "meh" for me. I'll take the blame when I make a mistake but in this case I feel the grapes were subpar.
When I inquired to our state extension office about it, they said that edelweiss was prone to high pH and browning. They suggested adjusting the pH down if it came in over like 3.4 and consider using activated charcoal to improve the color.
No matter what I think the grape is nothing to write home about. It is like a flabby Cayuga white.