Originally Posted by wickerman
Pitched champagne yeast on saturday, so its been fermenting for about 4 days. Its not going to be very strong either if that make any difference (around 8%).
Well, the danger with fruitflies (even one of them) isn't the fly itself, it's that it carries acetobacter. That is the bacteria that "eats" alcohol and produces vinegar. If you do get contaminated with that acetic acid bacteria, the wine will be ruined.
If it's happened, it's happened and not much you can do about it now unfortunately.
Hope for the best, and make sure than any avenues of entry to fruitflies and other critters are closed to protect the wine you make in the future.