James
They can coexist, it's normal actually. Well made wine is mostly
alcohol with very little acetic acid. It sounds like the wine you
tasted was the reverse. (Some vinegars are made this way, that stuff
may be good on a salad.) I have tasted a lot of horribly made
homemade wine that was a combination of acetic acid and something
else, it's kind of hard to get past the vinegar.

Here is what may have happened: Some winemakers use old barrels and
just tap the barrel, taking some day by day. It may have been wine
when they started, but sooner or later it's not exactly what they
started with, and after a while it's vinegar (best case, worst case is
not even worth discussing). They had it every day and the changes
were small, so they don't notice the stuff is changing. Now you come
along and taste and smell it and it's not exactly what you think wine
should taste like.

The testing is pretty compicated to be honest. You need to distill,
it's a lot of work to prove something you already know. Your nose and
tongue are pretty good indicators for acetic acid, if you think it's
vinegar, it probably is. To be honest, if they like the wine it's
doubtful any test you did would convince them there is an issue, it's
good enough for them.

I doubt this has anything to do with wild yeast, I have fermented
grapes in the past without adding any commercial yeast and they
fermented to completion. It's pretty common in France too, but they
make the same wine year after year in the same way and same place in
those wineries. I'm not saying you should not use comercial yeast
either, I alway did after reading one book.

To get back to your original premise, vinegar has to have oxygen to
grow. It's actually the byproduct of acetobacter, so you need to do
two things to make it. Infect the wine with acetobacter in sufficient
amounts for it to take off, and supply oxygen.

If the container they make it in smells like vinegar at all before
adding must, that's enough to infect the wine; if it's not topped up
properly, the air in the container suppled the oxygen. It does not
take a lot of aecetobacter to infect wine, but it hates sulfite and
needs air to grow, so those steps are probably the most important
thing a winemaker can do to prevent it's growth.

Hope that helps.

Joe

> Folks that I know like to make "wine" without using wine yeast. I
> guess that they depend on wild yeast. Some of their wine that I have
> tasted tastes like sweetened vinegar. They say that it is wine, I
> think that it is vinegar. I don't have a test that I can perform on
> the wine to prove an alcohol content.My nose is not sensitive enough
> to detect the vinegar odor. Is there an objective test to settle such
> a disagreement? Can alcohol and vinegar both exist in the same liquid?
> Thanks,
> James