May be a crazy question but does wine go bad?

Analy, spoken like a true californian

Tannins come from the grape skins, which are primarily left out of white wine making. So there may be some minimal tannin either from residual skin or from oak aging, but generally there is very little, if any, in white wines.

@J&R S "Real cork breaks down over time, letting air in, which continues the fermentation process until your wine is vinegar."

This is actually not true. There are bottles of wine, that are hundreds of years old, with real cork in them. The wine does not continue to ferment. IF a cork fails, air will oxidize the wine, not ferment it.

@Mrs T to be, Tannins are in the grape skins. Both white and red wines can and mostly do have tannins.

As far as the flavors one gets from wine. Many times that comes from the soil the grapes are grown in. For instance, if the vineyard site was once a cherry orchard, som of that flavor will still remain in the ground. Whatever has been in that ground will be picked up by the roots of the grapevines.

Actually, white grape skins are not primarily left out of wine making. Not sure where you are getting that info.

There are some white wines that are made using red grapes. In that case, yes, the skins are either removed before or shortly after crush. Rose' wines are made with minimal skin contact.