What is the technical term for the "vinegar/easter egg dye" smell in some wines? I frequently notice a very specific smell/taste in wine.  I find it rather unpleasant, so I presume it is a known commonly occurring wine defect (I notice it probably at least 30% of the time).  The trouble is, I don't know what it's called, so it's difficult to complain about it or send a bottle back because of it.  I know it sounds silly, but the taste I'm referring to reminds me exactly of easter egg dye, though it's not exactly a vinegar taste.  It often becomes more pronounced as the wine sits out in the glass.  I've tried reading up on common wine defects, but none seem to really match.  Does anyone have any idea what the taste is I'm referring to?
Probably what you are smelling is a combination of oxidized wine, ethyl acetate and acetic acid. Oxidized wine smells like sherry and the volatile acidity smells exactly like you described it. Vinegar. Ethyl Acetate smells like nail polish remover. 

What happens when you leave wine out, the metabisulfites break down and can't prevent oxidation anymore and also will allow the acetobacter bacteria to do it's thing, which is to convert alcohol into vinegar.