title_body: What is the technical term for the "vinegar/easter egg dye" smell in some wines?
upvoted_answer: 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.