Oxidation is more than one chemistry. For my wine making it took a leap forward when I assumed there was zero residual SO2 so add a 50ppm dose of metabisulphite every racking (0.2gm per gallon roughly one Campden per five gallon carboy). This will probably be overkill with red wines but Vinmetrica numbers say it is OK with whites and country wines.
It would help to know the process especially when you have dosed metabisulphite.
? Varnish flavor ? I wonder if you are looking at ethyl acetate. This starts as vinegar (acetic acid) and then is oxidized, ,, most folks describe ethyl acetate as nail polish remover, have taken a sample to a vinters meeting and in low levels it is pleasing so they drank it. (solvent like?)
Varnish is an oil as tung oil which is heated in the presence of oxygen for several hours, I have not had what I would call “painty” aroma. For rice guy a classic place to find oxidized oil is a two year old bag of parboiled rice, especially if stored in a glass jar in the sun.
oxidation:
.. slow addition of oxygen will produce the flavor of sherry example use a LDPE milk jug as a carboy
.. excess oxygen as in too much head space for a month will produce a burn in the back of the throat when you swallow, at low levels I would describe it like apricot flavor and I have had blue ribbon wine with low levels of this.
.. micro-oxidation, ,, one of the vinters club members swears by it but I think he does more beer, ,,,, what else am I missing folks
