Let’s assume there is an idiot… his name might be, I don’t know, Free Range Potter. Anyway, this man has several bottles of wine that he could not find the room for - reds, whites, etc. - and subsequently they ended up sitting in his kitchen for about 5 years. Most are from 2002-2003. They’ve been stored at room temperature, which can vary from high 60s during the winter to low 80s during the summer, and sometimes were exposed to sunlight.
What are the chances any of these wines are still good? How do I - I mean this other guy - tell the wine is bad without serving it to his guests and embarrassing himself terribly? When purchased these weren’t super cheap, but not really expensive. Probably about $25-40 each.
There’s a decent shot the reds are still okay, as they are structurally more robust. The whites are probably shot. Really there’s no scientific way to know for certain other than opening them and drinking them.
Have a party and right after everyone arrives, open them all and taste them. Serve only those that pass muster.
So here’s what you do. Plan the party. Go out and buy a few bottles of wine that you know to be good. Serve them first. Then open the questionable bottles. Some may say, “hey, this is really good.” Others may have a question mark with the first sip but will drink it anyway.
The New Testament parable about Jesus Christ turning water into wine was very instructive. JC gave them the good stuff and they were asking why the host was serving the good wine last. Take the lesson.
They probably won’t be actually bad. Although they do have a higher risk of being corked. What they won’t be is as good as they might have been, and indeed might simply taste rather ordinary. Light and white wine in clear glass isn’t good however - there is a risk that you will get some off flavours. Temperature variations are the thing that kills the quality, and makes ageing a waste of time. More so than simply too high a temperature, although keeping them cool is a good thing.
I would simply keep a bottle in reserve and tell the story over dinner. Or at least a story. You can be as creative as you like when explaining why these wines have a dubious history. If it tastes OK it is OK.
And if anyone tastes the wine, spits it out and stomps out then you didn’t want that person as a friend in the first place. You’ve just cut you losses several ways. Enjoy!
Why would the wines have a higher risk of being corked due to poor storage? My understanding of “corked” wines is that either a wine is or isn’t corked only due to the presence or lack thereof of TCA (trichloroanisole) in the cork, which is then imparted to the wine. A wine with a TCA-riddled cork will become more corky over time, so older wines will become increasingly unpalatable, but the “corked” aspect is going to be in the wine at a detectable level not long after bottling.
I also didn’t see anything in the OP that indicated that the bottles are clear glass…almost all wines are bottled in colored glass…usually dark green or black for reds and an off-yellow or green for whites.
“Corking” can also occur if a cork makes an imperfect seal, allowing some air into the bottle… see my post in the “wine swirling” thread. If a bottle were stored standing upright, the cork could shrink, allowing improper oxidation of the wine. The reason wine bottles are stored on their sides is to keep the wine in contact with the cork, keeping it moistureized and preventing shrinkage. With a good-quality screw cap or rubberized cork, this is less of an issue.
SS
Off wine (ie that has been over-aged) has a brownish cast to it. With the reds you won’t be able to tell until you pour, but if the whites have a clear or light bottle you can probably see by tilting the bottle and looking through the meniscus .
One wishes this were so. At least here in Oz (I live in South Australia - so our wine producers are not exactly a small time operation) there are altogether too many producers who still use clear glass for a lot of wines, some whites, and especially rose. Usually for pure aesthetic reasons. It isn’t the norm, but it happens. Same problem exists with beer and olive oil. Especially olive oil, where the colour is a big part of the presentation. Usually the cheap end of the market, but just plain stupid no matter what.
Just to expand on this, the browning is due to oxidisation - that is, the cork has not sealed off the wine from the air well enough for the time it’s been stored. That is by no means the only possible cause of damage to wine (corking - being tainted by cork that’s rotted or has mould - being another) but a very likely one, from the circumstances you describe.
Of course being stored somewhere with unstable temperatures is a problem in and of itself; you can tell your friend the kitchen is about the worst choice, I’m afraid.
If it tastes OK it is OK.