Here's a bad sign. You open a favorite bottle of wine, and the cork is soft and dark. If you look closely, you can see red streaks all the way up the cork in the photo.

This wine was "corked", and that makes it just about undrinkable. It gets a nasty chemically-musty smell that says for sure something's had gone terribly wrong. So wrong that you can't cook with it and it won't even make good vinegar.

Corking can happen to any wine that has been aging for a while.  

Old wines also drop sediment. It looks like little black particles in the wine and streaks on the inside of the bottle. But the sediment is not at fault. Excellent aged wines show sediment too.

So what's the problem?

The problem is an invisible but highly objectionable compound called 2,4,6-trichloroanisol (TCA to its friends). TCA comes into the wine when the wine saturates the cork. This can happen if the cork dries out, which it can do it it gets too warm or if it was just a bad cork.

What is to be done?

I discovered a nifty trick. It is mentioned here and there online, often with skeptical commentary. Naturally I had to try it.

The principle is similar to the old problem of oil and water not mixing. Wine is essentially watery, and TCA is more oily. If you wad up some plastic wrap and stuff it into a decanter with the corked wine, that nasty TCA prefers the plastic wrap to the wine, and sticks to it. After an hour or so you can pour the wine away from the plastic wrap and it has lost the TCA!

It has lost something more than the TCA. I don't think you can restore the wine to its original greatness, but it does salvage it to the point where you could cook with it or drink it for cardiac health.

If I get another corked bottle I will continue to experiment, but honestly I hope I don't get to make much progress with this project!