I guess that at least once in your life you have uncorked a bottle of wine and you felt like something wrong with it. Maybe you said: "It's corked!", and probably you just had to trash the bottle, since when a wine is corky, it is undrinkable. But let's try to find out what this unpleasant inconvenience is due to.
We should start saying that, understanding if a wine is "corked" or not, depends much from the olfactory perception of each of us.
A corked wine does not mean a wine that has particles of cork floating around in the glass, but itmeans that a wine has been contaminated with cork taint.
This taint is caused in the majority of the cases by the presence of a chemical compound, a natural fungus, the Armillaria Mellea (yup, the same as the honey mushrooms that we use for cooking), that develops and proliferates inside the faulty cork. This parasite is the responsible for that typical smell of mushroom or mouldy paper: this sensation is technically called Trichloroanisole, the TCA.
This fungus, that in nature sticks to the cork oak, when combines with certain chlorides elements found in the production cycle (as in bleaches and other winery station/sterilization products), transforms in TCA.
Also there are "false" cork smells: organoleptically they feel almost alike, but they are not due to the TCA.
Here is a curiosity: our olfactory system gets used very fast to the "corky" sensation, this is why it happens that when you smell it again you do not feel the corked sensation anymore...trust you nose at once!

If you do not know how to deal with a corked wine, our suggestion is not to be too shy: just ask the restaurateur to change the bottle, or return it to the retailer, it is the procedure and you will not be judged as a pain in the neck.
It can happen with wine, even if producers do their best to avoid this awful situation.
If it happens to find a corked wine and you cannot return it, make sure not to use it for cooking: it will ruin your dish as well!

Cheers,

VM