Nobody likes a wine “corked” with TCA. It exhibits aromas of wet cardboard or moldy clothes. Degrees of contamination with this chemical compound vary, and TCA is not always so obvious. Smaller amounts of it can merely subdue a wine, diminishing it, making it smell and taste flat and dull. With larger quantities of TCA the taste ranges from being off to being undrinkable.
It is best for both the winery and the consumer if you recognize a corked wine. If you do not recognize TCA, you may just think this is not a very good wine verses being a bad wine. You may then refuse to buy that label again, which is a much larger problem for the wine producer than if you recognized it was a corked wine and returned it. My first encounter—which I knew of—with a corked wine was while dining with, Wine Spectator's editor-at-large, Harvey Steinman in Napa Valley. Harvey asked me what I thought of one particular Cabernet Sauvignon. I tasted it and said I didn't like it at all. Certain that the bottle from which we were drinking was corked Harvey poured another glass of the same wine but from a different bottle. The second bottle was beautiful.
Beyond corks TCA has been found in barrels and can infect an entire winery's cellar including bricks and mortar. In extreme cases, wineries have torn out cellars and rebuilt them. Although there are other faults that can ruin a wine—more coming about these in following weeks here on Sipping—corked wine is the most common. TCA is found in five to ten percent of opened wines (less in fine wines). Follow the ritual of pouring a taste for the host to ensure the bottle is not flawed before serving to guests.