Dear Wine Girl:
I hosted a holiday dinner party recently and one of my guests brought a very special bottle from his cellar: a 1986 Château Margaux, in fact, which he’d bought upon release way back when. I was so honored — and so flustered — by his generosity that when we decanted the bottle and I noticed some off aromas, I dismissed them, telling myself that the wine couldn’t be bad. Also I didn’t want my guest to be embarrassed. But more than halfway through our plates of Argentinian carbonada (all of us trying, but failing, to enjoy the Margaux with it) my neighbor finally confessed he thought the wine was “really tannic.” Truth is, it was corked and the meal was ruined. What should I have done?
Signed, Corky in the Wine Country

Dear Corky:
Lots of bad things can happen to a good bottle of wine. My sister in law once ordered a case of artisinal zinfandel shipped to her home in Phoenix, Arizona, which seemed very convenient until the UPS driver left the package on her front doorstep on a 110-degree afternoon. By the time she came home from work, that big zin had boiled up through the corks, seeped through the seals, and puddled all over the bottom of the box. She tried a sample, but it was truly “cooked”: tinny, a little burnt, and just not fresh.

I’ve also tasted wines that are oxidized, which means that too much oxygen has been absorbed into the wine, either because I let it age for longer than I should have, or because it was bottled improperly in its youth. In this case, again the wine will look pale and taste flat and overalcoholic. (That’s because tiny bits of oxygen will soften and eventually erase a wine’s fruit flavors, leaving you with tasteless booze).

But what does it mean when a bottle is corked, and what should you do if this horror befalls you?

As for your Margaux, Corky, you seem sure it was corked, probably because you spotted the tell-tale wet cardboard taste of a corked wine. A bottle is deemed corked because it had the misfortune of being stopped up with a tainted cork. The chemical compound behind this tragedy is called TCA, and is actually very widespread in the cork-making industry. Some say one in ten bottles is stopped with a tainted cork, though how much TCA there needs to be in the cork before your average taster can detect its effect, is still hotly debated among the experts.

Don’t feel bad for not having identified the corked Margaux before it was too late. It’s hard to summon up the courage to declare a wine bad, whether you ordered it from a restaurant, bought it yourself, or (perhaps hardest of all) received it as a gift. There can be ego, expectations, and often a lot of money tied up in a wine. Not long ago I ordered a bottle of 2002 Brewer Clifton “Clos Pepe” chardonnay for $79 at a favorite restaurant in Sonoma, and because I’d spent ten minutes bragging about my smart selection and telling the whole history of the Clos Pepe vineyard, when the bottle arrived corked I wasn’t inclined to say so when the waiter gave me a taste. Let’s just say nobody, especially he, was pleased when I had to send the chardonnay back after it had been poured, sipped, and rejected by the entire table. By the time we got a new bottle and fresh stemware, we were done with the course I’d intended to pair the wine with. Boo, hiss.

So, to any reader saddled unexpectedly with a corked wine, I beg of you: speak now or regret later. Yes, if you detect anything off about a wine, it’s absolutely imperative that you raise a big red flag right away. In a restaurant, your waitstaff should be happy to taste and confirm your suspicions (or, if you’re being overly cautious, to reassure you that the wine’s not corked, but filled with the earthy flavors typical of this region, blah blah blah.) The trick is you’ve got to search out and destroy that corked wine before it gets into your friends’ glasses and literally leaves a bad taste in every one’s mouth.

Now, in your case, you had an easy out that could have saved both dinner and face: as you are opening any fine, older wine at home, you should taste it first. Explain to your friend that you are making sure it’s ready to drink or if it needs some time to breathe. If it tastes even slightly off, tell your donor that the wine seems okay, but has some funky aromas that are sure to blow off after a few minutes in the decanter. Serve the back-up bottle you pulled in case of emergency, and then after 15 minutes or more come back to your guest’s wine. If indeed it still tastes corked, then give a taste to your guest; especially after he’s been drinking an untainted vintage, he should be able to agree that –woe is me — the Margaux was cursed from birth.

Most of all, it’s good to remind yourself that after all, wine is not about ego or price; it’s about pleasure. And since no one wants to drink unpleasurable wine (no matter where it came from or how much it cost), there’s no shame in raising a red flag about a corked wine.

Oh, and feel free to ask your guest if he bought more than one bottle of that Margaux. If so, that’s great, because he can look forward to trying them; chances are, they’re fine, and he can experience them in all their intended wondrousness. There’s nothing so silky, so opulent, and so ethereal as Château Margaux. Maybe he’ll invite you too.