One of the most intimidating aspects of wine can be the prospect of sending back flawed wine in a restaurant. It’s an understandable anxiety inducer: You’re in a fancy public place, you have to know what you’re talking about enough to instigate an awkward situation, and some wine flaws can be tricky even for professionals to identify. But don’t fret! There are only a few wine problems you’re likely to encounter in a restaurant, and they can be easily identified once you know what to look for.
Serious Flaw: Cork Taint
When people say a wine is “corked,” they’re referring to 2,4,6-trichloroanisole, or TCA, a chemical caused by microbes in cork bark. TCA affects an estimated 5% of bottles—not insignificant, especially if you drink wine regularly. I encounter “corked” wines on a monthly basis.
Cork taint is extremely potent: it can be detected by humans at concentrations of five parts per trillion, and it stinks. Think of a wet, moldy basement, with maybe some wet cardboard boxes lying around. That’s what cork taint smells like. Cork taint also masks all the good flavors of wine, like fruit and earth and spices, so if your wine smells and tastes “dead,” that can be a sign of low-level cork taint as well.
If you suspect you have a corked wine on your hands, you’re going to want to get it replaced; that wine is considered undrinkable in the industry. In a restaurant, this is a matter of saying to your server or bartender, “Excuse me, I think this wine might be corked.” If you’re not very confident in your ability to detect cork taint, you might find it helpful to ask if the sommelier or bar manager could taste the wine and confirm for you; however, I’d caution that this should only be done at restaurants with decent wine service. If you’re at a family chain restaurant or something and/or your server is 16 and really doesn’t care what TCA is, you might be better served to just say, “Excuse me, I think this wine is a little off. Can I ask for a fresh glass from a new bottle?”
If you bought the bottle at a shop, it’s safest to bring back both the bottle (with wine in it, so the shop can see for themselves) and the receipt as soon as possible. Without proof that you bought the wine at that specific retailer and that you didn’t just leave the wine open on your counter for 6 months, a small retailer might be hard-pressed to replace it.
Finally, if you’re at a party and want to “fix” a corked wine in a pinch, float a piece of Saran wrap in a decanter with the wine. The polyurethane in Saran wrap absorbs TCA. This method will mute TCA’s nasty aromas and make the wine more drinkable, but it won’t replace the actual wine character that’s been lost.
Serious Flaw: Oxidation
Air is both friend and enemy to wine. If your wine smells syrupy, stew-y, overripe, or like prunes, or has a vinegar character to it, chances are it’s just been open too long. A scrupulous bar staff will keep wines open no longer than a day or two, checking them daily for signs of decline, and busy wine bars go through wines far too fast for oxidation to be a concern. But I’ve had oxidized wine at many, many wine-centric spots (and countless not-so-wine-centric spots), so it’s something to watch for. Next time you have wine open in your home, note how it changes over several days; once you start to smell the “off” aromas mentioned above, your wine is oxidized. As with corked wine, it’s best to ask the server or bartender nicely for a fresh glass, rather than accusing the staff of being lazy with their wine maintenance.
Moderate-to-Serious Flaw: Reductive aromas
I mentioned that air is wine’s friend and enemy; too little of it during the winemaking and aging process yields the classic rotten-egg smell of a wine that is “reduced.” The smell of reduced wine comes from mercaptans, which are volatile sulfur compounds that can be responsible for many appealing flavors in wine—like minerality, or sauvignon blanc’s notorious “cat pee” smell—as well as rotten egg and cabbage aromas. Some wines that are only slightly reductive improve dramatically with a few minutes of air time in a glass or decanter (see Sulfite aromas, below), but if the wine is really smelly you’d best just follow the steps for returning corked or oxidized wine.
Moderate Annoyance: Sulfite aromas
Sulfites are antioxidants and preservatives that occur naturally during fermentation, but are also routinely added during winemaking for stability and protection against wild yeast spoilage. Those of us who have worked with sulfite a lot in wine production (cellar rats pretty much live and breathe the stuff during harvest) can be extra-sensitive to its onion-like effects: an itchy nose and watery eyes. Discernible sulfite is common in young white wines, especially German Rieslings, but it “blows off’ (dissipates with air) after a few minutes of assertive swirling.
Kind of your fault: Wine stored improperly or past its peak
Please, please, please don’t try to return a bottle to a wine store or winery that’s been sitting in your hot car or your basement with a 40-degree temperature swing for two years. Know that when you purchase any bottle for cellaring, storage is your most important question, and you’re taking a risk with anything that isn’t being purchased from a reputable dealer. Know that drink windows are “flexible windows” and get advice from retailers and wine collectors you trust before investing in a very old bottle. If it tastes like a thin shadow of what could be, it’s light-reddish-brown (for reds) or dark brown (for whites), and it shows signs of oxidation, you probably just waited too long to drink it.
Not a Flaw: Broken or smelly cork
This is not necessarily an indicator of cork taint; it just makes a wine harder to open. Do not reject a wine based on its cork without tasting the wine itself.
Not a Flaw: Tartrate Crystals
“Wine diamonds” are pretty crystal deposits that precipitate in wine stored in cold conditions when naturally occurring potassium and tartaric acid bind together. Most mainstream wine has been “cold stabilized,” meaning it gets stored at a cold temperature after fermentation to trigger this precipitation before it gets bottled and hits the market. Small production wines, however, may not experience cold stabilization (or any sort of filtering) for fear of upsetting their delicate flavor, and so the crystals show up in the bottom of your bottle or on the end of your cork instead.
They’re odorless, tasteless,* and harmless, so there’s no need to worry about them. I find they are quite photogenic.
*Thanks to my pal winemaker Howie Hart for pointing out that if you actually pop tartrate crystals into your mouth you’ll be able to taste the acid. By “tasteless” I intended to convey that they won’t taint your wine. Wine geeks taste a lot of weird stuff (dirt, sand, rocks, pencils) in the name of field research.