1. What does the bottle look like?
If a wine bottle in a shop has dust on its shoulders, it has probably been stored standing up for a long period. This might mean that the cork has dried out and let oxygen seep into the bottle, which can oxidize the wine — giving it an unpleasant odor and flavor. On the other hand, if a bottle stored on its side doesn’t look quite full when it’s upright, wine might have leaked out, again possibly causing the wine to oxidize. Neither factor is a consideration, incidentally, with wines sealed with screw caps — increasingly common even for the good stuff.
2. Where does the wine come from?
Wine is made in every U.S. state and in more than 75 countries around the world. Sometimes, wines from unexpected places can be very good (Champagne-style sparkling wines from England have actually bested true Champagne in tastings, for instance). For the novice wine-buyer, however, a good rule is to stick to places that have long been known for high-quality wines (the list would begin with France, Italy, Spain, Portugal, Germany, Austria, California, Washington, Oregon, New York, South Africa, Australia, and New Zealand). A Maltese chardonnay or Ethiopian merlot might be perfectly good, but unless you’ve got a budget for experimentation, why take a chance?
3. How does the cork smell?
As noted, screw caps are becoming more and more prevalent. About two-thirds of what’s bottled is still cork-finished, though. Corks have been used to seal bottles since the 18th century, but they have a problem: It is estimated that between 1% and 5% of cork-sealed wine bottles are “corked,” meaning that they’ve developed an aroma often likened to wet newspaper or a moldy basement. The culprit for this so-called cork taint is a chemical compound called 2,4,6-trichloroanisole — TCA for short — which can be conveyed into the wine by contaminated corks (it can also come from winery hoses, barrels, and elsewhere). That’s why sommeliers in fancy restaurants proffer corks to diners before pouring the wine. If the cork smells funky, the wine almost certainly will too (and it’s okay to send it back).
4. How does the wine look in the glass?
Once the wine is poured, its appearance can reveal more about it. Whatever its color, it should be clear, not cloudy. (Wines described as “natural” or “biodynamic,” meaning that they’re minimally processed, are sometimes an acceptable exception.) A white wine that’s dark yellow or brownish-yellow color might be oxidized or maderizes (maderization is a form of oxidation, often due to exposure to heat).
5. Does it smell bad?
Cork taint and oxidation are only two elements of a wine’s aroma. Two more faults that show up in what wine-tasters call the “nose” include the rotten-egg or skunky smell of sulfur compounds, either added to the wine to stabilize it or occurring naturally during fermentation. The good news is that if it’s not extreme this character will usually largely dissipate 15 or 20 minutes after the bottle is opened. Then there’s volatile acidity, a vinegary acetic acid aroma that is sometimes unintentional but sometimes introduced by the winemaker as a way of adding complexity. If indeed it is intentional, the only solution is to simply avoid the wine.