Choice of:

• Deluxe Wine Tasting for Two with Souvenir Glass and One Bottle of Wine
• Deluxe Wine Tasting for Four with Souvenir Glass and Two Bottles of Wine

Wine Aeration: Breathing Out the Bad

Whether you swirl it, decant it, or leave it out, wine is changed by interaction with the air around it. Learn how its flavor transforms for the better with Groupon’s guide to aeration.

Drink wine with seasoned oenophiles and you may notice some strange rituals: lots of sniffing, swirling, and slurping usually takes place before they reach the bottom of the glass. They may even uncork the bottle and leave it out for an hour or two, or perhaps pour it into an oddly shaped vessel or through a futuristic-looking spigot. This is called aeration, or simply letting the wine breathe.

The latter description may actually be more precise. Aeration exists not so much to let air in as to let other stuff out—namely, sulfides, sulfites, and tannins. Sulfides are a natural byproduct of the winemaking process, and although wineries strive to keep them out of the finished bottle, they’re impossible to avoid completely. Although nearly 100 types of sulfides can be found in wine, there are only 10 that mess with a wine’s aroma. Uncork a wine with these compounds and you’re liable to smell anything from rotten eggs to burnt rubber. Sulfites, in contrast, are a class of antioxidants added by winemakers to keep products from spoiling, aging unpredictably, or growing up to hang out with wine coolers. Many believe they mask desirable flavors that might otherwise develop over time, or they may simply release a burnt smell upon uncorking.

Tannins, the third sip-spoiling culprit, impart a bitter flavor and an astringent mouthfeel. When you bite into an unripe banana or a raw walnut, tannins are what you taste; plants produce this molecule as defense against being eaten before their seeds are ready to be spread. Tannins come from the grape’s seeds, stem, and skin—which is why red wine is generally more tannic—but also from the wooden barrels the wine is aged in. Tannins help give reds character, but they can also can dominate the palate and overwhelm subtler notes.

Wine aeration seems to help break down these readily vaporized compounds, opening up the bouquet and bringing forth more pleasing flavors. Although the traditional method is simply to open the bottle and leave it out for one to two hours, a bevy of aeration tools helps those who can’t wait for that first sip. Wide-bottomed decanters expose the wine to oxygen by increasing its surface area and its motion while also allowing the sediment that clouds many older vintages to settle. Other devices fit on or into the bottle in order to swirl and expand the wine during the pour. In general, the older and more delicate the wine, the less aeration time it will need—leave it out too long and the delightful complexities and inspiration to start speaking French will begin to drift away as well.