There are few things more mesmerizing than watching a deep, ruby colored wine skillfully swirled around a large-bowled glass. Conversely, watching an “over-swirler” throw the wine around like a ride at an amusement park can seem quite pompous.

Regardless of style and technique, there’s a tremendous amount of value and purpose to the wine swirl. Most of it has to do with oxygen and aeration, but there are other reasons why the swirl is a key component in the 5 Ss of wine tasting.

It Opens the Wine

As soon as wine is exposed to oxygen, its aroma compounds become more detectable as they attach themselves to evaporating alcohol as it lifts from the glass. Oxygen also can help to soften harsh tannins on bigger wines, allowing them to become smoother and silkier.

Just about every wine will benefit from swirling to some extent, though younger, bolder wines may require more. But be cautious about overswirling an older vintage wine—oxygen can turn from friend to foe, and it’s easy to overoxidize a delicate, aged wine with too much swirling.

It Removes Off-Putting Odors

Oxygen will also help “blow off” a wine’s unwanted aromas. Sulfites, which may be added during the winemaking process or occur naturally as a biproduct of fermentation, can create an odor of burnt match or rotten eggs upon initially opening a bottle. With several seconds of swirling, those malodors often dissipate, leaving behind the aromas intended by the winemaker.

A Better Visual

By swirling wine higher up in the bowl, you can better analyze its color and viscosity. A given wine may seem medium ruby in color when resting at the bottom of the glass. But give it a few laps around the track, and its hue may appear lighter than originally detected.

Moreover, swirling leaves behind legs, also called tears, on the glass. They can indicate a wine’s viscosity and signify higher alcohol levels. The more legs that streak down the glass, the more you may want to watch how much you consume in one sitting.

How to Swirl Wine Correctly

There can be a fine line between executing an impressive swirl and potentially ruining everyone’s clothes with flying wine. Here are a few tips to keep in mind when perfecting your swirl.

Start small and keep the base of the glass on the table. Imagine there’s a small bead or pebble floating atop your wine, touching the side of the glass. See if you can envision moving that bead around the edge of the glass, without it off the table. Once the flow looks good, try to keep that same rolling motion as you raise the glass a few inches off the table.

Use a big-bowled glass. When it comes to wine glasses and swirling, size matters. Wider bowls create a lower center of gravity and better momentum for the liquid inside, allowing for a more stable experience. Start with one of these and save yourself the hassle of learning to swirl in a tiny tumbler—a recipe for disaster and nearly guaranteed to cause a spill.

Avoid the overswirl. Several seconds, or even a minute of swirling, does wonders for most wines (though again, be careful of those older vintages). But a glass of wine doesn’t need to be swirled constantly. After the initial swirl to kickstart oxygenation, the wine will continue to breathe and develop in the glass by itself. Also, all it takes is one overpowering flick of the wrist to send a nice Bordeaux sloshing out of the glass, left only to be enjoyed as a permanent stain on your favorite rug.

Article from Wine Enthusiast by Marshall Tilden III