Most oenophiles have heard of the term "breathe" in reference to wines, and you may know that it happens when you open a wine bottle and expose the contents to to air, but what exactly is it, and is it good for your wine? Arguably, the better question seems to be, is it always good to let wine breathe and how long should you let it breathe?

Letting a wine breathe is believed to allow the wine to soften and express its aroma and flavors, but the process and devices used to breathe wines are greatly misunderstood. It isn’t necessary to let all wines breathe, and in fact, allowing aged wines to breath too long can result in the wine going dead. We’ll look at what’s happening in wine when it is exposed to oxygen so you can decide which wines you want to let breathe, if any at all.

Wine Breathing, It’s Complicated

Wine and oxygen have a complicated relationship; as wines age and mature, a small amount of oxygen helps the wine to develop, and this oxygen comes from the bottling process in which small amounts of oxygen molecules are stored in the wine and in the neck of the wine bottle. However, if too much oxygen is in the bottle or the wine isn’t sealed properly, the wine can oxidize.

Oxidation is the result of too much oxygen and causes the wine to lose volume, color, flavor, aroma and can result in the wine turning to vinegar by promoting the growth of acetic bacteria in the wine; when this happens, it's referred to as vinegar taint. This same complicated relationship follows wine and oxygen when a bottle of wine is opened. When a wine is opened and allowed to breathe in the bottle, only the wine in the neck is exposed to air, which really isn’t that much wine, and doesn’t actually affect the whole bottle. Decanting wines into other containers and using devices to aerate the wine as it is poured, do effect the wines, as they expose the wine to oxygen in large amounts fairly aggressively.

What Happens When A Wine Breathes?

Allowing every bottle of wine to breathe is simply pomp and circumstance, but it is often done with good intentions. As this procedure is so often applied to red, white, young or old wines across the board, it is often done for show to add flair to a meal or anticipation to a wine. Wine is made through fermentation, which is a complex reaction of yeast converting sugar into alcohol and carbon dioxide with a whole chain of reactions from the multiple compounds in the wine. When the wine is opened and fresh oxygen is introduced, all of those compounds react to the arrival of the new element. Exposing wine to oxygen when you are serving it and getting ready to drink it, does two things; it causes the alcohol in the wine to evaporate (albeit in very small quantities), and it triggers continued oxidation. The oxidation that occurs in a young, bold or unbalanced wine over the course of breathing for 20-30 minutes, begins to soften the highly volatile compounds in wine such as sulfites or ethanol. If you’ve ever opened and poured a wine that had a sharp aroma of rubbing alcohol or smelled of rotten eggs and thought the wine was bad, and then tried it again to not find those aromas and thought you’d imagined it, congratulations, you’ve successfully breathed a wine. This same effect can backfire on wines that are not structurally unbalanced or that are hanging on by a volatile thread, so to speak.

When Wine Breathing Works & When It Doesn’t

Breathing also works well in young, unbalanced wines that have high tannin levels, as breathing will soften the tannins, allowing other characteristics of the wine to be expressed. While you want to soften tannins in an unbalanced wine, it’s tricky, as too much oxygen for too long will oxidize the wine and it will begin to turn into a sour vinegar. The same is true with many aged wines, except it doesn’t take hours or days. Wines can age in the bottle for decades when stored correctly, however, depending on the wine, breathing it for too long can result in the wine going dead. While the structure of some wines can withstand the oxygen in the wine and in the bottle, many aged wines are too fragile to be able to maintain their structure with the introduction of new oxygen and can turn flat in minutes. Wines that are over multiple decades old have already started oxidizing with their faded colors and mellow aromas and flavors, and the introduction of oxygen through aeration or decanting is simply too much. Aged fortified wines, such as port, are often allowed to breath, with great results, but remember, that ports are fortified with distilled alcohol, so structurally, the compounds are more stable and can interact with oxygen without breaking down and the wine going dead.

Wines that are considered light or delicate in flavor profiles such as white, rose or sparkling wines are often not breathed at all, as the introduction of oxygen would flatten the already softer flavors and reduce carbonation in sparkling wines. Bold young reds that are between 6 and 8 years can breathe for up to an hour, decanted or gently aerated, while older reds can be aerated when served or decanted and allowed to breath for 20-30 minutes.