If you’ve been drinking wine for more than a day or two, you’ve probably heard that you should let wine breathe, or aerate. I’ve talked about it, wine shops talk about it, sommeliers talk about it…you get the picture. The question is, have you ever thought about why it’s necessary or what it actually does?

Oxygen and Wine: A Love-Hate Relationship

When you open a bottle of wine, you expose it to oxygen. You know it’s important to minimize the length of exposure so wine doesn’t go bad before you drink it and why the major preservation options either remove oxygen from the bottle or prevent it from reaching the wine in the first place.

Oxygen isn’t all bad, though. Wine needs oxygen to reach its full potential in terms of smell and taste. It’s a fine line, though- too much and they reach their peak and fade before you have a chance to drink them, too little and you only get a tiny hint of what they could be.

It’s All Chemistry

Oxygen’s effect on wine can be explained with chemistry. I know, I know- you didn’t pay attention in high school chemistry because you never thought you’d use it in “real life,” huh? Me, too. If only I could go back to 16 year old me and make her listen! Since we can’t go back in time, here’s a quick explanation of what you need to know right now.

Two major things happen when you open a bottle of wine. First, compounds in wine begin to evaporate. Some of these compounds are normally considered bad. The ethanol makes wine smell like rubbing alcohol, and a few minutes of breathing will help reduce that smell. Extra sulfites are often added to prevent oxidation and microbial activity, and these evaporate fairly quickly as well- a good thing because they tend to smell like rotten eggs. Other, more pleasant compounds also evaporate but tend to do so less quickly than the negative ones, giving you a space of time to enjoy your wine.

Oxidation is the second major result of exposing wine to oxygen. This process occurs with all kinds of food and beverages, some more noticeable than others. Apples and avocados are two things you’re likely familiar with. They both turn brown and their taste and textures change when they’ve been exposed to air for too long. The same thing happens to wine. When it’s exposed to air, the color of wine deepens from red to brown for red wine and from yellow to gold with white wine. The smell and taste also change. Tannins soften, fruit flavors become more noticeable and then fade. The wine can also develop nuttier or earthier flavors (the tertiary ones we mentioned in the wine tasting series).

The oxidation process typically occurs slowly, over a long period of time for wines that age in the bottle. The cork allows a small amount of air into the bottle to interact with the wine over time.

Aerate, Decant, or Give it a Good Swirl

As with most things in the wine world, everyone has an opinion on how much air a wine needs and how best to get it. There are those who think pouring wine from the bottle into a glass is all the oxygen any wine needs, while others will not drink wine that hasn’t been poured through an aerator, while still others prefer a nice, long decant. Since every palate is different, it’s important to decide for yourself how you like to handle your wine. In the interest of preventing overwhelm, though, I’ll give you a few widely accepted rules of thumb, most of which I follow for my own personal consumption.

  • White wines- For the most part, don’t worry about these. Since white wines don’t have tannins that need to soften and most are made to drink young, you can almost always have a great experience with a wine poured directly from the bottle to the glass. It will benefit from a good swirl right before you sniff or sip because that will open up the smells and flavors.
  • Low tannin red wines- Beaujolais, Pinot Noir, and other low tannin red wines typically do not need a long decant. A few minutes with the bottle open to let the ethanol evaporate and a good swirl in the glass is a good idea, but then feel free to drink. If you have one that you think is a little harsh when you first take a sip, leave the glass for a few minutes and try again.
  • High tannin red wines- It is almost always a good idea to give Malbecs, Tannats, and Cabernet Sauvignons time before drinking them unless they have been aged for a long period. Air will let the tannins relax and open up those scrumptious fruit notes. You have a few options here: let the wine sit in the bottle or glass for awhile (30 minutes to an hour is a good bet), pour the bottle into a decanter and let it sit for at least 15 minutes, or pour a glass through an aerator to drink right away.
  • Aged wines- Be very gentle with aged wines. They have already been exposed to oxygen through the cork, so they really don’t need much time to rest once they’ve been opened. However, they do often have sediment in the bottle, which isn’t harmful but also isn’t very pleasant to drink. Pouring the wine carefully into a decanter helps keep the sediment in the bottle.

Above all, don’t be afraid to experiment until you know your preferences. I know that can be frustrating sometimes, but it’s important to remember that wine tasting is a blend of art and science. That’s what makes it so exciting!