Wine 101: Decanting

Why do we decant wine? Modern winemaking, after all, would seem to remove the need for the age-old practice. But there are several reasons to decant wines: to remove sediment, to allow young reds to breathe, and to raise the temperature of the wine. (And, of course, because you have a beautiful decanter and it looks really cool.)

While modern winemaking techniques often reduce the need for removing sediment, it’s still sometimes necessary. As wine matures, particularly when it reaches 10 or more years of age, there is a greater possibility that solid particles will form and settle along the side of the horizontally stored bottle. But even young reds may have sediment, most often due to not being filtered or fined.

The process of decanting is relatively simple. You want to remove the clear wine from the bottle without stirring up the solid particles. Two pieces of equipment are required. Obviously, a decanter or carafe in which to pour the wine, and some form of light source, traditionally a candle. To remove the wine but not the sediment, carefully hold the bottle horizontally (this avoids disturbing the sediment) to pour the wine into the receptacle. While you’re pouring, look through the neck of the bottle with the light behind it. As you slowly transfer the wine, you will see the sediment gradually move from the side or bottom of the bottle to the opening. When you determine that you have removed as much clear wine as possible without allowing the solids to exit, the process is complete.

The other reason for decanting is to aerate young and generally tannic reds. Aeration is a quick method of mimicking the aging process; allowing the wine to breathe will oxidize the tannins and give the wine a mellow, softer character. You will often see wine bottles opened ahead of time to allow the wine to breathe, but removing the cork only exposes the small surface area of the wine in the neck of the bottle to the air. Pouring the wine into a decanter increases the surface area exposed to oxygen.

I questioned how much this changed the wine, so I devised an experiment to examine how breathing changed the character of wine. I had three bottles each of four different Cabernet Sauvignons selected for a wine tasting at 7 p.m. They were all young, current vintage Napa reds. The first four were opened at noon. At 7 p.m., the second four were opened. The remaining four were also opened at 7 p.m. and immediately poured into decanters. The wines were then served in four flights. Each group contained three of the same wine with the only difference being when and how they were opened.

At the end of the tasting, the results were consistent: The wines opened at noon had no perceptible difference from the wines opened at 7 p.m. In all four flights, the wine in the decanter opened at 7 p.m. was noticeably softer and more aromatic. Conclusion: Wine does not breathe in the bottle. Since wine poured into a glass or decanter has much more oxygen available, you should always pour a newly opened young wine (less than 10 years) to get it breathing. (If opening an older wine, however, do not allow the wine to sit for any length of time since breathing will only diminish the character of its maturity.)

But reds aren’t the only wines that benefit from decanting. The first time I went to Martini House in Napa Valley, one of my favorite restaurants and always a stop when I am visiting wine country, white wines were served in carafes to take the chill off the wine. When served too cold, the flavors of a white wine are restrained; decanting allows the cold white to release its aroma at the higher temperature.

Another occasion in which a white wine benefits from decanting is if the wine is producing tartrate crystals. Most whites are cold-stabilized, meaning that, prior to bottling, the wine is chilled in a stainless steel tank to a temperature below freezing. The cold causes potassium bitartrate crystals to form and settle to the bottom of the tank. With modern winemaking, the clear white wine is then bottled and the crystals (sometimes called “wine diamonds”) remain in the tank. If a white is not cold-stabilized, those crystals will form in the bottle when the wine is chilled, creating solid, harmless, tasteless particles. These particles are heavy and will probably only come out with the very last glass poured. Sounds distasteful, but they are actually an indication that the wine was not overly manipulated or processed. Europeans don’t seem to mind their presence, but Americans tend to want pristine, clear wines.

So don’t be afraid of decanting. It enhances young wines, cleans up old wines and looks really nice on your table.

Certified sommelier Glenn Bardgett has overseen Annie Gunn’s award-winning wine list for the last seven years.