Before we get into what a decanter is used for, we’ll start with a definition for this handy item. A decanter is simply a vessel (typically made of glass or crystal) that is meant to be used during wine service. There are two primary reasons one might do this – to remove sediment, or to aerate. Let’s take a closer look at each of these.
Removing sediment is the traditional reason to decant. Sediment forms when phenolic compounds like color and tannins join together and precipitate out of the wine. It is rarely found in white wines, which not only have fewer of such compounds but are typically fined and/or filtered for clarity. You also won’t often notice sediment in young reds. But take a close look at a dark, aged red wine in its bottle (hold it up to a light source) and you very likely will spot the telltale smudge of sediment on whatever side it was resting on. Now, sediment is not harmful, but it is gritty and not much fun when you get a mouthful of it.
This is how you decant. Assuming the bottle has been properly stored on its side, retrieve it a day or two in advance and stand it upright. This allows the sediment to gradually sink to the bottom. When the time comes, open the bottle carefully. Pour slowly into your decanter. Traditional sommelier service calls for a candle beneath the bottle for prime visibility, but any light source will do. When the bottle is about 75% empty you’ll want to slow the pour even more, because very soon the sediment will appear. Stop pouring just before the grit ends up in the decanter. All that’s left is to serve and enjoy!
The next reason is to aerate wine. While a decanter can be and often is used for this purpose, this technically is not decanting per se. The process is properly called aeration, and it can be accomplished with any suitable vessel like a pitcher, carafe, etc. The idea here is simply to expose your wine to oxygen, which happens as you pour and then more so as the wine rests in the decanter. Why do this? Oxygen contact helps a newly-opened wine “wake up,” if you will. As the wine’s volatile compounds (many of which are responsible for aromas and flavors) interact with oxygen, they become more apparent to our senses. This process is often referred to as “opening up” the wine.
A great many wines benefit from aeration. It’s a good idea for almost any red, and for young, tannic wines like Cabernet Sauvignon, Petite Sirah and Nebbiolo it should almost be mandatory. 30-60 minutes is a solid guideline, and in some cases even more time is called for. Even many whites respond well to brief aeration, especially full-bodied varietals like Chardonnay, Semillon and Rhone whites like Viognier, Marsanne and Roussanne. However, there are some bottles you should not aerate. Older and/or more delicate reds can degrade quickly if exposed to too much oxygen. Be cautious, therefore, with old bottles of Pinot Noir, Chianti Classico and Rioja. Consider this factor when removing sediment as well.
There is one final aspect to using decanters that moves us from utilitarian reasons to an aesthetic one. They look great on the table! Many different decanter styles are available, with some of them quite complex and beautiful. Such choices of course are up to you. We simply recommend two things. That you ensure – assuming you’re using it for aeration – there is plenty of room for contact between wine and air, and that you actually use it.