The Art and Science of Decanting
Why decant wine? A lot of people think its sole purpose is to artfully separate the wine from any sediment that may have formed.
But there is also another reason to decant wine and this is to do with science.
And that is that decanting wine allows smelly trace components, known as thiols, to oxidize to form compounds (disulfides), which have an aroma that is much more difficult for humans to detect. These thiols will be removed or destroyed by the oxidation process after being exposed for one hour.
In 2012, a team at the Shenyang School of Pharmacy embarked on a study to investigate how decanting changed the chemical composition of a red wine.
The scientists discovered that the concentration of organic acids (which play a major role in sour flavours) and polyphenols (including tannins) decreased after decanting, which explains its mellowing effect.
Room temperature and light intensity also played a role in the decanting process, they found. Higher temperatures could lessen the sour-tasting acids, and when warmer conditions were combined with increased light intensity, the effect was to "accelerate the changes of polyphenols in red wine in decanting." So, if you are short on time and want to soften your red, put the decanter next to the fire and turn on all your lights!
However, the Shenyang researchers also revealed a drawback to decanting red wine: its antioxidant properties appeared to decrease after decanting. "Therefore, in view of the health-promoting properties of red wine intake, decanting was not suggested," the study concluded!!!!
Recently there’s been talk of “Hyper-decanting” using a kitchen blender. This process was championed by Nathan Myhrvold, among other things, a former chief technology officer at Microsoft .
Instead of waiting an hour or more for wine to breathe in a decanter, he advocates opening a (young) wine and blending it on high in a kitchen blender for 60 seconds. Sparky Marquis of Mollydooker has also advocated pouring off a glass of wine, putting the cap back on, and then shaking the bottle. Both methods leave a lot of wine experts as agitated as the wine.
Decanting devices can only accelerate the speed of the oxygen introduced to the wine. Once the air is present you then have to wait for chemical reactions to occur. These thiols take an hour to be destroyed by the oxidation process and the use of a blender won’t speed up this end game. Instead it is likely to bruise the wine. Try at your own peril.
There is also another type of decanting called “Bordeaux decanting”. This is where the wine is decanted to remove the sediment from the bottle, then the wine is returned to the original bottle, sans the sediment. This type of decanting is widely practiced when the amount of wine being poured exceeds the number of decanters available.
The principles of choosing glassware also apply to decanters. A clear, crystal decanter allows you to see the wine at its best; overly decorated or coloured decanters obscure the wine. Make sure that your decanter is spotless and free from any musty cupboard aromas. Rinse it with mineral water to remove any residual chlorine odour. And never clean your decanter with detergent, because the shape of a decanter makes it very difficult to get the soapy residue out. Instead, use a mixture of crushed ice and coarse salt -- they'll remove any residual wine without leaving behind any aroma of their own.
Now that we've done with the science, its time to revert back to the art of decanting. In order to decant wine, perform the following steps.
- Set the bottle upright for 24 hours or more before drinking, so the sediment can slide to the bottom of the bottle, making it easier to separate.
- Locate a decanter or other clean, clear vessel from which the wine can easily be poured into glasses.
- Remove the capsule and cork. Note that old wines often have a very long cork to make the wine last longer. Because of this, it’s important to make sure that your cork screw is fully inserted in the cork. Old corks are very delicate and will crumble easily; work slowly to remove them.
- Wipe the bottleneck clean.
- Some people like to hold a light or candle under the neck of the bottle so they can see the sediment before it is poured into the decanter.
- Pour the wine into the decanter slowly and steadily, without stopping; when you get to the bottom half of the bottle, pour even more slowly. If it’s a screw cap and therefore has no sediment then you can pour much quicker.
- Stop as soon as you see the sediment reach the neck of the bottle. Sediment isn’t always chunky and obvious; stop if the wine’s color becomes cloudy or if you see what looks like specks of dust in the neck. Alternatively place a wine strainer over the decanter and pour the wine through the strainer. The strainer should trap most of the sediment.
- The shape of a decanter exposes a larger surface area of the wine to oxygen. Swirl the wine around the decanter to exaggerate this effect.
- Wait at least one hour to allow the thiols to be removed or destroyed by the oxidation process.
- The wine is now ready to serve. Discard the remaining ounce or two of sediment-filled liquid in the bottle – goes well in a gravy.
And there you have it – I hope you understand a lot more about decanting now. Have a go with your next bottle and see what you think.