Decanting wine — a romantic notion or purely sedimentary

Do we really need to breathe or decant high quality wines to get the most enjoyment from them? For most wines, the answer is no. Breathing is almost never necessary and often detrimental. And the only practical reason for decanting is to separate clear wine from sediment in the bottle.

The idea of breathing wine almost certainly dates to a time when winemaking was more rustic than it is today. Without the rigorous controls of modern winemaking, many a bottle held traces of smelly aromas and flavours – principally sulphide compounds.

These are natural products of fermentation and because they are reductive – formed in the absence of air – the traditional method of elimination was by racking wine: moving it from one vessel to another in the presence of air. Winemakers still do this with red wines today.

Because racking doesn’t eliminate all sulphides, modern winemakers, where necessary, remove the traces by adding small amounts of copper sulphate, sometimes determining the need to do so by a simple triple-blind test.

This means taking a wine sample, pouring it to three identical glasses and adding a trace of copper sulphate to only one glass. Put the three unmarked glasses to a winemaker, and if one glass smells different from the other two, then sulphides are indicated and the wine is appropriately fined.

Interestingly, the advent of the screw cap in recent years forced winemakers to be doubly diligent in the search for sulphides. Because the cap is a far more effective barrier to air than cork, some of the earlier bottles showed signs of reduction.

That such a tiny ingress of air through cork kept sulphides below the human aroma threshold is a clear illustration of why breathing wine was once all the go: smelly wines could be cleaned up by a good splash from bottle to decanter – effectively a final racking.

So, unless we find a stinky bottle, there’s no need to aerate it. And if we do find one, give a good gurgle into a jug or just splash it around in a glass. Simply pulling the cork and leaving the bottle open won’t work because the surface of wine exposed to air is insignificant.

And what of the belief that exposure to air releases the aromas and flavours of sturdy young reds? Well, there’s not a lot of science to support the notion. Indeed, quite the reverse appears to be true as prolonged exposure to air disburses a wine’s positive attributes.

Modern winemaking, too, means that fewer wines throw a sediment or ‘crust’ and therefore the need for decanting is much less than it was.

Cold stabilisation means that white wines seldom lose excess tartaric acid prior to bottling. Hence, it’s rare, albeit not unknown, to see deposits of tartrate crystals in bottles or on corks as we once did.

Filtration prior to bottling also reduces sedimentation in most commercial red wines. However, many of our more robust wines still drop sediment as they age.

As this looks terrible in the glass and tastes gritty and bitter, it’s easily removed by decanting. Simply stand the bottle up twenty-four hours beforehand then, particularly in the case of very old wines, open and decant immediately prior to serving.

Fine crystal decanters certainly add a sense of occasion. But if you don’t have one, decant to any clean jug, wash the bottle, then tip the wine back in. Now, take a sip and breathe easy.

Copyright © Chris Shanahan 2006 & 2007

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