The chemistry of wine: Part 4 Drinking

Most of us have a friend or two who loves to spruik their wine knowledge. They take great joy in going through the theatrics of letting a wine breathe, selecting the right glass, swirling the wine around, inhaling a large whiff and then slurping in a mouthful before swishing it around in their mouth. Is there a point to all this, or is it just pretentiousness? Well, give your friend a break because each step in the process affects the flavour and experience of wine. And once again, it’s chemistry that’s coming in to play.

Decanting, aerating or letting a wine ‘breathe’ is common, but is it really necessary? Well, yes and no—it depends on the type and age of a wine. Decanting a wine or swishing it around in your glass (rather than just popping the cork and allowing the bottle to sit a while) allows it to take in more oxygen which can open up the aromas and flavours of the wine. Decanting can also benefit older wines, as it leaves the sediment in the bottle while the wine is poured into the new vessel. It’s usually the reds that benefit from this, though some whites can too.

Aerating a wine involves pouring the wine through a specially designed device, allowing air to mingle with it, which can help to soften the tannins of young or bold wines. These aerators can be used when you want to drink your wine without waiting.

As letting a wine breathe exposes it to more air, you can also see the wine change colour slightly over time as the oxidation continues.

If you’ve even been a bit bewildered by all those different shaped wine glasses, rest assured they’re not just for show. The type of glass you choose will affect the flavour of the wine, or at least, your experience of those flavours. Since flavours are actually mostly smells, the style of glass can help to concentrate the aromas and therefore enhance the experience.

So those big, wide glasses do a better job of increasing the surface area of the wine and giving aroma molecules a greater chance to diffuse into the air (and up your nose as you drink).

White wines tend to need less space to release their aromas which is why white wine glasses are smaller and narrower. The narrower glasses also help to reduce oxidation, keeping the wine brighter or lighter, a property often desirable in a crisp white.

Your friend’s sniffing, slurping and swishing around the mouth also helps to get the aroma molecules up the retronasal passage that connects your nose and throat so you can get the full flavour (‘smell by tasting’) of the wine.

And finally, is it true that reds should be served warm and whites chilled? Generally yes, but it’s easy to overdo it in the temperature stakes. Temperature is the measure of how fast molecules are moving. When they move faster, more of the aroma molecules can get up your nose more quickly. So, a warm red might be a bit overpowering and a white that is too cold might seem flavourless. Some good advice is to chill red wines for 15 mins before serving, and take the whites out of the fridge 15 mins before you’re ready to pour.

But really, it comes down to what you like. If you like your wines bold, warm, chilled or full of sediment, then that’s great. Just make sure you drink in moderation, and take a moment to enjoy that delicious mouthful of chemistry.