Assessing a Wine by Smell
We may think that we drink liquids and eat solids, but in fact we digest liquids and taste gases. It is only the action of saliva on solid foods that makes them digestible by turning them into liquids – and all we can do to ‘taste’ those liquids is to monitor them for the basics such as sweetness and acidity on our tongues.
To get to grips with the flavour of anything, we have to use our hypersensitive, and rather nasty sounding, olfactory receptors which are located at the top of the nose. These react not to liquid but to theor vapour that any substance gives off, and send complex messages about the make-up of that vapour to the brain. The vapour is made up of all the tiny volatile elements that spring up into the atmosphere from the surface of a substance and is known as its ‘smell’. Some substances give off more smell than others. Glass is not smelly at all (which is why it is such a good material from which to taste wine), while flowers, for instance, are very volatile and give off lots of vapour into the atmosphere.
Wine and most foods are very volatile, with lots of vapour sending intricate messages to the brain via the olfactory receptors. As we have seen, the mouth can only relay much cruder messages than these. In fact what we think of as a food’s or drink’s ‘smell’ is actually what most of us call its ‘taste’. ‘Flavour’ is perhaps a less confusing word for the mix of tiny volatile elements that go to make up each wine’s individual character.
The vapour can reach the olfactory receptors by two possible routes: either straight up the nose or from the back of the mouth up what is known as the ‘retro-nasal passage’. This is why even if you have never consciously snifted a glass of wine, you will have had some inkling of the different flavours. Some of the vapour will naturally rise up the retro-nasal passage from each mouthful. Far more efficient as a way of enjoying the flavour of a wine, however, is to make sure your nose has a good sniff of it before taking any of it in your mouth.
All of this takes a fair time to explain, but takes no time at all to put into practice. To maximize the amount of vapour released by the wine, it is a good idea to maximize the surface area of it in contact with air. You can do this by gently swirling the wine around in the glass before taking a short, concentrated sniff just over the glass. There is no need for a very deep breath. All that is needed is to channel the vapour given offup the nose to the olfactory receptors, not to suck it down into the lungs. A moment’s concentration on what messages this vapour has sent to the brain will be rewarded with one of the greatest pleasures that wine is capable of giving.