Wine tasting and sensory perception

The aroma wheel, originally designed by Professor Ann C Nobel of the University of California, Davis County, an indispensable tool in identifying and describing the aromas and flavours we encounter in wine.

A beautiful package arrived the other day by courier, a stylish wooden box from De Grendel Wine Estate, perched on the slopes of the Tygerberg Hills.

It is the kind box that, once you’ve consumed the contents, you’re inclined to keep as a storage receptacle for something rather special.

It was large, but not heavy enough, to contain two bottles of wine, so the opening was compelled by the need to satisfy curiosity.

Aside from the wine, a bottle of Charles Hopkins’ 2015 Amandelboord Pinotage, the other side of the box contained four little grey corked bottles of spices: cloves, fennel, Chinese five spice, and cardamom. Intrigued, I scratched through the box for the de rigueur literature, expecting a recipe, using the provided spices, which is deemed to perfectly complement the wine. Nothing.

It was only when I found the electronic version in my inbox, and read the tasting note, that the penny dropped. These four spices are the aromas that ought to be discernible in the wine.

I was reminded of a visit some years ago, to the tourism office in Worcester, where I encountered a sensorium, an array of cork-closed receptacles which contained substances which exude the aromas most commonly discernible in wine, both red and white. You could take a sniff of such smells as cassis, pepper, cinnamon, strawberry, and a whole lot more.

I spent a fascinating hour working my way through them. In some instances the smell the label told me to expect was quite familiar, in others, less so.

Reflecting upon that experience, I recalled a Moët et Chandon tasting I recently attended at The One and Only, guided by Moët chef du cave, Benoit Gouez. We tasted his Impérial NV Brut, Rosé Impérial NV, Grande Vintage 2006 and Nectar Impérial NV, and in the course of the discussion about the bubblies, he said “and you will smell whatever fruit you smell,” encapsulating in a phrase, the enigma in wine appreciation.

In an ideal world, we’d be able to describe with complete accuracy all aromas and flavours which present in each and every wine we drink. Trouble is, that capacity is dependent on two things, olfactory capacity, and olfactory memory.

Olfactory capacity, or palate, is the combined human tasting facilities in the mouth and nose. Whereas we can discern only five flavours – sweet, sour, bitter, salt, umami (savoury) – the nose can discern around one trillion different odours, according to a 2014 research study by neurobiologist Leslie Vosshall of Rockefeller University in New York City.

The paper does point out, that the chances of there actually being that many odours out there to discriminate are slim – the research study was conducted by making up complex odours out of different combinations of individual odour components, getting the subjects to discriminate, and then extrapolating the final number of discernible odours.

We also know that taste is dependent upon smell – try discerning flavours in a sip of wine, while holding your nose, and you’ll see what I mean.

There are literally hundreds of different odours or aromas discernible in wine, but not everybody is likely to discern the same set of aromas with the same intensity, because of palate differences.

Palate differences exist for a variety of reasons, including age, whether or not you smoke, medication you might be on, the frequency with which you taste wine and consciously discriminate aromas and flavours, and the simple fact that we are not all created equal, so our palates will differ.

Add to that, the fact that most of us suffer from a measure of taste “blindness” which precludes us from discerning one and possibly more, of the known five flavours. This emerged from research by sensory scientist Dr Hildegarde Heymann – a South African expatriate, who runs the sensory research unit at the Robert Mondavi Institute for Wine and Food Science at the University of California, Davis County. “If you’re bitter-blind, for example,” she told me during a visit there in November 2012, “and the wine you’re tasting has a bitter note, you will not be able to pick it up.” She runs an immensely popular course at the institute, “Sensory Evaluation of Wines” during which such palate peculiarities can be identified.

The other important – arguably the most important – dimension in wine appreciation is what I call olfactory memory: your ability to recognise and name aromas and flavours that occur in wine, and to accurately describe them.

Watching a neophyte wine taster struggle with the apparent contradiction of smelling in a wine, dried peaches, or petrichor – the smell of rain on warm, dry earth – but recognising the smell when it is pointed out them, puts this in perceptive.

That we can smell dried peaches, for example, in wine is no contradiction, because the individual odour components that make up the smell, occur in peaches as well as in wine. It’s as simple as that. Delve into the science of aroma synthesis, and you’ll see that it is possible to synthesise virtually any smell in a laboratory, without directly using what it is you’re synthesising.

You build olfactory memory by constantly calibrating your palate, and using a wine aroma wheel, developed by Dr Heymann’s colleague, Professor Ann C Noble, in 1984.

It is a laminated plastic circle, which breaks down wines into 12 broad categories (floral, spicy, etc.) at the centre, then moving outward to the edge of the disk, subdivides those categories into more specific aromas (orange blossom, anise, etc.), and it will theoretically equip you with a better vocabulary to describe various aromas and flavours in wine. And remember that practice makes perfect. Taste wine consciously, as widely, and as often as you can.

And yes, the four spices did emerge in Charles Hopkins’ 2015 De Grendel Amandelboord Pinotage, along with dark fruit aromas, and a delicate mocha undertone. But hey, that’s just my palate talking.