The Long Read: “I smell red”

by blog on May 26, 2021

Check out or previous Long Read, ‘I See Red’!

Smell, or olfaction to give its scientific appellation, is so important when we are talking about associations, memories and epiphanies.

Smell is often our first response to stimuli.  It seems to invade our consciousness unawares. It alerts us to danger before we see it. It warns us before we taste something unpleasant and potentially toxic. Although smell is a primal sense, it’s also hugely significant in modern neurological research. Scientists are still exploring how we pick up molecules of odour, process them and interpret them as smells. Smell has become an industry. Perfumiers create olfactory compositions with the very intention of conjuring moods and associations.

Smell, like taste, is a chemical sense detected by sensory cells called chemoreceptors. When an odour stimulates the receptors in the nose that detect smell, they send electrical impulses to the brain. The brain then interprets patterns in electrical activity as specific odours and olfactory sensation becomes perception — something we can recognize as smell.

Olfactory receptor cells are located in a mucous membrane at the top of the nose. Small hair-like extensions from these receptors serve as the sites for odour molecules dissolved in the mucus to interact with chemical receptors located on these extensions. Once an odour molecule has bound a given receptor, chemical changes within the cell result in signals being sent to the olfactory bulb: a bulbous structure at the tip of the frontal lobe where the olfactory nerves begin. From the olfactory bulb, information is sent to regions of the limbic system and to the primary olfactory cortex, which is located very near the gustatory cortex.

The olfactory bulb in the brain, which sorts sensation into perception, is part of the limbic system that includes the amygdala and hippocampus, structures vital in determining our behaviour, mood and memory. This link to brain’s emotional centre makes smell a fascinating frontier in neuroscience and behavioural science.  We will return to this later.

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Smell begins when airborne molecules – of wine in this instance – stimulate our olfactory receptor cells. If a substance is somewhat volatile, it will naturally give off molecules, or odours, more rapidly. That volatility is also dependent on temperature – of the liquid, of the glass, and the ambient air temperature.

How does the brain recognize, categorize and memorise the huge variety of odours? In 1991, Richard Axel and Linda Buck published a paper that shed light on olfactory receptors and how the brain interprets smell. Axel and Buck discovered a large family of genes – around 1,000, or 3 percent of the human total — that coded for olfactory receptor types. They found that every olfactory receptor cell has only one type of receptor. Each receptor type can detect a small number of related molecules and responds to some with greater intensity than others. Essentially, the researchers discovered that receptor cells are extremely specialized to particular odours.

Axel and Buck also found that each receptor type sends its electrical impulse to a particular microregion of the olfactory bulb. The microregion, or glomerulus, that receives the information then passes it on to other parts of the brain. The brain interprets the “odorant patterns” produced by activity in the different glomeruli as smell. There are 2,000 glomeruli in the olfactory bulb — twice as many microregions as receptor cells — allowing us to perceive a multitude of smells.

However these receptors respond to odours, the question remains: how do smells trigger memory and how does cognition actually influence perception? A single smell can instigate powerful responses and influence the mood of an individual, because, as said previously, the olfactory bulb is part of the brain’s limbic system, an area so closely associated with memory and feeling it’s sometimes known as the “emotional brain.”

The olfactory bulb has intimate access to the amygdala, which processes emotion, and the hippocampus, which is responsible for associative learning. Despite the tight wiring, however, smells would not trigger memories if it weren’t for conditioned responses. When you first smell a new aroma, you may link it to an event that has occurred in your life, to a particular person, an image, or a moment from the past. Your brain spontaneously forges a link between the smell and a memory. When you encounter the smell again, the link is already established, ready to elicit a memory or a mood. It is like walking on a path through a forest; the more you walk on it, the clearer the route becomes.

“I raised to my lips a spoonful of the cake . . . a shudder ran through my whole body and I stopped, intent upon the extraordinary changes that were taking place.” (Marcel Proust ~ A La Recherche du Temps Perdu)

A friend of mine recalls the first time she picked a ripe mango from a tree in South Africa and bit into it. Now, because of that memorial imprinting, the smell of mango (real mango or mango aromatics in a wine) evokes a mood of happiness and delight, as it taps into those carefree emotions she experienced when she first bit into one.

The salty smell of a westerly sea breeze may conjure spending time on a specific holiday on a beach, or simply make you feel content as you were in a happy place at the time. A different smell which is associated with an unhappy memory might agitate you without your knowing why. This is part of the reason why not everyone responds to or likes the same smells.

And because we encounter most new odours in our youth, smells often evoke childhood memories and the first time we experienced particular primal sensations, or were aware of them.

Wine is encountered in a glass that normally assists in aromatising its contents. The wine itself is composed of a variety of volatile chemical and microbiological compounds that evaporate at different temperatures and may be perceived at different moments. It is possible, with practice, to detach these aromatic compounds from one another. Wine tasting courses instruct one on how to smell wine in order to interpret the information given by primary and secondary aromatics. From the moment we receive the smells, our brains begin the complex tasks of processing reception into perception.

There are several approaches to smelling (and tasting). One is not to force it and to let the aromas come to you at their own speed. Another involves short sharp sniffs. A further approach is to deploy your nostrils like merciless magnifiers with deep inhalations, although this Dyson vacuum cleaner school of smelling invariably leads to a state called adaptation whereby the sheer focus on one particular smell renders one unable to discern other subtler aromas. The nose becomes exhausted, in effect.

Just as when we are using other senses to make our determinations, our intention at the outset of the process is important. If the wine is merely the means to an end (for example, we are really only interested in drinking it to get intoxicated) then one may not even twitch one’s nostrils at it, or, at most, give it the most cursory sniff to see if it might be corked or exhibit some other obvious fault. The filter comes into play, so to speak. If, however, our intention is to assess the wine thoroughly, then we may cultivate a more disciplined frame of mind in order to attend to every nuance of every aroma. The end of this focused approach is to place the smell of the wine into a category. This is based on what we remember being taught about smells; we use our learned experience to recognise patterns. Alternatively, by closing our eyes (as it were) and letting the smells wash over us, we can surrender to the wine’s aromas without the palaver of analysis. The context determines how we use our processing faculties. In a social environment we may smell without analysing and yet at the same time be more open to enjoyment. With that response comes the potential for epiphany, wherein the pleasure of shared experience and shared communication between two or more people, the excitement of experiencing the wine in company even, increases the intensity of the response.

Another impulse is the desire to receive smells, to push hard at being receptive, to place our needs before the wine. We want the wine to yield its message, we want to analyse, decode and define it. The harder you sniff, the less you get out of the wine. Smelling is more than sniffing, just as tasting is more than swallowing. To gain the most out of a wine, aromatically-speaking, you have to be sensitive to nuance and you have to take time.

“You know how to whistle, don’t you Steve? You just put your lips together, and blow.”

Those who are instructed on official wine courses in tasting procedure are given a precise vocabulary template and inculcated with a technique for smelling wine and recording one’s subsequent impressions. The analytical smell response involves discarding fanciful impressions and focusing on broad technical constructs, for example, discerning whether this a clean or an unclean smell, or if this is varietally correct – and so forth.  In this model approach, having established that it is clean and conforms to certain smell parameters, the next stage is to draw on our knowledge of scientific process to deduce how the wine is made, to put together all the pieces into one informed package.

Information derived from learning and previous experience will enable us to identify, for example, a sous-voile Jura wine by perception of the particular aromas of sotolon. A northern Rhone Syrah with its rotundone characteristic will activate that particular piece of information and prior experience. This additional information will be imprinted and added to the cache of memory. And whether or not we think of something as having rotundone or sotolon in those very words, then the more descriptive and everyday analogies of curry powder or cracked pepper may trigger the “image-word-smells”.

But which came first? You smell pepper and you think Syrah and that reinforces the sense of what you are smelling. Or you think Syrah, you have the expectation of smelling pepper, you find that smell, and then you close that associative circuit.

Whether it is down to the varietal characteristics, the yeasts, the by-products of fermentation or terroir, these smells become the certainties for us, and every time we encounter them, they also become a shorthand for the process whereby they are engendered. An aroma is not a two-dimensional construct either; particular characteristics sit within the wider context of the wine. A Chateau-Chalon from the Jura may reek of the sotolon character, but there may also be secondary and tertiary notes from slow oxidation and ageing in wood. All these different aromas are part of the smelling experience and that complexity leads to a more complex response. Our knowledge of a wine gives us the archetypes for the smell and taste of that wine (and expectation colours our taste, as I said before), but it does not describe the actuality of the smell and taste.

My sense of smell is not particularly acute. The pathways between my olfactory bulb and hippocampus are as furred up as a well-used London kettle. I know many individuals with a very keen sense of smell, who are instantly transported into colourful sensory realms with the merest whiff, and through association and memory are able to recall and describe the aroma of a particular occasion, such as when a peach was warming in the sun on a window sill, to the point of very tangibility.

Smell is a world in itself. Those who are highly sensitive will derive more actual and subliminal pleasure from wine. They will go on exotic journeys, perhaps, and surfing a sniff, revisit their childhood or a particular place and time with strong associations. It doesn’t have to be a pleasant association, perhaps, as the strength of the memory or the association is the important thing.

Mostly, I am not aware of what I am smelling other than in vague or broad terms. I register that there are aromas. They can be deep or complex or mysterious, but unless they are obvious (“woody”; “tarry”; “curry-powdery”) I am not delving into the memory stacks.  That lack of involvement means that I am missing something that could open up my mind.  My smell becomes more reactive when it is retronasal, that is when the wine is in the mouth, and aromas and textures are weaving an impressionistic web. Very occasionally, during an epiphany, when I am attuned to the experience of smelling and tasting, the clogged pathways clear and a poetic feeling is engendered.

Expectation also helps to clear certain neural pathways. If I open a Crozes-Hermitage from Dard & Ribo, my memory of this wine and my a priori knowledge of their wines in general and of Syrah, in particular, are pushing half-realised images of currants, kalamata olives, thyme and pepper into my surface consciousness. The sight of the label, the previous acquaintance with the work of the growers means that I am already looking for certain characteristics – I feel the smells somehow wrap around the existing images in my head because I have brought the association to the front of my mind, so to speak, and then I manufacture sensations out of them. The glossy olives and the thyme are particularly strong as I visualise images of marinated olives (say) and I process those impressions into actual words.

Habituation and surprise

Smell is normally our second encounter with the wine, the first being our visual perception of it. As mentioned, the act of visual perception serves initiate for the process of compartmentalisation. I see the colour red and different parts of my brain receive the “red” signal.  As I smell, I have the image of red already imprinted in my mind. I am conditioned to expect to smell aromas that I associate with the colour red. If the shade of red is light, then my brain is attuned to scope out red fruit notes. If the wine is purple, then purple fruits are the ones I am trying to describe, and if the wine is almost impenetrably dark, then the sensation of black fruits will be conjured. It is, of course, possible to detach what we smell from what we see, but cognitively it makes sense for us to put the pieces of the puzzles together.

Can I smell red? I can do, if I have a concept of what red is in terms of wine. Red is a primary colour in the spectrum, the colour of fruit. It can also be the concept of red. We know that every shade of every colour has powerful visual associations; equally that can be amplified if we receive a smell as an impression of a colour.

Epiphanies can be the shock of the new, or the perfect reinforcement of what has gone before, the reminder of a beautiful and deeply-felt experience, one which transports us to another place or another state.

The tapping into our subconscious world and the activation of memories and powerful emotions through smell can create the preconditions for an epiphany, wherein the smell effectively bridges present and past, or brings the feeling or sensation from the past to the present. Wine is one of many substances that has this capacity; it possesses complex aromas and as a thing in itself, it often compels us to focus or to open ourselves up to it, and in opening our minds allows us to rediscover a memory or recover something of ourselves.

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