Our Sense of Smell

Our sense of smell is perhaps the most underrated of our five major means of perceiving the world. Most of us hardly ever pay it any heed at all until we come in contact with a foul, recoil-inducing stench or have a cold and the subsequent loss of our ability to smell takes all the fun out of everything we eat.

But think about it. You have a highly sensitive instrument attached to the front of your head composed of hundreds of uniquely sophisticated olfactory receptors – exposed neurons acting as chemoreceptors – that are so mind-bendingly advanced that you’d dismiss the possibility as science fiction were it not as plain as the nose on your face. That we can detect and isolate different molecules and pass corresponding electrical impulse messages on to the olfactory bulb in our brain is complicated enough. But our brains then interpret the impulse patterns and, if recognized as a match within our memory databases, can even prompt us to name the odor from more than 1 trillion different olfactory stimuli (smells) that are said to be discriminable by humans simply by coming into contact with a sufficient concentration. Just by breathing. How awesome is that? Sure, we have to lock-and-load the precise smells of all those molecules in our memories in order to name them. It takes practice, like learning the basic words of a foreign language and then building-up an understanding of the syntactical combinations – smell fluency, if you will - but it’s possible. People can and are trained to do to speak the language of smell. Perfumers for one. And wine dorks.

Wine is slightly unique from other beverages and foods for, amongst other attributes, its complexity of aromas. There are estimated to be more than 800 different aroma compounds in a glass of wine as opposed to say a banana, which has closer to 300. What’s more, a lot of the aromas in wine become volatile, in other words airborne and smell-able, at lower temperatures (generally best at room temperature or slightly below) than many other scents, which may need heating before they enter a gaseous state that can be detected by the nose. You could say that wine and your nose were made for one another.

The world’s best-known and respected wine critic, Robert Parker, famously insured his nose for a million dollars. And this makes perfect sense because he and other wine professionals rely so heavily on our natural ability to smell that we would lose our jobs if we lost our noses. Without a fully functioning olfactory system it would be impossible to recognize the triumphs and failings in a glass of wine. So embracing the greatness of your nose is a prerequisite to understanding the meaning of wine quality.

Hold on. We don’t drink wine through our noses, do we? Sure, not everyone knows all the hoity-toity ins-and-outs of wine quality but most folks know what they like. So a normal person just out for a good time doesn’t need to get their nose sniffing all over the glass to have fun with wine, right?

Well, let’s start by asking this: Why did humans evolve the ability to smell? On a basic level it’s obvious that, similar to our other senses, our nose helps us to survive. It helps us to detect danger, such as a gas leak or the smoke from a fire. Awful smells like the stench of rotten meat or the pungency of bleach are so off-putting we’d be out of our minds to want to consume these potential killers. But some foul smelling things are good to eat, like Munster cheese or durian fruit and some enticing aromas emanate from poisonous plants and flowers, such as arsenic, cyanide and hemlock. So it isn’t all about sorting the wholesome from the deadly.


Did you know that when we eat or drink something it is the sense of smell that largely accounts for the flavors we “taste”? As we inhale and exhale while drinking or eating we continue to smell via the oral cavity located at the back of the throat. This is known as “retronasal olfaction”. When retronasal smelling is combined with our sense of taste within the mouth, the result is very different from smelling or tasting alone; it is that combined sensation which we have come to understand as flavor. Because we can only actually recognize five basic tastes with our tongues, in fact most of the flavors we “taste” in this manner result from retronasal smell. Our brains tend to combine the effects of our two senses into one. So although we have come to know and value flavors as something that we “taste”, the real heroes here are our noses and our remarkable sense of smell!

The olfactory bulb that controls smell helps to make up our brain’s limbic system, an area which also includes the hippocampus and amygdala. This part of the brain is involved in the functioning of our memories, behavior and moods. So more than hearing, seeing, tasting or touching, our sense of smell is closely connected to our emotions.

It appears that smells are extremely susceptible to inducing conditioned responses because the brain has a tendency to build strong emotional connections between occasions, people, places and times with a smell. So the scent of Chanel No 5 might remind you of your mother and therefore make you feel safe or uneasy, depending on your relationship with your mother. A sniff of a burning coal might take you back to a fun childhood BBQ or a fire that terrified you. You may not even know why a smell can make you feel a certain way. Perhaps you hate cinnamon because it unconsciously reminds you of an unpleasant place or experience.

These conditioned responses render smell to be a powerful motivator. The invigorating scents of roasted coffee beans and freshly squeezed oranges wake us in the mornings. The lactic sweetness of a baby as we bend to kiss its head bonds us. The yeasty, toasty goodness of baking bread or the saline meatiness of bacon frying makes us salivate with hunger. The musky sweat of a lover arouses us. The clean, comforting scent of lavender relaxes us. The seductively rich smell of melting chocolate drives us nearly insane with a longing to satiate our choc addiction. Our nose draws us to sustenance, emotions and people. It not only feeds and protects us, smell connects us to our lives.

When it comes to savoring epicurean indulgences, our senses of smell and taste work hand in hand. To a certain extent it’s true that smell initially pulls us in and taste satisfies us. But smell is also a vital bolster for taste. Bottom line – and you know this - we can smell far more than we can taste. Our tongues can only taste sweetness, salty, bitter, acidity and, that newly discovered sensation, umami, with perhaps a few other moot stragglers like metals and fatty acids. The many flavors that think we can “taste” are in fact the combined effect of taste and smell in the mouth. Smelling strongly influences flavor largely through the function of “retronasal olfaction” - the detection of aromas while drinking or eating via the oral cavity located at the back of the throat. The brain combines the effects of the two senses into one, resulting in what wine tasters have come to recognize as flavor. Therefore, the basic five tastes tend to exist merely as a handful of clear-cut delineations, outlining our flavor experience like a pencil drawing before the input of aromas fill the picture with colors and vividly bring the painting towards something much closer to life.

Although our tongues may be quite limited in terms of taste receptors, we are easily fooled into thinking we can taste much more because we can smell through our mouths. Just by swishing and sloshing liquids or liquefied foods around your mouth and you’ll get a whole range of flavors that are in fact mostly scents. If you should travel to Asia sometime, go to a noodle bar and watch a Japanese person eating Ramen or a Vietnamese person eating pho. They slurp…a lot! Why? Because they know that the noodles taste better and of more when they slurp. Taking air in with the soup will better volatize the aromas so that when they hit the back of the mouth they can more easily and intensely be picked-up by olfactory receptors through the oral cavity connecting the nose to the top of the windpipe. This is a clear example of retronasal smell in common practice. For this reason, hard-core wine dorks will go so far as to slurp their wine, but even if you simply leave it in your mouth a few seconds before swallowing there can be a significant boost to the flavors you “taste”.

So go on, I dare you. Smell it. Apple juice, iced tea, beer, whisky, Cabernet Sauvignon or Batard-Montrachet – give it a sniff, a slurp and a swirl around your mouth.  I’m not saying you have to make a big song and dance out of it. Please don’t. All I’m suggesting is an imperceptible whiff of whatever’s in your glass before you drink it; suck a little air in with your sip and let the fluid linger languidly in your mouth briefly before you swallow. This little change will make a big difference. The foremost, easiest, cheapest thing you can do to get more from your glass or in fact from anything is simply to smell it.

More articles from this author