My sister should have been a winemaker. Even beneath a new pillow slip, she could always smell which pillow was hers. And she refused to sleep on a pillow that had been slept on by anyone else in the family. Her sense of smell as a kid was legendary.
Ironically, I ended up making my living by being able to discern aromas particularly well, while my sister is a high-flying executive, living a rather glamorous life in New York – a place that either freezes your nose off in winter, or smells like a sewer in summer. Funny thing life!
In most vertebrates, the sense of smell resides in the front of the brain. In humans, however, our sense of smell is placed in a protected place on the underside of the brain, armor-plated by a bone called the cribriform plate. It’s as though our sense of smell was placed by design in the most protected part of the brain.
Amazingly, this boney plate is perforated by olfactory nerve axions – basically very tiny, but extremely sophisticated super highways of electrical activity which carry signals from the nose to this special inner-sanctum of our brain. Fascinatingly this is the only part of our brain that regenerates brain cells.
As a winemaker, one tends to develop a heightened sense of smell simply through doing the job – one is smelling and tasting critically for hours a day.
This hyper-sensitivity has its downside. Places and people smell, and some not very pleasantly. It gets to the point where one can smell if someone else has sipped from your glass, because the sweat pores around the mouth are the source of an unusually large amount of pheromones and aromas.
Our system of smell is an amazing arrangement, starting at the top of our nose with what we call olfactory receptors – which are, in a narrow sense, the nasal equivalent of taste buds. But they are so much more than this. These receptors cluster in the olfactory bulb which is a cavern of buzzing sensitivity at the the top of our nose.
This is the place where outside aromas hook up with the receptors. I guess its like a singles bar for loose aromas. The receptors latch onto aroma compounds passing through this upper part the nose – you need to sniff a little more deeply than normal breathing to get the scarce aromas in there. This smell information is then transmitted from the top of the nose to the inner-sanctum of the brain.
There are approximately ten million receptors in this top region of the nasal cavity. When one of these is activated a signal produces a nerve impulse – a sort of smelly twitch, which is transmitted in an instant through a complex set of impulses to the brain.
If you think that’s cool, the only other parts of the body that express odour receptors are sperm cells. These are thought to be involved in finding the egg cell. I bet you didn’t know that.
Although we humans have less sensitivity to smell than many other mammals, it is surprisingly easy to sharpen your sense of smell. A little bit of practise and your brain responds brilliantly. You soon realise you are training your brain, not your nose. This makes me believe smell played a much more important role in our development as a species. Obviously crucial to our survival, our sense of smell and taste must have at one stage been much, much sharper than they are now.
When I studied winemaking, we had a thing called Hell Tuesday – a full day in the Sensory Science Laboratory, training our sense of smell and taste. For the first three months of Hell Tuesday, we just tasted water, spiked with various combinations of sugar, acid, bitterness and astringency.
Thereafter, we were trained to detect different aromas and flavours. Perhaps the most important stuff was learning to detect wine faults. When you’re on the run during harvest you don’t have time to send a wine sample off to the laboratory in order to deduce what the problem is – your nose needs to be able to do that for you in an instant.
Perhaps the most fascinating thing about this whole smell business is that this receptor area also receives “top-down” information from other areas of the brain. This information helps us discriminate between odors, enhances our sensitivity to certain aromas and even filters out background odors.
This “intervention” by areas of the brain that are responsible for things like arousal and attention helps keep our smelling equipment focused on the information that’s going to benefit us more, at a particular time and in a particular situation. Our nose, it appears, is far more sophisticated than we think. Researchers have been fascinated by how we can filter incoming information so effectively and quickly, it’s almost as if our nose has a mind of its own.
While there is a difference between the ability of individuals to differentiate aromas, this difference is not as a great as one would expect. Far more interesting is the difference between the sensitivity individuals have to certain aromas. So while one’s ability to smell seems pretty equal, some people can differentiate certain aromas much easier than others.
We know our sense of smell is strongly connected to our memory. Specific smells (often made up from a combination of different aroma compounds) can take us back dozens of years to specific times, reminding us of places and people in incredible detail and with extremely accurate recall.
I worked with a winemaker in the Barossa Valley, Australia, who could detect most ingredients in a plate of food, just by sniffing it. He absolutely detested coriander and smelt everything suspiciously in case some dastardly chef had made the mistake of destroying his food with this ingredient. He would list the ingredients with successive sniffs.
“Garlic, fresh, not cooked. Cumin. Lime juice. Italian parsley… smells a bit old. Five spice,” All this, with his nose an inch from the plate.
It was always interesting to see how close he was to the actual ingredients.
So the next time you pick up a glass of wine and put it to your nose, concentrate a bit and listen silently to what your nose is telling your brain to tell you is in the glass.
Because wine is packed with hundreds of different aroma compounds in varying concentrations, you’ll always find something interesting in there. Hopefully the smells will make you want to have a sip. If they don’t, you’ve probably got a wine that has been spoiled by a contaminated cork. That’s why many winemakers prefer screw caps.
A regular wine disaster happens when wine is served in glasses that smell of the cupboard they have been stored in. If your wine smells of Granny’s ancient yellowwood cabinet, all you normally need to do is give it a rinse with fresh water. That usually gets rid of the most offending aromas.
That old expression, “Take time to smell the roses”, may be about slowing your hectic life down a bit, but it has a second meaning. If you slow down enough to listen to what your brain is detecting about your environment from your most sophisticated sense, you may start to see life very differently. I promise you will be a richer for it.