The importance of aroma

The importance of aroma

by Jozef Youssef 27 August 2015

In the third of our articles on multi-sensory dining, Jozef Youssef explains how it is aroma not taste that plays the largest role in flavour perception.

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Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating.

Jozef Youssef founded the collaborative gastronomic project, Kitchen Theory, to explore the multi-sensory elements of eating.

For those following this series of articles on ‘multisensory gastronomy’, ‘neurogastronomy’ or ‘gastrophysics’ (a term coined by Professor Charles Spence of Oxford University’s Crossmodal Laboratory), I hope you have begun to develop a much broader understanding of how we as humans not only perceive flavour but also how we appreciate and relate to food. We have looked at the importance of the visual aspects of plating and how this can potentially impact our enjoyment of a meal as well as the importance of sound and how it can affect our dining experience. So now let’s look at something we are all a lot more used to associating with the enjoyment of food – aroma.

What could be better than coming home to the smell of your favourite dish cooking on the stove or in the oven? For me, this would have to be the scent of plain white basmati rice. I can’t specifically say this is related to nostalgia or childhood memories, it’s just an aroma that gets my gastric juices flowing and opens up my appetite, something I believe most readers will be able to relate to with their own food of choice. But is that where it begins and ends? Is the aroma of a food just there for a bit of pre-mastication titillation? The answer is an emphatic ‘no’!


Taste vs. flavour

Scientists estimate that up to 90% of what we perceive as flavour is actually derived from our sense of smell.

We often use the expression ‘I can’t taste a thing’ when we have a cold; this one short phrase says a lot about our perception of flavour and the fact that we credit our mouth with all the glory. But even when one looks at a traditional definition of flavour (by traditional I am excluding contributing factors such as sight, texture, sound, perception etc.) we find that it is not only comprised of our sense of taste (which is centralised in the mouth and throat) but also our sense of smell (olfactory system). Only when these two senses are working together can we perceive flavours. The question now is whether one is more important that the other.

Scientists estimate that up to 90% of what we perceive as flavour is actually derived from our sense of smell. That may seem like a disproportionate amount but let’s put it in context: when you have a blocked nose on account of hay fever or a cold, foods tend to lose their flavour, although we say we can’t ‘taste’ our food, we can in fact taste saltiness, sweetness, sourness etc. It is, in fact, our lack of ability to detect aromas which renders the food so bland. In my previous article, I talked about the poor flavour of airplane food which is mostly caused by our sinuses becoming dry which inhibits our ability to detect aromas which in turn leads to us feeling that the food is lacking in flavour.

To illustrate this point, Professor Barry Smith (founder of the Centre for the Study of the Senses) has devised a simple test: put a random selection of jelly beans into a jar, close your eyes (so as not to be alerted by the colour cues) and pinch your nose tight so there is no air getting in or out, then pop a jelly bean into your mouth and begin to chew. Most likely you will detect sweetness and perhaps acidity, but can you tell what flavour the bean is? Before swallowing, release your nose, take a breath and all of a sudden the flavour comes rushing in.


Your tongue can detect a handful of tastes: sweet, sour, salty, bitter, umami, oleogustus (fatty) and metallic along with a few other prospects. Our olfactory system, on the other hand, is capable of detecting up to 1 trillion distinct aromas, hence we can perceive differences in flavour between, say, an orange and a tangerine which ‘taste’ pretty similar – sweet, slightly sour and perhaps even slightly bitter – because of differences in the aromas.

Orthonasal vs. retronasal smell perception

That pungent French cheese you love may not smell so great on the board but once it is in your mouth the flavour (which is up to 90% aroma) is wonderful.

What’s even more interesting is that we have two ways of perceiving aromas called orthonasal smell perception (when we detect external aromas) and retronasal smell perception which occurs during food ingestion as volatile molecules released from food are pumped by movements of the mouth from the back of the oral cavity up through the back of the nose. How do these differ from one another? Well as soon as food hits your palate, saliva does its bit to alter the chemical structure of the molecules which results in a different aroma being perceived retronasally. Hence that pungent French cheese you love may not smell so great on the board but once it is in your mouth the flavour (which is up to 90% aroma) is wonderful.

Given that aroma is so vital to flavour, during our multi-sensory dinners, we focus on making sure that guests actively trigger their sense of smell just before or during the eating of a dish by adding external aroma elements which encourage them to start actively detecting a particular aroma which matches with or is part of the dish. So finally, I’d like to discuss a couple of ways in which we at Kitchen Theory use this knowledge when designing our dishes and hopefully this will inspire you to create your own sensory gastronomic masterpieces at home.

Kitchen Theory at home

  • At Kitchen Theory, we have devised a dish entitled ‘Marrinetti’s Cubist Vegetable Patch’ – an homage to Filippo Tommaso Marinetti’s Futurist Cookbook written around the turn of the last century. Marrinetti was keen on using, among other things, external scents as a way of enhancing dishes. We designed a dish which incorporates several ingredients, three of which were tarragon, smoked bacon and pomegranate. As the guests ate this dish, each of these ingredients’ aromas were sprayed in the dining room using atomisers, in a specific sequence in order to heighten the guests’ flavour perception of these ingredients throughout the course of the dish.

  • Another example is when we sprayed the scent of wet earth (think of that moss-like smell in the forest after it has just rained) over the guests’ table just as they were about to eat a dish entitled ‘A Taste of The Earth’ – a leek consommé with leek ash, goat’s cheese and gold cress.

  • Another way in which we highlighted the aroma element was when we smoked our sweetcorn risotto with guinea fowl and cured miso egg yolk. Once the dish was plated, we simply slipped it into a clear food-safe plastic bag and pumped the bag full of smoke from old whisky cask shavings. The ingredients themselves were only briefly smoked within the bag during the time it took for the dish to be carried from the kitchen to the guests’ table. The bag was then cut open in front of the guests using a scalpel, releasing this wonderful plume of smoke, the aroma filling the air and lending a beautiful smoked aroma to the dish.

  • Showmanship is a big element when it comes to playing with external aromas, just think of the traditional waiter dramatically lifting the cloche off a dish and releasing a spectacular burst of aroma in front of the guest. Is what we do so different? It’s just a slightly more modern take on this old school bit of showmanship! Dry ice is a great way of both conveying aromas as well as adding to the spectacle of a dish. We have used this as a method of heightening the aroma sensation with several dishes, examples of which include the aroma of the sea served with a marinated crayfish, seaweed and green bean dish and a matcha tea aroma ‘cloud’ which we served with a sake, aloe vera and tapioca cocktail (created by Chef Helder Gila Alonso).

So here you have inspiring, practical ways of enhancing the scent element of dishes. Do try them out – not only will the food taste better but your guests will definitely get a kick out of the interactivity of atomisers or spectacle of dry ice smoke clouds!