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The secrets of flavour lie in your nose

Scents of place

Flavour is inhaled not swallowed. Sybil Kapoor finds out how chefs are playing with our senses to make our meals more memorable

Flavour is inhaled not swallowed. Sybil Kapoor finds out how chefs are playing with our senses to make our meals more memorable

Sybil Kapoor | December/January 2019

I walk along the beach at Seasalter in Kent, watching the wind whip froth from the grey waves, and try to focus on the smellscape. The cold breeze carries the unmistakable scent of seaweed strewn along the muddy shoreline, then changes to damp vegetal odours as I drop down behind the sea wall and head towards The Sportsman, a Michelin-starred pub that was voted Britain’s top restaurant in 2016 and 2017. I push open the door and am hit by a blast of warm air, heavy with beer, food and people.

Once I am sitting at an old wooden table, I forget the exercise of consciously sniffing my environment and focus on the menu. I order the slip sole in seaweed butter – a small, skinned sole grilled with homemade, unpasteurised butter that has been seasoned with sea salt and tiny flakes of dried sea lettuce from Seasalter beach. As I eat, the buttery flavour deepens and my mouth fills with the intense aroma of the seashore. It’s pleasurable but momentarily disconcerting: I have a strong sense that I am “tasting” my walk.

In reality, I’m not so much tasting as smelling the flavours. Flavour is the key element that enables cooks to manipulate our emotional reactions to a meal. What you smell affects your enjoyment of a dish, from feeling energised by citrus flavours in a drink, to comforted by a waft of cinnamon in a cake. To understand how this works, it’s important to distinguish between taste and flavour: though the words are interchangeable in conversation, each has a distinct meaning.

Taste refers solely to the five tastes: sweet, sour, bitter, salt and umami (savoury). These can only be detected in our mouths from water-soluble compounds. As soon as we place something in our mouths, ou

r saliva begins to dissolve the food, releasing chemicals called tastants, which stimulate our taste cells through pores that are located in the taste buds on our tongues and soft palates. We are born with an innate recognition of the five tastes, but our perception of them changes with time and exposure.

Flavour relates to the sense of smell and is restricted to our sensitivity to airborne compounds that are released from food as we eat. These compounds are detected by the olfactory receptor cells in our nasal cavities. As Gordon Shepherd, a professor of neurobiology, explains in “Neurogastronomy”, we sense flavour in our mouths “not by sniffing in, which we usually associate with smelling something like an aroma, but by breathing out, when we send little puffs of smell from our food and drink out of the back of our mouths and backward up through our nasal passages as we chew and swallow.”

Virtually everything we eat contains a combination of the five tastes and myriad different flavours. An easy way to understand the difference is to crush a bay leaf slightly and sniff the aroma it releases. It’s the same flavour that permeates a béchamel sauce. Now take a tiny bite from the leaf; your mouth will be filled with a horrible bitter taste. In other words, it is the airborne smell of the bay leaf, rather than its waterborne taste, that flavours food.

Unlike taste, our sense of flavour is learnt. According to Linda B. Buck, a biologist who won the 2004 Nobel prize in physiology or medicine for her work on olfactory receptors, we probably recognise and remember between 10,000 and 100,000 odours. The signals from our olfactory receptor cells take a surprisingly direct path to influence the activity of those areas of the brain related to emotion and memory.

Over time we build up reactions to each odour. The other senses are less immediately experienced because they are heavily filtered and modified by other areas of the brain before they hit us. So if someone were to show you a picture of your first car, you might be intrigued by the sight, but if they gave you a vial to sniff of its interior aroma, you might instantly feel the emotions you felt on first driving in it. In the same way, flavours we breathe shape our reactions according to our experiences. The whiff of a spam fritter still fills me with angst and repulsion because I was forced to eat them at school in the 1970s. This has led me to dislike anything that hints at those spam-like notes. Conversely, the aroma of fresh mint, which grew outside my mother’s kitchen door, makes me feel happy, regardless of whether it’s in a mint julep or tucked into buttered new potatoes.

Stephen Harris, chef at The Sportsman, grew up in Kent surrounded by rural smells, from apple orchards to oyster beds. “I’ve always been fascinated by my local Kentish landscape and whether it has its own unique taste,” he says. He realised that something as simple as butter could convey the distinct flavour of an area. “I discovered this unpasteurised cream from Biddenden in the Weald of Kent. It had an incredible flavour, a mixture of roses, iron steeliness and an earthy, cow-patty element. It reminded me of the smell of the grass and cows on a dewy morning, and the flavours are intensified when I turn it into butter. To me, it’s an expression of the Kentish terroir.”

Every ingredient on his menu is chosen to express the environment, and his dishes have a punchy intensity. He tells me that the slip sole in seaweed butter divides customers: some love it, others don’t, possibly because the ozone seaweed notes come too close to the sulphurous whiff of rotting vegetation.

The smell of our environment alters our perception of food, as Yoshinori Ishii, the two-Michelin-starred chef of Umu, in London, explains: “It’s very important in Japan that people attending a tea ceremony or a traditional kaiseki meal do not wear any perfume. This ensures that they can detect and enjoy the delicate flavouring of the food.”

This is particularly true in seafood. “When I serve sashimi, I want to present only the aroma of the sea,” says Ishii. He does this by training local British fishermen to kill their fish by the Japanese method of Ikejime, whereby a spike to the brain and spinal cord kills fish instantly. This prevents them getting stressed which, in turn, stops the release of sour-tasting lactic acid. The Japanese methods “give the fish a pure and natural fresh flavour”, says Ishi, “so that all it needs as accompaniment is sea salt or soy sauce.”

The Japanese are masters at using aroma to enhance anticipation and the attendant enjoyment of their food. A Japanese lacquer soup bowl is designed to release a puff of fragrant steam when its lid is lifted. Inhale the scent of yuzu in a clear broth, for example, and, if you’re Japanese, your mouth will water with thoughts of the homely winter nabes (hot pots) that your mother cooked during the winter months, flavoured with home-grown yuzu.

Some chefs take the importance of aroma a step further by spraying dishes with an essence that is designed to intensify the eater’s emotional reaction. Massimo Bottura of Osteria Francescana, a three-Michelin-starred restaurant in Modena, Italy, adds a spritz of what he calls “stormy, rough sea” essence to his insalata di mare, a pretty lettuce heart hiding different-textured seafood bites. The edible spray was created in collaboration with a fragrance house: the idea is that the diner smells the sea before they bite on a crisp clam cracker or a tender chunk of raw calamari.

With greater self-awareness we can develop our own perception of flavour, says Harris. “When chefs join, it’s important to calibrate their palates. We take a dish and ask whether they’ve noticed what things come through first and how different flavours develop in the mouth over time. It’s a way of giving them the vocabulary to understand how flavour works within a dish.”

I choose his strawberry ice cream for pudding and allow it to melt in my mouth. Its intense fruity, floral notes conjure up memories of illicitly eating strawberries from my parents’ garden on a hot summer’s day. Their flavour fades to be replaced by the scent of the coffee placed on the table. I sniff deeply, happy that the coffee, polished wood and strawberries will create a further layer of memories in my own smellscape.