Clarification is a straightforward process: remove suspended solids from a liquid to create a clearer, more stable drink. This can be done through fining agents such as gelatine or agar, through filtration, or through centrifugation. The same logic applies in winemaking, brewing and juice production, where clarification improves stability, reduces haze and refines texture. These effects are well documented and form the actual scientific basis of the technique.

What clarification does not do is allow flavour molecules to “shine through” by removing colour pigments. The commonly repeated explanation that pigments mask flavour is not supported by evidence. Clarification can change flavour only because solids themselves carry taste or aroma. Removing them alters the balance, mouthfeel or bitterness, not because colour interferes with flavour perception.

Colour, indeed, plays a real and well-established perceptual role, and it is an indicator of flavour. Visual cues shape expectation: certain colours imply acidity, sweetness, ripeness or intensity. When a drink becomes completely transparent, that information disappears. Therefore, by clarifying a drink, you might be actually ‘removing’ flavour.

When I worked behind the bar, clarification was used for practical reasons: if a drink had an unappealing or muddy natural colou (perharps due to oxidation during processing), clarification was used to removed the unpleasant haze. After that, we often reintroduced a deliberate, appropriate colour (using food colouring) so that the appearance matched the flavour profile. Clarification solved the technical issue; controlled recolouring restored the visual cue. The aim was coherence, not chasing trends.

The current trend of clarifying every possible drink has shifted the focus toward transparency as an aesthetic in itself. This sometimes results in cocktails that are technically clean but visually indistinguishable, even when the drink would benefit from retaining its natural colour. A vividly coloured drink can communicate flavour and intent more effectively than a transparent one. The decision to clarify should therefore be a response to a specific need, not a stylistic reflex.

Clarification remains a useful method when applied deliberately. It improves stability, refines texture and removes solids that distract from the intended structure of a drink. When applied without purpose, it offers no clear benefit and may remove desirable components (and, flavour). Transparency on its own is not a marker of refinement or quality; it is simply the visual outcome of removing suspended material.

In short, clarification is a technical tool. It can be valuable when a drink requires it, but it is not a universal solution.

Texture provides key information about the physical properties of food and drink. Mouthfeel—whether something is creamy, crunchy, viscous, thin, or chewy—affects the way we judge its quality and modulates how taste is experienced. Creaminess can make sweetness feel fuller and more rounded, while crispness or crunch signals freshness and produces a clearer contrast with softer components.

In drinks, mouthfeel contributes significantly to overall perception. The viscosity or “weight” of a spirit can influence how flavours develop across the palate. A whisky with notable oiliness will deliver a different sensory experience from one that is light and thin, even when the aromatic composition is similar. Mouthfeel alters the pace and distribution of flavour, shaping how the drink is interpreted.

Temperature modifies the release of volatile compounds and changes how tactile receptors respond inside the mouth. Warm foods and drinks generally release more aroma compounds, increasing perceived intensity. Cold temperatures suppress volatility and can soften or mute certain flavours, while accentuating others—such as the refreshing character of chilled beverages. These effects are tactile as much as they are olfactory: temperature shifts how the brain integrates both sets of signals.

Tactile feedback does not end at the mouth. The way a glass or utensil feels can shape expectations and subtly influence perception. The weight, shape and surface texture of a vessel can prime the brain before tasting begins. A lighter glass aligns more naturally with drinks that are delicate or aromatic, while a heavier glass suits drinks with greater concentration or structure. This is not a matter of “premium equals heavy,” but of aligning physical cues with the style of the drink so that the tactile and gustatory messages are consistent.

For chefs, bartenders and product developers, understanding the contribution of touch can support more deliberate design. Texture, viscosity, serving temperature and vessel choice all influence how taste and aroma are interpreted. Managing these factors helps ensure that the sensory message of the dish or drink is coherent, and that the tactile aspects support—not contradict—the intended flavour profile.

Touch is an integral part of flavour perception. Mouthfeel, temperature and hand feel all provide information that the brain integrates with taste and smell. These tactile cues shape how flavours unfold and add an additional dimension to the sensory experience.

Used carefully, this method can be informative. A well-known example comes from Heston Blumenthal, who demonstrated that white chocolate and caviar share key aroma compounds, which helps explain why the pairing works despite appearing counterintuitive. Another example is the shared aldehydes linking strawberries and coriander, which can complement each other when used in balanced proportions. These cases illustrate how chemical overlap can highlight new directions worth exploring.

However, chemical similarity alone does not guarantee a successful pairing. Many ingredients that look compatible on paper are challenging in practice because their shared molecules amplify strong or undesirable characteristics. A clear example is mezcal and asparagus. Both contain green, vegetal aldehydes and certain sulphur-related volatiles, suggesting theoretical alignment. In reality, the combination often intensifies the harsher facets of each ingredient, producing off-aromas that are difficult to manage.

A similar issue appears when combining multiple terpene-rich ingredients, such as juniper, grapefruit peel, eucalyptus, hops, and rosemary. While they share the same class of molecules, using terpene-rich ingredients together without restraint can result in a sharp, resinous profile that overwhelms other elements of the drink. The same applies to heavily phenolic ingredients. Pairing peat-heavy whisky with hop-forward components, for instance, can seem logical from an analytical standpoint but easily becomes acrid and unbalanced in practice.

These examples illustrate the core limitation of the molecular-pairing philosophy: volatile-profile similarity does not address intensity, volatility, mouthfeel, temperature effects or the way flavour evolves over time. Analytical data can reveal structural relationships between ingredients, but it cannot dictate proportion, balance or overall direction. Flavour perception depends on far more than the presence of shared compounds.

Scientific insights are valuable when used as a tool rather than a rule. Chemistry can point toward combinations worth testing, but final decisions must rely on experience, sensory judgment and an understanding of how ingredients behave in real contexts. The most successful outcomes occur when scientific information supports (rather than replaces) practical tasting and creative thinking.

A well-established example comes from texture perception. The sound of biting into a crisp provides a reliable cue about freshness. When that sound is strong and clean, the brain interprets the crisp as fresher (and more enjoyable). When the sound is weakened or absent, the product often seems less fresh, even if the texture and formulation are unchanged. In this case, the auditory signal acts as a quality indicator that shapes the overall evaluation.

Background noise affects taste through a different mechanism. Loud environments increase cognitive load, which reduces the brain’s ability to process subtle gustatory and olfactory information. Quiet settings minimise this competition and make it easier to detect small variations in taste and aroma, which is one reason fine-dining environments often avoid intrusive background music.

The influence of music on wine perception is another example of cross-sensory interaction. Research shows that wine can be judged differently depending on the music being played, not because the wine changes but because the auditory context alters interpretation. This effect arises from what sensory scientists call crossmodal correspondences: consistent associations the brain makes between features across senses.

Qualities such as “bright,” “soft,” “sharp,” or “heavy” can describe both sound and taste, and these shared descriptors reflect underlying perceptual mappings. When someone listens to music with heavy, low-pitched characteristics, the brain may lean toward interpreting a wine as fuller or more robust. Lighter, higher-pitched music can shift perception toward freshness or delicacy. The sound primes a particular framework through which the sensory information from the wine is resolved.

Music also modifies arousal and attention. Energetic or loud music can increase arousal, sometimes biasing perception toward intensity, while softer music allows more focus on subtle details. This is why the same wine can be judged as more powerful during intense musical pieces and more delicate during lighter compositions. The liquid is unchanged; the auditory environment shifts the cognitive weighting of taste and aroma signals.

Understanding these mechanisms clarifies why sound, music, and noise can meaningfully influence how food and drink are perceived. The interactions do not depend on subjective interpretation alone but on the way the brain integrates information across sensory systems.

By recognising these effects, professionals in food, wine, and hospitality can shape environments that support more accurate or more intentional tasting experiences.

Terpenes

Terpenes occur naturally in citrus peels, conifers, herbs, and many botanical ingredients. They are responsible for the pine character of juniper, the brightness of citrus, and part of the aromatic profile of hops. Their diversity explains why botanicals offer so many different aromatic facets. In spirits, terpenes are central to gin, while in beer they define many hop-driven styles.

Aldehydes

Aldehydes are primarily formed through the oxidation of primary alcohols, which can happen during production or ageing. They contribute aromas ranging from green, grassy notes (such as hexanal) to almond-like profiles (such as benzaldehyde). In whisky, brandy and aged wines, aldehydes increase through controlled contact with oxygen, adding complexity as the liquid matures.

Ketones

Ketones form mostly during fermentation and, in some cases, during ageing. They can contribute sweet, fruity or buttery notes depending on their concentration. Diacetyl is the best-known example: it can create buttery characteristics in beer or wine if fermentation conditions allow it to accumulate. Their presence is linked to yeast metabolism and how fermentation is managed.

Esters

Esters form when alcohols react with acids, especially during fermentation. They provide many of the fruity and floral aromas in drinks. Their formation is strongly influenced by yeast strain, temperature and fermentation time. Esters play a major role in the aromatic identity of rum, Belgian beers, and many fruit-driven spirits.

Lactones

Lactones develop largely during barrel ageing. They arise from interactions between the spirit, oxygen, and wood components. Depending on the oak species and toasting level, lactones can contribute coconut-like, creamy or stone-fruit notes. They are especially prominent in spirits aged in American oak, such as bourbon and certain rums.

Phenols

Phenols can develop through thermal or microbial processes. In spirits, they are most associated with peat smoke, where drying malt over burning peat introduces phenolic compounds that contribute smoky or medicinal notes in whisky. In beer and wine, some yeasts can also produce phenolic aromas that appear as clove-like or spicy characteristics.

Higher Alcohols (Fusel Oils)

Higher alcohols are produced naturally during fermentation as by-products of yeast metabolism. In excessive amounts they can appear harsh or solvent-like, but in lower concentrations they add weight and complexity. Their levels depend on fermentation temperature, yeast health and nutrient availability, making them an important aspect of producing clean, balanced spirits.

In beverage creation, understanding the molecular composition if an aroma source provides a solid foundation for designing more structured, layered drinks.

In a previous post, I used Damask Rose as an example. Returning it to here allows us to illustrate this principle more clearly. Rose aroma contains hundreds of individual aromatic volatile compounds, each producing a different olfactory nuance (floral, fruity, spicy, green, waxy, balsamic, or even solvent-like). This diversity is what gives rose its complexity, and it is also what allows us to shape and direct that complexity in a drink.

When building a drink around Damask Rose flavour, the goal is not to pile on ingredients, but to understand what facets of the rose you want to emphasize. Working with the existing aromatic palette of the ingredient lets you create a multidimensional drink without overwhelming it. Enhancing or contrasting specific facets (floral lift, fruity brightness, green sharpness, spicy depth, balsamic warmth) allows the rose to remain central while still offering layered development.

For example, adding black pepper to a rose-based drink can bring forward leathery and spicy nuances already present in the rose’s aromatic profile. Pink pepper introduces a gentle woody-spicy lift that strengthens its floral character. Pairing rose with labdanum emphasizes its deeper balsamic and resinous aspect, while bergamot lightens the structure and highlights its fruity, luminous side. Each addition works because it interacts directly with an existing facet of rose, rather than competing with it.

A key practice in drink design is therefore to choose one dominant aroma and build a structure around it. This is how complexity and depth are created. It is not about layering more ingredients: it is about manipulating what is already present with precision. Many drinks fail because additional ingredients blur the profile rather than refining it. If you’re working on a drink and something feels like it’s ‘missing’, simplification is often more effective than adding yet another element. Hence, if your composition is ‘not working’, instead of adding, try removing ingredients.

The aim is to create a drink that develops across a few seconds on your palate, with different facets of the main aroma unfolding in sequence, rather than a mixture in which the individual components are indistinguishable. Achieving this level of clarity requires restraints, not accumulation.

In essence, aromatic molecules shape how we experience drinks, and understanding their internal diversity gives us a practical framework for creating structured, expressive beverages. By focusing on one central aroma and using complementary elements to guide its evolution, it becomes possible to build drinks that feel complex, deliberate, and coherent, without unnecessary complication.

When an aircraft is cruising, its cabin is pressurized to simulate an altitude of roughly 6,000 to 8,000 feet. The pressure drop, paired with very low humidity (often under 20%), impacts both taste buds and olfactory receptors. Dry air hampers the nasal and mouth linings, reducing sensitivity to aromas and thus diminishing flavours. Moreover, low cabin pressure has been shown to raise thresholds for sweetness and saltiness, meaning passengers perceive less of those tastes under these conditions.

Another key factor is background noise. Research shows that loud ambient conditions (such as the hum of an aircraft cabin), can reduce perceived sweetness and saltiness, while possibly enhancing umami tastes. The combined effect of low pressure, dry air, and acoustic stress dampens much of what we expect to taste and smell.

Understanding these environmental constraints helps explain why your in-flight meal may lack the punch you’d find on the ground. Recognizing what’s happening allows for more informed choices, for example seeking dishes with stronger seasoning, texture, or umami presence, or choosing a drink with more aromatic depth to help compensate.

Our ability to detect bitterness evolved as a defense mechanism: many potentially harmful plant-derived compounds are bitter, so detecting bitterness allowed early humans to avoid toxins.

Humans are equipped with around 25 functional bitter taste receptors genes (the TAS2R family) expressed in taste cells. This far exceeds the number of dedicated sweet or salty taste receptors, reflecting the evolutionary importance of identifying a wide array of bitter (and potentially harmful) substances.

Yet, the complexity of bitter taste extends beyond survival. That richness allows us to appreciate a spectrum of bitterness: from the subtle bitterness of certain vegetables to the sharp bite of dark chocolate, or the complex and depth a of robust coffee.

By contrast, sweet and salty tastes are associated with nutrients critical for our survival: sweetness signals sugars (energy source), and saltiness signals sodium (essential for fluid balance and nerve function). Because their presence is beneficial fewer receptors types suffice.

In culinary and drinks context, bitterness now plays a key role in adding complexity and depth. Whether through a well-crafted artisanal beer, a piece of dark chocolate, or a rich espresso, bitterness introduces sophistication to our flavour palette.

But why and how that works?

Bitterness contributes depth because it activates a broader and more diverse set of taste receptors than any other basic taste (as we have around 25 different bitter receptors, each tuned to detected different classes of bitter compounds).

This diversity produces a wider and more complex pattern of neural signals compared with sweetness or saltiness, which rely on fewer receptors types. The brain interprets this richer patterns as greater internal variation within the taste, which we perceive as nuance. In practical terms, bitterness rarely appears as a single uniform note. Instead, it often carries gradations (sharp, earthy, herbal, roasted, vegetal, or dry), depending on which receptors are activated. This receptors-level complexity is a core scientific reason bitterness feels more layered than other tastes.

Bitterness also adds depth through its interaction with other tastes. Bitter compounds can suppress sweetness, sharpen the perception of acidity, and create contrast within a drink or food. These interaction prevent flavour from becoming uniform and introduce small shifts that the palate detects over time.

Because many bitter compounds clear more slowly from the mouth than sweet or acidic molecules, they also create a longer finish, allowing other tastes and aromas to unfold against a stable backdrop. This combination (receptors diversity, cross-interaction with other tastes, and longer persistence) produce a sense of structure, which adds depths and complexity to the overall sensory experience.

In In Search of Lost Time (1913), the narrator tastes a madeleine dipped in tea and is immediately transported back to childhood. The flavour triggers a cascade of vivid, detailed memories that had long been inaccessible. This ‘madeleine moment’ has become a cultural shorthand for the sudden return of forgotten experiences through sensory cues.

The idea is not simply literary; it reflects how the brain actually works. Smell is processed in the olfactory bulb, which has a direct neural connection to the hippocampus and the amygdala (regions involved in memory formation and emotional processing).

Because of this direct pathway odours can access memory circuits more rapidly and more strongly than most other senses.

This is why a specific aroma or flavour can instantly evoke a place, a person, or a moment from years earlier. Proust’s description captures a real neurobiological phenomenon, one that continues to be investigated in modern sensory and memory research.

When you have a cold , the infection triggers inflammation in the nasal passages. The lining of the nose swells, airflow is reduced, and mucus production increases. These changes physically block odour molecules from reaching the olfactory receptors at the top of the nasal cavity. In some cases, the virus may also irritate or impair receptors themselves, temporarily reducing their sensitivity.

Both pathways of smell are affected:

Orthonasal olfaction (smelling through the nostrils) declines because airflow is restricted.

Retronasal olfaction (aroma released from the mouth during eating and drinking) weakens because inflammation and mucus prevent odour molecules from travelling up towards the olfactory region.

Since most of what we perceive as flavour comes from smell rather than taste, this obstruction leads to a noticeably muted experience. Sweetness, acidity, bitterness, saltiness, and umami are still detectable, but without aroma they feel flat and incomplete.

The good news is that these changes are temporary. As inflammation decreases and normal airflow returns, both orthonasal and retronasal smelling recover, restoring the full sensory profile of food and drink. This process highlights how dependent taste is on the ability of the nose to function properly, and why something as simple as a cold can have such strong effects on flavour perception.

Dryness is not a basic taste. It does not come from taste buds or olfactory receptors. Instead, it is a tactile sensation that emerges from how certain chemical compounds interact with the mouth.

The Astringency Mechanism

In wine, dryness is closely linked to tannins. These compounds, found in grape skin, seeds and stems, bind to proteins in saliva. When this happens, saliva becomes less effective at lubricating the mouth. This results in an astringent, drying, slightly rough sensation on the tongue and cheeks.

Tannins however, are not the only contributors. Alkaloids and Polyphenols can produce similar effects.

Caffeine can create a noticeable drying, puckering sensation. Polyphenols in fruits such as quinces, persimmons, and green bananas can also trigger a dry, chalky mouthfeel.

These compounds act on the mouth mucous membranes in a way comparable to tannins, reducing smoothness and lubrication and contributing to the sensation of dryness.

Spirits such as Whiskey also show dryness. During ageing, the liquid extract tannins and phenolic compounds from the wood. These contributes bitterness, structure, and a drying finish, influencing both flavour and mouthfeel.

How does it work?

Dryness works by changing the friction inside the mouth. When these compounds bind to salivary proteins, they reduce the natural lubrication on oral surfaces; with less lubrication, the tongue and cheeks move against each other with slightly more resistance. This increased friction sharpens the sensory input coming from both taste receptors and mechanoreceptors (the touch receptors in the mouth). It becomes easier for the brain to detect small shifts in acidity, bitterness, or aromatic lift, because the mouth is no longer coated in a smooth film.

When dryness is balance, this increase in friction makes tastes feels clearer and more defined. If the effect becomes too strong, friction rises too far, saliva is stripped away, and both taste and aroma becomes less detectable. In short, Dryness improves perception only within this narrow controlled range.

Dryness highlights the complexity of flavour perception. It reminds us that flavour is not just aroma and taste; texture and tactile sensations are part of the experience.

In a separate post, I will explore how to work with dryness deliberately when creating drinks.

However, smell and taste are closely linked. They use distinct sensory systems, but the brain combines them to form what we recognize as flavour.

Certain aromas (such as vanilla, cinnamon, fennel seeds, anise, etc.) are strongly associated with sweetness. This association comes from repeated exposure throughout life: these aromas usually appear in sweet foods, baked goods, or desserts. Over time, the brain learns these pairings and builds an expectation.

When these ‘sweet-associated’ aromas appear in a drink, the brain integrates the smell input with the taste input. This can enhance the perception of sweetness, even when the actual sugar content is unchanged.

This makes aromatic ingredients useful for adjusting flavour without adding more sugar. For example, in cocktails like a Fizz or Collins, adding just one dash of absinthe can subtly increase the perceived sweetness. This can help create a balanced drink with less sugar added.

It is worth noting, however, that sugar does more than adding sweetness: it also contributes to mouthfeel and structure. If you reduce it, make sure the drink does not lose body or feel thin.

Using aromas strategically lets bartenders build richer, fuller flavours while keeping sweetness under control.

The Bordeaux Wine Study

Researchers at the University of Bordeaux presented participants with two identical glasses of white wine. One glass, however, had been dyed red. The aim was simple: test how colour influences flavour perception.

Although both samples were chemically identical, participants described the dyed wine using typical red-wine descriptors. The aromas and flavour notes they reported aligned with what they expected from a red wine, not from a white wine.

This demonstrates a clear example of cross-modal influence: the visual cue (red colour) created an expectation strong enough to override the actual sensory input.

The Coffee Mug study

A study from the Federation University in Australia looked at colour effects in a different way. Researchers served the same coffee in three mug colours: white, blue and transparent.

Participants reported the coffee in the white mug as more intense and bitter. In the blue mug, the same coffee tasted sweeter. In the transparent mug, it was perceived as weaker overall.

Again, the drink never changed. Only the visual context did.

These findings show that flavour perception is not solely determined by what is in the glass. Visual information (colour, brightness, clarity, vessel shape, and context) can shift how we interpret taste and aroma.

For bartenders and chefs, understanding this interaction is essential. The visual design of a drink should align with its flavour profile. A mismatch between appearance and taste can create confusion, while a cohesive presentation can strengthen the intended flavour message.

When sight and taste reinforce each other, the drink becomes more precise and compelling. Visual choices are not decoration, they are part of the flavour itself.

The Pyramid of Perfumes

To analyze a perfume, perfumers often use the pyramid of notes, an empirical method used to describe how a fragrance evolves over time. The pyramid is divided into three parts: top, heart, and base.

Perfumes are made up of individual notes belonging to different families (citrus, floral, woody, spicy, etc.). Each note falls into one of the above categories based on volatility (how quickly it evaporates)

Top notes are the most volatile. They are the first impression when a perfume is sprayed and usually last between 15 minutes and one hour. Citrus aromas and aromatic herbs like mint, thyme and basil, are examples of top notes.

Heart notes come next and have medium volatility. They can last for several hours (up to 8-10 hours). Floral, fruity, and spiced aromas are typically heart notes.

Base notes are the least volatile. They can linger for days, giving weight and depth to the fragrance. Woody, musky, resinous, and earthy notes are typical base elements. Even in small amounts, they add length and help anchor the lighter, more volatile notes.

However, this models has its flaws. Many aromas do not fit neatly into one layer. A scent can behave as both top and heart, or heart and base, depending on its strength and context. Notes also interact: base notes can help pull top notes down and extend their presence, or even make them reappear later; a classic example of this is the combination of bergamot and oakmoss, where bergamot can re-emerge hours after evaporation because of this interaction.

You could also argue it is not a pyramid, but a triangle. True.

Despite its flaws, the pyramid remains a useful tool. It helps visualize how a fragrance evolves and provides a practical framework when composing or describing a perfume.

Translating this to drinks

The same logic applied to aromatic compounds in drinks. When tasting or smelling a liquid (whether a whiskey, a martini, or a gin and tonic), the order in which aromas appears depends on their volatility and dominance (concentration) in the composition.

You never perceive all aromas at once. Instead, flavours unfolds in layers, just like perfume, only over seconds rather than hours.

Gin is a great example. It is a distilled composition of botanicals (citrus, spices, herbs, flowers, roots…), much like perfume ingredients. A well-balanced and crafted gin should take you through a sequence: bright and volatile citrus top notes, floral and spicy heart notes, and deeper woody or earthy base notes. Each sip becomes a miniature version of the perfume pyramid.

Cocktails behave in the same way. Their flavour evolves across a few seconds rather than hours, but the same principles apply. Every aromatic ingredient (spirits, liqueurs, syrups, tinctures, juices, bitters) contains compounds with different volatility and impact.

To create a balanced drink, you need both bright and heavy elements. A drink made only of highly volatile notes will open up well but fade quickly. Base-note ingredients provide length, depth and complexity, allowing lighter aromas to linger and evolve.

The citrus twist example

The citrus peel expressed over drinks like the Martini, Manhattan, or Negroni, is the clearest example of top notes in cocktails. It lasts only for the first few sips but makes a striking difference to the entire drink’s profile. The brief burst of fresh citrus brightens all other flavours and changes the final perception of the drink.

Try tasting two Manhattan side by side - one with and one without an expressed orange twist. The difference is immediate. The twist lifts the other notes, giving structure and life to what would be otherwise a flat composition.

Top, heart, and base notes in cocktails

Perfume evolve slowly, revealing different stages as volatile molecules evaporate. Drinks evolve more rapidly, but the same hierarchy applies. Each ingredient brings molecules with its own volatility, intensity and persistence.

Most spirits already contains a mix of top, heart and base notes. Gin, whiskey, rum, brandy - each hold a natural pyramid within them. The bartender’s task is to manipulate and balance those layers, sometimes reinforcing certain aspects with complementary ingredients, sometimes restraining others.

In perfumery, the focus in purely olfactory; in drinks, the experience involves both olfaction and taste, and both must work in harmony.

The takeaway is simple: a cocktail, like a perfume has a structure. Each sip is a condensed version of that pyramid, evolving briefly but distinctively, and understanding this helps design drinks with more balance, depth, and movement .

The Pyramid of Perfumes offers a clear way to visualize that roadmap of flavour and aroma. It helps analyze how ingredients interacts and how they can be arranged to create a drink that evolves on your palate.

Compounds like capsaicin and menthol activate receptors that normally respond to changes in temperature or irritation, producing the illusion of heat or cold.

The Heat of Capsaicin

Capsaicin, the pungent compound in chili peppers, creates the sensation of heat by binding to the TRPV1 receptors. These receptors normally respond to physical heat above 43C and to tissue irritation.

When capsaicin binds to TRPV1, it opens ion channels in sensory nerve endings, allowing calcium ions to enter the cells. This triggers the release of neurotransmitters that signal the brain to interpret the sensation as heat and pain, even though there is no actual rise in temperature.

The ‘spicy’ feeling is therefore not a taste but a pain response transmitted through the trigeminal nerve, which carries sensory information related to touch, temperature, and pain, from the mouth and the face.

The Cool of Menthol

In contrast, menthol, the compound responsible for the cooling sensation of mint, activates the TRPM8 receptors. These receptors are sensitive to temperature below 25C.

When menthol binds to TRPM8, the ion channels open and calcium ions flow into the nerve cell, sending a signal to the brain that mimics the sensation of cold. the mechanism is similar to that of capsaicin, but the sensory outcome is the opposite.

This last information can be quite interesting in the formulation of food and beverages.

The activation of the TRPM8 by menthol can happen at concentrations far below its odour threshold, meaning the cooling effect can be felt without adding a recognizable aroma of mint. In other words, you can induce a perception of freshness or temperature change without altering flavour.

At sub-threshold levels (where the mint aroma isn’t detected), the menthol can create a clean, cooling sensation that enhances the perceived freshness of a drink. You could make a Martini feel ‘colder’ a juice taste ‘fresher’, by adding tiny amounts (below 0.02-0.05ppm) of menthol.

This is the result of neural activity rather than chemistry in the glass: the mouth experiences a lower ‘felt temperature’ although the liquid itself is unchanged.

In short, both capsaicin and menthol activate the trigeminal nerve, adding sensation of temperature and pain that blend with taste and aroma to form the overall flavour experience.

While heat and cold are not basic tastes, they strongly influence how we perceive food and drink. The burn of chili, or the subtle chill of menthol, shows how chemical compounds and neural pathways work together to shape flavour beyond taste itself.

However, this representation is not accurate.

The map originates from a 1901 paper by German scientist David P. Hanig (picture below), who tested sensitivity to basic tastes across the tongue. Hanig found small differences in thresholds (certain regions were slightly more sensitive to particular tastes) but he clearly stated that all parts of the tongue could detect all tastes.

The misunderstanding came later. in 1942, Harvard Psychologist Edwin G. Boring reinterpreted Hanig’s data and published a simplified diagram. Boring’s version exaggerated Hanig’s findings, suggesting that each region of the tongue was solely responsible for one taste. This misrepresentation became the ‘tongue map’ myth still seen today.

It is to be mentioned that neither Hanig or Boring accounted for Umami, which was identified much later (note: umami was first recorded in the early 20th century by Kikunae Ikeda in Japan, but only widely recognized by Western scientists in the 1990s)

Modern research, shows that the taste receptors for sweet, sour, salty, umami and bitter are distributed throughout the tongue and palate. While sensitivity may vary slightly by area, all regions can detect the basic tastes.

How taste detection work

Taste buds are clusters of sensory cells located on the tongue, palate and epiglottis. Each taste bud contains multiple receptors type tuned to detect different classes of molecules.

When we eat or drink, molecules of our food and drink dissolve in saliva and interact with these receptors. Binding triggers chemical signals that travel through the cranial nerves to the gustatory cortex in the brain, where the taste is identified.

Different molecules activate a unique combination of receptors: sugar molecules stimulate sweet-sensitive receptors, while acids in lemon juice trigger sour-sensitive ones. The brain recognizes the pattern of activation to identify the taste.

Because the receptor types are evenly spread, each basic taste can be detected across the tongue rather than in isolated areas.

Sensitivity and Variation

Taste sensitivity varies from person to person. Genetics, age, diet, and health all affect how strongly someone perceives flavour. For instance, genetic variation in TAS2R bitter receptors explain why some people find certain vegetables extremely bitter while others do not (more on this in the future)

The Role of Saliva

Saliva is essential to gustation. The enzymes in our saliva break down the chemical components of what we eat and drink, allowing the resulting molecules to interact with the taste receptors.

The efficiency of this breakdown affects which tastes are detected first. For example, enzymes in saliva (such as amylase) rapidly act on carbohydrates, releasing sugars and helping sweetness appear early. By contrast, bitter compounds tend to resist breakdown and dissolve more slowly (bitter molecules are often bigger and more complex than sweet molecules), so bitterness often develops later on the palate.

In essence, the sequence in which we perceive basic tastes largely depends on how effectively saliva processes each compounds.

Next time you’re drinking a Negroni, try to pay attention to which basic tastes are registered first: sweetness from residual sugar in the liquors will be detected first, followed by the slower emergence of bitterness.

This sequence highlights how taste is a dynamic process, not a static map

From there, the information moves to other regions of the brain for further analysis. the brain creates “smell images” (internal representations that help identify and distinguish different odours)

Over time, the brain builds a collection of smell images, forming an olfactory memory bank. When a new scent is detected, it is compared against this memory bank to find a match. this process allows us to recognize familial aromas and categorize new ones.

Scent recognition is closely linked to memory end emotion. Familiar aromas often trigger personal association. For example: a particular smell might recall a specific place, moment, or feeling.

Confusion can occur when different odours share similar chemical components. Citrus aromas for instance, can be misidentified because lemon, lime, and orange contain overlapping molecules that activate related neural patterns. The brain gradually learn to separate these through experience.

Each person’s olfactory memory is shaped by individual experience, making it unique. As a result, two people may perceive the same scent differently.

When encountering a completely new smell, the brain initially relates it to the closest familiar scent it knows. With repeated exposure, it forms a new, distinct smell image for that odour.

This underlines the importance of developing a vast “aromatic vocabulary” by repeated exposure and analysis of different scents, for anyone who works within the flavour industry.

When food or drink enters the mouth, taste receptors on the tongue detect five basic tastes: sweet, sour, salty, bitter, and umami. At the same time, volatile compounds travel from the mouth to the nasal cavity through retronasal olfaction, activating olfactory receptors. This combination of taste and smell forms the basis of flavour perception.

Taste signals are sent to the gustatory cortex, while Smell signals are processed first in the olfactory bulb and then passed directly to brain regions involved in emotion and memory, such as the amygdala and hippocampus. This direct link explains why smells and flavours can trigger emotional reactions or vivid memories with little conscious effort.

The information from taste, smell, and other sensory inputs converges in the orbitofrontal cortex, where they are combined to form the perception of the food and drink we consumed.

The orbitofrontal cortex is also sensitive to expectations. Before tasting, visual and olfactory cues generate predictions about what something should taste like. When those cues are consistent, the experience is reinforced; when they conflict (thin of a purple liquid tasting of orange) the brain detects the mismatch and reduces perceived pleasantness.

Past experiences also strongly shape this process. If a particular flavour or aroma has been associated with a negative event (such as illness, stress, or an unpleasant social situation) the hippocampus and amygdala can store that association and reactivate it later. Even when the flavour itself is neutral, the emotional memory can alter how it is perceived.

The same mechanism explains why positive experiences, like a drink linked to celebration or comfort, can increase liking and perceived quality through emotional recall.

Flavour is therefore not a property of food itself but a construction of the brain.

It results from the integration of sensory input with memory, emotion, and expectation, producing a unified experience that defines how we perceive and respond to what we eat and drink

Aroma compounds are typically composed of a combination of Carbon, Hydrogen, and Oxygen atoms, and they may also contain other elements such as Nitrogen and Sulphur

It goes without saying that everything that possesses a scent is made up of different aroma compounds.

What we experience as an aroma (the scent of a flower, fruit, spice, herb…), is a composition of different aromatic molecules (up to several hundreds) combined.

Aromatic molecules can be classified into several different types based on their chemical structure and properties. Some common types are: terpenes, esters, aldehydes, ketones and lactones (I’ll describe them in detail in another post).

For example: a rose’s aroma is produced by a complex mixture of different aromatic compounds. Each of these compounds has its own unique aroma in isolation (either floral, citrusy, fruity, spicy…), and when they are combined in the right concentrations, they create the overall aroma of the rose.

Some of the compounds that contribute to the characteristic aroma of roses are:

Geraniol: is a terpene alcohol that is responsible for the rose-like aroma, and it is also found in other flowers and fruits (such as geranium, lavender, lemon grass, plum, peaches…)

Citronellol: is a terpene alcohol with a strong lemony character. Is also the main aromatic component of lemongrass, and naturally present in eucalyptus, lemon verbena, lemon balm, etc.

Phenylethyl alcohol: is an alcohol that gives a rose and honey-like aroma, and it’s also found in some fruits such as apricot and raspberry, and in a variety of flowers like ylang-ylang, hyacinth, orange blossom, carnation, etc.

Eugenol: is a phenylpropanoid that is present in cloves and has indeed a pleasant, spicy, clove-like scent. It is also present in cinnamon, nutmeg, basil, bay leaf, etc.

Rose Oxide: is a chemical compound with a strong rose-like aroma. It is also one of the main aromatic compounds in lychee and Gewurztraminer grape.

Linalool: is a terpene alcohol that is known for its floral and lavender-like aroma (it is indeed one of the main aromatic compounds in Lavender), and it is also found in other herbs like mint, basil and coriander.

Limonene: is a terpene that is known for its fresh, citrus-like aroma. It is present in the essential oil of all citrus fruits, and it is also found in several flowers (such as jasmine and chamomile) and coniferous such as pine, spruce, juniper, etc.

The type and concentration of aromatic molecules in roses can vary depending on several factors such as the variety of rose, the growing conditions, the method of harvesting, as well as the processing and extracting methods of the aroma.

However, this is an average concentration of the aromatic compounds mentioned above:

Damask Rose composition:

Geraniol: 2-5%
Citronellol: 2-7%
Phenylethyl alcohol: 2-5%
Eugenol: 1-2%
Linalool: 1-3%
Limonene: 1-2%
Citral: 1-2%
Nerol: 1-2%
Rose Oxide: 0.01-0.4%

What is interesting to note here, is the concentration of each aromatic compound, and the effect it has on the final perception of the rose aroma.

For example, rose oxide, despite being one of the main compounds responsible for the characteristic aroma of roses, is only present in tiny concentrations, around 0.1-0.4% (and normally never over 1%)

Consider that the full list of aromatic compounds in roses is likely to contain hundreds of different molecules, and the ones listed above are only the main ones responsible for the scent of Damask Rose.

Out of all the other compounds, some of them may not have a pleasant smell (if taken in isolation), and some others may possess no scent at all. However, they all contribute to the final overall aroma, and removing even just one of the compounds can greatly change the aroma of the rose, removing complexity and nuances.

How does this affect us?

Let’s see what factors affect our ability to detect, identify and recognize aromas. For example, let’s take the molecule hexyl acetate, commonly found in white wine.

Hexyl acetate has a fruity aroma and can be described as having notes of apples, pears and tropical fruit.

While drinking a glass of white wine boasting this particular molecule, different people may perceive the flavour of the compound differently: one person may perceive a stronger apple-like aroma, another person a pear-like aroma, and a third person may identify it as pineapple, or even banana. The aromatic molecule is always the same, but our perception of it changes.

This variation in perception can be caused by several factors. One explanation is the difference in the number and sensitivity of olfactory receptors between individuals. Some people have more receptors for certain odours, making them more intense for them, while others may have fewer receptors, making them less intense.

Most importantly, personal experience and cultural background play a role in how individuals perceive aromas. Consider the scents that we are familiar with from our upbringing, as well as the variety of cuisines and flavours of different cultures – those can have a significant impact on how a person experiences different aromas, especially new ones.

When we drink our glass of white wine (or whatever else) our brain quickly compares the detected smell to stored memories, information and representation of different scents. If the representation of the current scent matches a stored representation, the brain can quickly identify it. If the brain cannot identify the scent, it will try to match it with the closest perception it can find based on the person’s cultural background and personal experiences. This explains people commonly mistake simple scents for similar ones.

In conclusion, an aroma is a complex mixture of compounds that our olfactory receptors detect. The composition and concentration of these compounds determine the overall aroma, and factors like personal experience, cultural background and genetics, can influence our ability to identify and recognize them.

We will explore aromatic compounds, our ability to detect and identify them in another post, and how understanding them can help us improve our tasting knowledge, as well as the ability to combine and create flavours in beverages.

Olfaction, or the sense of smell, works by detecting molecules in the air. When we inhale, aromatic molecules are picked up by the smell receptors of the olfactory epithelium (a special tissue responsible for detecting odours)

The olfactory epithelium is located in the upper part of the nasal cavity, and it is connected to the olfactory nerve, which is the pathway that transmits signals from the receptors (epithelium) to the olfactory bulb.

Once the signals reach the olfactory bulb, they are processed and sent to other areas of the brain for further identification, such as the olfactory cortex, orbitofrontal cortex, and the limbic system, which are responsible for interpreting the signals and creating the final perception of a scent. These areas of the brain are also involved in processing our emotions and memory, connecting them to the different odours we sense.

The brain is able to distinguish between different aromas because each type of molecule activates a unique combination of receptors. For example, the molecules that give roses their characteristic smell activate a different combination of receptors than the molecules that give lemons their smell.

The sense of olfaction is not just about detecting and identifying different scents, it is also closely linked to our sense of taste.

The link between olfaction and taste

Our sense of smell plays a dominant part in the perception of the flavours of the food and drinks we consume. Indeed, when eating or drinking, pretty much 80% of the perception of flavours comes from our nose (our sense of smell) and only 20% from our palate (our sense of taste) - (Note: Let’s use this 80:20 ratio as a guideline only: in reality, smell accounts for most of the overall ‘flavour perception’, easily up to 95% of it)

This is because with our tongue we can only detect five different things: sweet, sour, salty, bitter and umami (these are called the basic tastes). With our nose, on the other hand, we can detect more than 10,000 different odours.

Even when we sip, or chew, the different flavours we perceive are actually picked up by our nose and not by our palate. This is because our sense of olfaction is divided into two parts: orthonasal olfaction, and retronasal olfaction.

Orthonasal olfaction refers to the process of detecting odours through the nose by inhaling air through the nostrils. This is the most common way that we perceive smells, and it allows us to identify and detect the various scents we encounter.

Retronasal olfaction, on the other hand, refers to the perception of odours that occur when air is exhaled back through the nostrils after being inhaled through the mouth.

Retronasal olfaction plays a key role in our sense of taste, as it allows us to perceive the flavours of the food we consume. When we eat or drink something, the aromatic molecules of the substance enter the mouth and are mixed with saliva. As we chew or sip, these molecules are released into the air and are inhaled back through the nostrils, activating the olfactory receptors in the nasal cavity.

When we perceive an aroma, whether orthonasal or retronasal, the brain receives a signal from the smell receptors. This signal, along with signals from other senses (taste, sight, touch, etc.), is used by the brain to create the final perception of the flavour of the food we consume.

But before explaining this process, let’s talk about the sense of taste.

The Sense of Taste

The sense of taste, or gustation, works by detecting the chemical composition of substances that we put in our mouth. There are only five primary tastes that the human tongue can perceive: sweetness, sourness, saltiness, bitterness, and umami.

Each of these tastes is caused by the activation of specific types of taste receptors by different types of molecules. For example: the sweetness of sugar is detected by sweet taste receptors, while the bitterness of coffee is detected by bitter taste receptors.

When we eat or drink something, the molecules of the substance dissolve in our saliva and come into contact with the taste buds on the surface of the tongue and palate.

Each taste bud is made up of a group of taste cells, which have tiny hair-like structures called microvilli on their surface. These microvilli are covered with special proteins called taste receptors, which bind to specific molecules in the food or drink, triggering a chemical reaction. This reaction sends a signal to the gustatory cortex in the brain, which interprets the signal as a particular taste.

How the final perception of flavour is created in the brain?

When the brain receives signals from the sense of smell and taste (and other senses too), it integrates them to form a comprehensive perception.

The gustatory cortex, located within the insular and opercular region of the frontal lobe, specifically processes and interprets signals from the taste receptors in the tongue.

The olfactory system, on the other hand, processes signals from the smell receptors in the nose and sends them to the olfactory bulb in the brain, which then relays them to the olfactory cortex.

Additionally, the orbitofrontal cortex and the limbic system play a role too in the perception of flavour, by integrating the information from the gustatory cortex and olfactory cortex, with other sensory information from memory and emotion.

This explains why certain flavours can evoke specific emotions and memories, and how our mood at a given time can impact the perception and quality of the flavours perceived.

It is a bit more complex than just putting something in your mouth and deciding whether you like it or not.

This is obviously a very simplified version of the process and other areas of the brain are also involved in the perception of flavour. Overall, it is a fairly complex topic (although a fascinating one) and I’ll break it down slowly in different posts, to uncover all things flavours, spirits, cocktails and scents.