All a Matter of Taste: Sensory Science at the Bar
“Tastes can vary.” This phrase often comes up when we talk about preferences of our guests, colleagues or ourselves. I argue that many of us are unaware of the full implications of this assertion. Research findings from the last few years shed new light on our perception of flavour and offer much food for thought, especially for bars and restaurants.
How does sensory perception work?
Sensory perception begins orthonasally, i.e. through our nose, even before we taste anything. Smells are basically volatile components within our environment, i.e. chemical substances that reach our nose in evaporated form. When we inhale, they are transported to the olfactory mucosa in the upper nasal cavity. In addition, our nose is equipped with pain receptors that are activated, for example, when we smell chilli or heavily carbonated drinks.
The five tastes
When we eat or drink something, our tongue perceives tastes via taste receptors. There are five of these: sweet, savoury, umami, sour and bitter. By the way, umami was first identified as a taste in 2000. Incidentally, the notion that the receptors for each of these tastes are concentrated in certain areas is a long-outdated idea that is unfortunately still frequently invoked. In reality, all the receptors are spread all over the tongue, so you can’t taste sweet only on the tip of your tongue, as is sometimes claimed.
Perception beyond taste
But apart from taste receptors, there is much more going on in the mouth. We can tell if something is hot or cold, or even cooling like menthol. Our mouthfeel can distinguish between impressions like astringent, metallic, viscous or greasy. We also analyse by touch whether something is crunchy, sticky or fluffy. Our pain receptors register sharpness or even the burn of alcohol. That’s quite a lot, and yet not enough to inform us whether a wine gum tastes of cherry or orange.
How flavours are perceived
We can only experience retronasally, what we rather incorrectly refer to as “taste”, in other words the flavour of food. This means that volatile substances are transported through our throat to the olfactory mucosa by breathing, chewing and swallowing. This sends the information to our olfactory bulb and thus to the brain, just as is the case with orthonasal smell. So, what’s the difference? Don’t we simply perceive the same thing retronasally as in the nose? – Yes and no. Elements of orthonasal perception often coincide with retronasal perception. For example, a caramel sweet certainly smells and tastes very similar. However, orthonasal and retronasal perception can also differ greatly. As bartenders, we are sure to have tasted something where the nose did not match the “taste” or where completely different flavours emerged in the aftertaste. So what happens in between?
Maria Gorbatschova from the Green Door Bar in Berlin already gave a rousing talk on the topic of sensory science at BCB 2021.
What happens in our mouths
For one thing, the temperature of the drink (or food) changes in our oral cavity; a cool wine or cocktail is warmed up, releasing more volatile substances. Secondly, food reacts with our saliva. This contains enzymes, substances that our body produces to regulate our metabolism, for example. Enzymes split molecules and thus release substances in our mouth that can then be perceived retronasally. The fascinating thing is that the composition of our saliva is entirely individual. It is genetically determined and different for all of us. This also has an impact on our perception of flavour.
The reason for different perceptions
In 2018, for example, it was proven that some people do not like cabbage because components of their saliva release sulphur, making it unpleasant to taste. Variations are not only found in saliva – the way one and the same molecule is perceived in the olfactory receptors of the olfactory mucosa also depends on genetic factors. The best-known example of this is probably the flavour of coriander, which many people perceive as soapy and unpleasant. The likelihood of such genetic variations also increases depending on the region. While in South Asian countries 3-7% of all inhabitants avoid coriander, in East Asia the figure is as high as 21%. These examples are probably just the tip of the iceberg.
“Blindness” and differences in intensity of flavour possible
It is not only possible to have different perceptions of the same flavours. We can even be anosmic, i.e. completely “blind” to them. 1% of the world’s population cannot perceive the flavour of vanilla. Theoretically, all possible flavours could be affected, over 10,000 can be perceived by humans. It is quite conceivable that many of us react anosmically to something specific and never find out because we don’t know what is missing.
Differences in intensity of perception are also possible. While one person may perceive a certain flavour as very intense, another may hardly perceive it at all.
Supertasters and non-tasters
In connection with flavour intensity, we should mention supertasters and non-tasters. Both groups make up roughly 25% of the world population; in between, 50% of all people are average tasters. Supertasters have considerably more receptors on their tongues and are therefore more sensitive to flavours. Especially bitter tastes can appear stronger and unpleasant to them, but also tannins or acidity are perceived more intensely, for example at wine tastings. Supertasters often dislike fatty foods and avoid foods high in sugar. They weigh less on average, are picky eaters, consume less alcohol than non-tasters and often have an aversion to foods such as coffee, grapefruit or dark chocolate. Their taste perception relates to that of non-tasters like neon colours to pastel.
Spread of supertasters and non-tasters
The statistical spread of supertasters is strongly linked to origin and gender. Women are twice as likely to be supertasters as men. People from Asia or Africa are much more likely than people of European origin. Non-tasters, on the other hand, are most often white men. You can check your own status with a simple test that can be found online.
What to do if you identify as a non-taster and work on the bar?
First of all, stay calm, because taste is only part of flavour perception. And yet it is not exactly irrelevant for bartenders who work on the fly with sweet-acid balances and bitter ingredients. In any case, it is worth hiring a varied team and developing or tasting recipes together. Any criticism should be accepted and taken seriously. Even a very experienced colleague cannot simply train away their possible sensory limitations. In this respect, the opinion of a service employee or guest is just as valuable as their own and should be treated as such.
“The most important palate is always that of our guests”
When dealing with customers, it pays to develop a good service strategy for recommendations and complaints. Taste is subjective. So wounded bartender pride is out of place if a drink comes back once, as are comments about special requests and preferences. The guest at the bar just sent back a Negroni because it was too strong and too bitter? Careful, there is a good chance that this person can taste better than you. With a little empathy and tact, they’ll like the second round better. The most important palate is always that of our guests. We live in different flavour worlds. On the one hand, this complicates our job, on the other hand, knowing this makes us better bartenders.
