Why four’s the aroma limit

four aromas

I recently had an article published in Circle Update (the magazine of the Circle of Wine Writers). It concerned the number of aromas used in wine tasting notes. If you are interested you can view and download a PDF offprint of the article here: Why four’s the limit.

It draws heavily on a four-part series of blog posts I wrote late last year. Compared with the Circle Update article, these contain more words – not necessarily a good thing – but also, in “the science” post, there is considerably more information about the scientific basis for the notional limit of only four aromas being identifiable in blends.
How many identifiable aromas in a wine – the dilemma
How many identifiable aromas in a wine – the science
How many identifiable aromas in a wine – tasting experience
How many identifiable aromas in a wine – my conclusion

How smell is like vision, and what that means for wine

Considering the very different impressions that vision and smell make on us, there are surprising similarities in how the two senses are processed before they reach the brain. And it is quite possible that these similarities may throw some light on how we describe the aromas we find in wine.

The olfactory bulb (we actually have two of them) is an elongated protuberance lying close to the underside of the brain, but attached only at the back end. The surface of the human olfactory bulb has on it some 6,000 spherical bundles of cells called glomeruli, each one being connected by neurons to several thousand olfactory receptors in the nasal cavity. When odorous compounds enter the nasal cavity, each glomerulus is activated to a greater or lesser extent, creating a pattern of activity on the surface of the olfactory bulb that is a representation of the odours detected. That pattern can be regarded as analogous to the pattern of activity on the retina of the eye when an image falls on it. In fact the similarity does not stop there, because just as the image on the retina is further processed to facilitate detecting edges and motion, the activity pattern in the glomeruli is also enhanced by subsequent layers of cells in the olfactory bulb. Examples of smell images, reproduced from Gordon M Shepherd’s book Neurogastronomy (reviewed here), can be seen below – click to enlarge and make the text legible.smell images

In the same book, Shepherd proceeds to speculate that the smell images created by glomeruli activity are similar to visual images of faces. He suggests that this explains why smells, like faces, are difficult to describe in words but relatively easy to recognise. As a result, if asked to describe a smell we need to resort to comparisons with the smells of well-known objects. Also, neither smells nor faces are processed as the sum of distinctive component parts – we tend to recognise both of them holistically, not so much by the detail as by a general impression, and the relation between the parts of the image. Only occasionally can we recognise a face if we only see a small part of it, and usually only for faces we are very familiar with.

This speculation of Shepherd’s can be plausibly taken even further, and related to how we recognise and describe wines. Regardless of whether we are nosing a complex wine or sniffing a single chemical compound, at one level in our perceptual system the result is a glomeruli smell image. I would propose that, in the case of wine, certain aspects of that smell image may remind us of the smell images of other objects – blackcurrant maybe, or lemon – which then become the descriptors we use for the wine. In some cases, the aspects of the smell image that cause us to identify other objects in wine may arise from chemical compounds in common, but this need not necessarily be the case and similarities might be coincidental. The aspects in common may be as simple as discrete fragments of the smell image, or possibly with their root in common relationships between different parts of each image. To continue with the face analogy, the identifying of blackcurrant in a wine could be like saying that a baby’s face has his grandfather’s eyes – the eyes need not be identical, but there is however something that seems somehow similar, perhaps the relationship between the eyes and the nose. Something else that has a counterpart in wine is the idea that if we are very familiar with a face is it easier to recognise it from a partial image. In a smell image of wine, presumably the types of fruit etc. we may recognise in it are only partially represented, and that could explain why it we are more likely to recognise the aromas we are more familiar with, either from the experience of the actual fruits or from other wines.

I totally accept that most of this is speculation on the part of Shepherd and me, but nevertheless I think how we experience and describe wines is consistent with the idea of smell image recognition, and an interesting way of conceptualising it. Only time and more research will be able to refute or support these ideas.

Tasting order and wine scores

It is well known that your perception of a wine is affected by what was tasted immediately beforehand. This is similar to how other senses behave. If, for example, you sit in the dark for several minutes and then expose yourself to normal daylight, it seems to be exceptionally bright until your eyes adjust. With wine, if the previous wine was flabby, your current wine will tend to taste sharp; if it is was very dry, then sweet, etc.


However, in addition to that effect, the order in which you taste wines can help determine how much you like them. I have already written about Antonia Mantonakis’ research, where she presented sequences of wines to consumers, and asked which wine they liked best. In actual fact the same wine was offered in each glass, but the tasters still expressed a preference. For shorter sequences (2 or 3 glasses) they tended to prefer the first wine tasted, while for longer sequences (say 5 glasses) they preferred the last one. If you are thinking “that just goes to show how little the average consumer knows about wine”, you should be chastened by the fact that those with better wine knowledge were even more prone to this bias. But how much practical significance does it have? The consumers were after all asked to distinguish between identical wines, and they may have thought any differences were very small.

Later work[1] by French researchers throws more light on this order effect. Here the experiments were performed on wine professionals  tasting in competitions that awarded medals to Beaujolais Nouveau wines. Here, in each of two competitions of around 400 wines, approximately 100 tasters scored wines on the 100 point scale, each taster being given two flights of between 10 and 12 wines. But into each tasting sequence of wines registered in the competition, the experimenters added the same wine (an unregistered one) into the first and penultimate positions. For each competition, the average score for the penultimate wine in the sequence was greater than that for the first wine: 82.99 vs 79.78 for one competition, and 83.93 vs 81.78 for the other. Those differences are not only statistically significant, but also significant from a practical point of view. To get some feel for the practical significance, note that the difference between a silver and gold medal winning scores is 6 points. Also, as the required score to achieve a silver medal was 81, in one of the competitions the position of the wine would have decided whether the wine received a bronze or silver medal.

If wine scores and medals are important to as a consumer, then you should probably be concerned about the sequencing used in tasting flights. On the other hand, if you do not pay much attention to such things, you can now add order effects to the list of reasons that justify your position.

[1] Carole Honoré-Chedozeau, Jordi Ballester, Bertrand Chatelet and Valérie Lempereur, “Wine competition: from between-juries consistency to sensory perception of consumers”, BIO Web of Conferences 5, 03009 (2015)

Gestalt perception of flavour

coffee_cuppingGive your Man On The Street a glass of wine and ask him how it tastes, and you could well get the response “it tastes like wine”. Nothing wrong with that – it is what might be described as a gestalt perception. Wine contains hundreds (if not thousands) of chemical compounds, many of which will individually give rise to different flavours, but overall the impression is clearly recognised as wine. In the same way, when someone is shown a chair they will immediately recognise it as a chair – they won’t say there are four near-vertical sticks of wood supporting a horizontal square board etc.

It is only people who are relatively skilled in wine appreciation that will dive into a more detailed description like “blackcurrant with a hint of coffee on the finish” – and if we are honest “it tastes like wine” is arguably more useful in many circumstances. Also note that, while we might be feeling superior for spotting the nuances in our glass, we are saying one of the flavours is coffee. We have an idea of a generic coffee flavour, in the same way as many have a generic wine flavour. But coffee is another complex drink that experts analyse and describe in terms of other flavours. Worse than that: wine is a descriptor that is sometimes used in coffee tasting notes, in the same way that coffee is used for wines. So in an extreme case we could have a wine that happens to taste like a coffee that tastes of wine!

Joking apart, the idea that the human perceptual system can sometimes regard aromas that are chemically complex as a single entity, and sometimes analyse them into component parts, is an interesting one. I mentioned in an earlier post that, when considering the number of identifiable aromas in a wine, a chemically complex recognisable aroma behaves like an aroma that is due to a single chemical compound. In fact, the researchers reference other work showing that the two aroma types seem to act in very similar way even at a level as low as the olfactory bulb. But surely that cannot tell the full story. It is undeniable that, for some at least, wine does not merely taste of wine. Neither does coffee merely taste of coffee.

How does a sniff compare to a sip?

I have received no comments directly addressing the issue posed in my last blog post: whether aromas detected on the palate mirror those on the nose or not. However, I did get 34 wine-enthusiast responses to a poll on the UK Wine Forum.


The results are not entirely clear cut, and my question could perhaps have been better, but it does seem that experiencing very different sets of aromas on the nose and palate tends to be the exception rather than the rule. I would thus very tentatively suggest that the results support the applicability to wine of the experiments regarding the number of aromas we can detect.

However we need solid experimental evidence to be sure. It is quite possible that those who detect different aromas when the wine is on the palate are imagining the different aromas – in the sense that there are no chemicals present that could account for them, that is. But, neither can we rule out the possibility that those who detect the same aromas on the palate do so due to expectations created by the wine’s nose aromas.

Aroma recognition by sniff and sip

In everyday life, and in wine tasting notes, we often distinguish between what we smell through our nose, and what we taste when something is in our mouth. However, in practice the distinction is not so simple, and smell is important in both cases. In the image below, you can see that in fact we have two very different openings through which odours can gain access to the olfactory bulb where smells are detected: through the nostrils (orthonasal olfaction), and through an opening between the mouth and the back of the nose (retronasal olfaction).

When we sniff a wine, we perceive its volatile molecules though our nostrils, and that is all. But when we sip it, we sense the wine through a number of distinct mechanisms. With the tongue we experience relatively simple flavours: sweet, sour, salt, bitter and umami. On all the inside surfaces of the mouth, we experience physical sensations such as the temperature of the wine, its weight and viscosity, and we may also feel a slight alcoholic burn. At the same time, and most importantly, the olfactory bulb senses the volatile components retronasally. It is this that gives rise to how we perceive the most interesting aspects of wine, which are its volatile components, e.g. blackcurrant, lemon, vanilla, coffee, leather – in fact everything we call flavours apart from sweet, sour, salt, bitter and umami. Because we experience the volatile components as the wine is in the mouth, we are given a strong impression of sensing them on the tongue, but this is an illusion.

So, and here I get to the nub of this blog post, if we smell for example apples and lemon when we sniff a wine, wouldn’t you then expect to taste apples and lemons when it is in your mouth. And if it smells of oak, shouldn’t it taste of oak? Probably very few of us have actually chewed on a piece of oak, and the same goes for other non-food items, but we seem intuitively to understand how things should taste if we can smell them. As the volatile molecules are the same, as a starting point I would indeed expect the taste to be consistent with the smell.

However there are complicating factors. One is that the relative concentrations that arrive at the olfactory bulb might differ in each case, as molecules are carried there in different ways, and the temperature of the liquid will be different. As a result, the dominant aroma might be different in each case.  The concentration differences might also be such that certain aromas are above their detection thresholds in one case but not the other. These effects can be mimicked to an extent by sniffing wine at different temperatures, in different glass sizes and shapes, and after the wine has been agitated to different degrees in the glass, all of which can cause a wine to smell differently.

Synaesthesia is another complicating factor. Above I analysed how the flavour of wine in the mouth can be broken down into the taste on the tongue, aromas in the nose, and physical sensations. However that is a simplification, because the different senses interact with each other. For example, Westerners are more sensitive to almond aromas if there is a drop of a sugar solution on the tongue, amazingly even if the sugar concentration is below the detection threshold. That is one interaction we know about, but it is a safe assumption that there are many others. Thus, synaesthesia might be another reason why aromas could be perceived differently orthonasally and retronasally.

But what happens in practice? Well, people seem to differ alot. Speaking personally, the flavours I get in the mouth are nearly always very similar to those I get on the nose. Sometimes one flavour might be more dominant on the palate than on the nose, or some might be wiped-out by excessive acidity or astringency, but that is about the extent of the differences for me. On the other hand, some tasting notes have totally distinct sets of aromas for orthonasal and retronasal olfaction. For example, take the one I referred to a few weeks ago in my first post about the number of aromas we can identify in a wine: fresh fruit aromatics of mandarin orange, black raspberry and grilled watermelon spring from the glass. On the palate, pretty nuances of rose petal, gardenia and oolong tea mingle with herbal notes of sandalwood, star anise, fresh thyme and fennel seed. So that is 3 aromas orthonasally, and 7 totally different ones retronasally.

In fact, it was my number-of-aromas posts that got me thinking about this, as the experiments, which found we can recognise no more than 4 aromas in a blend, were all based solely on orthonasal olfaction. So does retronasal olfaction make these experiments of limited applicability to wine, or are markedly different aromas detected retronasally merely a tasting note conceit?

I suspect the latter, but I really don’t know and I would love to hear how much wine orthonasal and retronasal aromas differ for you. I am going to try to run a few straw polls in various places, and will report back. Feel free to leave comments here too.

Update: My reporting-back can be seen here.

How many identifiable aromas in a wine – my conclusion

I have now done enough scene-setting and pussyfooting around: see my previous three blog posts (in chronological order 1, 2, 3). It’s time for me to nail my colours to the mast and say what I really think about tasting notes that mention many different aromas when science tells us we can only identify four in a mixture.

Jan_Brueghel_I_&_Peter_Paul_Rubens_-_Smell_(Museo_del_Prado)First of all, I cannot find any particular problem with the scientific evidence for our poor ability to identify aromas in a mixture, and I see no reason to doubt its applicability to wine. If anything I would expect it to be an easier task to identify aromas in the experimental situation than with wine, as in the experiment there were always subsets of the same 7 or 8 odours, as opposed to the much larger number that people find in wines.

There is a lingering doubt in my mind because the experiments presented odours only to the nose. With wine however, aromas are also detected when it is in the mouth. Does that cause a greater number of aromas to be detected in total? My personal experience suggests that happens only very occasionally, and to a small extent. However, in the tasting note example I gave in the introductory blog post for this small series, the aromas detected on the nose and palate are markedly different. I may return to this issue in the future, but my initial feeling is to go with my personal experience. And what about letting a wine develop over a few hours or days? Does that let additional aromas develop and become identifiable? It is possible, but again in my experience it is rarely the case.

I acknowledge that there is also experimental evidence that it is possible to tell if a single very familiar odour is present in mixture containing up to 12 odourants. Additionally there is anecdotal evidence of perfumers and chefs being able to detect single missing ingredients in complex familiar recipes. But these tasks are very different to identifying aromas in an unfamiliar wine.

For now, let us take the identification of an odour object in a wine literally, by which I mean that identification means there are key aromatic compounds in both the wine and the actual odour object. With this literal interpretation, I think it is fair to say that the limit of four correct identifications will apply. Indeed, the experiments suggest that even with fewer named aromas it is unlikely they will all be correct.

The literal interpretation of aromas I have just described is not totally unreasonable. Certainly in some cases it seems that the same chemical is responsible for the aroma in both the wine and the real aroma object. Rotundone, which is found in black pepper and Syrah, is one example. However, aroma objects mentioned in the tasting note may merely be reminiscent of the real thing. Or, as some less kind people might put it: imagined or made up. In these cases, there can clearly be no limit of the number of identifiable aroma objects, but by what criteria can we judge the value of such lists?

For me, the main criterion for a successful tasting note is its ability to communicate the experience of drinking the wine to the reader. And here I mean to communicate accurately; not just to give an impression of what the experience might hypothetically be.  When I am tasting, the correspondence with tasting notes independently written by others is usually minimal. I have seen no formal studies into how common this experience is, but we can also get hints by comparing tasting notes of the same wine written by different people. Usually there is little similarity, and sometimes the differences are huge. It is interesting to speculate about to what extent the differences are due to the subjective nature of taste, and to what extent it is imperfect communication; but differences there are.

Speaking personally, the tasting notes I find communicate best are those where the aromas listed are few and vaguely described. For example, it can often be accurate, and still helpful, to identify citrus fruit in a wine. But when someone else describes a wine as tasting of lemon, I often decide it is closer to lime. And does anyone actually care? It is difficult to imagine a disgruntled customer returning a bottle of wine to a shop because the type of citrus fruit was incorrectly described on purchase. The precision of description is linked the issue of the number of aromas: one person’s citric could be another’s lemon, lime and clementine. The level of detail we use in tasting notes is another interesting topic to which I might return.

In summary, as promised, here are my colours on the mast stated with an unjustified sense of certainty. There are two reasons why I am suspicious of tasting notes with a long list of aroma objects:

  1. If you take a more literal interpretation of aromas in tasting notes, it is impossible to produce correct lists containing more than four aroma objects .
  2. I am not convinced about how useful long lists are anyway. I favour a shorter tasting note that contains only the dominant aromatic components, and one that is not over-specific in its aroma descriptors.

In the words of Carveth Read: It is better to be vaguely right than exactly wrong.

How many identifiable aromas in a wine – tasting experience

I continue to investigate the number of aromas we can detect in a wine. There seems to be a conflict between scientific research, which has shown that we are incapable of identifying more than four odours in a mixture, and the testimony of wine tasters who name as many as 10 or more aromas. For the story so far in more detail, see my previous two blog post here and here. Now I will look more closely at how wine tasters come to identify so many aromas, and what it means when they do.


I know that some tasters sample their wine over the course of an evening, with and without food, and possibly even continue with the same bottle over two of more days. That is potentially going to lead to longer tasting notes, and the naming of more odours, because the wine, the context, and even the taster might change over that period, and the changes could result in different proportions of various aromatic chemicals, different chemicals becoming available to the nose in the form of vapour, and different taster sensitivities.

Other tasters however are perfectly capable of reeling off a list fruits, herbs and spices within the space of a few minutes. The people I have seen doing this have all been Americans with some level of sommelier qualification, and my preliminary conclusion is that it is related to their training and culture. In the case of professional wines critics who name many odours in a tasting note, I suspect those lists are also usually produced quickly due to pressures of time. This is a very different situation to the tasters who make their notes over an extended period, as nothing has chance to change much after the first nosing of the wine.

But do the odours named in these long lists actually exist in any real sense in the wine? Here, by “in any real sense” I mean as chemical compounds in concentrations that could stand any chance of detection. Note that Laing’s limit of four applies not to the taster’s imagination, but to the correct identification of odours physically present in the mixture as chemicals. To answer the question about whether the odours exist, we would need to perform a detailed chemical analysis of the wine.

Even if the odours do not really exist, there may be understandable reasons why they may be perceived. In Avery Gilbert’s book What the Nose Knows, there are several examples of how suggestible we are when it comes to our sense of smell, and suggestions of what we might find in a wine can come from many sources. The best known example is perhaps that the addition of red food dye to white wine prompts people to find aromas usually associated with red wines. In real life all manner of things might suggest what aromas should be in the wine, not least any hints as to what type of wine is in the glass. There is no shame in being suggestible in this manner. It is simply the way we humans work perceptually, and as we also are the ones that drink the wine does it really matter?

We must also acknowledge that odour perception is a complex multimodal process, and seemingly unrelated stimuli can affect our sensitivity to odours in ways that are not explicable by suggestibility. For example, a drop of a sweet substance on the tongue has been found to increase the sensitivity of Westerners to an almond aroma. Effects like that could also cause us to identify more odours than Laing’s experiments suggest we should.

Finally, I am convinced that some tasters fabricate flavours because they feel, for whatever reason, a few more are needed. I too would do that under certain circumstance – if I were taking some sort of test for example, and I was required to list a certain number of flavours. If you have a good idea what the wine is, it is very easy to throw in a few extra flavour descriptors that would not raise eyebrows. Claret? OK, that will be blackcurrant, pencil box and French oak then. In fact, come to think, I have done it, in a tasting competition a few years ago when I really thought the wine was so mediocre there was little to say about it.

On the subject of how many identifiable aromas there are in a wine, that is now all the detail and preliminaries out of the way. So far I have tried to be as objective as possible in describing the evidence, but in my next post I promise will stick my neck out and say what I really think. I just have to first decide what that is.

How many identifiable aromas in a wine – the science

This is the second post in a series that looks at the number of aromas we can detect in a wine. My first post explained that many tasters claim to be able to identify several aromas in the same wine, while scientific research has shown that we are incapable of identifying more than four. Here I will explain more precisely how the research was carried out, and what it found.

The research was carried out by David G Laing and co-workers in the 1980s and 90s. As far as I know it has not been replicated in other laboratories, but as will become clear the experiments were effectively repeated in the same laboratory, and as far as I know the results are not controversial. They are, for example, described in Avery Gilbert’s book What the Nose Knows without being questioned.

In Laing’s first published work on this subject[1], mixtures of odourants were delivered to the noses of the subjects in vapour form through a duct 150cm long and 55cm in diameter, and the subjects were asked to identify the odours present. Each of the 7 odourants was a single chemical compound with a distinctive smell, and introduced to the subjects under its everyday name: vinegar, almond, spearmint, fruity, cloves, orange or camphor. Odourant concentrations were chosen to be moderately strong perceptually, and roughly equally strong for all odours individually. The odourants and were also known to be identifiable in binary mixtures in the chosen concentrations. The mixtures were created in vapour form for delivery to the subjects’ noses. Vapour, rather than liquid, mixing was chosen to reduce the possibility that the odourants would react chemically. It seems to me that all reasonable steps were taken to give subjects the best possible chance of identifying the odours.

The subjects were first allowed to familiarise themselves with the individual odours for several minutes. Then they were given mixtures that varied in terms of the odourants used and the number present, and asked to identify the odours in the mixture. The results are summarized in the figure below[1], which is the basis for the assertion that no more than 4 odours can be identified.laing_1989A few possible reasons for the low number of identifiable odours spring to mind: maybe the subjects were not skilled enough, or maybe the odours chosen were particularly difficult to identify. The investigation of those two possibilities was the subject of two further studies [2, 3], which were based on the same experimental setup.

To determine the effect of training and experience[2], two different sets of subjects were used: experts, and trained non-experts. The non-experts were trained over the course of 5 days, and on day 5  they were tested to ensure they could reliably identify all 7 odours when presented individually. The other group were expert perfumers and flavourists; they were “highly familiar with the test odourants, had daily experience with odour discrimination, and had a prerequisite before entering their respective professions of an excellent ability to discriminate and identify odours”. The experts and trained non-experts performed slightly better than the subjects in the initial study, with the experts being the most competent, but nevertheless the number of correct judgements still dropped to negligible levels when more than 4 odourants were presented.

The next study[3] looked at the importance of the type of odours used in the mixtures. A panel of 10 perfumers and flavourists selected two sets of 8 single compound odourants: good and poor blenders. The poor blenders were judged to be perceptually very different, and thus easier to identify in mixtures than good blenders. The common names of the good blenders were rose, musky, cinnamon, coconut, fruity, orange, burnt caramel and almond, while the poor blenders were bad breath, mushroom, cut grass, Dencorub, garlic, antiseptic, aeroplane glue and mandarin. The results were as suspected in the sense that the poor blenders were easier to identify. However, the differences were not large, and for 5 or more poor-blender odourants the number of correct identifications was still very low indeed.

The fourth study[4] brought the experiments one step closer to the reality of wine. Here, none of the odourants were single chemical compounds, but complex mixes of chemicals usually identified as a single odour: smoky, strawberry, lavender, kerosene, rose, honey, cheese and chocolate. Again, the results were similar to those of earlier studies, suggesting that we identify the smell of familiar objects as a single gestalt odour, even if multiple chemical compounds are involved in creating it.

In the last article of Laing’s I will discuss here[5], subjects were trained to identify the test odours, and then required to detect a single highly familiar odorant in stimuli consisting of one, four, eight, twelve, and sixteen odorants by using a selective-attention procedure. Identification fell to chance level when sixteen odorants were present. Unfortunately I only have access to the abstract of this article, but I presume that the important distinction between this and earlier studies is that the subjects were attending only to one odour, and that the odour was highly familiar. It seems that it was those factors that enabled some people to identify an individual odour in blends of twelve, which is a big improvement on the limit of 4 found in earlier studies.

For now, I shall let you draw your own conclusion on the applicability of these results to wine tasting notes.  I will return to that subject eventually, but in my next post I should like to take a closer look at how wine tasters arrive at long lists of aromas that seemingly break Laing’s four odour limit. In the meantime, if you found this blog post interesting you might also like to take a look at this one on the subject of olfactory white.

[1] Laing, D. G., and Francis, G. W. (1989). The capacity of humans to identify odors in mixtures. Physiology & Behavior, 46(5), 809–814.

[2] Livermore, A., and Laing, D. G. (1996). Influence of training and experience on the perception of multicomponent odor mixtures. Journal of Experimental Psychology Human Perception and Performance, 22(2), 267–277.

[3] Livermore, A. and Laing, D. G. (1998). The influence of odor type on the discrimination and identification of odorants in multicomponent odor mixtures. Physiology and Behavior 65 (2): 311– 320.

[4] Livermore, A. and Laing, D. G. (1998). The influence of chemical complexity on the perception of multicomponent odor mixtures. Perception and Psychophysics, 60 (4): 650– 661.

[5] Jinks, A., and Laing, D. G. (1999). A limit in the processing of components in odour mixtures. Perception, 28(3), 395–404.

How many identifiable aromas in a wine – the dilemma

Tasting notes with flowery language and long lists of descriptors divide opinion: Many wine geeks seem to expect them, and writers oblige, but on the other hand the wine-drinker-in the-street, when not ignoring them completely, will probably dismiss them as nonsense. Personally, I look at them quizzically, and ask myself if they are really communicating anything of value. There are a number of contentious issues in tasting note style and content, but in this and the next few blog posts I want to tackle just one: the number of aromas mentioned.

By aroma I mean something that is detected by the nose. It can be detected either ortho-nasally, by sniffing; or retro-nasally, through a passage between the back of the mouth and the nose. Because retro-nasal detection occurs when food or drink is in the mouth, most people get a strong but false impression that it is the tongue doing the sensing. Examples of aromas are orange, apple, vanilla, chocolate and coffee, as opposed to other non-aroma sensations like sweet, salt, acid and bitter, which are detected by the tongue.

The problem with the number of aromas in some tasting notes is that a series of experiments performed in the 1980s and 90s showed that people are incapable of identifying more than four in a mixture. So how can tasting notes meaningfully refer to more than four? For example, a tasting note taken from International Wine Cellar, lists ten aromas by my counting: fresh fruit aromatics of mandarin orange, black raspberry and grilled watermelon spring from the glass. On the palate, pretty nuances of rose petal, gardenia and oolong tea mingle with herbal notes of sandalwood, star anise, fresh thyme and fennel seed. So what is happening here? Was there a problem with the experiments that were performed? Or, after the first four most prominent aromas mentioned in the tasting note, are we merely reading the results of an overactive imagination?

I shall be weighing the evidence for these alternatives over the next few blog posts, starting with an examination of the science. I’m trying to keep an open mind, but am currently leaning a little in the direction of the scientific research.