Jamie Goode: Can professional assessment of wine be objective?

It’s perilous to practice philosophy without a licence. Having said this, I think it’s important to look at the theoretical underpinnings of what we do when we taste wine professionally. So as a non-philosopher, I’m daring to enter the dangerous territory of the philosophy of perception – if you are a philosopher by training, then go easy on me.

Why is the theory behind wine tasting important? It’s because this can inform how we act, how we teach, how we communicate and how we set exams (where there is a tasting component to them). A few years ago (2016) I wrote a book on the topic, called I Taste Red (University of California Press, Berkeley). My interest in this subject was initially prompted by a book that I edited back in my day job, based on a scientific meeting our organization held. Titled Higher Order Processing in the Visual System (Novartis Foundation Symposium 184, Wiley, Chichester, 1994), it alerted me to a significant fact: our sensory systems don’t work like measuring devices. Rather than give us a read out of what is out there, they do a lot of processing before we are consciously aware of the outside world at all. The brain creates a model of the environment we encounter, and this model – our internally generated ‘reality’ – is what we use to perceive. This is important to understand.

My interest in perception was further prompted by a conference held a decade later on the philosophy of wine, convened by Professor Barry Smith, then exclusively a philosopher, but who has since gone on for form an interdisciplinary research group looking at the senses from all angles. As I sat and listened to the presentations by professional philosophers, I thought that there was room here for some science. Neuroscience has advanced a lot in terms of understanding perception, and these insights can constrain philosophical enquiry in a useful way. Philosophy is doing something different to science, of course, but the constraints that the science of perception bring to the philosophy of perception are helpful ones.

Wine writers often seem conflicted about judgements of quality. When they speak to consumers, they are quick to say that wine appreciation is subjective, and that everyone should be free to like what they like. At the same time, they make recommendations, rate wine, and try to point people towards the ‘best’ wines, making pronouncements that seem very far from subjective. Of course, for someone’s personal consumption, they are free to like whatever they want. If they like their wines bretty, or oxidised, that is their choice. But when we act in a professional capacity, whether as critics, or wine buyers, or wine judges, we are treating the flavour of wine as an objective property of that wine, something we are trying to reach by judging and tasting in ideal conditions, using the right glassware and so on. We behave as if the taste of a wine is objective, even though we claim subjectivity.

What do the terms objectivity and subjectivity mean? Their definition can vary a little, but here we use them to distinguish properties that are of the object, and properties of the subject. The weight of a bottle of wine, or its height, or its diameter are objective properties of the wine. They can be measured, and if 10 people measure them accurately and carefully, there will be close agreement. On the other hand, if 10 people are discussing the acidity in a Riesling, we might expect a range of views. Some might say that the acidity is too high; others might say it is just right; others might say that there isn’t enough. We might suggest on this basis that the perception of acidity in a wine is subjective. So far, no controversy.

But let’s look at the nature of perception itself. We model the world around us, and perceive this model of the world. This is true for the visual system, but it’s also true for flavour perception as well, which is multimodal, involving different sensory modalities, principally taste, smell, touch and vision. This information is gathered together, and joined up into a unified perception of flavour. From the information out there (the objective reality) the brain synthesizes what we perceive as flavour, extracting the useful information and discarding that which isn’t needed. It follows from this that all human experience is subjective, and on one level we can’t have knowledge of what another’s experience is like: we are all perceiving a model of reality that our brain creates from what is out there. Add into this picture the fact that at the sensory level, there is inter-individual variation: we differ in the density of taste receptors in the mouth, and we have genetic differences in our taste receptor repertoire and also the particular set of olfactory receptors that we possess. Furthermore, experts use knowledge when they come to perceive wine and this knowledge can change the nature of the perception that we experience. And there’s some evidence that language also affects perception.

So we can’t argue with the assertion that wine tasting is subjective. More broadly, we cannot disagree with the statement that all perception is subjective, because we each generate our own ‘reality’.

But if we leave things there, we put ourselves in an odd position. If wine tasting is entirely subjective, then our wine assessments are merely autobiography, and are not relevant to anyone else. And why is it, if tasting is entirely subjective, that we behave as professionals as if it were objective, and our verdicts were normative – that we’d expect them to apply to others as well?

One answer is inter-subjectivity. In the wine trade we decide which are the best wines together, as a community of judgement. We open bottles, taste the wine, and we talk. Over time, a sort of  consensus emerges as to which wines are the best. For our opinions to be included in this consensus building, we need to have certain levels of competency. We must be open-minded and fair, we must have normally functioning senses of taste and smell, we must have some experience of tasting wine. And then we must be able to communicate our perceptual experiences properly.

But we can move beyond inter-subjectivity. I used to believe that flavour only exists in the brain, which is a viewpoint that neuroscientist Gordon Shepherd has put forward in his books, and which tallies with the idea that flavour is multimodal and is constructed in the brain with lots of processing steps before we are consciously aware of it.

‘Flavor is not in the food; it is created from the food by the brain. There is a clear analogy with other sensory systems. In vision, for example, color is not in the wave lengths of light; color is created from the wave lengths by the neural processing circuits in the visual pathway; these include center-surround interactions for color-opponent mechanisms. Similarly, pain is not in the agents that give rise to it, such as a pin or a toxin; pain is created by the neural processing mechanisms and circuits in the pain pathway, together with central circuits for emotion.’

Gordon Shepherd, 2015, Neuroenology: how the brain creates the taste of wine.

I’ve since changed my mind, after listening to the arguments put forward by Barry Smith. He argues that flavour is an objective property of the wine. Wine has a chemical composition, and in the wine exist many flavour-active molecules that we perceive when we taste the wine. Together, these molecules create the flavour of the wine, and this is an objective property of the wine – wine flavour – which we then attempt to ‘get’ when we taste the wine. If flavour was just in the brain, and not a property of the wine, what happens to the flavour of the wine if we taste from a bottle, then recork it, then revisit it the next day? Does it go away, only to reappear when we return to tasting?

Yes, our perception of this wine flavour is subjective, but we are trying to taste as objectively as we can. Consider sensory analysis, where panels of tasters look to remove all the background noise from tasting in order to produce data that can then be analysed statistically. Or look at tasters who are examining wines blind with a view to uncovering their identity, or competition judges who are trying to assess quality across a range of wines to award medals.

Seeing flavour as an objective property of the wine makes sense of the way we practice wine tasting as professionals. We optimize the conditions of tasting, in our attempt to get as close as possible in our subjective tasting to the objective property of wine flavour. We taste together and compare opinions. We practice tasting so we can better at it. Students of wine are taught how to assess wine in a standardized manner: it doesn’t always work easily, because by breaking wine into its components in order to assess it we are trying to undo the work the brain has done bringing all these components together in the first instance to create our unified perception of flavour.

It follows from all this that wine tasting is really complicated, and hard to do really well, and we struggle against the way our brain works in modelling reality, as well as our biological differences and differences in experience, when we try to taste objectively. There will always be subjectivity in wine tasting, even for skilled professionals. But by doing our job well, we can rescue quite a bit of objectivity, and I think it’s really helpful to consider the flavour of wine to be a property of the wine, and really unhelpful to think of the flavour of wine only existing in each of our heads, inaccessible to others.

• Jamie Goode is a London-based wine writer, lecturer, wine judge and book author. With a PhD in plant biology, he worked as a science editor, before starting wineanorak.com, one of the world’s most popular wine websites.