tasting: subjective or objective?
Exploring the nature of wine perception
guilty of it. When I’m presenting wine tastings to consumers,
I’ll encourage them to trust their own palates, and not to be
deterred by the seeming mystical ability of some wine writers to
detect a shopping list of flavours, spices and fruits in a simple
glass of wine. ‘There is no right and wrong in tasting wine,’ I
find myself saying. ‘Your views are as valid as those of the
expert.’ Effectively, I’m telling them that wine tasting is
then in my working life, my colleagues and I act as though wine
tasting were anything other than subjective. We give wines a
numerical score; we argue about the merits of particular bottles; we
take part in competitions that award medals to some and not to
others; we think that our expertise in wine assessment is of a level
where we can charge others for it.
which is it? We can’t really have it both ways. To suggest that
wine tasting is merely subjective is not intellectually honest in
light of the way that we, as professionals, work. This conundrum is
highlighted by philosopher Cain Todd in his recent book.
Equally, anyone who has been around wine for a while can’t really
argue that wine tasting is utterly objective. So the goal of this
article is to begin to explore just how subjective or objective wine
tasting actually is.
a hidden set of assumptions underlying attempts at wine education,
all the way from the most basic WSET (Wine and Spirt Education
Trust) courses up to the tasting exams of the MW (Master of Wine)
qualification. This nested set of assumptions concern the objective
nature of wine tasting.
begin with the assumption that the taste of wine is a property of
the wine. They continue along the line that as we taste together, we
are all experiencing pretty much the same thing as we taste, as long
as we have a properly functioning nose and palate. There is the
recognition that good tasters can have subjective preferences, but
that these can be set these aside to facilitate objective wine
when it comes to competitions and the act of wine assessment and
criticism, this assumption of objectivity continues. Some notable
wine guides and websites are in the business of charging readers for
access to tasting notes and scores of wines. Because the wine world
is now a large one, these sites involve teams of tasters. The belief
underlying this is that this currency of a ‘professional tasting
note’, when authored by a competent wine critic, is of some value
because competent critics will read the wine correctly. It follows
from this that it doesn’t really matter who authors the note from
the team, as long as that wine is covered.
increasingly convinced that there is no single correct way to read a
wine. There are two reasons I have come to this conclusion. First,
from working up from the physiology, psychology and neurobiology of
perception, and second from working down from looking at wine
assessment in practice.
assessment in practice
start with the latter. It is plain to see that even the most
experienced and acclaimed wine professionals disagree quite
significantly in their assessments of wine. This is shown
beautifully in the tastings section of the magazine The
World of Fine Wine. Here we have teams of three experienced
tasters looking at the same wines together. The great thing about
these tastings, though, is rather than average out scores to reach
some sort of consensus, the individual scores of each taster are
given. Often there is a large variance.
wine tasting were objective and there was one correct way to read a
wine, then the only conclusion that could be made is that where
tasters disagree significantly, one of them has got it wrong. But
this is an uncomfortable conclusion that doesn’t chime well with
course, there is such a thing as ‘getting it wrong’ in tasting
wine, even if we are to take the view that there is a strong
subjective element in wine tasting. Broad-brush categorizations of
wine by quality level are appropriate and fairly robust among
example, wine pricing varies dramatically, and such price
differences would not persist if there was not such a thing as
differences in quality levels. The word ‘quality’, however,
needs to be used with care here, because we are entering the realm
of aesthetics. Who gets to decide that one wine is great and one
wine ordinary? Or that a wine is faulty? [After all it is quite
common to find wines that are highly acclaimed by some but dismissed
as faulty by others: for example, wines affected by Brettanomyces
or with some reduction characters.]
characteristics of wine are regarded as positive attributes, and
contribute towards a wine’s quality level. We have to tread
carefully here, because we are dealing in generalities, not
absolutes. Factors such as balance, concentration, elegance, purity
and complexity are seen as positive attributes. You might reasonably
expect professionals, when faced with an array of wines of rather
different categories, to be able to separate these wines out
according to their quality level, in a very general sense.
is a level that is fairly objective, and one which is loosely
reflected in the price of the wine. Take for example, a simple
Bourgogne rouge available for £6 in a supermarket, compared with a
Grand Cru red Burgundy from a good grower and decent vintage,
costing £60 in an independent merchant. Even a vaguely competent
taster could attribute quality correctly here. If a taster
pronounced the former to be a better wine, then by all accepted
standards of quality in wine, they got it wrong.
it’s hard to think of too many examples like this when we get to
wines of more-or-less equivalent price. Different professionals
apportion value to certain characteristics of wine in different
ways. For example, I love the elegance and freshness of some of the
‘natural wines’ that have emerged in recent years, largely from
lesser French and Italian wine regions; many others, whose palate I
respect, just don’t get them. Some critics swoon over ripe, dense,
dark, concentrated red wines with lavish new oak; others criticize
these wines for being made in an international style. Some prefer
their wines young; others like them very old, at a stage others
would refer to as senescent.
differences of opinion transcend preferences. Most professionals are
able to have their own style preferences while still being able to
appreciate the quality of wines that are not to their liking. There
is, however, a level beyond preferences where professionals score
certain wines down as unbalanced, acidic, light or clumsy when
others rate these same wines very highly.
divided are wine professionals about some wines that there are only
two ways out. The first is to question the critical competence being
displayed; the other is to recognize that wine assessments have a
large degree of subjectivity to them. The former is a much more
problematic course to take: it means war with your colleagues!
physiology, psychology and neurobiology of perception
critical disagreements in the absence of incompetence present
problems to the objective view of wine tasting, then our emerging
understanding of the biology of sensory perception is the nail in
old-fashioned, simplified view of wine tasting sees us as acting as
measuring devices. The taste buds in our tongues and the olfactory
receptors in our nasal cavities detect chemicals present in the
wine, and our brains read out the information thus gained in terms
of smells and tastes: the flavour of wine.
is quite wrong. Our conscious perception of flavour is formed in the
brain. In the interaction between us and the wine we taste, the
impression we form is a conscious experience that involves the
fusion of inputs from at least four different senses, coupled with
some sophisticated brain processing. It’s a unified
‘representation’ that can’t easily be dissected into its
component sensory inputs, which we commonly try to do with taste and
readers who have ever walked a dog will be aware that for them, the
world of smell is as important and dynamic to them as the visual
world which we are so familiar with. In contrast, we humans live in
a vastly diminished smell world, having traded our olfactory acuity
for enhanced colour vision—an evolutionary change that took place
during primate evolution. Many of the genes encoding olfactory
receptors in our genome are now redundant. Rather than being
important for orientation, social organization and mate choice, as
it is for many mammals, our use of the chemical senses, taste and
smell, is largely restricted to food choice—a reduced but still
and smell begin with receptors in the mouth and nasal cavity that
turn chemical information into electrical signals, which can then be
processed by the brain. The nasal cavity contains olfactory receptor
neurons which express, between them, around 2000 different
receptors, each tuned to recognize different volatile odorants. But
it’s wrong to think of our sensory systems as complicated
measuring instruments, which give a read-out of the taste and aroma
molecules that they encounter. This is a common misconception: that
wine perception is a result of a combination of such linear inputs.
what the brain does is to model the world around us. Our sensory
systems are bombarded constantly by a mass of information, which, if
attended to uniformly, would swamp our perceptive and
decision-making processes. So the brain is able to extract from this
sea of data just those features which are most relevant. This is
done by a procedure known as higher-order processing.
experience is an edited version of reality that is based on the
information that is most relevant to our survival and functioning.
For almost all purposes it does no harm for us to think of the world
around as revealed to us to be ‘reality’—indeed, life would
become quite complicated if we operated any other way—but for the
purposes of this article we should be aware that the version of
reality we experience is an edited and partial one.
higher-order processing in the visual system is the best understood
for any of the senses. Scientists have worked out how visual
processing extracts features of the environment that are most likely
to be relevant. For instance, our peripheral vision is sensitive to
motion: moving objects immediately stand out, because neurons are
tuned to respond to them. This motion detection ability is much
stronger in the periphery than it is in the central visual field.
Faces are also likely to be significant cues, so our visual systems
have special brain mechanisms for face processing.
it is less well studied, this sort of higher-order processing is
also important in flavour detection. We are bombarded with chemical
stimuli all the time and the brain has to filter this information so
that only the important bits get through. It seems that much of the
brain is dedicated to producing a suitably edited view of reality,
just as the staff in a newsroom work hard all day sifting through
the output of their journalists to produce a fifteen minute news
bulletin for broadcast that evening.
when we taste wine, before we are even aware of it, our brains are
doing quite a bit of complex processing of the information we are
getting from this wine. In addition, there are inter-individual
differences in the ability to detect certain flavour or aroma
molecules. For example, one-fifth of people can’t smell the
chemical rotundone, recently found to be important for the peppery
aroma found in Syrah/Shiraz wines. And around a quarter to a third
of the population seem to be quite insensitive to bitter tastes.
this reason, it is only correct to say that the taste of wine is not
a property of the wine, but a property of our perceptual apparatus,
but strongly based on the characteristics of that wine. We bring
something of ourselves to the wine tasting experience: our context,
our biology, the information we have about the wine, our previous
experiences of wine, and even our own internal state at the point of
tasting the wine. Because in our sensory perception we are
effectively modelling the world around us, our perception itself is
study by New Zealand psychologist and sensory scientist Wendy
Parr, working on the perception of Sauvignon blanc, shows that
professionals and novices approach wine in quite different ways.
‘We have recently done a study that is quite cognitive,’ says
Parr. ‘We gave people a large A1 sheet of paper, and had around 70
descriptors of Sauvignon that had come out of our previous studies.
Each one was written on a separate sheet of paper with a sticky
back. We asked people to draw a picture of a high typicality
Sauvignon in a hierarchical structure, like a tree shape. We had a
group of wine consumers and a group of wine professionals. People
had to sit and think. They did this experiment twice: they came and
did it totally from memory (we want you to think about a good
example of a Marlborough Sauvignon), and they drew these pictures.
They came back two weeks later and we gave them three Sauvignons
that had been rated in a previous experiment as highly typical. They
tasted these wines, and did the picture again. So this is a
perceptive condition, versus a conceptual condition (doing it from
memory). The findings showed some interesting results and
differences. Some people had broad pictures of Sauvignon; others had
more linear ones.’
The idea behind these two separate experiments is that
the first condition was what is known as a ‘semantic’ condition,
relying on top-down cognitive processes of memory and linguistic
skill. The second is a ‘perceptive’ condition, in which tasting
the wine takes place at the same time as a classification task: this
is a bottom-up experiential process. The three questions being posed
were: (1) would experts and novices employ the same descriptors in
the same way?; (2) would expertise influence reproducibility across
both semantic and perceptive conditions?; and (3) do both groups
exhibit a shared concept of Sauvignon blanc?
The results showed that experts classified the
properties of Sauvignon blanc according to their own internal
descriptions of typical New Zealand Sauvignon blancs, while the
novices were much less consistent in their descriptions. The experts
had a stronger underlying cognitive concept of New Zealand Sauvignon
blanc, producing stronger hierarchical trees. They were also more
consistent among themselves: this higher within-group consistency
indicates a shared conceptualisation of Sauvignon Blanc knowledge.
The experts and novices used different levels in their hierarchical
descriptions, with stronger super-ordinate nodes. That is, the top
descriptors for Sauvignon are seen as more important.
From this Parr concludes that the experts use
top–down processes in their wine judgements involving prototypes
shared by all experts. For the novices, it seems that their
descriptions are driven by bottom–up processes, and are based on
the taste of the wine.
The notion that the way that professionals describe
wine is ‘prototypical’ was also found in some (now famous)
studies by Frédéric Brochet (here).
Among other observations, his studies showed that in blind tasting,
professionals first seem to decide what sort of wine it is, and then
select descriptors to match that type of wine. In effect, their
assessment is only partially based on the chemical nature (the
reality) of the wine.
subjective, but to a degree
are clearly problems, then, with any view of wine tasting as an
objective exercise. There is a good deal of subjectivity involved in
the tasting of wine. We bring a lot of ourselves to the tasting of
wine. However, it would be a mistake to say that because there is a
strong subjective element to wine tasting, that anything goes, and
that there is little value in expertise. Or that there is ‘no
right and wrong’ in wine.
While our perception may be largely subjective in its
nature, there is a strong learned component to wine appreciation.
Expertise plays a strong role in being able to appreciate great
wine. While there is a hedonic component to the enjoyment of wine
(‘this tastes good’), learning about wine, and learning to
recognize and appreciate some of wine’s complex flavour
characteristics, has the potential to enhance the enjoyment a great
deal. And, clearly, despite the fact that our perceptions of wine
are unique to us, when we share a glass together, we can usually
have a good deal of common ground when we discuss the merits of the
wine in question.
why discuss subjectivity and objectivity in wine appreciation at
all? Because I think it is important that we have a more accurate
– if more complicated – understanding of the theoretical basis
of wine assessment. People are sitting exams with tasting elements
to them, and these exams could have an important bearing on their
professional lives. Yet the assumption of those setting the exams is
clearly that wine tasting, as carried out by professionals, is an
objective practice. As we develop our understanding of the nature of
sensory perception, however, this assumption is found wanting. It is
time for a more grown up understanding of the wonderfully rich and
interesting practice of wine appreciation.
reality: some thoughts on the nature of perception, and how this
applies to wine