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Taste and the taster: Part One

This is the first part of conversation between Les Caves’s Doug Wregg and wine scientist, author, lecturer and self-described “flavour obsessive” Dr. Jamie Goode concerning the nature of taste and the overall experience of “perceiving wine.” We start by examining the sensory processes and how taste is framed by a priori knowledge and filtered through expectation, how the ability to retrieve memories is crucial to understand how our responses are encoded and decoded and simply how we can become better tasters. 

With wine tasting, experience is vital. We are changed each time we taste a wine.

Doug Wregg: How do the physical, reflexive responses to wine manifest at a neurological level? What is going on when we process information about wine, for example, when we look at wine in a glass? To what extent do we start to judge the wine on its appearance alone? If so, why do we do it? Is it something primal, or is it part of our prior wine education? Or both? Do we start to calibrate our response at first glance? Or do we take numerous glances? How soon does the process of assessment begin? I was once taught at WSET to look for cleanness in wine. Now, I tend to think a wine that looks very clean might be inert, lacking depth and a quality of realness.

Jamie Goode: I think our preconceptions are highly important in the actual perception we have of the wine. Certainly, I have strong preconceptions as I taste a wine sighted (which is how normal people drink wine). And it’s impossible to separate those preconceptions from the actual perception of the wine. They shape the perception in ways that we don’t have access to – that is, the brain is processing a lot of information at a preconscious level. By the time we are aware of our perception, a lot of combining has already gone on.

This is a really interesting question, and to answer it, I think we have to do some preliminary unpacking. Perception of wine (the same would apply to food) is multimodal. It involves all of the senses, pretty much – including hearing, although this only plays a minor role in some circumstances. Information travels from our sensors to the brain, but we don’t perceive it until it has gone through some fairly hefty processing: it’s like a newsroom gathering information that is then used to make a 30-minute bulletin. Quite a bit of information ends up not being used.

We project the flavour on to the food or drink, even though the flavour is a perception in our brain created of many different sensory components.

There’s touch (the feel of the wine in the mouth), smell (both orthonasal, as we sniff the wine, and also the round the back route – retronasal – as we smell the wine once it is in the mouth), taste (five or six different modalities, or maybe more? Not just sweet, sour, bitter and salty, but also umami and fat, and maybe also water) and vision. These senses are all combined at a level we can’t access. By the time we are aware of the ‘taste’ of the wine, a lot of processing has already gone on. The ‘flavour’ of wine is then localized to where the wine is in the mouth. I think that’s why we refer to it as ‘taste’. It’s much more than just taste. The reason it is localized to the mouth is because that’s where we need to take action if any is needed: if the food or drink in our mouths is bad, then we need get it out fast, and so we need to know exactly where it is. We project the flavour on to the food or drink, even though the flavour is a perception in our brain created of many different sensory components.

So when we look at a wine bottle, what is happening? The perceptive event also combines information that we have about what we are eating or drinking with the information from our receptors. Studies comparing experts and novices have shown that both groups taste wine quite differently. The experts recruit their knowledge and this is an important part of their perception: different parts of the brain light up when they try to taste wine compared with novices (although this is in a magnetic resonance imager which is not the normal way people taste wine). Studies like the Pepsi challenge show that information about what people are consuming becomes part of the perception.

So when someone looks at the label, depending on their experiences in the past, their knowledge, and their preferences, this will already begin to frame their perception, even before they have tasted the wine. They are primed, to a greater or lesser extent. Then, when the glass is poured, there will be another priming.

Wine education is great, but when people have been educated, they frequently hold fast to what they have been taught. If you have been told that a wine must be clear and bright, and this is a positive attribute, then you’ll find it difficult to appreciate a cloudy or hazy wine. The colour of the wine is also a massive sensory cue: Frederic Brochet’s famous experiments with wine professionals, where they described a white wine, and then later a red (that actually was the same wine, coloured red), and used very different descriptors in both cases, demonstrate this in its most obvious form. But the depth of colour and the actual hue itself can provide information about the wine. These cues can be deceptive, though. The problem is, the priming that vision provides is not something we are good at ignoring, because we aren’t usually aware that it is happening. All our sensory judgments after we have seen the bottle, or the wine in the glass, will be clouded somewhat.

When we smell a food or drink, before we put it in our mouth we want to reject it if it is going to be harmful. It helps if we have a strong memory for the smell of things, which we can access quickly when we need to make this call.

And using black glasses isn’t the answer if we want to remove the bias. Drinking from a black glass is a weird thing to do, and I think the strangeness of it is going to make it very hard to draw interesting conclusions. Vision is such an intrinsic part of ‘tasting’ wine.

DW: And with smell (and what is going on – neurologically – when we smell a wine?). Is there really a pathway between the olfactory bulb and the part of the brain that stores memories? Are these memories, or associations, images, actually triggered by the smells? How does that work? How does our brain operate? Is different information stored in different parts of our brain? Are there specific triggers – pathways – that can be activated by certain sensory experiences?

JG: Smell is intrinsically bound with taste most of the time. When the wine is in our mouth, we smell it retronasally. We can’t taste without smelling. But we can smell without tasting.

Once you’ve smelled something, the information enters the olfactory bulb of the brain, and then heads to what is called the limbic system. This is heavily involved in controlling mood, memory, behaviour and emotion. This is why smells and memories are closely linked, and also why certain smells can help set your emotional tone.

Putting it another way, there is a good explanation for this link between smell and memory: when we smell a food or drink, before we put it in our mouth we want to reject it if it is going to be harmful. It helps if we have a strong memory for the smell of things, which we can access quickly when we need to make this call. So there must be some context-dependent lability in our sense of smell and how we remember these smells. If something has a certain smell, and it makes us sick, we must be able to recategorize this as an aversive smell. Some smells are always going to be aversive (this protects us), but we need to add to this group the smells of things that have made us ill.

Wine tasters are made, not born. As long as you have a more-or-less normal taste and smell, then it’s about practice, experience and ability to process information.

DW: Why do different people respond so differently to the same wines? Is it due with their differing abilities to discern smells, or to do with their ability to process and evaluate sensory information? Or is it as simple as who are doing determining how we judge things and what is important to us whilst we are judging?

The same with taste. Does liking a taste reflecting a certain physiological need within us? For example, I like salty and umami – does that mean that my need for these tastes is stimulated when I sense a wine that displays those properties. Or maybe I am looking for those flavours when I taste a wine?

JG: This is an interesting question. The topic of individual differences in flavour perception is a big one, and it has also been one that has been misinterpreted and over-simplified.

We all differ in the subset of olfactory receptor genes that we have. We each have around 400 of these, but we are able to distinguish thousands of different aromas. Each olfactory receptor cell expresses just one type of receptor. People differ in their olfactory receptor repertoire, and so they differ in their ability to smell – some are much more sensitive to certain smells than others. And there are some well-studied differences in the ability to taste bitter compounds. Thus the experience of wine might differ among people at this very first level – that of receptors.

But with wine tasting, experience is also vital. We are changed each time we taste a wine, albeit in small ways. We learn to taste, and we develop our palates through experience. So it wouldn’t be right to say that some people are programmed to like certain wines. Human taste preference is remarkably plastic. It makes sense – this opens up the world of eating and drinking more things, as long as they don’t make us sick and have some nutritive value.

People differ in their olfactory receptor repertoire, and so they differ in their ability to smell – some are much more sensitive to certain smells than others.

There’s also adaptation. When we are hungry, food becomes more appealing. When we are full, less so. Sensory-specific satiety is also a thing: if you’ve had four bananas, you might find bananas less appealing. But you might still fancy a chocolate. If you have been tasting Sauvignon all day, you might find Sauvignon unappealing, but a Pinot Noir very tasty.

DW: Are some people simply better tasters? In what way better?

Yes, but tasting ability is not simply biological. The studies that have been done (and there are quite a few of them) suggest that wine tasters are made, not born. As long as you have a more-or-less normal taste and smell, then it’s about practice, experience, ability to process information and this sort of thing. It’s not that ‘expert’ tasters have much better senses of taste and smell. So some people are better tasters because they have trained themselves to be, in the majority of cases.