How Does a Better Understanding of Wine Science Fit with Understanding Wine?

I came to wine from a background as a scientist. I spent six years at university—three each for my undergraduate degree and doctorate—and so I became pretty good at thinking scientifically. Many of you will have come to wine from careers or studies that are similarly quantitative. You can measure things; you can formulate hypotheses; if you study enough you can nail down the answers. Cause and effect. 

And then you hit wine. It is frustratingly imprecise. There are so many inconsistencies, it seems, in the world of wine. Wine education itself is often built on a frail scientific basis, with many of the "truths" simply passed down from generation to generation, without firm backing from research.

In particular, there are three areas that struck me as scientifically imprecise and dubious when I entered the world of wine, coming from my own particular scientific perspective. 

These were biodynamics, terroir and taste. I’ll consider each in turn. Over the years, my attitudes have changed. I now think that science is an incredibly useful tool for understanding wine, but it’s not the only way we can understand wine. And a broader approach—not a sort of scientific fundamentalism—is needed if we are to make sense of this most complex and wonderful of liquids. 

When I first heard about biodynamics, I couldn’t quite believe it. Here are otherwise smart, capable people being taken in by a system of agriculture with a completely ludicrous theoretical background. Just what were these energetic life forces that were being invoked? And how could the alignments of the planets affect things here on earth? And the homeopathic preparations, fermented in strange bits of animals?

Biodynamics does seem to clash with a scientific understanding of soils and plant physiology. But it would be a mistake to dismiss it without looking a little closer. There are many aspects of biodynamic practice that could be having an interesting effect on grape vines, aside from the rather unusual mechanistic claims of some of its practitioners. For example, scientists are beginning to understand the importance of soil microbes in vine growth. There seems to be a cross-talk between bacteria and fungi in the soil and the vine roots, to the extent that soil microbes can alter the physiology of the vine, causing changes in the grape composition and then in turn the taste of the wine. Much of biodynamic practice is focused on soil health. Who is to say that the various preparations and composting don’t, for example, help the vine find a better balance, producing physiological ripeness in the grapes at lower sugar levels in warm climates, via changes in soil microbial life? There are real limits in our understanding of all the complexes processes that take place in the vineyard. Sometimes people working the vines might have more to contribute to our understanding than the limited scientific studies that have taken place in the vineyards. It’s just that we need to adjust our language in order to have a conversation, and as scientists we can’t always insist that our language is the only legitimate one.

I was trained as a plant scientist. I learned about root uptake, and how all that plants took from the soil were water and soluble mineral ions. So when I heard people talking about how you could taste the vineyard origin in the wine, I was immediately sceptical. How could a place imprint itself on the grapes so much that subtle changes in grape composition would yield wines—after a complex fermentation process—that would taste completely different, depending on small differences in aspect, climate and subsoil?

Once again, with terroir we meet the gap between what we know to be the case from the experience of those working in the vineyard, and what scientists have been able to show by proper studies. It’s hard to control all the variables in the vineyard, and the sort of work needed to produce publishable results is time-consuming and expensive. And it often doesn’t address the really interesting questions. But when we taste wines from adjoining plots and spot the difference, which in this case we assume must be due to changes in soil type, we want some answers. What is causing this difference? What’s the mechanism? No one has really studied terroir in a truly satisfying way. The result is that terms like "minerality" and "chalky" and "slatey" and "gravelly" get used without any consensus as to what they really mean, and with a vague sort of mechanistic claim implicit in their use.

But science can inform us about terroir. The more we understand vine biology, ranging from fruit uptake to grape composition, the more we can link this with factors such as soil water relations, soil chemistry, soil microbiology, the effect of ultraviolet light exposure, canopy architecture and the role of thermal amplitude, to name but a few of the physical factors that constitute a "terroir." It’s about piecing together a limited set of scientific data points with a set of real world experiences, and then doing some intelligent interpolating to fill in the gaps. Hopefully, then, a clearer picture emerges.

As a science editor, I’d dipped into the physiology, psychology and neurobiology of flavor perception. I knew that flavor was constructed by the brain from sensory information coming from the senses of smell, taste, touch and vision. I knew that individual differences existed; for example, to the extent that people are either tasters, non-tasters, or supertasters, they have different abilities to taste the bitter compound propylthiouracil (PROP). And I’d seen studies that seemed to indicate that our experience and knowledge of what we were drinking could also change our perceptions. So to suddenly encounter a wine education system where the taste of a wine was regarded to be a property of the wine, and where a careful student with a normally operating sense of taste and smell could nail down the taste of the wine with an almost scientific accuracy, was quite a shock.

I still think that the wine world operates with a rather simplistic understanding of taste and smell. The perception of wine is wonderfully complex, and there’s currently a renewed interest in flavor perception more generally among scientists. The modern view is that flavor is a multimodal sense, wherein smell, taste, touch and vision—and even hearing—are merged together in complex ways at a preconscious level to create this unified sensation of flavor. We don’t operate like measuring devices; instead, we have a sense of flavor that’s really flexible and different factors change our perception without us being aware of it. This flexibility and adaptability helps us navigate the real world, but in wine education, where to pass exams we have to behave like machines, it causes no end of problems.

What we "get" in a wine depends on lots of things. It depends on the vocabulary we have for wine (words act like pegs we can hang sensations on), it depends on what we pay attention to in the wine, and it depends on other factors such as our previous experience of wine, our mood, how hungry we are and the time of day. It also depends on our own unique biology: for example, people differ in their ability to taste bitter substances, in their salivary flow (which affects mouthfeel of red wines) and in their olfactory receptor repertoire.

It’s good to try to taste as scientifically as possible. But it is an illusion to think that if we all worked harder, trained more and became more expert in our use of flavor descriptors, that we’d all reach the same conclusion about a wine. I think the wine world needs to adopt a more sophisticated, nuanced view of what happens when we taste wine, and the notion that we bring quite a bit to the wine tasting experience needs to be factored in to wine exams that have a blind tasting component. Yes, learning does help to iron out some of these creases – because we share our impressions, adopt an aesthetic system of wine, and grow more alike in our assessment of what constitutes a good wine. But there’s no room for control freaks in wine tasting, because so much of what we do in perception is beyond our conscious control.

Closing Thoughts
Wine education is incredibly valuable, but the whole process can be quite frustrating for ambitious, driven wine professionals who want to get to the top. This is because wine is so inexact. This is because we can’t really address its complexity in any rigorous scientific way, and also because the read-out at the end of the process is a sensory one: us tasting wine. Research on interesting questions in the vineyard is so complex and expensive that very little of it is done (who would fund it?), and our sensory systems are very complicated. The perception of flavor is an area of intense current interest because it is fully multisensory, and cross-disciplinary approaches involving neuroscience, physiology, psychology and philosophy are now producing some very interesting results. We need to re-examine the way that tasting is taught in wine education to take these latest results into account. For now, there is a frustrating mismatch between the way we are taught to taste (and are examined in blind tastings) and the real life experience of wine. Science has a lot to offer wine, but it needs to be considered as just one of the useful tools for helping us understand this most remarkable of liquids.

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