Is there an art to wine science?

In this short article, I’m going to outline how mainstream science usually works, and why it is so useful for answering questions about the nature of the world around us. Then I’ll discuss why, despite its utility, the scientific process is of only limited real-world use for wine scientists, giving answers to just a limited subset of important questions in viticulture and winemaking. I argue that there’s somewhat of an art to good wine science, even though this sounds dangerous and even heretical to most trained scientists. Jamie Goode

The scientific method is an incredibly useful tool. It helps us overcome our biases and prejudices, and allows us to answer difficult questions. It helps us to be objective. It presents a coherent model of the world around us that assists our understanding of this environment, and enables us to develop new technologies that actually work.

One of the keys to the successful practice of science is objectivity. People usually aren’t objective. We are pulled and pushed in various directions by our inbuilt preconceptions, predilections and prejudices. Good scientists will step aside and try, as much as is possible, to be ruthlessly objective about the phenomena they are studying. The two arms of scientific enquiry are observation and experiment. Scientists look at what’s there, formulate hypotheses, and then test those hypotheses by experiment, trying their hardest to disprove them—this is the only way they can be sure that they are correct.

The scientific community is a remarkable global enterprise, uniting researchers across the world by a common currency—data published in peer-reviewed scientific journals (I’ll explain what I mean by this below). It’s an inclusive club, open to all-comers, as long as they have good data and are prepared to play by the rules.

To gain credibility and status, researchers need to publish their work in reputable peer-reviewed journals: their publication record is how they are assessed. There are many thousands of these journals, and they vary in their scope from broad to very narrow. Not all journals are created equal: some have much higher reputations than others. Typically, a scientist (or more commonly, a group of researchers) will write up their results and then choose the most appropriate journal to send them to.

They will want to have them published in the highest-ranking journal possible (there’s a sort of ‘pecking order’ of journals), but they won’t want to send their paper to a journal where it will be rejected, because of the delay in publication that will ensue. How do journals decide which papers to accept? This is where ‘peer review’ kicks in, a process vital to the integrity of the scientific literature.

Each journal has a board of editors made up of leading researchers in the field covered by the journal, and also a larger pool of scientists willing to act as referees for papers in their chosen subject areas. A paper coming in will be assessed by one of the editors: if it is clearly unsuitable it will instantly be rejected, but if it is potentially good enough, it will be sent out to two or more scientists for review. They will prepare a report on the paper, checking that it is correct, is suitable for the journal it has been submitted to (if it is a high-ranking journal, are the results exciting, novel and significant?), and that the science is good. If they recommend it to be accepted, they might also suggest possible revisions or further experiments. Then the paper and the referees’ reports are sent back to the editor, who makes a final decision whether to accept it, accept it with revision, or reject it. Journals with good reputations are more fussy than others. Getting your paper into one of the elite band of leading journals can make your career.

This all sounds great, doesn’t it? But if wine scientists restrict themselves to the scientific method as detailed here, I’d argue that they’d be of limited use to the wine industry. It’s my contention that there is more than a little art involved in good wine science. Let me explain why.

First, there has only been relatively little peer-reviewed research on many of the most interesting topics in wine. This is because many of the key issues for winegrowers are hard to address by good scientific experiment, for reasons of tractability and cost. It’s possible to do experiments in the winery, although this is complicated by the fact that working with very small batches of say half a ton at a time will introduce its own artefacts, and microferments with even smaller quantities present further technical challenges. Also, wineries are busy places at vintage time, which makes experimentation difficult. In the vineyard experiments are even more difficult, largely because to get statistical power you’d need to have lots of randomized plots which would then have to be managed differently. And add to this the long time-scales involved in setting up a vineyard from scratch, and it’s clear that the sorts of experiments needed to answer some of the most interesting questions in viticulture are pretty much impossible.

Then you could also ask the question about the usefulness and reliability of the wine literature. Peer review itself is a slightly controversial process because (1) it involves scientists reviewing the work of their peers who may well be their competitors, (2) it can take a long time, and (3) because some consider it not to be as rigorous as it should be: good papers are sometimes rejected while less good ones get through. To be frank, it is not unusual for scientists to behave like assholes when they are reviewing the work of others. Add to this the limits of reductionistic science (breaking complex problems into little bits and then observing these little bits in isolation has great explanatory power, but it can only answer some sorts of questions), and we end up with a body of peer-reviewed literature that is only partly helpful—a jigsaw puzzle with half the pieces missing.

This is where I would argue that wine scientists need to blend in a bit of art. They need to ski off piste. To be a good wine scientist you need to make use of anecdotal evidence and the experience of wine growers to fill in the gaps. To do this successfully is very tricky: it involves making judgement calls, weighing up the reliability and credibility of those you are speaking to, and assigning confidence to extremely soft data points.

I guess I need to explain here what I mean by ‘anecdotal’ evidence. Say over the course of a year you open a lot of bottles and find perhaps a dozen that are suffering from musty taint. Or you find that the grapes from one vineyard are considerably better if you prune the vines short, or turn off irrigation just before veraison. These observations may cause you to forge strongly held opinions, but they aren’t data in the strict scientific sense. Nor are they data when they are combined with the observations of others whose judgments you trust. Even though the evidence may seem to you to be unquestionable, what you have is an ‘anecdotal’ report.

That’s not to say that anecdotal report is of no use—far from it. Data collection is expensive and time consuming, and limited resources don’t permit experiments on all the interesting aspects of wine science. Instead, good scientists use hunches and anecdote to decide where to look and which experiments offer the best chance of success. And where we still lack data we have to use our understanding of the science to fill in the gaps by educated guesswork. This is a common theme in wine science.

Of course, this sort of approach horrifies many professional scientists, because it goes against the way they have been trained to work. It relies on the ‘art’ of the wine scientist in holding on to what she or he believes to be useful or reliable information, and rejecting less useful reports, often on the basis of no more than a hunch. Yes, it has its perils. But I’d argue that in the fields of viticulture and winemaking, to insist on peer-reviewed research only puts us into a straight-jacket – we’re like the drunk searching under the lamp post for his keys, not because this is where he lost them, but because this is where the light is. In an ideal world we should try to get solid experimental data, but in the meantime, wine scientists need to begin practising a bit of art, too. Some will do it well, some will do it badly. That’s where the art comes in.

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