WAC 2014 Recap Series : Sensory science, in its own right

            Sensory science is one of the most delicate areas of wine science, as the sensory mechanisms are only beginning to be understood, and questions of subjectivity abound.

At WAC 2014, Wendy Parr of Lincoln University in New Zealand launched the sensory session with a provocative introduction. She asserted that sensory science takes on two major identities in wine science, first as a sort of “nexus” linking culture, psychology, oenology and viticulture, where it plays a “collaborative” or supplementary role in projects aiming to understand the effects of different winemaking or grape growing practices. The second face of sensory science is as a discipline in its own right.  A discipline based in psychology that “makes the role of the perceiver explicit.” When seen in this way, she argues, sensory science can allow for the integration of psychological phenomena to understand individual differences between tasters or the impact of context – the order the wines are presented, the background noise in a room, even the mood of the taster herself when evaluating a wine.  In the collaborative approach of sensory science, these individual and contextual variables are seen as sources of error, and thus researches strive to “eliminate” and “control” them at all costs.  Costs that, in some cases, can be extreme, resulting in conditions so far removed from reality that the study results are near-meaningless in the real world. Thus more research in the second sense, with sensory science being done for the sake of sensory science, could help us to understand physiological differences between individuals and the impact of contextual factors, which ultimately might make our wine science more relevant.

Anthony Saliba of Charles Sturt University in Australia, a self-proclaimed “wine psychologist”, picked up on this theme of contextual and individual factors, elucidating the nature of these sources of “error” with a series of examples.  He discussed how humans are much more influencible than we tend to think. This influence could come from within, with physiological phenomena, or from the exterior – contextual cues that change our perception without us even realizing it.

For example, individual variation in sensory thresholds (the minimum concentration of a substance for it to be perceptible) is a physiological constant – humans cannot be trained to smell a substance at a concentration lower than their individual threshold level.  Optical and auditory illusions, such as a musical scale that seems to continuously go up or down, demonstrate the fallibility of our senses.  Yet it is these same senses, limited by physiological factors, that hold us so tightly at their mercy.

Continuing with the theme of sensory tricks, neuroscientist Gil Morrot from the University of Montpellier described a study in which the best sommeliers of France were able to blindly identify the region of origin of Bordeaux or Burgundy wines in only about 50% of cases. If even these experts can be tricked, clearly our physiological limitations are inhibitory. Moreover, he discussed the important influence of wine color on our perception.  Our descriptions and differentiations of wines are principally based on a color-based dichotomy, but we know that we can so easily trick tasters into mixing up red and white wines when they can’t see the color. It turns out that unlike sight or hearing, which each activate a specific region of the brain, olfaction causes a global activation – activating parts of the brain normally responsible for the other senses.  Thus we cannot smell properly without seeing, explaining the close link between color and sensory perception in wines.

All this taken into account strongly supports Wendy Parr’s call for sensory science to be practiced as a “real” science in its own right. The understanding of such sensory phenomena can allow us to delve deeper into our sensory studies, hopefully developing methods that can take into account individual variation and contextual influences, rather than simply eliminating them. Thus we can begin to foster a more holistic approach to sensory science, rather than cutting out factors that could turn out to be detrimental to the applicability of the results.

WAC 2014 Recap Series : Steven Shapin – Modernity in a Glass

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The Third Edition of the International Conference Series on Wine Active Compounds, affectionately known as WAC 2014, was an overwhelming success in many regards, but most notably in the bridging of disciplines.  Partly a result of the participation of the UNESCO Chair “Culture and Traditions of Wine”, based at the University of Burgundy, the organizers of WAC strove toward the integration of natural and social sciences, rather unique for an international congress – particularly one that is, at its core, focused on wine chemistry.  Social science lectures were interspersed throughout the conference, falling between the more traditional lab-based research talks, but always maintaining a coherent link to the session theme. In honor of the success of this project, I will be devoting a series of posts to exploring some of the themes that were brought to light during the convention, including the regulation of enological practices, role of the sensory sciences, the notion of complexity, the neuroscience of perception, biodynamics, and the role of wine compounds in some key human diseases including Parkinson’s disease, Alzheimer’s, diabetes, metabolic disorders, intestinal inflammation and cardiac disease.

To kick off the series, I’ll begin with what for me was the most exciting talk of the conference – the keynote given by Harvard historian of science Steven Shapin.  I walked into the first day of WAC 2014 with stars in my eyes, as after 4 college years filled with as many History of Science and Science Studies courses as I could fit, to me Shapin is a true celebrity, and I’d had no idea that he took an interest in wine.

His talk was entitled “How does wine taste? Sense, science, and the market.” He dove right into a lecture about the history of how we describe what we taste in a wine.  There is, he argues, a dramatic split that occurred in the 20th century, fundamentally altering the manner in which we talk about wine. And this division corresponds to significant scientific and market changes in the same period.

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From the time of Aristotle up until the pre-WWII era, the specific lexicon used to describe wines was quite restrained, with only such words as “sweet”, “acute”, “austere” and “mild”, as well as terms for faulty wines, being regularly employed. Wines were more often described in terms of their medical properties or physiological effects, and people were more inclined to compare wine to poetry or particular emotions than to specific flavors. It wasn’t that people didn’t appreciate and evaluate wines – they certainly did as evidenced by the 1855 Bordeaux Classification – clearly wine aficionados were interested in differentiating and evaluating wines here, but they didn’t need to be able to describe the wines to make an opinion about it.

So what changed?  How did we end up with the current trend, wines “described as more or less complex aggregates of individual [flavor] components” – an “analytical” approach that reduces a wine to a series of comparisons to other foods or smells? The answer, according to Shapin, lies in the interplay between scientific and market changes that occurred around the mid-20th century.

A general trend began in chemistry, biology and physics, resulting at least partially from increasingly powerful analytical techniques, toward a focus on constituents of substances or organisms rather than their more general qualities.  The modern reductionist paradigm began to characterize science, attempting to understand systems by first understanding their constituent parts. This trend was reflected in the development of enology and sensory analysis in French and American institutions (notably the University of Bordeaux and UC Davis), where a focus on discovering the particular molecules in wine became paramount.  The understanding of the molecular composition of wine aroma fit effortlessly with a sensory model that breaks the aroma into its individual components, each of which associated with a corresponding molecule that can be isolated and measured.

Ultimately, this type of reductionist description trickled down into consumer culture, but how? The key, says Shapin, was the concomitant expansion of New World wine drinking markets. Wine has always been associated with a certain prestige and connoisseurship, and these new consumers were seeking an accessible vocabulary with which they could discuss their newfound beverage of choice. The most accessible, setting aside the flowery, poetic descriptions of the past in favor of more direct and analytic language with a clear link to chemistry, was UC Davis sensory scientist Maynard Amerine’s lexicon of descriptors that were systematically associated with “real wine compounds” (published in 1976 and available on Amazon). This type of description was, perhaps most influentially, adopted by Robert Parker in his publication the Wine Advocate, the first edition of which was released in the same year as Amerine’s book.

Thus, argues Shapin, the style of tasting notes that remains most widespread even today, a list of individual flavors of which a wine is comprised, is not a natural consequence of physiological sensation. No, like all human activities, wine description has a historical background, a past linked to concrete events that have shaped how we understand and articulate our thoughts. Wine is, he says, “modernity in a glass”, bringing together the sensations of taste with the worldview of modern science and consumer culture.

Scottish treasure in Burgundy : A tale of whisky, terroir, and biofilms

A secret treasure lies beneath the little house off the main road in a tiny village in Burgundy. A treasure one wouldn’t expect to find in this region monopolized by the grape vine.  A pot of thousands upon thousands of liters of liquid gold.

IMG_0782 Cellars at Michel Couvreur Whisky

Appropriately located, the cellars of Michel Couvreur Scotch Whiskies, a minuscule operation led by a team of 3 dedicated employees, are found in Bouze-les-Beaune. The village is named for the nearby river Bouzaise, named for the Celtic word “bosa”, meaning pocket of water, which later evolved into “bouse” in medieval English, and then the contemporary equivalent, “Booze.”  But despite this nominal link to spirits, one would never know what lies in the cellars of the unmarked house.

 The cellars, dug out by Michel Couvreur himself to a depth of 15 meters, are a fantasyland evoking an underground scene in The Lord of the Rings.  The trickling sound of an underground source fills the damp air and the walls are covered in a wet, slimy substance.  A biofilm of microorganisms that seem to thrive in the humid atmosphere, sipping in the alcohol vapors as they grow.

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This, according to Blend master Jean-Arnaud Frantzen, is the terroir of the locale of “Finishing,” or the aging of whiskies in 500 L wooden casks. Whether this represents a “true” terroir is of course debatable, but it is clear that the aging environment has an impact.  The level of humidity will dictate, by the law of partial pressures, the alcoholic composition of the angel’s share (the portion of a cask’s contents that evaporates over time) and thus of the final alcoholic composition of the whisky remaining in the barrel.  But might the environment have even more of an influence than this? Perhaps an influence from the biofilms, which, like the black fungus characterizing the walls of buildings in the region of Cognac, Baudoinia compniacensis (aka Torula compniacensis) flourish in the presence of alcohol vapors?  Or the depth below the surface?  We all felt a slowing of our own internal rhythms upon descending into this cool, dark space, pressurized place, why couldn’t this have an effect on the whiskies as well?

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Biofilms on the cellar walls at Michel Couvreur

But this terroir of “élevage,” as this type of slow, deliberate aging of alcohol is referred to in France, is difficult to pinpoint, difficult to define. All the more complicated by the fact that these whiskies have, in effect, a multiplicity of terroirs.  The barley is grown, harvested, and transformed into alcohol in Scotland (and, apparently, individual ‘terroirs’ of barley fields are effectively nonexistent, the ‘taste of place’ not seeming to infuse into a perennial plant that is then severely transformed into a distilled product).  The ‘mother’ alcohol is then shipped to France, where it is funneled into specially chosen casks.  These casks are full of history, which they subsequently instill into the whisky with which they are impregnated.

Michel Couvreur Whiskies chooses each cask individually.  The histories of the casks can be quite varied, but they all contained a potent, richly aromatic wine for a period of 40 to 50 years. The most typically used casks are those of Sherry wines, but also sought-after are variants such as Pedro Ximénez, the local sherry-like wine, Vin Jaune from the Jura region, or Colheita and Tawny Ports.  The casks are shipped to Bouze-les-Beaune immediately after being emptied (when regulations allow, Couvreur prefer to ship the casks filled, as dryness is the enemy of wooden casks, making them vulnerable to spoilage and prone to leakage later on) and are refilled, without rinsing or the addition of sulfur, with the mother alcohol.  Then the casks are sealed and stocked, for 3, 8, 10, 20… years – as long as it takes to achieve the desired result.

Frantzen adheres to a philosophy of the 8-year plan for whiskies.  During the first three years the grains of the original alcohol tend to dominate.  Then the whiskies enter the adolescent phase, commencing their maturity but with remaining marks of hotness and youth from the alcohol.  Around the 8 year point, the whisky begins to integrate and complexify, ultimately reaching a point of balance – the sweet spot where you aren’t whopped over the head with alcohol when you take a sniff, and you notice a proper level of complexity.

This complexity can be overdone however, spinning out of control and going more towards overwhelming than enjoyable. Towards the end of its life in barrel, the whisky begins to take on more of the aromas that reflect the history of the barrel, seemingly reverting to a reflection of the barrel’s unique aroma fingerprint. This fascinating transformation (that should be carefully considered in attempting to understand the aging processes of any alcoholic beverage, including wine), can, unfortunately, go too far.  The sweet spot can give way to earthy, mushroomy, woody, sherry-like aromas that overpower the freshness of the cereals and ultimately destroy the complexity that is so prized in a quality whisky.  The difficulty is that the point of maturity, and thus of overripeness, is different for each barrel.  Frantzen compares this to individual human beings – we don’t all age at the same rate, with genetics, and more importantly, lifestyle, playing an important role in whether we look and feel our age.  Someone who leads a high-stress lifestyle might feel ‘older’ at 40 than an individual who has learned to manage their stress.

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My personal favorite name for a whisky, “Intravagan’za” is meant to evoke the complexity, sparkle, explosion of this whisky in the mouth, all with measured restraint, internalizing the extravaganza. 

Besides overaging, other factors can lead to imbalance in whisky.  The problem is primarily due to attempts to ‘modernize’ the production process, using shortcuts to mature a whisky in a reduced amount of time, and thus turn a profit more quickly.  This is the general trend of innovation in whisky production, with some trial being more effective than others.  Tests have been run on the fineness of the grind used to produce the base alcohol, with higher surface area thought to give more complexity to the resulting distillate. The use of different yeast strains, as in winemaking and beer brewing, is used to alter the aroma profile of the base alcohol (note that in whisky production, as for beer, spontaneous fermentations by indigenous yeast do not occur as the grains don’t contain sugars that are accessible to these yeasts until starches are broken down by enzymatic processes).  Microoxygenation has been considered (though the high alcohol content of the whisky clears the pores of wood casks, rendering even old casks effective microoxygenation systems), though whisky making is a very secretive process, and this method shares a similar, skeptical, reception amongst whisky consumers as it does amongst certain wine consumers (justifiably or not), and thus is not widely communicated about.  Some producers use smaller cask (i.e. 50 L instead of the typical 500L used by Couvreur) to increase the surface area of the cask and thus the contact of the whisky with wood and with oxygen. According to Frantzen, this method often results in unbalanced whiskies.  Most of this innovation occurs outside of Scotland, as Scotch producers are focused on replicating the consistent quality that they have built a reputation for over the centuries.  Thus a producer like Couvreur gives us the opportunity to taste a Scotch that has branched out a bit from its roots (in particular those aged in barrels from Vin Jaune or even Burgundy wines).

And the results?  Personally I found them stunning.  Frantzen told us that given the origins of the barrels and the complexity that they seek to create at Couvreur, wine aficionados are often particularly apt to appreciate their whiskies.  With the two whiskies I was fortunate enough to taste (Overaged Malt Whisky and Blossoming Auld Sherried Single Malt Whisky) I wholeheartedly agree – these are definitely whiskies for wine lovers, and whisky lovers too.  Any producer that puts this much passion and care into their product is bound to have a good chance of creating something delicious.

 

 

 

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“Fleeting” is the producer’s whisky that is a different blend at each bottling, eternally changing and evolving.

When Worlds (science, humanities & wine) Collide : WAC 2014

I have recently started an internship at the Jules Guyot Institute, otherwise known as the University Institute of the Vine and Wine (Institut Universitaire de la Vigne et du Vin) at the University of Burgundy in Dijon.  

For three years now, the Institute has thrown a big annual wine geek party (ie research conference) that is called the WAC (Wine Active Compounds) International Conference.  This year, March 26-28 in Beaune, I am thrilled to be able to attend, as the program promises to be quite interesting.

There are plenty of classic research talks on the schedule, with speakers from across the world including Wendy Parr (sensory science) from New Zealand, Elisabeth Tomasino (enological chemistry) from Oregon State University, and Georg Meissner (known for research on biodynamic viticulture) from the University of Geisenheim, Germany, all of whom are particularly interesting to me for various reasons.  

But the subject matter varies enormously – there are talks not only on phenolic chemistry, health effects of wine components, effect of viticultural practices on wine composition, minerality and wine aging,  but also on consumer choice, reputation of organic and biodynamic viticulture, winemaking legislation, and the sociology of winemaking, to name a few (the full program is available here).

All of this should make for a well-balanced conference that covers not only the science, but also some of the humanistic and social aspects of grapegrowing, winemaking, and wine consumption.  An appropriate menu, I think, for a subject that so naturally links the sciences with the humanities.  

But most exciting to me, and what gives me hope that these two aspects will be able to intermingle and a dialogue will occur that unites the natural science and the social sciences during the conference, is the keynote speaker. The keynote to WAC 2014 will be given by Professor Steven Shapin, Historian of Science from Harvard University.  A superstar of Science Studies.  His talk is entitled “Historical and cultural construction of the wine perception,” and I am thrilled to see a conference framed by a keynote from a history of science perspective, from an author that I have read since the very beginnings of my academic exploration of science studies, well before wine was part of my subject matter.  

All of this to unite the worlds of science, humanities, science studies, and, of course, wine.  I will certainly be reporting back.

“Does bottle age reveal terroir ?” A discussion.

When  I received the notification from Erika Szymanski’s (also of Palate Press) blog Wine-o-Scope that a new post was up entitled “Quantifying terroir with chemistry: still searching for the Holy Grail”, I knew immediately that I’d find myself responding.  The destiny became reality when I saw the article she was citing – the most recent release from the laboratory where I had started my internship just days before.

In the final phase of my Master Vintage program, I am currently doing a 6-month internship in the laboratory of Régis Gougeon, at the Institut Universitaire de la Vigne et du Vin, (Institut Jules Guyot) of the University of Burgundy.  His current PhD student, Chloé Roullier-Gall, has taken me under her wing, and is the first author on the concerned paper discussed on Wine-o-Scope.  Thus I had no choice but to seize the opportunity to respond.

The paper, published in Food Chemistry, presents findings using an ultra-high resolution method of mass spectrometry, known as Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS), which is capable of determining the exact masses, and thus the exact chemical formulas, of thousands of compounds in a sample. Gougeon and his collaborator, Phillippe Schmitt-Kopplin of Helmholtz Zentrum Muenchen in Germany, use this methodology to look at the metabolomic profiles of grape, must and wine samples, effectively ‘fingerprinting’ them to look for particularities of individual or groups of samples.  In the present paper, the team looks at a series over 3 vintages of grapes, musts, and wines from four different vineyards, two in the Côte de Nuits region and two in the Côte de Beaune region of Burgundy.

Vougeot 1View from Château Vougeot in the Côte de Nuits

In the grapes, musts and just-fermented wines, no major differences were seen based on the vineyard locations.  Each of the three vintages gives a distinct profile in the freshly-made wine, but wines from the Côte de Nuits and Côte de Beaune region cannot be distinguished based on statistical analysis of their FTICR-MS profiles.

However, the team re-analyzed the wines in 2013, thus when the 2007s had been in bottle for 5 years, the 2008s for 4, and the 2009s for 3, and this is where the story gets interesting.  In her post, Szymanski wonders whether this follow-up analysis was out of desperation or always part of the plan, but frankly, it doesn’t matter.  In science, it is certainly true that many experimental decisions are made ‘out of desperation’, and honestly I don’t know the motivation in this case, but what is key is that they did the analysis, as this is where the most interesting result of the study was revealed.

Unlike in the wines analyzed immediately post-fermentation, the bottle aged wines do appear different based on the vineyard zone (the vintage effect remains important, as well).  Thus there is an evolution that occurs in bottle, that actually takes us back to a point where we can see differences based on the origins of the grapes – how do we explain that?! In the article, Roullier-Gall et al. propose that the terroir “impacts the initial chemical complexity of a wine, but time – i.e. bottle ageing – might be required to fully reveal it through the in-bottle diagenesis of complex chemical signatures.”  In other words, the terroir imprints its characteristics on the wine, but these signature elements are not revealed until the wine has aged in the bottle.  Could this correspond with some of the language that we employ to talk about bottle aging?  That wines need time to “open up,” “assimilate,” “integrate,” “mature” ?  Maybe there is a deeper truth to these statements than we know – something that goes beyond tannin softening and integration.  Maybe there are certain elements of a wines terroir ‘trademark’ that are only revealed after a bit of time in bottle.

Szymanski isn’t happy with this conclusion, as she says they haven’t gone this far in the study, that they have simply shown that “different wines are different.”  This is true, in effect, but dismissing it as such overlooks the real importance of the study, which is exactly this :  some kind of change is occurring in the bottle that allows us to characterize wine metabolomic fingerprints differently than immediately after fermentation.  Key changes are thus occurring to the chemical makeup during bottle aging, and we thus need to be keenly aware of this fact when choosing at which moment to analyze a wine, as this choice of time point may have an enormous impact on the results obtained.  And from a more romantic standpoint, yes, perhaps there are important changes occurring during bottle aging that reveal a wine’s identity.  But here Szymanski is right to be hesitant – it is a key finding of this study that opens up new questions to be explored, but for the moment, these questions remain wide open (but likely tied to the 95% of compounds found that are as-yet unidentifiable).

st aubin 2014 st vincentSaint Aubin, in the Côte de Beaune, during the Saint Vincent Festival 2014

In defending her statement that this paper’s sole valid conclusion is that “different wines are different,” Szymanski characterizes the researchers’ definition of terroir as broad.  They define it as the “vine-soil-climate-human ecosystem”, which I find to be an accurate summary of the most widely-accepted definitions of terroir, such as that of the OIV (Resolution OIV/VITI 333/2010) which states :

 Vitivinicultural “terroir” is a concept which refers to an area in which collective knowledge of the interactions between the identifiable physical and biological environment and applied vitivinicultural practices develops, providing distinctive characteristics for the products originating from this area. “Terroir” includes specific soil, topography, climate, landscape characteristics and biodiversity features.

For me, then, the authors’ definition of terroir is correct and incorporates all of the key elements, not broadening it by any sense.  In any case, even if they are only saying that different wines are different, that is not a conclusion to be dismissed.  It is, in fact, precisely the point that is interesting about this paper, which is that said differences only seem to appear after a certain time in bottle.

The criticism of merely two time points not being enough is a valid one, but this is only one article, and this work will surely be followed up, by this group or another, with a longer-term study that attempts to verify and further characterize these changes over time.  The present experiment is a proof-of-principle, successfully showing that this methodology can be applied to show differences from wines from different places, and further experimentation will need to be done to understand these differences, including additional sampling points, and certainly increasing the sample size as well.

Yes it is true that the vintage effect remained more prominent than the effect of vineyard location, but this does not, as Szymanski suggests, nullify the methods ability to distinguish terroir.  The vintage effect is stronger, yes, but the profiles of the wines can also be statistically grouped, within these vintage years, by location.  This is not surprising, as year-to-year climactic variation can be much more significant than the variation that occurs between vineyards located only a few kilometers apart (the entire zone of Côte de Beaune and Côte de Nuits spans a length of around 60 km), though this is complicated by the fact that terroir includes not only climate, but also geographical, pedological, and vitivinicultural factors.

In sum, the paper presents some interesting findings, not on the existence of measurable terroir effects so much as a methodology that allows us to elucidate distinguishing characteristics of wines only after a certain amount of time spent aging in bottle.  With further research this may eventually be traced to terroir fingerprints that are only revealed over time, but for now this remains an interesting theory, one to be questioned, debated, and explored, as Szymanski has already begun to do.

Personal note to Erika Szymanski : I must say that despite a bit of healthy debate here, I adore the concept of your work and of your PhD.  You hit precisely upon the theme that launched me into the world of wine with my Watson Fellowship – that it is an extraordinary context in which to understand relationships between scientific disciplines, between scientific research and those who put it into practice, and between empirical research and artistic expression. Wine is a fascinating subject matter precisely because the boundaries between all of these are constantly being pushed, prodded, dissolved, and redefined in ways that we don’t always see in other fields.  I’d love to read your thesis once its finished, and if ever you run across material that is particularly interesting in this regard, I’d be thrilled if you’d pass it along, either directly or via your blog!

The public weighs in on wine science : questions from the ACS Webinar with Susan Ebeler

I just sat in on the ACS Webinar (acswebinars.org or facebook.com/acswebinars) by UC Davis researcher Susan Ebeler on “Wine Science: Designing Wine.  While the content itself was very interesting, most of it was familiar to me as Dr. Ebeler came to give a lecture series to my class in Valencia (as mentioned in this post), what I found particularly fascinating was the stream of questions rolling in from audience members over the course of the hour-long lecture.

The audience consisted of over 1001 participants, from all around the world (Argentina to Poland), and ranged from winemakers to bloggers to researchers to an entire “Chemistry of beer, wine, and bourbon” class.  Thus the questions represent an interesting cross section of what the world wants to know about wine.  What people don’t understand, such as the question wondering if the floral and fruity notes in wine just come from the added flavors, or if there is another source, as well as suggestions that those embedded in the wine world on a day-to-day basis might never have considered.

Dr. Ebeler didn’t have time to respond to most of the questions (something like 180 were posed), but I collected some of the ones that I found particularly intriguing, for one reason or another, whether they were answered or not :

  • “Do you think most of the flavor components in wine have been chemically identified, and can be measured with current GCMS technologies?” – this one Dr. Ebeler was able to get to.  Her response was that we’ve found all the major compounds, and anything else would be trace compounds (such as Rotundone, the compound responsible for the black pepper aromas of syrah) and that finding new compounds will continue to get more difficult as we already have found the ‘easy’ ones.  I don’t disagree with any of what she said here, but I think that it is important to qualify this statement given her description of the complexity of the sensory effects of wine.  Since there is often little correlation between the concentration of a compound and our ability to perceive it, as well as the complex interactions possible between different aromatic and flavor compounds, it is very possible that molecules present in trace quantities could have a significant impact on the perceived flavor, aroma, or even texture of a wine.
  • “I have heard that some people, particularly in Japan, choose their wines based on their GC spectra, what are your thoughts?” – this one she didn’t have time to answer, but I thought it was a particularly interesting comment.  I don’t know if this is indeed the case, though it does ring a bell.  I’d love to know if anyone has more information about this.  If it is true, I think that this is a fascinating use of what most nonscientists would consider a highly complex analytical technique into popular culture, and would really like to know how this came about and the specifics of how it is used.
  • “Has there been any work on transesterification during fermentation, to tailor the finished wine for a specific bouquet?” –   Dr. Ebeler responded that this would likely be too complicated and difficult to target any specific ester, and wasn’t confident that it would be able to reliably give the desired effects.  However, I thought it was a very interesting question, and one that could only come from the mind of a chemist approaching wine from an outside perspective.  I doubt many winemakers or even wine chemists would consider attempting such a reaction on wine, but why not? And ideas like this one, though they may never lead to technological advances in wine, could help us think of processes that already occur in wine in a different light, giving new insight that may lead to new or deepened understanding.
  • “Is there an objective testing mechanism that does not involve subjective human perception?” –  I thought this was a great question to be posed, in terms of how it reflects upon the current scientific paradigm. Why do we feel the need to eliminate ‘subjective human perception’ from the evaluation of a process (tasting wine) that is entirely dependent on human perception, in fact, it IS human perception.  But this is a quest that we are constantly on, how to remove subjectivity from a subjective experience.  This should, I think, cause us to raise our own questions about how science works, where its limits are, and what new approaches/philosophies might be able to help us resolve this quest to understand rigorously a subjective, sensory process.

You can see coverage of the webinar (mostly mine) by checking out #ACSwebinars

For ACS members, the webinar will be available after 1 week at acswebinars.org/wine-design

Follow ACS webinars on Twitter @ACSwebinars or facebook at  facebook.com/acswebinars

Autour de la vigne : Insight into the public perception of wine science

A recent piece on Radio France International (RFI), the French international public radio, reveals some of the current wine research questions being investigated at INRA, the French National Institute for Agricultural Research.  But more importantly, the format of the interview gives us some insight into what aspects of wine science are intriguing to the public, thus pointing out some trails to follow to better communicate wine science with the non-wine industry public.

The context, of course, is a bit particular to France, as the French public has a special relationship with wine that is unlike that of many other countries.  French culture is historically and traditionally tied up in the production and consumption of wine, so it is naturally a subject with importance to the public. The wine industry carries huge economic weight in France, being the second most important export industry after aviation.  Production is widespread and diverse, with a major impact in almost all regions of the country.  And the concept of terroir is one that is well-integrated into society, commonly referred to, if not always completely understood in its technical sense, as it is a concept that is used not only in wine, but also in discussing other food products with a fundamental tie to their birthplace.

This context must be kept in mind, but does not mean that the issues addressed in the piece are not pertinent to the public in other countries.  France is an example of a nation that takes wine very seriously, but this trend is being picked up in other regions with growing production and consumption of wine.  Thus the presence of wine science in French public media can be a model for other cultures, of ways in which we can approach scientific questions of pertinence to wine, giving us an indication of the elements of wine most intriguing to an inquisitive public thirsty for understanding and for wine.

The panel interviewed on Autour de la question included researchers from INRA in Montpellier and Colmar.  Véronique Cheynier, the research director at Monpellier whose research is focused on polyphenols, Jean-Luc Legras who studies the role of yeasts in winemaking, and Philippe Hugueney, research director at Colmar who studies primary aromas produced in different grape varieties.

The host, Caroline Lachowsky, launched the conversation with a question that I know well.  A question that intrigues me to no end and thus delighted me to hear on this show, confirming its relevance and interest : is winemaking a science or an art, or some combination of the two ?

The response picked up on a classically French element of this discussion : terroir.  Dr. Legras took the idea that a wine is an infusion of vineyard stones and defended it, at least for certain varieties, in proposing as an example the wines of Alsace, which can have entirely different profiles, even coming from a single producer who treats all of his wines equally, the only difference being the vineyard site.  What doesn’t come up until later is that this idea of minerality, of typicity of place, has not yet been linked directly to the soil.  But here he plays on the fascination aspect, the magic that is what intrigues the public about wine.  He openly admits that these differences in terroir are perceptible, but doesn’t expand on the science (or lack thereof) behind it at this point.  The panelists wait until the question is posed a bit differently, in terms of how the specificity of a soil might be injected into the wines, to clarify the state of the science on this matter.  Here Philippe Hugueney discusses the known direct influences of soil on grape quality – that soil nitrogen content impacts grape color, but that the roles of the minerals in the soil remain mysterious.  He explains that the popular term minerality has no agreed-upon definition and how this characteristic might come from the soil is still unknown (here I would add that we don’t even know whether this is the right question to be asking – there is much debate as to whether minerals in the soil even have an influence on this ‘mineral’ character, and thus we are not even yet at the point of working out how, but still at the level of if they have an impact).

Typical terroir of France's AOC Côte-Rôtie, in the northern Rhône valley

How is it, then that such an intriguing question, one of the first to be posed in this interview, in an accurate reflection of its frequency amongst wine lovers, remains unanswered?

Lachowsky later asks what types of evolution wine and wine styles have undergone over the years – if the identity of wine is changing, becoming sweeter, more or less acidic, or higher in alcohol.  Dr. Cheynier jumps to respond that the wines are certainly higher in alcohol, due to faster maturity and higher sugar levels, which are then converted through fermentation into elevated alcohol levels in the final wines.  She attributes this major shift to climate change, another hot topic in wine science as well as in the public eye.  Though a hugely important element to explore, here I think that the conversation was left isolated a bit too far into the scientific realm, as there are a host of other factors influencing the evolution of what we consider to be quality wine, or wine that consumers are interested in purchasing.  There is an element of taste, of fashion, here, that, while perhaps more fickle and trivial than climate change, is important to consider, especially when communicating with the public.   This is yet another aspect of the complexity of wine, and the complexity of understanding climate change, as we often cannot differentiate cause and effect in the race toward bigger, bolder, more powerful wines that has been occurring over the past 20-30 years.

Here is a potential disconnect between how researchers see the world – focusing on climate change as the primary factor influencing the evolution of wine styles, while consumers might be more interested to hear about the interaction between climate change and changing tastes with the introduction of new producer countries, the expansion of consumption in nations where wine-drinking was not traditionally part of the culture, et cetera.

The host was quick to pick up on the great complexity of wine science – of the distinct parts that must work together – plant physiology to understand the compounds present in the grapes, microbiology of the yeasts that produce the fermentation, and how these two interact to create the complex chemistry of finished wine.  And furthermore, the complexity of all of the environmental factors that go into making a wine – the elements of terroir : soil, climate, geography, and viticultral and winemaking techniques, the influence of pests, diseases, beneficial insects, yeasts, bacteria and other organisms that play a role in determining the final product.

This complexity, at every level, at every turn, is where we should really focus in communicating wine science.  This is what makes the system endlessly interesting, but also endlessly difficult to study.  But this is where the magic is.  And it is precisely this magic, this wonder, that is what attracts people to wine.  So to incite and interest in science in those already intrigued by wine, we can use this ‘magic’,  this complexity, to unite the two and spark passion for a new level of understanding in those who are enthralled by this fascinating beverage.

You can listen to or download the radio show (in two parts), Autour de la question (French) at the following links :

Part 1: http://www.rfi.fr/emission/20131218-1-pourquoi-le-vin-soif-recherche

Part 2 : http://www.rfi.fr/emission/20131218-2-pourquoi-le-vin-soif-recherche