A Baltic Love Story: The Intrigue of 170-year-old Shipwrecked Champagne

The internet is bursting with news of champagne: the BBC1, Fox2, NBC3, Discovery News4, Science5, Nature6, Popular Science7, Smithsonian Magazine8 (who published the most complete summary I’ve seen), and many more are all bubbling with excitement over the discovery of 170-year-old champagne bottles shipwrecked in the Baltic Sea.  Granted, the discovery itself dates back to 2010, but has been brought to the attention of the masses as a result of an article published Monday in the Proceedings of the National Academy of Sciences of the USA (PNAS)9. I had the pleasure to be a coauthor on this paper, and am thus that much more thrilled to see the media excitement surrounding its publication. But my attention is particularly piqued by the manner in which the science journalists and the twittersphere are talking about the article, as it gives a clear view of what the public finds most interesting about the discovery.  This public perception of science is always a topic of interest to me, but here I have the particular privilege of being an insider, and thus comparing the public reaction to that of the scientists who worked on the paper.

Such a discovery, of 168 bottles of label-less champagne bottles dating from the first half of the 19th century, is one that intrigues and excites.  The article begins in language uncharacteristically enthusiastic for a scientific article: “Discovering ancient objects from excavation sites or simply at the back of a cellar has always piqued human interest because of the messages from the past they may contain. Unsurprisingly, our interest increases even more when exhuming old bottles or even jars that seem to have contained grapes or wine, giving a glimpse into the little-known history of winemaking.” Clearly (and I can attest to this), the scientists were intrigued by this project for reasons that go beyond the scientific value of the study – here is a case where one of the fundamental motivations for a research project is simple curiosity and wonderment. This is, after all, one of the most essential wonders of wine itself – its ability to transport us in time and place, whether that be to the year of its production, a memory of a candlelit evening where a particular wine was first tasted, or to the vineyard itself. So this study does lend itself particularly well to popular interest, and indeed, the public has weighed in, expressing their curiosity as to what such an old champagne, aged in such particular conditions must taste like.

The study includes, of course, a sensory analysis, and thus can answer this most pressing question that the media poses. At first whiff (known as the “first nose” in French, smelled before swirling the glass and thus oxygenating the wine), the expert sensory panel remarked odors resembling cheese, animal notes, and wet hair or fur, none of which are particularly surprising given the oxygen deprived environment that these champagnes were aged in (during normal storage, a small amount of oxygen, does diffuse through the cork over long periods of time, but underwater, it was, in fact, the carbon dioxide responsible for champagne’s signature bubbles that diffused out of the bottles, leaving behind a ‘flat’ champagne with only a bit of tingly, prickly sensation in the mouth). After swirling a bit to expose the wine to oxygen, the predominant aromas shifted to far more appetizing “grilled, spicy, smoky, and leathery” as well as the more expected floral and fruit notes. All of these sensory impressions were corroborated by the detection of corresponding aroma molecules using advanced chemical analysis methods.

Despite the inherent intrigue of the champagnes’ organoleptic profile, the paper’s discussion goes far beyond sensory analysis, delving into the domain of “archaeochemistry,” or the use of chemical evidence to unravel the archaeological mysteries of this shipwrecked champagne found in the Baltic Sea. Evidence such as the content of sugar, alcohol, metal ions, salts, and wood-derived compounds were all analyzed with an eye to reconstructing of the methods employed in making these wines, and these results even give insight into the viticultural practices and the probable intended destination of the bottles. This careful detective work is of great interest to the chemically-, enologically-, historically- or archaeologically-minded, but it appears that the question of these wines taste remains the issue that most profoundly captivates the public.

1 http://www.bbc.com/news/science-environment-32388123

2 http://www.foxnews.com/science/2015/04/22/170-year-old-champagne-recovered-from-bottom-sea/

3 http://www.nbcnews.com/science/weird-science/shipwrecks-170-year-old-veuve-clicquot-reveals-champagne-history-n345176

4 http://news.discovery.com/history/archaeology/shipwrecked-champagne-leathery-still-pretty-good-150420.htm

5 http://news.sciencemag.org/chemistry/2015/04/what-does-170-year-old-champagne-taste

6 http://www.nature.com/news/cheesy-metallic-sweet-170-year-old-champagne-is-clue-to-winemaking-s-past-1.17361

7 http://www.popsci.com/popping-cork-170-year-old-shipwrecked-champagne

8 http://www.smithsonianmag.com/science-nature/170-year-old-champagne-recovered-and-tasted-baltic-shipwreck-180955050/

9 A PDF of the original article is available here on the University of Reims’ website.

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Wine science takes on the Chesapeake

I have just landed on home soil. Coming back to my roots, my terroir, to deepen and round out the research project I’m working on at the University of Burgundy.  I have come to spend two weeks at the University of Maryland’s Chesapeake Biological Laboratory, with our collaborator Michael Gonsior.

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They grow wine in the Chesapeake?  Actually its possible… I’ll have to find out (in any case this weekend I’ll be spending some time in another surprising wine region, at Galer Estate in western Pennsylvania).  But that’s not the reason I’m here.  I am here to work with environmental chemists, to learn their methods, typically applied to marine water or other environmental samples, and apply them to wine.  This collaboration started a couple of years ago, Gonsior and my mentor, Régis Gougeon having been introduced by another non-wine collaborator, Phillipe Schmitt-Kopplin (whose lab in Munich I spent three weeks in back in March), and the research looks quite promising.

In brief we are using fluorescence spectroscopy methods to study the global signatures of different wines.  This has been done before (see Airado-Rodrígeuz et al., 2011), but we hope to combine the information gleaned from the “fluo”, as it is affectionately called (at least in French) with our already well-developed metabolomics approach (see Gougeon et al., 2009; Liger-Belair et al., 2009; Roullier-Gall et al., 2014) to gain a more well-rounded view of a wine and the effects of different factors, such as terroir and bottle age (Roullier-Gall et al., 2014), cooperage (Gougeon et al., 2009), or vinification choices. Early results were presented at WAC by Christian Coelho and Chloé Roullier-Gall.

 

Personally, this experience brings me full circle, in a way, as a major part of my chemistry training took place in an environmental context (my senior thesis, at Haverford College, was carried out in Biogeochemist Helen White’s lab), and I am looking forward to seeing how my project and intentions are received in such an environment, seeing that I work on a very different substrate, with very different stakes and objectives.  This was less of a factor in Munich, as the collaboration is a long-standing one, and several PhD students have already passed through their lab, desensitizing them to what might otherwise seem a strange topic in the context of the “Environmental Health” focus of that particular institute.

 

Additionally, this puts the study of wine in a new context for me, one that is less bathed in wine than the French context I have been working in. Though in Munich wine is not the beverage of choice either, the lab’s PI (Schmitt-Kopplin) is French, and has a vested personal interested in wine.  In the US, particularly outside of the more longstanding winemaking regions, wine is often viewed quite differently from in the Old World, particularly France, as America does not have the longstanding, deep-rooted history into which the vines and wine issue from them, spread their roots.  I’m looking forward to seeing (and sharing!) how this all plays out during my stay.

 

 

Airado-Rodrígeuz, D., Durán-Merás, I., Galeano-Díaz, T., Wold, J. P. Front-face fluorescence spectroscopy: A new tool for control in the wine industry. J. Food Comp. Anal. 2011, 24, 257-264.

Gougeon, R. D.; Lucio, M.; Frommberger, M.; Peyron, D.; Chassagne, D.; Alexandre, H.; Feuillat, F.; Voilley, A.; Cayot, P.; Gebefügi, I.; Hertkorn, N.; Schmitt-Kopplin, P. The chemodiversity of wines can reveal a metabologeography expression of cooperage oak wood. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 9174-9179

Liger-Belair, G.; Cilindre, C.; Gougeon, R.; Lucio, M.; Gebefügi, I.; Jeandet, P.; Schmitt-Kopplin, P. Unraveling different chemical fingerprints between a champagne wine and its aerosols. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 16545-16549.

Roullier-Gall, C.; Boutegrabet, L.; Gougeon, R. D.; Schmitt-Kopplin, P. A grape and wine chemodiversity comparison of different appellations in Burgundy : Vintage vs. terroir effects. Food Chem. 2014, 152,100-107.

WAC 2014 Recap Series: Holistic science? The study of Biodynamics

I’ve often mused about biodynamics (some examples here, here, and here), how it should be interpreted, and how it should be studied.  At WAC, two starkly different takes were presented on how it is being studied : one from the production side, and one from the commercial side.  Both of them focused on a particular factor – quality.  This is often a primary reason cited for converting to biodynamics (BD for short) amongst winemakers, but the scientific world, and many consumers, can have trouble finding any concrete reason that the esoteric practices of BD should have such a positive influence.

Georg Meissner has been studying BD practices since 2005, in what is probably the largest and most in-depth scientific study being conducted on BD (at least in Europe – let me know if there are others in other parts of the world!). He explains the long-term project as taking a “holistic” approach, which, in theory, sounds exactly like what I have often proposed as necessary to understand BD.  If we want to understand this holistic system, we will never succeed with a reductionist approach, as we would inevitably be excluding some of the variables imperative to the functioning of the multidimensional system (if indeed the explanations of BD are correct, and its functioning relies on the synchronization of all parts of the system).

But I’m not sure where we draw the line between “holistic” and simply looking at as many factors and responses as one can possibly think of.  To me, holism implies a sense of unification, a “whole is greater than the sum of its parts” element, that we can’t necessarily access simply by looking at all of the variables simultaneously.  There is a missing link, that extra little edge that boosts our sum into a bigger whole, that doesn’t come so easily.  This project does the best that science can do, I believe, looking at the effect of biodynamic preparations (particularly 501), but seemingly not the more abstract aspects of BD, notably the role of the lunar calendar, on a multitude of factors: the soil, the worms residing in it, the vines, diseases, biodiversity, grapes, juice, and wine, and even the copper chloride crystallization (“sensitive crystallization” – a subject often spoken of in the same breath as Bonny Doon Vineyard’s Randall Graham, who uses this technique in his marketing materials) patterns resulting from it. The first three years of the study were dedicated to getting an overall picture of how each of these factors is affected by different viticultural systems (BD, organic, and conventional), and since 2010 they have attempted to dive deeper. I fear only that in diving deeper they may lose sight of the holistic picture they are striving to create, in focusing, as science tends to do, on the micro-level details that tend to be seen as disconnected from the greater whole. All of this remains to be seen, but in any case I applaud this team of researchers for their dedication and effort in pursuing a subject not always appreciated in scientific circles, and attempting, within the bounds of the scientific system, to take an approach that remains true(r) to the integrated spirit of biodynamic agriculture.

BDprepsBD Preps at Weingut Hirsch in Autstria 

Giacomo Negro, a Business professor and sociologist at Emory University, presented quite a different approach to studying BD. His work focuses on the consumer perception of BD, and he proposes that BD is a “signal” of high quality.  The work is based on the concept of “collective signals” which are one of the mechanisms by which a consumer can glean information about the products available for purchase. To study this, Negro’s work compares a winery’s scores in two important wine reviews, Wine Spectator and Gault & Milau’s Le Guide des Vins de France to their chosen method of cultivation.  The work looks at a winery’s rating before and after conversion to BD, and finds in general that there is a positive correlation of quality rating, as expressed in the scores, and BD production. He also looks at price, though here I worry that too many confounding factors may be present, as it is generally accepted that BD (and organic) producers incur slightly- to highly-elevated production costs, which can also be linked to higher bottle prices.

Quite clearly a different type of study and thus one that confronts a whole host of different issues, this work also represents a way of thinking about BD.  Can we evaluate its quality (or that of any wine, for that matter) properly by a one-dimensional numeric score?  What other factors play into quality?  Does the story of a wine count as well?  I think, in BD especially, consumers are often inclined to purchase more than simply the bottle’s contents.  Their reasons for buying may have ecological, moral, even borderline spiritual (especially when it comes to BD) undertones, so perhaps further consumer perception studies on BD wines could take aspects of this complexity into account.

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.

“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.

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