If you’re a winemaker, a vineyard manager or viticulturist, or in a similar role, and if you have ten minutes to help a PhD student gather some data (and improve the state of research communication in the wine industry), I’d be most grateful for your response to this survey on your feelings about winemaking and growing information and where you go to find it. Find the completely anonymous survey here: http://fluidsurveys.com/s/winescienceinformation/
My Palate Press piece for this month (which I really wish was entitled something involving “water” to make the subject more clear) is a bit about Waiheke Island, just off the coast of Auckland, and a bit about water footprints in the wine industry. The relationship between the two is that Waiheke — shockingly, for a North American accustomed to consistent public amenities like central heating and easy wi-fi (both unlikely propositions in New Zealand) — has no public water supply. In good years, residents and businesses and wineries meet their individual needs either by collecting and filtering rainwater (most folk) or with a “water bore” into the under-island aquifer (large and/or resource-full folk). In bad years, all of the above buy water from private companies with private water bores, and do laundry less often.
Waiheke is a good reminder, though, that whether water comes out of a tap or off the cistern parked next to your car, it’s always coming from the same two places: the sky, or underground (which isn’t to say that the two aren’t connected, but only that it’s helpful to think of the two compartments). Tap water is a bit like packaged boneless skinless chicken breasts from the grocery store. Someone else has done all of the hard work for us. Both distance us from the hows and wheres of the stuff we use. Butchering chickens is a pain*. It makes endless sense to divide labor, specialize, and let someone else with better equipment and skills and economy of do it for you. And bake your bread, change your car’s oil, and collect and filter your water. Still, all of these things make it easier to abuse the system. We don’t pay as much attention to our dinner’s living conditions when it didn’t live with us before it appeared on the table, nor to how it died if we didn’t kill it. I’d never really thought about water that way before wandering around on Waiheke; I try to conserve it, but I don’t usually think so graphically about what my convenient kitchen faucet implies. I’d never wish drought on anyone (and California and its people have my sympathy). But maybe it’s no bad thing to look for a drinking fountain in a place with no public water and find none, and remember that I should be just as conscientious about my water as I am about my free-range, local, organic Sunday supper.
More about my Waiheke visit, and about water, is on Palate Press.
*As I know from recent experience. The Great Chicken Experiment is, regrettably, over. The first two hand-me-down hens lived happily with us until the neighbor’s rooster discovered them and decided that they were his, after which they lived happily with the neighbor until she decided she was done with poultry and she invited me to dispatch the lot of them (after which they lived in my freezer and my stockpot). Save the (charming, darling) several month-old chicks, who we adopted. Unfortunately, having been raised entirely outside in our mostly fenceless environs, they’d learned to be very freely free-range. A trip through someone’s spinach was more than anyone was willing to tolerate (save, maybe, the chickens) and we handed them on to someone else. We miss them, though my garden does not.
Scenario #1 – You’re sitting next to your fire after dinner, relaxed, with a few ounces of fine Canadian or German icewine, maybe a few slices of blue cheese and a ripe comice pear, and the current evening reading book. You enjoy all three for an hour or so and retire, happy and sleepy, to bed.
Scenario #2 – You’re sitting next to your fire after dinner with a few ounces of icewine and an active mind in search of a target, maybe two active minds if you have a companion. Conversation turns to the wine, how desperate those first Germans must have been to salvage their inadvertently frozen grapes and how arduous and expensive repeating the process on purpose now is. You speculate that cutting real icewine with something else must be mighty tempting, and the gaze you cast on your glass turns wary. And then you cast your gaze on Google and find this new article in the American Journal of Enology and Viticulture on a new strategy for testing the authenticity of icewine.
Icewine production is very expensive and no International Body of Icewine Authenticators polices producers to ensure that they’re doing it right or in good faith. Canada produces the bulk of the world’s stock (though I also enjoyed some fine examples in the Finger Lakes, not too far south of Ontario), and the Canadian Vintner’s Quality Alliance (VQA) legislates use of the term: a Canadian bottle with “icewine” or “ice wine” on the label must be made from approved varieties, from grapes harvested during “sustained” temps of at least -8°C, naturally frozen on the vine, coming in at at least 35°Brix, with no added sugar or alcohol, all overseen by a VQA representative. European producers employ similar standards, but the Asian sweet wine market is apparently well-populated with “Iced wine” and other unauthorized and fraudulent variations on the theme. Having a reliable means to verify that an “icewine” is really icewine made from frozen grapes seems prudent.
Per Armin Hermann’s new research, tracking oxygen isotopes could be that way. The idea is clever and conceptually simple. When grapes freeze, water partitions unequally between the part that turns to ice and the part that remains liquid. That’s the point of icewine: more water freezes, leaving sugars and other dissolved molecules concentrated in the syrupy liquid that remains. The naturally occurring isotope 18O, present in the water, will also distribute into the frozen and the unfrozen parts unequally. Since the frozen ice is more or less excluded from what ends up in a bottle of true icewine, then, icewines will contain a characteristic amount of 18O. All we need to do is determine — theoretically, using mathematical equations, and empirically, by measuring a bunch of icewines — what the “icewine” versus the “not icewine” 18O ranges are. Simple, elegant, and probably effective.
The plots of 18O measurements Hermann created show what looks like reasonably convincing separation between the ice- and non-icewine samples (understanding that judging how convincing is outside my expertise). BUT, there are two important caveats. First, the comparison was lab-frozen grape musts against the unfrozen originals. Again, it’s simple: “Frozen grapes, when pressed, will produce a must that is always depleted in 18O relative to its marc and also to their unfrozen counterparts.” The study didn’t include creating a database of icewine samples from various regions to establish reasonable 18O ranges. That’s solvable in theory, though the success of the whole method still depends on finding good, clear separation between real live ice and non-icewines.
Second, the method provides no way of determining how the wine was frozen. The 18O-depleted wine could have just as easily been frozen after harvest, in the winery, illegally. So, no matter how successful that empirical database is, the method won’t perfectly solve the how-do-we-detect-fakery problem. It is, as Hermann notes, an “additional” means giving a “strong indication” of authenticity. I wonder: is there a detectable chemical difference between the kind of slow freezing that would happen naturally on a grapevine in a cold Ontario winter and fast winery cryofreezing? Until then, looking for the Canadian VQA mark on the bottle — and avoiding anything labeled “iced wine” — remains the safest option, North American privilege notwithstanding.
My favorite Thanksgiving pairings are pinot noir with Burgundian leanings and sparkling brut rosé. (I’m not aiming for points on originality here). Since I’m a member of the drink-American-on-Thanksgiving club, the pinot noir is likely to lean Burgundy without actually being so in the form of an Oregon pinot noir that remembers that Oregon isn’t California. The sparkling is likely to be Schramsberg if I can get it and Ch. Ste. Michelle if I have to share. That being out of the way, my favorite Thanksgiving pairings have everything and nothing to do with what’s in the bottle.
Growing up, dinner came in two general forms. “Dinner” was eating. I was sometimes allowed to bring a book to the table (don’t judge), my parents talked about business or watched the evening news, and we didn’t have wine. “Nice dinner” was dining. We lit candles. We had wine. The conversations were longer, more thoughtful and, silly or serious, involved more stories. “Dinner” could be over in 45 minutes. “Nice dinners” sometimes took three hours. I blame the wine.
Thanksgiving (and Christmas) was the paragon “nice dinner:” just the three of us, the nice plates, and a meal that took most of the day and a spreadsheet to prepare — because what is Thanksgiving but an excuse for excessively social cooking for a family that doesn’t watch football and does own three mortar-and-pestle sets? And definitely wine. We sometimes thought about a movie afterwards, but as often as not we just talked and listened to music until everyone was warm and sleepy and full of pumpkin pie and single malt and ready for bed. Again, I blame the wine. And the single malt, but mostly the wine.
Thanksgiving and nice dinners have everything to do with science and science communication. I remember the evening when my father first explained color spaces (a fundamental element of color theory) to me. I was somewhere in the second half of my teens and I’m pretty sure the bottle on the table was a Dr. Frank merlot from New York’s Finger Lakes, because that was our house red at the time. We talked about F-stops or the zone system, how sub-woofers work, the finer points of gardening or birdwatching. Later, we talked about my research and I practiced science communication on my father, for whom “cell” was more likely to refer to a battery than a bacterium. Sometimes we were mundane and just rehashed old stories. We always talked about the wine at least a little.
I’m sure that I would have been interested in science and communication and maybe even in wine without those dinners. But “nice dinners,” and holidays especially, were the crystalline form of the stuff that taught me to be inquisitive, to value good conversation (and to hold up my end), and to understand why wine isn’t just about flavor and definitely doesn’t need to be about prestige. Good wine meant good conversation, and good conversation means everything.
I’m all in favor of thoughtful wine and food pairings that reveal exquisite and otherwise-unseen elements of each, or even simply pairings that taste good. But the absolute best pairing with Thanksgiving is just wine, whatever wine makes space for conversation, whether at a quiet table for three or a potluck affair for thirty. Because that, not an exquisite flavor experience, is the wine’s real job.
Having a spare two days in Auckland last week, I paid an all-too-short visit to Waiheke island which — thankfully, if you’re like me and are always looking for an excuse to get out of a big, crowded city — is only a pleasant 40-minute ferry ride from downtown. While the island is still best known for Bordeaux-style blends, syrah has of late become the island’s new darling. So, as it will when wine science geek meets winemakers in a spicy red zone, rotundone came up.
Rotundone is, quite fairly, one of the better known contributors to wine aroma. Unlike so many other more or less mysterious molecules, rotundone produces a specific, distinct, and very characteristic aroma: the black peppery note we associate strongly with Syrah (or Shiraz, if you’re speaking Aussie). We’ve only had specific evidence of that rotundone-pepper-syrah correlation since 2008, when an Australian group identified the compound, showed it to be the heretofore most powerful wine aroma compound (i.e. the one with the strongest impact at the lowest concentration), and demonstrated that 20% of their experimental syrah-drinkers couldn’t smell it at all even while the other 80% were being overwhelmed. In 2008, it was “an obscure sesquiterpene.” Six years later, I had a winemaker ask me whether there was really anything more to learn about rotundone.
Two articles have been published on how rotundone develops in the vineyard in 2014, both from Australia (including researchers involved in the original rotundone research), both confirming that viticultural practices and vineyard conditions generally can affect rotundone concentrations. One, working from a precision viticulture stance, gave evidence that rotundone concentrations vary across a vineyard in ways that might be related to how soil differences and topography affect temperature. The other showed that rotundone concentrations decreased with leaf pulling (which increases grape sunlight exposure and therefore temperature) and increased with irrigation; dropping unripe clusters (as growers do to control yields and even out ripening) didn’t have an effect.
The winemaker’s point was: “Um, duh? We knew that already.” Whether or not he could, in fact, have predicted all of the details of these experimental results matters less, I think, than that he perceived the research as useless. Vineyards on Waiheke aren’t irrigated. The estate vineyards with which he deals are small enough and local enough for him to walk and taste regularly, observe when and where the peppery flavors he wants (or doesn’t) are happening, and give picking orders accordingly. None of this rotundone research changes what he’s going to do in his vineyard so, to him, it’s pointless.
His comment highlighted a question increasingly on my mind of late. Who is wine research for? It’s obviously for scientists, and there’s nothing wrong with that: knowing about the world is a worthwhile goal on its own merit apart from any specific practical outcomes that knowledge might have, and long live basic research. Scientists and the community at large say that it’s for the benefit of “the wine industry” and, in part, that’s true. For a large operation manufacturing a specific wine style calling for a “dialed in” level of pepperiness and relying on fruit from many vineyards, that rotundone research might change things. Maybe they think about calling for a different leaf plucking regime on some of their syrah vineyards that aren’t quite meeting quality targets. But is the research for small producers, like this skeptical Waiheke winemaker? Call him provincial or even selfish for thinking that research doesn’t continue to help “us” understand more about rotundone, but he still knows what he needs to do to make a syrah that, by all indications, sells like roses on Valentine’s Day, out his cellar door, at prices that folks without the million-dollar views find hard to justify.
The syrahs I tried, at Mudbrick and Obsidian, were pretty convincing. Both relied more on freshness than power to make their case and certainly didn’t lack for rotundone, even minus irrigation and with leaf plucking common across the island. Obsidian’s 2013, carrying enough fruit and tannin for its lightness and brightness to be delightful and refreshing (and a pleasant alternative to the overpowered, clumsy or pretentious syrahs too easy to find in many New World climes), would accompany a sweaty Waiheke summer afternoon as nicely as a grilled lamb chop.
Is there anything more to learn about rotundone? Unquestionably. But, maybe, the more pertinent question for a Waiheke winemaker is whether there’s anything more to be learned about making well-balanced, pleasantly but not overpoweringly peppery syrah. Realizing that those two questions are in fact different is key, I think, to furthering both goals.
My piece for Palate Press this month asks what California (proto-Davis) wine researchers were doing in the era before mass spectrophotometers and DNA sequencers and even automated pH meters and all the other fancy stuff wine scientists consider essential today. The short story is that they were trying to figure out what grows best where, and how, which is fundamentally what we’re still trying to do. The long story is on Palate Press.
The long story didn’t have space for me to really geek out over the fun of reading old research articles. I think it’s fair to say that science writing — of the by scientists, for scientists variety — wasn’t as dry then as it is now, not just because antiquated language is quaint but because the distance between normal-talk and science-talk was shorter then than it is now. It’s pretty accessible and often entertaining. There’s the simple, voyeuristic pleasure of being astonished at just how backward they sometimes were, and sometimes at realizing that they weren’t as backward as we tend to assume. And then there’s the higher-order pleasure of making stories by connecting what they were doing to what we’re doing and finding new meaning in both the historical and the modern.
But reading about someone else geeking out over light archival wine reading isn’t near as fun as doing it yourself, and the archives of Hilgardia: a Journal of Agricultural Science from the University of California, including much about wine, are freely available via the University of California Agriculture and Natural Resources Respository. When so much is pay-walled and protected, free access to land grant university resources — not just for subscribers, not just for local winemakers, and not just for the taxpayers of California or even the United States — seems increasingly meaningful, and a good reminder of this massive, excellent, egalitarian knowledge-sharing project we practice through land-grant universities and agricultural extensions. I won’t ask you to excuse my unfashionable patriotism.
I’ve recently been reading piles of wine science communication texts: viticulture and enology extension newsletters, research articles in Wine Business Monthly and Wines and Vines, and university press releases and news items, among others. Many, many of them exhibit the same dysfunctions: the data sandwich, the shape-shifting audience, and inconsistency in rhetorical framing.
Those are three different ways of referring to the same problem, but each addresses a different audience. “The data sandwich” takes the point of view of the reader. The shape-shifting audience speaks to the author. Inconsistency in rhetorical framing appeals to the researcher. If I wanted to exemplify the problem, I’d now define “data,” “audience,” and “rhetoric.” And then I’d launch into a number- and jargon-laden discussion of how my data illustrate that many science writers (scientists in particular, though by no means scientists alone) don’t hold on to a single picture of who their readers are and what those readers know while writing a piece from beginning to end. And then I might conclude by saying that my data suggest that this is a concern of which it’s worth being aware.
Many science-focused articles begin with big, broad, contextualizing statements about wine. The rest of the first paragraph or two introduces concepts and defines terms with which someone who’s been working in the wine industry for a while — or who took a chemistry or microbiology class in their V&E associates’ program, or who read Wine Business Monthly on and off last year — probably feels pretty comfortable. Having set the scene, the author, somewhere around the third paragraph, begins describing their recent research project as though they’re talking to the guy in the lab down the hall instead of the person they were talking to a paragraph ago who’d never taken Wine Chem 101.* Two to ten paragraphs later, when the details of that project have been exhausted, the author concludes with a paragraph or two about how it all means that we should be aware of something, or that whatever-it-is is more complicated than previously thought and very important.
Let’s say we’re writing about new research on anthocyanin development in the vineyard. In the first paragraph, I’d describe why red grape color is important in winemaking. In the second paragraph, I’d define “anthocyanin” as one type of a class of molecules called phenols and describe how anthocyanins are mostly responsible for red wine’s color. In the third paragraph, I’d begin talking about how empirical evidence has recently demonstrated that deficit irrigation may intensify color density in Australian Shiraz not only by upregulating anthocyanin synthesis via unknown mechanisms but also by stabilizing the flavilium form of specific anthocyanins via hydrogen bonding with flavanols whose biosynthesis is also upregulated**, and I’d keep that up for a while. I’d finish either with a short paragraph about how the role of anthocyanins in wine color development is very complex and it is necessary for scientists to understand these relationships in order to more accurately model wine color, or suggesting that deficit irrigation might help winemakers reach stylistic color goals.
Anyone who was actually well-served by the first two paragraphs is floundering in deep water for the middle part of that data sandwich. Anyone who could follow the middle bit was bored or insulted or at least skimmed or skipped the first two paragraphs. And anyone who stuck with it to the end might be wondering why they bothered.
We’re used to this. We see it a lot. Because it’s so common, it’s easy to ignore and not remember that there are better ways.
There are. The solution is even relatively easy. First, envision who’s most likely to read what you’re writing, what they do with their days, and what they probably already know about your topic. Next, decide what you hope they’ll get out of reading your piece. Write with those ideas in your head. Then, crucially, revise. Go back through the whole thing and after reading each sentence ask yourself: did I slip up and use a word/reference a concept my reader won’t understand, or explain something they surely already know? Did I end having told them what I wanted them to get out of this, and preferably finishing on that note?
You may or may not have to guess a bit to get started, depending on whether you’re writing for a publication with a pretty well-defined readership (a newsletter that goes out to regional growers and winemakers, for instance) or a broader one (Wine Business Monthly, where you can still guess most folk are familiar with intermediate-level wine terms, or the local newspaper, where you can’t). But if you make a decision and stick with it, you’re less likely to confuse your readers even if you’ve guessed wrong.
Regardless, you’ll have avoided creating an indigestible data sandwich, or asking your audience to shape-shift as they read, or been inconsistent in your rhetorical framing. However you’d like to put it, you may have saved your well-intentioned reader from toughing it out only to find that they’re not sure how all this is relevant…
*Or, if a non-scientist writer/reporter is doing the talking, they describe the research on which they’re supposed to be reporting using the terms the scientist used when they talked last week or in the peer-reviewed research article that just came out.
**Cortell, J. M., Halbleib, M., Gallagher, A. V., Righetti, T. L, J. A. Kennedy. 2005 “Influence of vine vigor on grape (Vitis vinifera L. Cv. Pinot Noir) and wine proanthocyanidins.” J. Agric. Food Chem. 53 (14): 5798-808.
If you already know what I’m talking about, the good news is that the California DWR plans to preserve the Jose vineyard when it renovates the surrounding marshland. If that didn’t make sense to you, keep reading.
This past March, a small hullaballoo arose in response to a California Department of Water Resources plan to reconstruct a tidal marsh in Eastern Contra Costa County in the general, Sacramento-San Joaquin Delta area. The project, while an otherwise lovely effort to protect and maintain verdant wetland habitat, would have destroyed a historic and utterly irreplaceable 14-acre Carignane vineyard (“the Jose vineyard”) originally planted in the 1880’s. I wrote about the project and reasons for saving the vineyard here: Let’s stop a bad thing from happening for a good reason: saving a historic California vineyard.
This morning, the Dept. of Water Resources released their final plan and recommendations for the project, revised after a comment period during which 115 people (including me), and the city of Oakland, voiced concerns about losing the vineyard and supported changing the project to preserve it. The good news: the revised plan keeps the vineyard in place, along with a perimeter access road and an adjoining “buffer area.”
The original plan read: “The proposed project will result in the removal of the Jose Vineyard in order to achieve proper elevation and vegetation consistent with the tidal marsh restoration, which would be considered a substantial adverse change to the property under CEQA. Project redesign in order to avoid this impact while still meeting restoration goals has been determined infeasible.” Well, somehow they found the will to make it feasible, mostly by looking for soil fill elsewhere.
.6 acres of obviously newer, replanted vines at the vineyard’s edge will be ripped out and replanted with native dune vegetation, but the remaining 13.4 acres will stay put. This seems entirely sensible. While I think an argument could be made for keeping the whole vineyard intact as a historic site, the old vines are the most important concern here. It’s hard for me to argue for why we should value .6 acres of newish vines over .6 acres of good native habitat without intimately knowing the vineyard.
The project report recommends restrictions on what vineyard management techniques can be used in the interest of protecting the surrounding flora and fauna which, again, seems entirely sensible unless and until some deadly disease threatens the whole vineyard with salvation available only by drastic chemical means. I don’t know how significant the restriction is for this specific vineyard or if it changes anything about the way the vineyard is currently managed. But, again, it’s hard for me to argue in favor of using environmentally-damaging chemicals in agriculture ever, period.
In short, I feel comfortable calling this good news: for the herons and frogs, for the wine industry, and for however we represent the general interests of California history. And if you need to spend more time thinking about good news today, or if dense legislative language gives you thrills, you can find the full revised report here along with a summary of comments and the Department’s replies here.
Some wine research is revelatory: it provides an “aha!” moment for some long-standing grape growing or winemaking question. Some wine research is disappointing: it doesn’t come up with the answer we wanted, or an answer at all. And some wine research is just plain weird. This week, a few entries in the weird category:
Using fruit flies as model sniffers – Drosophilia melanogaster, the common fruit fly, ranks right up there with the mouse and Escherichia coli as a hyper-common lab animal: their giant chromosomes make them easy targets for genetics research. What I didn’t know before? They’re also good for sniffing research. Some computational neuroscientists in the UK used flies to look for differences between brain responses to familiar and unfamiliar odor molecules? Familiar for a fly? Wine aroma molecules, of course. No word from the research group on whether the flies’ tasting notes will be released at a later date.
Impregnating yeast with wood aromas – We have oak adjuncts: cheap, convenient chips to mimic expensive, bulky barrels. We have lees aging: letting wine sit on the sludge of dead yeast cells left over after fermentation to yield flavor and texture. Ever thought of putting the two together? The idea somehow occurred to a group of Spanish enologists, who used the sometimes-spongelike qualities of yeast cell walls to absorb flavors from wood chips, then steeped the yeast gunk in red wine. The “wood-aromatised yeast lees” released woody flavors back into the wine, and both tasters and chemical analyses could show a difference (tasters particularly appreciated chestnut-infused wine, which was more plummy and spicy than oak, acacia, or cherry wood). The idea appears to be making wood-flavored wine faster, though it’s hard to see why using dead yeast as wood chip sponges is better than just using the wood chips.
Grape marc as an herbicide – Grape marc (or pomace, or solid leftover grape bits) isn’t usually considered toxic. Quite the contrary: it’s a common livestock feed for ranchers who live in wine regions. So it seems odd that mixing a chemical herbicide with marc made the herbicide a more potent plant killer, but that’s what a group of French plant scientists found: the mix specifically increased the herbicide’s cell killing capacity. The herbicide in question is less toxic than many other agricultural chemicals, but strategies to use less of the stuff by augmenting it with a natural (and otherwise pretty darn safe) waste product are mighty appealing nonetheless.
None of these studies will win an Ig Nobel — for research that makes you laugh, and then makes you think — though Ron Washam recently had a few suggestions for MW thesis topics that just might, should anyone have enough chutzpah to take them up. Embarrassingly and disappointingly enough, the only instance of wine-related research or a wine-related researcher being granted an Ig Nobel was in 2005, when Yoji Hayasaka of the Australian Wine Research Institute was part of the team that won that year’s biology prize for carefully creating a catalogue of the smells 131 different frog species produce when they’re stressed. Enology is such an excellent repository of enjoyable, engaging, thought-provoking, and sometimes silly research; surely, we can do better…or worse?
An enormous lot has been said about the relationship, or lack thereof, between grape yield and wine quality. So why is my October piece for Palate Press about whether higher yields mean lower quality?
1. My Palate Press colleague W. Blake Gray took an interesting economic tack on the problem a few months ago, reminding me that I wanted to revisit what we know via the scientific approach.
2. I’ve been more than a bit obsessed with the contacts (and conflicts, and congruencies) between anecdotal and scientific knowledge of late. The yield-quality problem is a fantastic case of the scientific evidence we have strongly suggesting one position (higher yields ≠ lower quality) while some peoples’ experience suggests that more may be going on than science has yet to document.
3. It’s a perennial question for a reason (or two): it’s interesting, and it’s important. And revisiting interesting and important things is worthwhile.
4. Richard Smart wrote an article for Wine Business Monthly back in 2004 proving, via contrary anecdotes, that higher yields don’t always mean lower quality, and that the principle isn’t true from a scientific perspective. He also implied that anyone who thought that myth had a place in winemaking was 1) a moron, and 2) unscientific, and that riled my epistemological feathers enough to want to write on the same topic from a different (better)* perspective. More on myths another day.
The short version: the oft-cited yield-quality relationship is more about correlation than causation particularly from the perspective of the scientific evidence, but whenever we’re talking quality things get fuzzy (and social) and our perceptions about wine quality involve more than just measurable scientific variables.
* Yes. I’ve just compared myself to a highly-accomplished viticultural scientist and found him wanting. Dr. Richard Smart is a marvelous scientist. He also, by this single account at least (I’ve not tracked down more examples), has ideas about which forms of knowledge-making are valid that I find deeply misguided.
Flor yeast are something like that one strange guy with the office down the hall, the one who’s always pleasant, who has a kind word when the rest of the world seems out to either hate or bother you, who sometimes holds the door open when you’re carrying coffee, and who does goodness-only-knows-what when he closes the door to that office of his. You’re really glad he’s there, but he’s a mystery.
I’m stretching, but you get the point: flor yeast are useful, we’re glad they’re there for us, and we don’t understand them. Flor are the film-forming, surface-dwelling yeast best known for their role in making sherry, though they’re also key actors in Hungarian dry Szamorodni**, Xeres from Jurez, and Jura’s Vin Jaune. “Biological aging” — the yeast metabolizing and spitting out acetaldehyde, glycerol, a bit of ethanol, volatile acids, and some other stuff — is responsible for much of the unique and complex nutty-freshness these wines share. Though it’s entirely possible to purchase and inoculate flor yeast, the film often comes and goes on its own in traditional production schemes. All of this happens after ordinary alcoholic fermentation finishes.
Flor are Saccharomyces cerevisiae, but they’re evidently not the same yeast responsible for alcoholic fermentation in these wines. Previous flor research also tells us that being flor is more about a lifestyle choice than about the yeast’s innate characteristics. Being flor is about surviving under stress: the yeast develop as a “velum” or skin on a high-alcohol (fortified) wine with little remaining nutrients. Yeast strains that survive here are generally those that have been able to make a few rapid, key genetic changes that researchers see as a common pattern across flor. By definition, one of those changes is the ability to form a film or skin on the wine’s surface, which signifies that the yeast have become more hydrophobic than usual: they don’t mix well with water, so they stick to each other and find the least-liquidy environment they can…given that they’re living off of a liquid.
Flor aren’t exactly like that guy down the hall, unless he’s been the subject of 34 studies published in the American Journal of Enology and Viticulture. Even still, how and why flor come and go isn’t something we understand well, and neither is what exactly makes flor yeast flor in the first place.
Wine microbiology research is often very local: researchers study the vineyards and wines near them (they’re convenient, but they’re also, often, the primary interest of whichever regional body is helping to fund the research). A study of flor yeast recently published in PLoS One (which means that it’s open-access; no paywall!) is notable for including samples from Hungary (Tokaj), Spain (Jerez), France (Jura), and Italy (Sardinia). This group of French enologists set out to build a better genetic tree for these yeasts, both to see how they’re related and to establish more data about what makes them flor-ish. My genetics knowledge is too poor to comment on how their data look, but it’s satisfying to note that they used more than one method.
How they’re related — The strains from different locations formed genetically similar groups: all of the strains from Jura were more similar to each other than to the strains from Jerez, and Jura strains were similar to other strains from the same cellar, too. My genetics knowledge is too poor to comment on how their data look, but it’s satisfying to note that they used more than one method to judge relatedness and kept coming up with the same relationships.
What makes a flor yeast a flor yeast — The best that can be said here is that this study makes one more incremental step forward in solving a big, complex problems. The researchers found two genetic changes shared across all of their flor yeasts, involving the duplication of two known genes. We know they’re genes; we don’t know much about what they do. So goes the story of modern genetics, caught between the past of not understanding how DNA mapped to functions at all and the future in which (we hope and presume) we’ll know what all (heck; I think we’d settle for most) genes actually do. This study also reinforces some previous findings about genetic characteristics shared by flor which, again, all point toward them having some kind of shared ability to deal with their high-alcohol, low-nutrient, clingy lifestyle. Gosh, now I feel as though I’ve really insulted that guy down the hall…
** An earlier version of this piece wrongly named the Hungarian wine as Tokaj Hegyalja, which is how the authors of the paper name that wine. A reader working in the Tokaj Hegyalja wine industry helpfully pointed out that Tokaj Hegyalja refers to the region and that the name of the wine I’m calling out is actually dry Szamorodni. She suggests that good descriptions of this wine can be found on the producer Samuel Tinon’s website. Thanks, Katherine.