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/
I have a horrible (given my current location) admission to make: Central Otago pinot noir is, to date and as far as I can tell, not my favorite thing in the world. That said, Otago pinot noir is lovely and fulfills a completely different function at table. One of the best meals I’ve ever had with an Oregon pinot was the whole salmon I roasted with a bunch of herbs and various alliums for my last Thanksgiving in the States. A guest serendipitously brought a Lange pinot, and it was memorable. On the other hand, Grasshopper Rock’s example – grown on the Clutha River in Alexandra, Otago — didn’t really grab me on its own, but was just lovely when I tried it alongside some smoked hoki that I’d brought home from the Auckland fish market (yes, in my backpack, on the airplane). Those rather robust smokey flavors emphasized the wine’s structural and savory notes and took the focus off cherry flavors that were a bit more candied than I prefer.
What I just offered you is a lay theory. To make it more than that, I’d need an empirical study or three to examine the interaction of smoky foods with various potential sensory qualities found in pinot noir. The problem with that idea, apart from it having nothing to do with my current main priority, i.e. the PhD, is that food and wine pairing research is obnoxious. .
Food and wine pairing articles (I’m quoting this one) are full of statements like this: “This research found that eating cheddar cheese before drinking Shiraz reduced some of the negative characteristics of the wine and enhanced the preference for the wine. This indicates that consuming food and wine together can minimize some of the less desirable flavors of both.” And hypotheses like this one: “Certain food and wine combinations will be perceived as significantly better than others.” The latter of which, I suppose, points out that food-wine preferences could be completely personal, like favorite colors (except that favorite color preference isn’t random, either).
Perhaps this sort of research really interests sommeliers who could think about the benefits of a shiraz and cheddar pairing in a tasting menu, though I doubt they need reassurance that their choices will work for someone other than just themselves. The question still arises: is science, in all its reductionist glory, really the best way to attack food and wine pairings?
First, let’s get a methodology point out of the way. Apparently, the best way to evaluate food and wine pairings is to ask people to eat and drink at the same time rather than, say, munching a bit of cheese, swallowing, and waiting thirty seconds before taking a sip of wine or vice-versa. Because that’s the way people usually eat.
Moving on. Research to date says that wine sweetness and astringency, but not its acidity, are significant in determining ideal food pairings. The most recent food-wine pairing article I’ve encountered tried to suss out whether acidity was in fact important, and the role of wine expertise in food-wine preferences, along with moving beyond many previous studies by pairing wine with foods other than cheese. The chosen foods? Chevre, brie, salami, and milk chocolate, paired with an Ontario chardonnay, an Ontario sauvignon blanc, an Argentinian cabernet sauvignon, and an inexpensive LBV Port. Needless to say, this study isn’t going to give me any insight into my pinot noir pairing theories. Or, for that matter, any insight into any real food and wine pairing conundrum anyone ever faces anywhere.
I’m poking fun, but I’m not being wholly fair. The authors of this article have more expertise in what they’re doing than I do. It’s obvious to any wine or food nerd which of the above pairings will and won’t work, but that evidence is anecdotal, not scientific, and maybe those assumptions are worth testing. But when the authors begin asserting that this study provides evidence that acidity, sweetness, and tannins are all important in pairings, just from showing that milk chocolate works better with port than with chardonnay? No. Four examples aren’t enough to allow for that conclusion, not near enough to weed through and rule out all of the other things (confounding factors) going on in both the wines and the food.
So we’re back to where we started with pairing food and wine. What says our weight of accumulated, non-scientific wisdom? And does it taste good? The reductionism of sensory science may have useful ways to tackle the hyper-complexity of food + wine (don’t ask me whether that’s more or less complex than, say, the human immune system, which science seems to tackle with at least some success), but I’m not sure they’ve figured them out yet. And when I’m trying to decide what to serve with my next glass of pinot noir — Oregon, Otago, or otherwise — the only research I expect I’ll do will be on my favorite cooking blogs.
**All sorts of other fascinating alternate-scientific approaches have been taken to food and wine pairing, Chartier’s fascinating Taste Buds and Molecules: The Art and Science of Food, Wine, and Flavor being perhaps the most interesting example. What I’m talking about here is the mainstream pairing science found in peer-reviewed journals.
With so much interesting research, so many papers published, so many nit-picky little things to remember about temperatures and acidity and bugs and the rest, it’s easy to lose the forest for the trees in enology. When the much-beloved chimpanzee expert Jane Goodall came to visit the Centre for Science Communication that I call home about a month ago, in talking about the African forests she actually reminded me to step back and look at the metaphorical enological ones, too. Maybe studying chimps isn’t all that much like making wine, but I’m not sure they’re that different, either: technology and training can get in the way of both, and stories win people over more than arguments whether you’re talking primates or pH. The full story of what Jane Goodall taught me about wine science is here on Palate Press.
Why does it always seem that we know the least about stuff that’s the most important? Tannins garner a lot of wine researcher’s attention, and for good reason. No one needs convincing about how important tannins are to wine quality (especially not the consulting companies who’ve correlated high tannin concentration with high wine magazine ratings). The amount of noise made about tannins, though, could give someone seriously inflated ideas about how well we understand them.
Excellent wine chemists are, in fact, still thinking about really good, consistently accurate, and every-day-practical ways of measuring a wine’s tannin concentration. The well-known Harbertson-Adams assay went a long way in that direction, but isn’t the last word on the topic. But just looking how much tannin a wine has doesn’t tell us enough. “Tannin” describes a whole group of molecules, and those molecules behave in different ways.
What we really need is a way of measuring not just how much tannin a wine has, but how astringent it’s likely to feel. That’s a tall order – astringency is a complicated sensation affected by alcohol concentration, sugars, polysaccharides, the person doing the tasting, and undoubtedly other factors. Just tasting the darn thing is, without question, the most elegant and reliable way to measure wine astringency. But it would still be useful to have a way of measuring the relative astringency of different types of tannins to correlate with how different production techniques affect those tannins and make some predictions. And, just as importantly, if we’re ever going to figure out what tannins do, how they behave, and how astringency works, having more tools to look at them is important.
James Kennedy’s group at Fresno State is working on a way to go beyond traditional tannin measurements, which just tell you how much tannin you have, to develop analyses to tell you what the tannin you have does and how it’s likely to produce astringency. More particularly, they’ve developed a way to measure the stickiness of any particular type of tannin molecule. Stickiness, as defined in the article, is “the observed variation in the enthalpy of interaction between tannin and a hydrophobic surface.” Or, to put it a lot more simply, stickiness describes how strongly a tannin is inclined to attach itself to something else (without actually reacting with it). This seems pretty commonsensical — if we sense astringency when tannins glom together with our salivary proteins, then we’d like to know how glom-inclined those tannins are. They’ve shown that their stickiness measurement for a particular set of wine tannins remains constant no matter how much of the tannin you test — in other words, they can measure stickiness as a tannin quality, not tannin quantity.
It’s a trickier puzzle than it might seem. How do you measure how tightly two molecules are holding on to each other? And when you’re interested in how different tannins interact with proteins, which are themselves a very diverse group of molecules, how do you choose which protein is going to be the protein that represents all other proteins?
For Kennedy and company, the solution involved choosing something that isn’t a protein at all but polystyrene divinylbenzene, a polymeric resin that holds on to tannin in remarkably the same way as the specific amino acid (proline) that acts as the tannin-attractant in salivary proteins. The resin allows for a standardized stickiness measurement and no doubt has all sorts of advantages in terms of working with it in the lab. It won’t actually behave like real salivary proteins which, being folded up into various shapes with proline more or less accessible along their various crannies, don’t bind tannins in ways so predictable. The upshot is that this is a standardized measure of stickiness (a defined scientific parameter), not an actual measure of astringency (a subjective sensation). Nevertheless, stickiness values and astringency should be related in predictable ways. We’ll very likely see a publication verifying that relationship with human tasters before too long.
Stickiness assessment involve some fairly complex chromatography, improving on a method the lab published last year. The methodological details are less important than realizing that this isn’t something that even a well-equipped winery lab is going to be able to do on their own (unlike that Harbertson-Adams assay, which is pretty accessible for a lot of winemakers). Though some wineries may measure tannin concentrations with that Harbertson-Adams assay, which is pretty accessible for a lot of winemakers, stickiness measurements aren’t going to become the new best thing in figuring out how long your syrah needs to spend on its skins before being pressed off. Too expensive (the chromatography columns needed for this kind of work run hundreds of dollars each), too training-intensive (unless you have a chemistry grad student hanging out in your winery), and too little of an improvement over just tasting the darn thing. This research isn’t likely to change the way anyone makes wine tomorrow or even for the next year or two. But it very well may change the way scientists study and think about tannins, the kinds of questions they can answer — those tricky issues around the relative astringency of various seed and skin tannins, for example — and what they can tell winemakers about targeting specific wine styles a few years down the road. And that’s worth making some noise over.
Yesterday, Tom Wark snarked off (I mean that nicely, Tom) about “alcohol ‘researchers’” who seem to think that wine, beer, and spirits are social evils to be restricted and discouraged as much as possible. I’ve read plenty of papers that appear to start (and finish) with that agenda, but not all “alcohol researchers” are anti-alcohol. In fact, you could call me an alcohol researcher.
More properly, I’m a wine science communication researcher. (Yes, I know that that’s a mouthful.) While at one point I researched the microbiology of wine production, I now look at how wine research information moves around the industry among scientists and writers and winemakers and growers (and sometimes even consumers). I’m trying to understand how scientific ideas about winemaking and growing come to exist in the industry. When science moves from a peer-reviewed scientific article to a trade magazine, what changes? What can those changes say about how we can better design experiments and better communicate their results. Of course, I can’t say how all of this communicating is important if I don’t know what winemakers and growers are reading and using — and, to my shock, no one seemed to know (if they do, they’re not telling). So I’m also investigating how winemakers and growers navigate the morass of resources available to them: what they read and listen to, who they talk to, and their frustrations about the process. If you’re a winemaker, vineyard manager, or someone in a similar role, you can help me out by taking ten minutes to complete a short survey around those questions. (The link is also tacked to the top of this blog). Finally, I’m writing a popular (that is, not academic) book about how the story of wine is also the story of the sciences, from physics to medicine and everything in-between. More on that later.
I probably don’t need to argue for why wine is worth researcher’s time as a public good to promote instead of a social ill to eradicate, but it’s good to note that it’s fundamentally about humanity as much as science. Wine is a food nourishing to body, mind, and spirit when taken in appropriate quantities. It’s also a cultural icon and a historical treasure. If you want to talk to me about restricting wine because too much alcohol can kill you, your agenda had better also include restricting access to and advertising of butter and cheese — because too much saturated fat can kill you — and honey and jam — because too much sugar can kill you, too. Then show me your thoughtful plan for accommodating the essential cultural and social roles that all of those foods play around the world.
My research is aimed, at the biggest picture level, at making scientific research more efficient, but it’s also about helping people make better wine by improving the information available to them. Besides, when getting a PhD involves wine, science, and writing — and rhetoric, and philosophy, and talking to winemakers, and trying out living in New Zealand — it’s hard to see how things could be much better.
I opened a bottle of Rippon’s lovely 2011 Gewürztraminer a few nights ago in a small act of celebration upon having an academic manuscript accepted for publication (hooray!) As I bathed my nose in pretty peach and lime and rose notes, to my surprise, my very non-oenophile husband commented that he didn’t find it very aromatic. (I blame the tahini-miso oca, or New Zealand yams if you prefer, that he’d just noshed). Conversation ensued about white wine aromas. Conversation turned technical, as it’s inclined to do around our table (he may not be an oenophile, but my partner is unmistakably an academic and a knowledge-hound), and an interesting conundrum turned up.
Modern winemaking dogma says that white wines should be fermented at fairly cool temperatures to maximize their aromaticity. Aromatic molecules are, by definition, volatile — they can leave the liquid and travel into the air, where we can sniff them into our nostrils and bring them into contact with aroma receptors. Fewer of those volatile molecules will leave the liquid at cool temperatures than at warm ones because (to simplify), warmer molecules have more energy, are moving faster, and consequently have a better chance of flying off the liquid’s surface. Fermenting at cool temperatures, then, keeps more aromatics in the wine for you to enjoy on a later occasion rather than liberating them into the atmosphere of the winery.
Fermentation creates heat, sometimes even enough to kill off the yeast and stop fermentation in mid-stride. To keep that from happening, winemakers have a few different options. Smaller containers have higher surface area to volume ratios than large ones, release more heat into the surrounding air, and generally stay cooler. The old-fashioned solution, moving small tanks or barrels outside to take advantage of cool night-time temperatures, can work for small operations in cool places. Keeping the room where fermentation is happening cool helps, though that’s a pretty inefficient and energy-expensive option. Far and away the standard contemporary solution, the jacketed stainless steel tank, lets cellar staff dial in specific temperature programs and is near-ubiquitous in modernized operations of decent size. Near-ubiquitous, but not entirely so. Two of my favorite wineries near my old home and my new one, Eyrie in the Willamette Valley (an Eyrie pinot blanc would have been on my celebratory table if I’d had any) and Rippon in Central Otago, both do without. They’re expensive, and they also don’t fit with the low-manipulation philosophy both espouse.
So here’s the quandry. Both Eyrie and Rippon turn out deliciously aromatic whites. Neither uses sophisticated temperature control during fermentation. Both McMinnville, OR and Wanaka, NZ are coming on cool roundabouts harvest time and both operations use small tanks, but it’s still safe to say that those ferments are exceeding the UC Davis-endorsed temperatures.
Why don’t they (and every lovely white wine made before the advent of modern refrigeration) seem vapid, empty, and unappealingly burnt out? I can’t be certain. When I asked Jason Lett, winemaker at Eyrie, this question, he suggested that I do an experiment to try to find out. Having left my lab days behind me, I’m not in a position to do so (it would be a big project in any case) so I’m left to speculate.
The situation is too complex with too many variables for me to evaluate with any chance of accuracy. Yeasts produce different arrays of aromatic compounds at different temperatures, for example. But I also speculate that these wines would, in fact, be more aromatic if they were kept cooler. They don’t seem to be lacking anything, I suspect, because spontaneous fermentations, excellent grapes, and attentive winemaking are already contributing plenty of aroma in any case. A recent study (that actually concerns itself with the possibility of using non-Saccharomyces yeasts to alleviate some of the potentially harmful side-effects of fermenting at low temperatures) suggests that the microbial diversity that comes with spontaneous ferments is probably helping hold up aromatic diversity, and it’s not the only one (this excellent article on sauvignon blanc aromas points to advantages from yeast diversity, too).
In other words, I can’t help but wonder if fermenting at artificially-controlled cool temperatures is something we’re told we need to do because modern industrial practices strip aromas in other ways; that is, if we’re not compensating for less-than-ideal winemaking. Cooler fermentation might (or might not) make that gewürztraminer I enjoyed more aromatic, but it wasn’t wanting. The $15 mass-market version, on the other hand, probably needs all the help it can get.
Those oca, incidentally, threatened to steal the show from the wine. (I think the wine won, though: a bit off-dry, but well-balanced, with the sort of creamy richness I look for in a gewürztraminer and, of course, plenty of peach-lime zest aroma.) Should you catch some of these unusual almost-potato tubers in the market — or, like me, should the house you’ve rented have a patch of them resident in the back garden — here’s a suggestion. North American yams take well to the same treatment.
Tahini-miso oca for four (or two plus leftovers)
1 lb (450 gm) oca, washed and cut into approximately 1″ pieces if large
2 tbsp tahini
3 tbsp white or barley miso
2 tsp butter
~ 1 tbsp fresh thyme leaves, if available (or substitute 1 tsp dried thyme)
Heat about an inch of water in a medium-sized saucepan over moderate heat until steaming, then add the oca, cover, and steam over moderate heat for about 10-15 minutes or until tender all the way through when prodded with a fork. While they’re cooking, combine the miso and tahini in a small bowl. (The purpose of doing this, rather than just adding both to the pot individually, is to help the miso mix more easily into the oca. If you’re really interested in saving dishes you can just do the former, but you may end up with miso-lumps.) Drain any remaining cooking water from the pan. Add the tahini-miso mixture, the butter, and the thyme and toss gently until all of the tubers are coated in the sauce. Serve immediately.
Ever wonder why yeast make alcohol? Probably not, I realize, but you should. Yeast throw off ethanol in the process of metabolizing sugar, so alcohol is a byproduct of survival; fair enough. But alcoholic fermentation is, in fact, a surprisingly inefficient way to get energy. The standard oxygen-requiring way of breaking down sugar used by most cells, our own included, wrings somewhere between 30 and 38 ATP (38 is the ideal number; it’s probably never quite that high in practice) out of a single glucose molecule. (ATP is the cellular currency in which energy is transferred and spent.) Nevertheless, alcoholic fermentation has the distinct advantage of not needing oxygen and so it makes perfectly good, intuitive sense for Saccharomyces cerevisiae to use it when oxygen isn’t available.
Here’s the quirk: S. cerevisiae uses inefficient alcoholic fermentation even when it does have access to oxygen, even though it has the machinery for the much, much more energetically worthwhile aerobic metabolic process. Yeast will only switch to aerobic metabolism when the amount of sugar available for them to eat is very low. Why? A good question, and one microbiologists haven’t had much success answering.
Our best hypothesis according to a brand-new review on the subject comes in two parts:
- Alcoholic fermentation lets yeast act fast to use up the “public goods” while squirreling away private resources for later. Every microorganism you’ll encounter in grape juice can consume sugar. Very few can also consume (and get energy out of) ethanol, but yeast can. So, by converting sugar to ethanol, S. cerevisiae can starve out other microbes and leave itself with a food source for later.
- As an additional and maybe even bigger benefit, ethanol is toxic to most yeast and bacteria at concentrations that Saccharomyces can tolerate with relative ease
Possibly the most bizarre thing? We don’t know much about what determines the circumstances under which S. cerevisiae, our long-time compatriot and coworker, produces alcohol versus making energy in some other way. We’ve looked at when and where different yeast genes are expressed and when and where it makes different byproducts but, like so much else in the wonderful and frustrating world of modern-day genetics, putting together the whole story is still a work-in-progress.
My June article for Palate Press aimed to take a sensible look at rationale for allowing sulfur dioxide in “natural wines” when adding anything other than sulfur dioxide is widely accepted as not okay. (The short version: the only logical argument I can see is that sulfur dioxide aims to protect what the wine already has rather than add or change something; otherwise, we’re left with the entirely unsatisfactory argument that SO2 is extremely useful…but so are other additives.) Trying to pin down “natural wine” is trouble, but “authentic wine” is even worse. I’ve been thinking a good deal recently about both.
First, let me be clear: I think that the idea of authentic wine has a lot going for it. It’s intuitive: wine that’s less “messed with” seems as though it should have more soul, be somehow truer and realer than wine pulled and pushed through lots of chemical manipulations. And you can taste it. Revelatory wines — the ones that make you stop to think that wine is capable of more than just yumminess — are usually less manipulated, more authentic.
That said, talking about “authentic wine” as “wine the way it’s always been made” or wine made using traditional methods raises my hackles. “Traditional” is only ever relevant with respect to a specific time frame. I can say that a family cookie recipe is traditional, but at some point a grandmother must have come up with it or cut it out of a magazine, and in any case if we go back very far the grandmothers wouldn’t have had modern baking powder, so are my cookies authentic?
Russian tea cakes are a traditional Christmas favorite in my family, passed down from my mother’s side. What we call a Russian tea cake is similar to the nut balls or Mexican wedding cookies many folk make – a half dome-shaped mouthful of nutty, buttery yumminess dusted in powdered sugar – but no one else’s recipe is quite like ours. Betty Crocker and Smitten Kitchen and a pile of other bakers think they have a Russian tea cake recipe, but they’re wrong. Ours are the best. Unlike most, just a few tablespoons of flour are used to bind the nuts together and the concoction is only very lightly sweet: the flavor of the nuts and the butter is the point. And it is, of course, sacrilegious to make these at any time other than Christmas.
For as long as I can remember (until I moved to New Zealand and couldn’t come home for Christmas), every third week of December my mother and I have whipped up at least one and usually two batches in her 1980′s-era Cuisinart, first processing the whole walnuts (or pecans, for the second batch) into meal, then adding the butter, then the two tablespoons of flour and sugar and the all-important vanilla. But as a girl, the eldest of six children growing up in a tiny square house in semi-rural Ohio, it was my mother’s job to do the whole job by hand. Fail to chop the pecans (because in those days they were always pecans) finely enough and the cookies wouldn’t hold together properly. Naturally, my grandmother didn’t own a Cuisinart: I don’t think they’d been invented yet and, even if they had, I’m sure she wouldn’t have owned one with her tiny kitchen and tight budget.
One year when I was in my early twenties, I decided that I wanted to make a batch of Russian tea cakes for my friends before I flew home to my parents’ house for Christmas. I didn’t and still don’t own a food processor, so I chopped those nuts by hand – and the cookies weren’t as good. Doing it the traditional way made for frustratingly crumbly, uneven cookies. In this case, the machine could do a better job than me and my knife. I’m glad to have done it, for the sake of appreciating how my mother and grandmother operated, but I’ve not attempted it since.
I don’t know where my mother’s mother’s mother got the recipe, or if I need to add more mothers to that litany. I do know that my grandmother always used pecans because my grandfather had friends and family in Louisiana where they could get bountious bag-fulls of the genuine Southern article, and that my mother usually uses walnuts, because my father prefers walnuts and because they moved to California after getting married where walnuts came in bag-fulls and pecans mostly didn’t. I know that the cookies I’ve grown up eating aren’t the same as the ones my grandmother knew, not only because of the Cuisinart but because my rather well-to-do mother has switched to using excellent European butter and mail-order Tahitian vanilla instead of the McCormick’s stuff. My own innovation is to use whole wheat flour—the cookies are ever so slightly crumblier (only a problem sans Cuisinart), but the flavor accentuates the cookies’ nuttiness. Mine are the best.
Are my cookies inauthentic? I’m not sure, because if every woman in her turn tweaked the recipe a little, was there ever any such thing as an authentic Russian tea cake in the first place? Who’s to say? Did the Cuisinart technology corrupt the genuine article? Quite the contrary. No woman and her cleaver are going to be able to chop nuts as finely and evenly as a good food processor and, in this case, uniformity is a good thing.
I won’t make Russian tea cakes without a food processor…well, maybe I might twist my own arm on that one of these years if I continue to live food processor-less. What I definitely won’t do is make Russian tea cakes and add butylated hydroxyanisole to them to “preserve freshness.” Sure, these cookies go stale if you let them sit on a too-warm counter too long because all of those nut oils which you’ve liberally exposed to the oxygen-rich air will oxidize or, in other words, go rancid. (Mother-approved tip: this is why you wait until the first batch is nearly gone before making the second instead of trying to whip everything up in advance.) I won’t not add butylated hydroxyanisole because it isn’t in the traditional recipe. I won’t add it because it’s butylated hydroxyanisole. Ewww. To be perfectly clear here, I’m not cringing because BHA has a polysyllabic chemical name – there; the abbreviation solves that problem – but because it’s a synthetic laboratory product that never occurs in food. It doesn’t help that several lab studies say it causes cancer in rodents, even if those rodents were given far more than two or three mouse-sized cookies’ worth of the stuff. Maybe more relevantly, I wouldn’t add even the best concentrated nut flavoring to “beef up” the nut flavor because I want to taste the real nuts here. It’s important to take care to choose really good, fresh, flavorful nuts for this recipe, and it would be anathema to the spirit of the recipe to make the flavor about some artificially constructed ideal of perfect nuttiness. Moreover, the cookie wouldn’t be as good.
I’ve been talking cookies. What if I instead imagine a traditional family chardonnay recipe? If I’m staying true to the spirit of the recipe – maybe it’s a nutty, buttery little chardonnay – but using better technology because doing so allows me to make a better wine, splendid. Who cares whether it’s “authentic” or not (keeping in mind that we can only define “authentic” with respect to a specific version of the ever-changing recipe to call the wine), if it’s tasty and meaningful? Adding potentially dangerous non-food ingredients isn’t okay because people shouldn’t eat non-foods. Adding (or removing) extra sugar or acid might be a problem if the point of doing so was mimicking some ideal wine at the expense of doing justice to really good grapes. But using contemporary technology (does Cuisinart make winery equipment?) to make the wine taste better, or to make the wine more consistent?
The College of Humanities at the University of Utah produced a splendid poster featuring what has become one of my favorite maxims: science can tell you how to clone a tyrannosaurus rex; humanities can tell you why this might be a bad idea. Maybe authentic wine is made the way wine should be made, in contradistinction to the way wine can be made. Maybe that makes authentic wine a very personal concept, or maybe the well-educated wine philosophers and wine scientists among us can help establish a sense of universal wine ethics for us to live by. But, in any case, those judgements about authenticity have to come from thoughtful reasoning about the difference between what we can do and whether or not it’s a good idea. The historical argument is a lazy oenophile’s shortcut.
Our society has a bizarre habit of mislabeling things by color. The familiar case in point: white people are never white but always various tints of pink, peach, and yellow; black people are invariably not actually black but some shade of brown or tan. Less familiar case in point: white wines are really always somewhere in the yellows, and the grapes themselves range from green through yellow to pink. (Red wines are, at least, red, even if the grapes which give them birth are more aptly blue, black, and purple).
We do talk about the color of white wines, from the pale straw of a light-bodied sauvignon blanc to the amber of an elderly riesling. Anything not firmly lodged on the green-yellow to brown-yellow spectrum, though — including forays into pink — is considered a fault. Now, that judgment (like some other “wine fault” decrees) seems a bit arbitrary to me: would I really mind sipping a pinkish chenin blanc? (No, I would not). But “pinking,” as it’s called, is a problem, if for no other reason than consumers might have a hard time coming to grips with it. Gewürztraminer grapes are unquestionably (and beautifully) pink, but gewurztraminer isn’t one of the grapes prone to pinking and, in any case, we’re not talking about color derived from skin contact — those wines are “orange,” not pink. Real pinking qua pinking can show up before bottling or suddenly after pouring and seems to be the result of exposing a reductively-made wine to oxygen.
A group of chemists from Portugal have done a convincing job of demonstrating that — at least in the Siria grapes they tested — pinking is caused by…anthocyanins. Yes, the very same pigmented molecules that make red wines red. But, what are anthocyanins doing in white wine?
In some sense, they were there all along. All grapes have the genetic machinery to be red. White varieties are mutations, the result of genetic changes in the genes responsible for the production of red anthocyanin pigments in grape skins. The same mutations seem to exist in all white grape varieties, which suggests that they probably all descended from a common ancestor.
Anthocyanins would seem the obvious culprit for pinking, even if it does seem odd to think of them being found in whites — that genetics of grape color research isn’t especially new. One of the classic wine science textbooks, Ribéreau-Gayon and company’s Handbook of Enology, says that pinking is caused by unknown compounds that can’t be anthocyanins because they don’t respond to sulfur dioxide and pH in the expected ways. That book was published in 2006, though, and folks like James Kennedy at Fresno State University and Jim Harbertson at Washington State University (along with a good many other researchers) have, since then, made a fair bit of headway into figuring out how anthocyanins react with each other and other wine components. (It remains a terribly complex and incompletely understood topic.) This team of Portuguese researchers could still observe that the pinking-related anthocyanins they observed didn’t act exactly like “normal” anthocyanins because they polymerize over time in the wine, which makes them more resistant to the color-bleaching effect of sulfur dioxide. Suffice it to say that they go through some complicated chemical acrobatics to show that the molecules they isolate from their pink Sirias are indeed anthocyanins.
The researchers responsible for this study speculate that Siria, the rather obscure Portuguese white grape variety with a persistent pinking problem that they chose to examine, may have regained the ability to manufacture some anthocyanins. Not enough to make the grapes overtly pink in the vineyard, but enough to belie their presence after at least some kinds of winemaking operations. (Anthocyanins are unstable molecules susceptible to changing in the presence of oxygen and other molecules.) Though they haven’t substantiated that speculation with molecular analyses, it’s not out of the question that additional mutations in those anthocyanin-producing genes might restore some of their functionality or cause them to be transcribed under specific circumstances.
If you’re not a winemaker with pink problems, why is this research interesting? It’s a good reminder that white grapes aren’t necessarily simpler than red ones, as it’s so easy to imagine, and that we’re still learning a lot about the very complicated pigments that make wine color happen. But it also makes me stop and think about how flexible plants really are. We can select for and preserve features we want through careful clonal selection of the most highly desirable plants, but vines are still going to change and mutate and do new (or redo old) things on the sidelines.
Wine Searcher ran a story this past week about new technology from the University of Ljubljana that speeds traditional sparkling wine processing times by magnetizing yeast cells. Magnetic nanoparticles affixed to the cells’ surface don’t interfere with fermentation and let winemakers literally and near-instantaeously pull the yeast into the neck of the bottle by applying a magnetic current. Since riddling — slowly inverting and rotating bottles to remove (unattractively cloudy) dead yeast after the secondary in-bottle fermentation responsible for effervescence-generation — traditionally takes a few months and a LOT of hands-on work, a 15-minute flip-a-switch solution looks pretty attractive. BUT:
Interesting fact #1 – This technology isn’t new, though applying it to the sparkling wine industry is. Bioengineers came up with magnetic yeast in 2009.
Interesting fact #2 – If actually adopted by the industry, magnetic yeast will be far from the only use of nanoparticles in food. Quite the contrary, which you know if you follow the American health and science news. Titanium dioxide nanoparticles are common additives to everything from chewing gum and toothpaste to yogurt and soy milk, generally to the effect of making whateveritis whiter. Nanosilver particles are common both as agricultural pesticides and in antimicrobial coatings for household goods, and nanolipids and nanoproteins and assorted other nanostuff finds its way into all manner of food-related items. The consensus is that we don’t yet have a consensus on whether and to what degree ingesting nanoengineering is safe (a peer-reviewed take on that question here; a more accessible and more inflammatory story from Mother Earth News here). Logically, magnetic force should effectively pull all of the magnetic particles (made from magnetite, if the Ljubljana authors are using the same general strategy published in the 2009 paper) out of the wine, but nothing is perfect. If residual particles remain, drinking them might be a health risk, but it won’t be a unique one.
Interesting fact #3 - Alright; this one isn’t a fact. It’s a speculation based on fact. I speculate that we needn’t worry too much about magnetite in our celebratory libations. Champagne in particular and high-quality, methode champenoise sparkling wine in general, is not about fast. Exactly the contrary. Champagne legally has to spend at least 15 months in bottle and at least 12 months on the lees, and usually exceeds that by a year or two because age on the lees is vital to the flavor profile of high-quality sparkling. I reviewed some of those considerations in this article for Palate Press.
The problem with riddling isn’t the time per se so much as the labor: some poor guy has to spend his days jiggling bottles (and if champagne riddlers don’t have a high incidence of occupation-induced carpal tunnel syndrome, I suspect that it’s just going undiagnosed). The gyropalette solves that problem by loading a box full of bottles onto a modified forklift and letting the machine jiggle them for you. That bit of technology has been popular and successful, but it seems to me that it’s also a lot less expensive than magnetic yeast.
Think about it. Yeast reproduce in the bottle, a lot. So, every yeast cell used in inoculation needs to be loaded with magnetite particles to ensure that all of its many, many offspring has at least one magnetite particle.** Don’t even think about generating your own yeast innoculum. And that’s before we get to the magnetic set-up to actually pull down the yeast. I don’t know. Storing wine (and paying that poor guy) is expensive. Maybe this is a cost-effective solution. But if high-end producers aren’t going to be seduced by speed, and if lower-end producers are disinclined to spend more money on production technology, and if the wine industry in general tends to be stuck in the mud, I suspect we needn’t worry too much about drinking magnetite anytime soon.
** Maybe effective clarification doesn’t require that every yeast cell be magnetic, if the yeast tend to stick together (flocculate) and magnetic cells will help pull down their non-magnetic neighbors. Without reading the paper I don’t know, and since I can find neither the paper (maybe it’s not yet been published, or maybe it wasn’t published in English) nor the specific names of the researchers nor any other mention of the research on the University of Ljubljana’s website I have to speculate. It’s disturbing that I can’t find another source backing up the Wine-Searcher article (and I don’t personally know it’s author and can’t locate him via the usual tricks) but, then again, I don’t read Slovenian.