White grapes: more colorful than you think

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.

Will magnetic yeast make better Champagne?

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.

Hooray for Oregon: two counties vote for no GMOs

Oregon’s Josephine and Jackson counties have both, at least per the preliminary counts (official ones will take weeks), voted in favor of banning the planting of GMO crops inside their borders. Find accounts of the highly contested ballot measures at Oregon Live and The NationCommercial GMO wine grapes aren’t yet available, but it’s likely they will be soon with research in that direction underway in Florida and France. GMO wine yeast are already for sale — ML01, which has the bacterial genes for malolactic fermentation — though whether the ban applies to its use, since the yeast aren’t a crop per se, is a question.

Plenty of pro-GMO publicity relies on the lack of scientific proof that GMO foods are in any way harmful to eat or nutritionally inferior. That’s true, but it’s also not the point. In my opinion, the strongest reasons to oppose GMOs are:

Biodiversity – GMOs are usually designed to be more disease-resistant, more vigorous, and/or higher-yielding than non-engineered varieties, which means that they have a competitive advantage in the wild. With yeast and bacteria, or if GMO plants make it out into the wild, that means that they’ll out-compete native varieties, which means that we lose biodiversity. Biodiversity is good. Natives and rare variants among natives may harbor as yet-undiscovered genetic and biochemical solutions to diseases or bioengineering problems. Diversity makes systems more resilient to disease and changing environments. And there’s the aesthetic argument: life is beautiful in its many shapes and colors.

Food security and sustainability (the biology side) – At least 70% of the US corn crop is Monsanto “Roundup Ready,” and something like 90% of the soybean crop. What if a disease struck to which Roundup Ready X was specially susceptible? Bacteria and viruses mutate to adapt to their hosts; this isn’t that unlikely. Not only do we need farmers growing a diversity of varieties, but we need to ensure that in the case of wind-pollinated crops (like corn) hypercompetitive genes don’t spread to infiltrate even non-engineered crops.

Food security and sustainability (the economic side) – GMO crops are patented. Growers can’t legally save their seed from one year to replant the next; they’re obligated to pay the giant corporation to provide their next crop and set of paychecks. Monsanto has aggressively defended this “right.”  I understand that the economics here are complex, but I can’t see a way to slice this argument that doesn’t come down to feeding mega-business, collecting power and money in the hands of the few who are already powerful and wealthy, protecting and encouraging increased commodification and commercialization and engineering of our food supply, and hurting everyone who A) isn’t a corporate billionaire and B) eats. And if all of that is a bit much, just imagine being the family farmer who gets sued by Monsanto. The layers of anti-sustainability, anti-farmer, pro-big business unprintable evil this represents are too many to explore in full here, particularly because I may need to go out and chop some wood now just to burn off the anger I feel thinking about this nonsense.

All of that is in addition to the possibility that GMO crops may pose some danger to human or animal health, both of which are still untested possibilities insofar as we haven’t been studying them long enough for a full assessment.

The Josephine and Jackson measures still need to be put into effect and enforced, neither of which are yet certain bets. But the vote is a definite step in the right direction and, more importantly, sets a precedent for other counties in other states. More reasons why, along with some very fine pinot noir, I’m proud to be an Oregonian.

Why thinking of wine as food solves the natural wine debate

Wine is a food. A surprising number of people are surprised when I say this. It seems obvious: wine is nourishment. Nourishment with specific effects, yes, but all foods have some kind of effect on us, if some more profound than others.

Saying that wine is food isn’t the same as saying that wine is harmless. Nearly every food will cause you some sort of harm if eaten in inappropriate quantity, and any amount of some foods are bad for some people. Jack Sprat and his wife are really caricatures of all of us: some people are happiest and healthiest as vegetarians and some really live best with meat, some feel their best eating dairy-free and some can’t digest soy, some thrive on lots of carbs and some on more protein, some need to avoid salt and some don’t. Guidelines apply, sure, but setting down universal rules about what’s healthy for everyone just doesn’t work. Alcoholic beverages are food, dangerous for nearly everyone in large quantities (allowing that what qualifies as large varies from person to person), not tolerated by some, and healthy and useful for many.

Remembering that wine is food fundamentally solves the debate about whether or not wine must be “natural” in order to be valid. The short answer is no. The slightly longer answer is still no, but with some elaboration.

The reality about food in our post-Wonder Bread, post-Michael Pollan, post-Hugh Fearnley-Whittingstall world is that we* near-universally know that locally-grown, minimally-produced, food with clearly identifiable ingredients that came out of the ground, off a tree, or from a recognizable piece of a pastured or wild animal represent “real food” and the ideal of what we should be eating. On the other hand, anonymous food processed out of recognition in large factories, wrapped in plastic and trucked about the country feeds most people most days. This is not ideal, but it’s the situation we have. Wine is the same. Boutique, caringly-crafted, often minimally messed-with wines are the ideals much lauded by our leaders. Still, Gallo and Yellow Tail and their ilk are still responsible for most bottles (and boxes, and jugs) on most tables most of the time. This is also not ideal.

The conundrum: while real food — including wine, and meaning ingredient-focused, sustainably grown, minimally processed, and preferably local — is ideal, it’s usually more expensive and sometimes unavailable. Especially in economically impoverished urban areas (and even very rural ones sometimes, perversely), wholesome fresh food sometimes is simply unavailable. Some people don’t have the know-how or time to prepare fresh food well. Even if just about everyone knows that eating mostly out of packages is bad, many still do so for a variety of reasons that may or may not be their “fault.” My husband once said that if the United States wanted to create an effective and complete anti-hunger program, the government should contract McDonalds to administer it. Neither of us voluntarily choose to eat fast food. But you can’t deny McDonald’s expertise in delivering enormous quantities of consistently edible food to essentially every corner of the nation. When it comes to hunger, food is better than no food, even if the food is a mass-produced hamburger. Even though wine isn’t a basic necessity, mass production of what the natural folk would call fake wine makes wine accessible to people who would otherwise not be able to afford or access it at all. And much as I spurn the capitalist-driven food production system, I have to give credit where it’s due. We have industrialization to thank for safer food supplies and clean, well-made (as in not overtly faulty) wine. Understanding the benefits science and technology can bring, our task now is to undo the additive-filled and soulless damage we did to what nourishes us in figuring all of that out.

We can and should put community gardens into empty city lots, teach children how to grow their own radishes and encourage them to tear up the grass in the yard to do it, support fresh food markets in food deserts, make food production and cooking classes part of the school curriculum, and design economic policies to support local and organic food production. How to do this stuff is complicated. People specialize in economics and food policy. I’m not one of them. I’m not going to pretend that I know how to make these changes happen. I don’t believe that we need GMOs and factory food to provide enough food to feed the world, but I recognize that as a belief based on gut feeling and emotion and philosophy because I haven’t worked through all of the data. I’m consistent, though, in believing that the entire world could and should have access to real, honest, well-crafted wine if we changed the infrastructure surrounding how wine is produced and distributed. And we should.

So, the obvious conclusion. Appreciate mass-produced wine for providing volume and access while actively working toward making real wine — defined the same way we define real food — available to as many people as possible. Those of us with the money and education to buy real wine should, something we pretty much do already for cultural reasons, but perhaps without seeing the connection to the local and real food movements. Realizing this connection is important: it brings into focus the privilege inherent in preferring real wine and, in tandem, should help motivate us to work for change in both spheres. Think of real wine as part of real food, prefer both if you have the resources to do so, and think about what you can do to support its production and improve access. The Michael Pollans and Hugh Fearnley-Whittingstalls of wine have yet to step up in terms of consumer education at least in the United States, hardly surprising considering our short history and present state of wine education, but something toward which to look forward nevertheless.

Now, what we define as “natural wine,” as in where we set the line between wine that’s allowed to carry that distinction or to show up at The Real Wine Fair — that’s a different question, and a semantic and philosophic more than a practical one. So is what we call “authentic wine,” and the issue of drinking local versus global is an entirely different discussion. More on those another day.

Incidentally, if we’re post Michael Pollan, I’d say that fermentation revivalist Sandor Ellix Katz (upon whom I’m inclined to wax poetic) is the prophet of our future food revival. Does that mean that I love quirky “natural” wines? You bet.

 

*I may be defining “we” rather narrowly as reasonably well-educated Westerners, but I doubt it. I haven’t surveyed people shopping for packaged foodstuffs with food stamps, but I know that my friends who fall into that category know what healthy food looks like and aren’t choosing it for a variety of reasons. Less well-educated folk may not know who Michael Pollan is, but the collective media we has achieved pretty high penetration if not on his message, than on the message of fruit and veg and whole grains good, processed foods and added sugar and salt and fats bad.

Waiheke Island and why I’ll probably never be an entrepreneur

Before I arrived in Auckland on Saturday evening, I’d planned to spend Sunday at the art museum and wandering around town. I was there for a two-day “PhD Research Innovation and Commercialization Course” hosted by the University of Auckland Business School on Monday and Tuesday and flying in on Saturday proved the least expensive and most reasonable option. Having never been to Auckland before, I figured that I’d enjoy the extra day in the city to explore. I was wrong. Walking from the bus stop to my hostel was more than enough of crowds, air pollution, and garish shops, thank you. Fortunately, I was also wrong about how easy it was to get out to Waiheke Island, as I discovered upon realizing that the ferry terminal was a five-minute walk from the hostel with ferries leaving nearly every hour. So, on Sunday I discovered that my favorite view of the city is from a boat headed away from it.

Waiheke Island is about 40 minutes by ferry from Auckland and home to something along the lines of 12 wineries, additional vineyards, and the inevitable mix of eccentric artists and rich people one finds on beautiful little islands. Being a completely spur-of-the-moment decision, I unfortunately didn’t have time to call in advance and arrange for proper winery visits. Also unfortunately, it was Mother’s Day and I was on foot. Not an ideal visit, and I’ll have to remedy its deficiencies with a better-planned future one (and one that includes visiting some of the island’s olive oil producers, I hope). But I did learn something interesting that, as it turned out, helped me think about what we were doing at the business school’s course.

Vines at Te Moto, Waiheke Island

Vines at Te Moto, Waiheke Island

I walked into Te Moto at the same time as a trio of Oregonian girls who’d just finished working harvest in Marlborough, and the tasting room host kindly offered to show the lot of us around their itty bitty production facility. As the girls cooed over the adorable little tanks, she explained that winemakers didn’t come to Waiheke unless they were interested in staying small and hands-on. An expanding business model just isn’t going to work on a 36 square mile island with astronomical land prices: at the most basic level, you can’t afford business here unless you can afford small, expensive, and precious. But you’re also not likely to plant roots (or rootstock) in this place unless you want a lifestyle that’s a little bit precious. Te Moto was founded in 1989 by the Dunleavy family, notable because patriarch Terry Dunleavy was the first CEO of the Wine Institute of New Zealand (one of two parent organizations to the present-day New Zealand Winegrowers), and though they’re clearly doing well, their crush pad-cum-open-air fermentation space is barely bigger than my office. And they’re doing something that’s the envy of many winemakers: holding on to their vintages until they think they’re ready to drink. The tasting room is currently pouring the 2006, 2007, and 2008. Even with their second label, Dunleavy, for more immediate cash flow, holding onto their flagship wine is an expensive proposition and an interesting choice.

A day later, I was sitting in the Owen G. Glenn building on the University of Auckland’s campus (a structure that could have been dropped into Starfleet Academy without anyone thinking twice about it) listening to a business professor tell me that my chances of becoming a successful entrepreneur increased with the size of the city I called home. Per capita, more start-ups are born in Sydney and Melbourne than in Auckland. Auckland fosters more than Wellington or Christchurch (the second- and third-largest cities in New Zealand, respectively), and Christchurch more than Dunedin, the seventh-largest city (and less than a tenth the size of Auckland) that I currently call home. The moral of the story was three-fold: first, aspiring innovators should live in densely-populated places; second, New Zealand innovation is hamstrung by its relative lack of large-scale urbanity; third, connections between people lead to innovation, and connections are easier in big cities. The prof was trying to convince us that making connections was easier in big cities than in smaller ones, simply because more “talent” was readily available, and that connectivity is important for business growth. Sure. But he ignored an important complicating factor: what kind of people choose to live in big cities versus small towns? Moreover, what kind of place would New Zealand be if we had six Aucklands and a Melbourne?

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Te Moto’s tiny winery/restaurant/tasting room complex

I can’t but wonder if part of why big cities grow small businesses is because the kind of people energized rather than irritated by the bustle, people who value or will tolerate constant motion, people willing to give up quiet porches for dirty pavement, are the kind of people willing to trade freedom of information and generosity of spirit for fatter wallets. I work hard, but being the person I want to be and living a good life is more important to me that climbing ladders, closing deals, and building an investment portfolio. I wouldn’t have come to New Zealand — and I dare say neither would most of my American friends here — if more of the country looked like Auckland.

And so I think about what Waiheke. Te Moto’s definition of success involves a couple of compact car-sized fermenters with no plans to expand. You’re not going to start a winery on Waiheke unless you have money, but you’re still making a deliberate choice in favor of a particular kind of lifestyle. And so the community develops a particular flavor because the place attracts people with similar values.

My experience with Kiwis, at least outside of Auckland, is that they take time to enjoy the outdoors, sit with friends to drink their coffee, and spend money on experiences more than on fancy houses. Most folk I know in Dunedin wouldn’t live in Auckland because it wouldn’t afford them the lifestyle they treasure. Start-ups and entrepreneurs can do great things, and Villa Maria and Kim Crawford and Cloudy Bay are tremendously important for the New Zealand wine industry. But as for me, I’ll be watching the bell birds splashing around in the bird bath on the porch of my quiet little cottage on the bay, hopefully sipping something from a winemaker who’s decided to find the space to do her own thing.

 

 

The complicated business of recreating a wine aroma

How wine aroma happens is both very simple and very, very complicated. The simple version: molecules capable of leaving from the surface of the liquid (or carried up to the liquid in the tiny gas bubbles that make sparkling wine sparkle) are carried through the air up to our nostrils where those molecules meet sensory receptors that, when bound to the right kind of molecule, trigger a “smells like” response in our brain. Hence why we swirl and sniff: swirling encourages aromatic molecules to leave the wine; sniffing encourages those molecules to travel into our noses. As you’d expect, the complicated version elaborates on what kinds of molecules are capable of leaving the wine — of moving from the aqueous phase to the gaseous phase, we’d say — and what has to happen between an aroma molecule and a smell receptor for a message to be sent, and how activating a receptor turns into a perception of “smells like” in our conscious minds. But it’s actually even more complicated than that, because molecules that aren’t aromatic and that don’t ever leave the wine for the air influence what we smell, too.

A new study of the aromas of two different Australian shiraz (shirazs just doesn’t look right to me) is a good example of what it takes to make up a wine’s nose.

Wine — talking all wines collectively, not any one in particular — involves at least 800 or so different aroma compounds. The strategies used to figure out that sort of thing, and to analyze the aroma composition of specific wines, are all fundamentally based on separating out all of the many different molecules a wine contains. A common way of doing this is with gas chromatography which, to put it simply, separates molecules by the differences in how they interact with specific solvents. How long it takes a particular molecule to let go of the solvent — its “retention time” — is unique, so seeing a molecule’s retention time is as good as knowing the molecule’s name…at least when someone else has already done the meticulous work of correlating the two. Of those 800-some-odd wine aroma molecules, we can actually only name something like 10-20%. But we know the rest exist, because we can see their retention-time fingerprint pop up on the chromatography results. Even better than gas chromatography, for wine aroma purposes, is gas chromatography-olfactometry, which takes the apparatus for chromatography and adds a smelling port so that scientists can sniff the separated-out molecules as they come up in turn. In the case of the Australian shiraz, the gas chromatography came up with about 100 “odorants,” but the consensus among sniffers was that only about half of those actually smelled like anything. Of those, for only 27 or 28 were their concentrations in the wines high enough to theoretically be detectable (they exceeded their odor threshold). It took 44, added to a wine-alcohol-acid-sugar base, to make something that credibly mimicked the original wine.

Then the researchers asked their trained sensory panel to do something interesting: sniff  the aroma + base wine-like synthetic and the same mix minus one of several key aroma compounds with the goal of identifying which molecules contributed to which perceived smells. The details get long-winded, but the final message stands out. Removing non-aromatic constituents changed aroma perceptions — sometimes more intense, sometimes less, depending on the aroma and the other molecules involved — even when the key aroma compounds themselves were left untouched. And some very obviously smelly compounds present in the wines in quantities far above their odor thresholds had a much smaller impact on wine aroma then their high concentrations would make you think.

In other words, wine aroma isn’t as simple as just pairing up odiferous molecules and their corresponding smells. And we can’t yet predict how or why wine will smell the way it does from first principles. Synthetic wine, then — or at least synthetic wine that replicates real wine — is going to take some time, and a lot more sniffing.

Astringency is not a flavor (thank you, wine physiology)

It’s generally agreed that we have five basic tastes — sweet, salty, bitter, acidic, and umami — all of which make appearances in wine.** The nuances described in baroque tasting notes — fruits and flowers and tar and tobacco and the rest — are, of course, smells. But where does that leave astringency? In the hands of physiology researchers, evidently. Anatomy is the science of labelling the parts of the body and where all the bits are. Physiology is the science of understanding how those parts work. So when we ask questions about how wine triggers responses in the mouth, we ask physiology.

Astringency is the dry, rough, puckery feeling left in your mouth by a sturdy red wine, strong black tea, dark chocolate, or (best example ever) an underripe persimmon. Some astringent molecules also taste bitter, but that’s not what we’re talking about. Astringency doesn’t seem to be a taste. It’s definitely not a smell. It’s…something else. But since descriptions like “something else” leave scientists (and wine drinkers, maybe) feeling unsatisfied, physiology researchers at Ruhr University in Germany have been trying to pin down astringency more precisely.

Research on astringency isn’t new, but it’s been confusing. Astringency triggers the same nerve that’s used to carry flavor sensations in mice; since flavors and feelings (like touch and temperature) are carried by different nerves in the mouth, that’s a useful observation. But astringency can be sensed by parts of the mouth that don’t have taste receptors. We know (or we think we know) that tannins are responsible for red wine astringency, and what we’re taught in food science classes is that tannins bind to the proteins in your saliva and cause them to glom together, which simultaneously decreases the slipperiness of your saliva — making your mouth feel dry — and creates a bunch of big rough tannin-protein blobs that themselves feel rough. The problem with that explanation is that the intensity with which we sense astringency doesn’t seem to be related to how much protein gets bound up, and not all molecules that seem to cause astringency bind up proteins at all.

This new German study, unfortunately, doesn’t help resolve most of those conundrums. But it did use a simple, elegant little trick to pretty firmly say that astringency isn’t a taste, and that it is a feeling.

Since completely different nerves carry taste sensations and mechanical feelings like pressure or roughness back to the brain, these researchers used anaesthetic — the same injectable kind you’d get at the dentist — to numb up either the taste nerve for the front of the tongue alone or both the taste and the feeling nerve of some real live humans, then subjected them to astringent things like quinine (the stuff in tonic water) or powdered chestnut. They also found some folks whose mechanical feeling nerve had been cut in the course of middle ear surgery, which means that they couldn’t taste on half of the front of their tongues (these and most nerves are paired with one for the right and one for the left side of the body). The folks who couldn’t taste — either because of surgery or because of anaesthetic — had no trouble detecting astringency. But the folks who couldn’t feel were numb to the astringent sensations. That suggests that we don’t sense astringency in the same way as mice, but that’s not outside the realm of possibility.

The study also included tests on isolated nerve cells (from mice, not those human subjects; don’t worry) to look for exactly what molecules were triggering the mechanical nerves and what kind of triggering was going on. Those experiments showed that astringency isn’t just the roughness you feel when you move your tongue around, but that nerve cells are being activated directly. In other words, you could still feel astringency if you couldn’t tell whether the inside of your mouth was rough by moving your tongue and cheeks around.

But, still, that’s an open question: is the sensation of astringency caused just by chemicals triggering nerves, or is it also the product of rough feelings when we move our mouths around? Since knocking out the mechanical sensation nerves knocks out both of those feelings, these experiments couldn’t say.

So when astringency comes up over a glass of tannic red, you can continue to confidently say that the wine feels astringent rather than tasting astringent. Cocktail-party trivia, sure. And maybe this research has other functions, in understanding and knowing how to fix peculiar diseases of messed-up mouth nerves. But in some ways, it’s about what science has always been about: looking at something — in this case, our own bodies — and asking, “Well gosh, how does that work?” The earth is a giant puzzle book, and we’re certainly in no danger of reaching the last page any time soon.

 

**Yes, yes: what constitutes a basic taste is a matter of debate, but that’s an interesting topic for another day.

“Feminine” wine: Why are we still having this conversation?

I’d thought that “masculine” and “feminine” wines were on their way out. Or, rather, I’d thought that the use of gendered stereotypes to connote particular wine styles was on its way out. One small sign that my hopes were premature: Wine Enthusiast’s online feature on “Top Wine Terms Defined” not only includes “feminine” but asks me not to “automatically bristle at this gendered wine term.” Okay. Tell me why. Unsurprisingly, their reasons are unconvincing and point back to why we shouldn’t be using this term in the first place.

The article praises the term for being easy to understand and quotes a beverage director to the effect that feminine wines share a woman’s “best qualities,” being “light, refined, and delicate.” So, I’m being asked not to bristle because, first, everyone knows the female stereotype of womanly refinement and, second, because it’s implied that we’re paying women a favor, referring to their best qualities. After all, “feminine” wines aren’t moody, flighty, or hysterical, equally stereotypical but negative characteristics associated with women. Nope. I’m bristling.

We’re being invited to agree that women are supposed to be — or at least that the best women are — gentle, fair, and fragile. I don’t need to belabour the point. Women can and should be praised for being a lot more than that: strong, intelligent, capable, funny, and any other praiseworthy characteristic we appreciate in people. Heck, we have plenty of television ads of women getting muddy playing sports or brokering business deals but — stereotypically — at least some part of the wine community is being backward. It would be funny if it wasn’t damaging first. Asking to be mollified by the idea of being paid a compliment just makes it worse.

Men aren’t treated well by the gendered wine phenomenon, either; stereotypes of big, burly, strong, rich masculinity put them in a box just as much as do the female stereotypes for women. Suggesting so is hardly new. Steve Heimoff’s blog hosted a promising debate over his reference to the feminine aesthetic in winemaking last year, for example. Nonetheless, Googling “feminine wine” suggests that the term remains reasonably common. Backwardly.

What’s the problem? The short answer: stereotyping is bad. One better: stereotyping is bad because it limits individual’s identities in terms of who they feel they can be and in terms of who other people allow them to be, because it let’s us treat others as something less than human — because when we label them with a stereotype we apply and expect the contents of that category to how we see them and stop seeing them in their fullness as people — because we make categories and then fill them. Ideas don’t exist out there on their own. We construct them. And so every time someone uses the term “feminine wine,” they help build the cultural phenomenon of the associated stereotype. In a small way, sure, but large ideas are built of small instances. Castles and bricks.

I’d like to hand the editor of Wine Enthusiast some Michael Foucault (or Judith Butler, or pretty much any other late-2oth c. critical theorist). Instead, I guess I’ll just rail a bit and embody the outraged middle-aged woman. You know the type.

Does cross-flow filtration affect wine flavor? No easy answers.

Cloudy wine (mostly) doesn’t sell. Neither does (most) wine spoiled by spoilage microbes that produce off-aromas. And so, while it is entirely possible to remove floating particles that make wine cloudy and (most) microorganisms via careful winemaking without sterile filtration, most winemakers appreciate the extra insurance it gives. Filters are essentially membranes punctuated by lots of little pores: all good stuff should flow through the pores; bad stuff you want to keep out of the bottle should be too big to pass. To reliably remove yeast and bacteria, filters need to have really tiny pores, and the question always is: are those filters excluding stuff other than the microbes, good-tasting stuff that I want the wine to keep? We’re talking .45 μm pores here, an order of magnitude smaller than the diameter of a red blood cell; anything bigger risks allowing bitsy bacteria through.

Pro-filtration folks say that all molecules important to wine quality are much to small to get caught in even these super-stringent filters. Filtration-shy folks say that wine tastes different post-filtration; no matter what molecular measurements say should happen, something is happening. For an excellent discussion of the arguments on both sides, see Tim Patterson’s excellent review in Wines and Vines (updated here, but this one is still behind a pay wall). Bottom line: scientific evidence suggests that while some important molecules could get stuck to the surface of the filter, all the important stuff can pass through safely; dissenters can still taste a difference, and maybe that has something to do with big conglomerates of molecules.

So it stands for conventional filtration. But what about cross-flow filtration, they shiny new-ish solution to some of the conventional process’s major hassles? Conventional filtration points a stream of flowing wine directly at the filter membrane and waits for it to percolate. Enough push needs to be behind that wine stream to keep things moving, but too much push and the force of the flowing wine will rip right through the filter. And the wine must be almost entirely free of particles in the first place, else biggish stuff will cover the surface of the filter, block the holes, and slow down flow. Either way, the filter membrane will need to be replaced, and they’re expensive. Cross-flow filtration instead points the wine stream across the surface of the membrane. Liquid still flows through but with less direct pressure on the membrane, and the constant stream sweeps pores clean of junk, too.

So cross-flow is better than traditional filtration for a few technical reasons. Is it also better for wine quality?

A study addressing that question has just been published (as a provisional draft; it’s not yet appeared in the print journal) with work done by a team from UC Davis. A few published articles have shown chemical analyses of cross flow-filtered wines, but this study is unique and helpful in two ways: 1. The emphasis was on whether a trained tasting panel could detect flavor differences in filtered wine; and 2. Wines were tested not just immediately after being filtered, but from bottle samples taken at intervals out to eight months post-filtration. Kitchen-sink white and red blends were included.

Though the group’s experiments aimed at looking for sensory differences following filtration, their results uncovered something else. The flavor of the unfiltered red wine changed more over time — more earth, less fruit beginning at two months and continuing to the eight-month end point — while the flavor of the filtered red remained more or less constant; in other words, the filtered wine was more stable. The obvious explanation is that the unfiltered wine suffered from some kind of microbial growth after bottling, even though the idea of a UC Davis-crafted experimental wine having microbial spoilage issues does seem strange.

More to the original point: even though chemical analyses showed that filtration decreased phenolics in the wine — filtered reds had lower pigmentation and up to 26% lower tannin levels — the tasting panel didn’t pick up corresponding differences in astringency. That’s surprising. The only explanation offered in the paper is that the magnitude of the change mustn’t have been big enough to be detectable.

In the end, then, this study probably does more to fuel the filtration debate than to help resolve it. Pro-filtration folk can point to filtration’s apparent lack of sensory impact, and to the likely spoilage of the unfiltered wine. Filtration-caution folk can point to the color and tannin changes and say that, even if those changes didn’t affect flavor in this wine, similar changes might indeed be important in other wines. So instead, we have one more example of what may indeed be Rule No. 1 in winemaking: there are no easy answers.

Why playing music to wine may not be a cockamamie idea

When is a train like a jazz tune? When someone tries using them to improve wine quality. Recently, Wine-Searcher ran a piece on Juan Ledesma, a Chilean winemaker using waterproof speakers submerged in the barrel to – infuse? – his malbec and cabernet as they age. If you believe that some kind of spirit inheres in all living things even through their killed and processed forms, and also believe that music has spiritual effects, then it might also be logical for you to believe that music has some kind of metaphysical effect on wine that transmutes through its spirit into its physical form, affecting both the taste of the wine and, perhaps, the spirit of the person who consumes it. Fair enough logic. But when I think about music, I think about trains. Trains and music, both, are sources of vibrations which at least theoretically affect on wine quality. What kind of an effect has been a matter of speculation and maybe a little superstition or wishful thinking, but not much research. A few years ago, a winemaker contacted me to ask whether his barrel room being under a railway overpass – and, consequently, being subject to the rumbling vibrations of frequent passing trains – might have some kind of softening effect on the tannins in his reds. Had he consulted what turns out to be a century-long history of winemaker interest in train-derived rumblings, from  he would have found as much or more worry about negative effects as positive. His spiritual predecessors, 1920’s London wine merchants, hoped that their wines stored in barrel under the city’s railway arches would mature faster and to good effect. Sixty years later, a great vinous uproar occurred when the French government proposed a new TGV route to transgress Vouvray in the late 1980’s, not only for fear that vineyards might be destroyed but that vibrations from the train might disrupt cellaring wine. (The not-entirely-equitable solution: a tunnel under the vineyards and anti-vibration mats under the tracks.) The TGV folk purportedly did their own research and found that passing trains had no effect on wine quality, but they never published any details from their studies. Playing music to wine could be dismissed as new-aged nonsense and worrying about trains as old-timer technology resistance. But, both trains and music are sources of vibrations. Vibrations may not make wine “mature” faster, but they could do something. The obvious effect of vibration, at least on wine being aged before fining and filtering, is in stirring up lees. Sound vibrations jostle and stir up wine a bit — just a little, but enough perhaps to keep dead yeast cells that would settle to the bottom of an unjostled tank stirred up and suspended in the wine a bit longer. Interaction with dead yeast cells — lees, when they collect at the bottom of a tank or barrel — changes wine quality: as yeast cells die and decay, they release a slew of interesting cellular leftovers. Some of these add directly to flavor, some give weight and richness to mouthfeel, some we certainly haven’t yet figured out. Increasing “must turbidity” — stirring up the wine — increases the amount of these yeasty components in the finished wine. To date, research on wine and music has involved how shoppers respond to in-store playlists (French music improves French wine sales, German music improves German wine sales) or how ambient music alters our sensory perceptions while tasting (people’s ratings of the weight and sophistication of the wine they drank tended to match the weight and sophistication of the music they heard). We’ve yet to see research on playing music to the wine rather than to the customer, though that looks to change as the Chilean Agricultural Innovation Fund has, the Wine-Searcher piece reports, invested in studying the wine-plus-music phenomenon. Regrettably, no indication from Amtrak that they plan to participate.