Minéralité

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Minéralité

Message par Don Max » mer. 05 mars 2008 18:35

Suite à la lecture du fil sur le Muscadet "Expression de Granit". J'ai décidé de démarrer un fil au sujet de ce qu'on nomme la minéralité dans le vin. À titre d'introduction, je recopie ici un texte solide comme le roc à ce propos!!! C'est long, mais très sérieux, et pour qui le sujet intéresse, c'est une lecture qui en vaut vraiment la peine.

Don Max




Talk Dirt to Me


By HAROLD MCGEE AND DANIEL PATTERSON
Published: May 6, 2007


It’s hard to have a conversation about wine these days without hearing the French word terroir. Derived from a Latin root meaning “earth,” terroir describes the relationship between a wine and the specific place that it comes from. For example, many will say the characteristic minerality of wines from Chablis comes from the limestone beds beneath the vineyards (although, when pressed, they generally admit that they’ve never actually tasted limestone). The idea that one can taste the earth in a wine is appealing, a welcome link to nature and place in a delocalized world; it has also become a rallying cry in an increasingly sharp debate over the direction of modern winemaking. The trouble is, it’s not true.

You are here? If that Chablis tastes like schist (or limestone), it’s only partly due to what kind of rock lies beneath the vines.
When terroir was first associated with wine, in the 17th-century phrase goût de terroir (literally, “taste of the earth”), it was not intended as a compliment. Its meaning began to change in 1831, when Dr. Morelot, a wealthy landowner in Burgundy, observed in his “Statistique de la Vigne Dans le Département de la Côte-d’Or” that all of the wineries in Burgundy made wine essentially the same way, so the reason some tasted better than others must be due to the terroir — specifically, the substrata underneath the topsoil of a vineyard. Wine, he claimed, derived its flavor from the site’s geology: in essence, from rocks.

In recent years, the concept that one can taste rocks and soil in a wine has become popular with wine writers, importers and sommeliers. “Wines express their source with exquisite definition,” asserts Matt Kramer in his book “Making Sense of Wine.” “They allow us to eavesdrop on the murmurings of the earth.” Of a California vineyard’s highly regarded chardonnays, he writes, there is “a powerful flavor of the soil: the limestone speaks.” The sommelier Paul Grieco, in his wine list at Hearth in New York, writes of rieslings that “the glory of the varietal is in its transparency, its ability to truly reflect the soil in which it is grown.” In his February newsletter, Kermit Lynch, one of the most respected importers of French wine, returns repeatedly to the stony flavors in various white wines from a “terroirist” winemaker in Alsace: “When he speaks of a granitic soil, the wine in your glass tastes of it.”

If you ask a hundred people about the meaning of terroir, they’ll give you a hundred definitions, which can be as literal as tasting limestone or as metaphorical as a feeling. Terroir flavors are generally characterized as earthiness and minerality. On the other hand, wines with flavors of berries or tropical fruits and little or no minerality are therefore assumed not to have as clear a connection to the earth, which means they could have come from anywhere, and are thought to bear the mark of human intervention.

If this seems confusing — especially given that wine is made from fruit — it gets worse when you ask winemakers about how to get the flavors from the rocks into the glass. According to them, a good expression of terroir requires more work in the vineyards, or possibly less; it’s the hotter climate in California that leads to its high-alcohol, fruit-forward, terroir-less style, or possibly not; even the oft-heard contention that a winemaker must “work with what the vines give you” is contradicted by Ales Kristancic of Movia winery, whose family has been making wines from vineyards on the Italy-Slovenia border for hundreds of years. “Plants need to understand what the winemaker wants,” Kristancic says. “Only a winery with great tradition can make great vineyards.”

Since there’s so little consensus among winemakers about how to foster the expression of place — what Matt Kramer calls “somewhereness” — in their wines, what are our wine experts tasting? How can a place or a soil express itself through wine? Does terroir really exist?

Yes, but the effects of a place on a wine are far more complex than simply tasting the earth beneath the vine. Great wines are produced on many different soil types, from limestone to granite to clay, in places where the vines get just enough water and nourishment from the soil to grow without deficiencies and where the climate allows the grapes to ripen slowly but fully. It’s also true that different soils can elicit different flavors from the same grape. Researchers in Spain recently compared wines from the same clone of grenache grafted on the same rootstock, harvested and vinified in exactly the same way, but grown in two vineyards 1,600 feet apart, one with a soil significantly richer in potassium, calcium and nitrogen. The wines from the mineral-rich soil were higher in apparent density, alcohol and ripe-raisiny aromas; wines from the poorer soil were higher in acid, astringency and applelike aromas. The different soils produced different flavors, but they were flavors of fruit and of the yeast fermentation. What about the flavors of soil and granite and limestone that wine experts describe as minerality — a term oddly missing from most formal treatises on wine flavor? Do they really go straight from the earth to the wine to the discerning palate?

No.

Consider the grapevine growing in the earth. It takes in elemental, inert materials from the planet — air and water and minerals — and, using energy captured from sunlight, turns them into a living, growing organism. It doesn’t just accumulate the earth’s materials. It transforms them into the sugars, acids, aromas, tannins, pigments and dozens of other molecules that make grapes and wine delicious.

“Plants don’t really interact with rocks,” explains Mark Matthews, a plant physiologist at the University of California, Davis who studies vines. “They interact with the soil, which is a mixture of broken-down rock and organic matter. And plant roots are selective. They don’t absorb whatever’s there in the soil and send it to the fruit. If they did, fruits would taste like dirt.” He continues, “Any minerals from the solid rock that vine roots do absorb — sodium, potassium, calcium, magnesium, iron, a handful of others — have to be dissolved first in the soil moisture. Most of them are essential nutrients, and they mainly affect how well the plant as a whole grows.”

Most of the earthy and mineral aromas and flavors that we detect in wine actually come from the interaction of the grape and yeast. Yeasts metabolize the grape sugars into alcohol, along the way freeing up and spinning off the dozens of aromatic chemicals that make wine more than just alcoholic grape juice. It’s because of the yeasts that we can catch whiffs of tropical fruits, grilled meats, toasted bread and other things that have never been anywhere near the grapes or the wine. The list of evocative yeast products includes an organic sulfur molecule that can give sauvignon blancs a “flinty” aroma. And there are minor yeasts that create molecules called volatile phenols, whose earthy, smoky flavors have nothing to do with the soil but are suggestive of it, especially in wines from the southern Rhône.

Grape minerals and mineral flavors are also strongly influenced by the grower and winemaker. When a vineyard is planted, the vine type, spacing and orientation are just a few of many important decisions. Growers control the plant growth in myriad ways, such as pruning, canopy management or, most obviously, irrigating and replenishing the soil with manures or chemical fertilizers. The winemaker then makes hundreds of choices that affect wine flavor, beginning with the ripeness at which the grapes are harvested, and can change the mineral content by using metal equipment, concrete fermentation tanks or clarifying agents made from bentonite clay. Jamie Goode, a British plant biologist turned wine writer, describes in his superbly lucid book “Wine Science” how techniques that minimize the wine’s contact with oxygen can increase the levels of sulfur compounds that may be mistaken for “mineral” character from the soil.

So, if vines absorb only rock that is dissolved in water, if grape and wine minerals are not a reflection of the rocks’ minerals, and if earthy aromas in wine come from microbes and not the earth, do soil minerals have any real role in wine flavor?

Hildegarde Heymann, a sensory scientist at U.C. Davis, is skeptical about the usefulness of the terms ‘terroir” and “minerality” as they’re used today. But she is intrigued by “minerality.” “People who talk about minerality are describing something they perceive that’s hard to grab on to,” she says. “My guess is that it’s a composite perception, something like ‘creaminess’ in dairy foods. ‘Minerality’ might be a way of describing a combination of complexity, balance and a substantial body. We do know that mineral ions can affect wine flavor by affecting acidity, chemical reaction rates and the volatility of aromas. And we’re just now looking at whether they can affect the body of wine, its ‘mouth feel.’ They might.”

It’s possible, then, that soil minerals may affect wine flavor indirectly, by reacting with other grape and yeast substances that produce flavor and tactile sensations, or by altering the production of flavor compounds as the grape matures on the vine.

The place where grapes are grown clearly affects the wine that is made from them, but it’s not a straightforward matter of tasting the earth. If the earth “speaks” through wine, it’s only after its murmurings have been translated into a very different language, the chemistry of the living grape and microbe. We don’t taste a place in a wine. We taste a wine from a place — the special qualities that a place enables grapes and yeasts to express, aided and abetted by the grower and winemaker.

In the years following Dr. Morelot’s missive on terroir, the quality of a wine became synonymous with the quality of the vineyard where it originated. This meant the value of that wine was tied to the land instead of to the winemaker, which allowed it to be handed down from generation to generation. The French went on to codify their vineyards into legal appellations, creating gradations within those appellations that demarcated clear levels of quality (grand cru, first growth and so on), the economic effects of which are felt to this day. Given that it was landowners who benefited most, the commonly held idea of terroir — wine as proxy for a piece of dirt — looks a lot like one of the longest-running, most successful marketing campaigns of the modern era.

Today, it’s easy to ascribe all this terroir talk to commerce, to the European reaction to California’s recent rise in viniculture status. It’s been suggested that terroir is just the Old World saying to the New: It’s the land, stupid — we have it and you don’t. But that doesn’t explain why so many Americans have embraced the concept with near-religious zeal. To paraphrase the great French wine historian Roger Dion, why have so many brilliant and passionate wine professionals been so eager to attribute solely to nature what is actually the result of hard work by talented winemakers?

The answer lies in the complex relationship between tradition, culture and taste. Those wine professionals have all spent vast amounts of time and energy learning what traditional European wines taste like, region by region, winery by winery, vineyard by vineyard. The version of terroir that many of them hold is that those wines taste the way they do because of the enduring natural setting, i.e., the rocks and soil. These wines taste the way they do because people have chosen to emphasize flavors that please them.

The pioneering French oenologist Émile Peynaud wrote nearly 25 years ago: “I cannot agree with the view that ‘one accepts human intervention (in vinification) as long as it allows the natural characteristics to remain intact,’ since it is precisely human intervention which has created and highlighted these so-called natural characteristics!” Modern European views of terroir recognize that typical local flavors are the creation of generations of growers and winemakers, shaping the vineyard and fine-tuning the fermentation to make what they feel are the best wines possible in their place. Typical flavors are expressions not of nature but of culture.

But culture, unlike nature, isn’t static. It evolves in response to shifting tastes and technological advances. Over the past 30 years, the staid world of European winemaking has been roiled by an influx of American consumers, led by their apostle, the writer Robert Parker. In his reviews, Parker has brushed aside the traditional practice of judging wine according to historical context (that is, how it should taste), focusing instead on what’s in the bottle. His preference for hugely concentrated, fruit-forward wines — the antithesis of distinctive, diverse terroir wines — has dramatically changed the economic landscape of the wine industry. Throughout the world, more and more winemakers are making wine in the style that Parker prefers, even in Europe, where this means abandoning distinctive local styles that had evolved over centuries. “Somewhereness” is being replaced by “anywhereness.”

The simplistic idea of terroir as a direct expression of nature has become a rhetorical weapon in the fight against this trend. Kristancic — who interrupted our interview to raise his fists and shout to the heavens, “They’re ruining wine!” — sees an advancing wave of homogenization that will eventually turn wine into a soulless, deracinated commodity. Like many others, he is afraid of losing what is special about the traditional role of wine in human life, its way of connecting people to the land and to one another. Conjuring granite in Alsatian rieslings and limestone in Chablis puts that connection to the land right in the bottle, ours for the tasting.

If rocks were the key to the flavor of “somewhereness,” then it would be simple to counterfeit terroir with a few mineral saltshakers. But the essence of wine is more elusive than that, and far richer. Scientists and historians continue to illuminate what Peynaud described as the “dual communion” represented by wine: “on the one hand with nature and the soil, through the mystery of plant growth and the miracle of fermentation, and on the other with man, who wanted wine and who was able to make it by means of knowledge, hard work, patience, care and love.” “Somewhereness” is given its meaning by “someoneness”: in our time, by the terroirists who are working hard to discover and capture in a bottle the difference that place can make.




http://www.nytimes.com/2007/05/06/style ... ted=1&_r=3



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ludwig
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Message par ludwig » mer. 05 mars 2008 18:53

Très intéressant cet article qui déboulonne certains mythes...

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Message par Don Max » mer. 05 mars 2008 19:33

Bien que j'apprécie beaucoup le contenu de cet article, je ne suis pas d'accord avec tout ce qu'il avance. Je pense vraiment que la relation vigne-terroir, au sens strict, est très importante. Ce n'est pas vrai qu'on peut faire le même vin, peu importe le sol et la vigne qu'on y associe. Il y a des sols qui permettent une meilleur expression de certains types vignes. Je dis vigne, au lieu de cépage, car des lectures récentes m'ont appris que parler de cépage, sans parler de son système racinaire n'avait pas de sens, et c'est un aspect généralement très négligé. La vigueur d'un plant de vigne est influencée par ses racines. Avec le greffage qui est la norme, sauf au Chili, parler de cépage dans le contexte de la relation de la vigne avec le sol n'a pas de sens, car les porte-greffes peuvent varier pour un même cépage. Toujours est-il, que je suis convaincu de l'influence du sol sur la nature des raisins qui seront produits par un plant de vigne donné, cela inclut ce qu'on qualifie de “minéralité”. Toutefois, l'influence du sol, selon moi, n'a rien à voir avec le passage de minéraux dans le raisin. La nature physico-chimique du sol a une influence directe sur la physiologie végétale. En d’autres termes, la nature du sol influence le métabolisme d’un plant de vigne donné. L’expression biologique d’un plant de vigne change selon ce que les racines peuvent lui apporter. La vigne, dépandant de sa nature, réagira face à spécifiquement face à certaines carences, à certains stress. Elle réagira aussi face à l’abondance, voire l’excès de certains éléments. Donc, pour moi, il est clair qu’un bon mariage, racines-cépage-sol est essentiel et influence la nature et la qualité du vin final qui pourra en être produit, mais cela n’a rien à voir avec l’idée que la nature chimique du sol, à proprement parler, se reflétera directement dans le vin. La nature du sol influe sur l’expression physiologique de la vigne, et cela peut, dans certains cas, se traduire par une impression organoleptique qu’on associe à un caractère évoquant une nature minérale.

Don Max

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Message par ludwig » mer. 05 mars 2008 19:44

Donc le sol transmet des éléments chimiques à la vigne, et non pas des éléments minéraux comme tel?

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Message par pango » mer. 05 mars 2008 20:31

Don Max a écrit :Donc, pour moi, il est clair qu’un bon mariage, racines-cépage-sol est essentiel et influence la nature et la qualité du vin final qui pourra en être produit, mais cela n’a rien à voir avec l’idée que la nature chimique du sol, à proprement parler, se reflétera directement dans le vin.
Dans l'ensemble, je suis d'accord avec l'article et tes propos, mais je ne pige pas la citation ci-dessus, il me semble qu'il y a contradiction.
"Les hommes boivent et ils ne sont pas heureux." Albert Camus (variation)

Bloc d'annonce

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Message par Don Max » mer. 05 mars 2008 20:43

Il transmet et des éléments minéraux, mais de simples ions, rien qui puisse être associé à "l'odeur" du sol. Il transmet aussi l'eau et certains éléments nutritifs. Toutefois, la nature et la quantité de ces éléments influencent la physiologie de la plante. Pour prendre un exemple simple, prenons l'apport en eau. Le niveau d'hydratation aura une influence importante sur le comportement métabolique de la vigne. En carence en eau certaines voies métaboliques seront favorisées pour compenser. Même chose pour un excès d'eau, la vigne favorisera d'autres voies métaboliques, favorisant le feuillage au dépend des fruits. Cela peut varier selon le stade végétatif. Ce qui est vrai pour l'eau est vrai aussi pour les autres éléments nutritifs apporter par les racines. Un sol fertile ne produira pas le même raisin qu'un sol pauvre. Je suis loin d'être un expert en physiologie végétale, mais il est clair pour moi, que la nature et le niveau d'apport en élément nutritifs influence le métabolisme de la vigne. Cette influence peut se moduler de différentes façon au cours d'un cycle végétatif, et c'est la somme complexe des divers éléments qui détermine la nature du raisin qui sera cueilli à la fin. Bien sûr, l'influence du sol n'est qu'une des variables, et le climat, ainsi que les méthodes de culture peuvent influer grandement sur le comportement d'un type de vigne donné, mais au bout du compte, l'influence de la nature physico-chimique du sol demeure, et ne peut être éliminée totalement.

Don Max
Modifié en dernier par Don Max le mer. 05 mars 2008 21:21, modifié 1 fois.

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Message par Don Max » mer. 05 mars 2008 20:50

pango a écrit :
Don Max a écrit :Donc, pour moi, il est clair qu’un bon mariage, racines-cépage-sol est essentiel et influence la nature et la qualité du vin final qui pourra en être produit, mais cela n’a rien à voir avec l’idée que la nature chimique du sol, à proprement parler, se reflétera directement dans le vin.
Dans l'ensemble, je suis d'accord avec l'article et tes propos, mais je ne pige pas la citation ci-dessus, il me semble qu'il y a contradiction.
C'est vrai que ce n'est pas parfaitement clair. Ce que je voulais exprimer, c'est que même si le mariage racines-cépage-sol est primordial, cela ne veut pas dire que "l'odeur" ou la "saveur" du sol se reflétera dans le vin. L'influence du sol est indirecte. La nature physico-chimique du sol influe sur l'expression biologique de la vigne, sur sa physiologie. J'espère que c'est plus clair ainsi.

Don Max

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Message par pango » mer. 05 mars 2008 21:17

Don Max a écrit :Il transmet et des éléments minéraux, mais de simples ions, rien qui puisse être associé à "l'odeur" du sol. Il transmet aussi l'eau et certains éléments nutritifs. Toutefois, la nature et la quantité et la nature de ces éléments influencent la physiologie de la plante.
Don Max
En fait, un exemple encore plus simple est le pH du sol. Certains éléments chimiques ne sont pas absorbés par un végétal selon le degré d'acidité d'un sol. Le phosphore, par exemple, est sous un forme chimique non assimilable par une plante en-dessous ou en-dessus d'un certain pH. Règle générale, dans un sol légèrement acide, la majorité des éléments minéraux dont la plante a besoin sont optimalement disponibles, car mieux dissous et sous une forme assimilable.

Mais l'élément central pour l'absorption des éléments chimiques du sol par une plante, c'est le complexe argilo-humique et la capacité d'échange cationique d'un sol. Je ne vais pas vous bassiner avec plein d'explications techniques, mais si on veut vraiment saisir la base des échanges chimiques entre une plante et un sol, ce sont des concepts qu'il faut comprendre.
Modifié en dernier par pango le mer. 05 mars 2008 21:23, modifié 1 fois.
"Les hommes boivent et ils ne sont pas heureux." Albert Camus (variation)

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Message par pango » mer. 05 mars 2008 21:23

Don Max a écrit : Ce que je voulais exprimer, c'est que même si le mariage racines-cépage-sol est primordial, cela ne veut pas dire que "l'odeur" ou la "saveur" du sol se reflétera dans le vin. L'influence du sol est indirecte. La nature physico-chimique du sol influe sur l'expression biologique de la vigne, sur sa physiologie. J'espère que c'est plus clair ainsi.
Oui c'est plus clair. Et heureusement que "l'odeur" du sol ne se communique pas dans les raisins, car après une application de purin...

Blague à part, l'ammoniac est retenu par l'argile et l'humus du sol, c'est le complexe argilo-humique que je parlais précédemment.
"Les hommes boivent et ils ne sont pas heureux." Albert Camus (variation)

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Message par Don Max » mer. 05 mars 2008 21:32

Pango,

La nature de la plante doit aussi y être pour quelque chose dans la capacité d'absorption. J'ai lu le livre "Wines of Chile" dernièrement, et une chose qui retenu mon attention, c'est le fait que les vignes franches de pied sont souvent un problème au Chili. Car dans ce cas, racines et cépages viennent ensemble, et souvent les racines d'origine d'un cépage s'adaptent mal à certains types de sol, alors que l'utilisation d'un porte-greffe d'une vigueur bien adaptée permet de planter le même cépage sur le même sol avec plus de succès. En d'autres termes, l'utilisation des porte-greffes permet une meilleur adaptabilité des cépages à différents types de sols, alors que pour la vigne franche de pied, c'est l'ensemble qui doit être bien adapté. Ce qui est plus restrictif. Ironiquement, il semble que le phyloxera aurait pu avoir un effet positif majeur.

Don Max

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Message par pango » mer. 05 mars 2008 22:01

Don Max a écrit : La nature de la plante doit aussi y être pour quelque chose dans la capacité d'absorption.
Définitivement, comme tu le précises initialement, c'est le mariage racine-cépage-sol qui prévaut avant tout. Mais cultive une vigne avec une "excellente capacité d'absorption" dans une milieu très très pauvre en matière organique, tu constateras rapidement la mort de ton plant de vigne.

Pourquoi penses-tu qu'il existe si peu de végétaux dans les déserts? Certes, il y en a, mais c'est un mécanisme d'adaptation qui privilégie que certains végétaux.
"Les hommes boivent et ils ne sont pas heureux." Albert Camus (variation)

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Message par Cros Parantoux » mer. 05 mars 2008 22:07

Je trouve cet article vraiment simpliste. Comme si les apôtres du terroir ne tenaient qu'à boire de la roche et que les auteurs sont des génies pour avoir affirmés que le terroir est plus que la géologie, mais aussi le micro-climat ou la micro-biologie ou les levures (naturelles?)... bravo ! je suis persuadé que les grands vignerons de bourgogne n'y avaient jamais pensé !!!! Well duh!

Je trouve aussi que, contrairement à Ludwig, cet article ne déboulonne rien du tout, les arguments sont minces et spécieux. Ils y a tellement de phrases toutes faites que ça en est ridicule:

But culture, unlike nature, isn’t static.
Franchement, et l'évolution c'est quoi? (les auteurs sont peut-être créationistes)

The trouble is, it’s not true.
Mais encore...
Today, it’s easy to ascribe all this terroir talk to commerce, to the European reaction to California’s recent rise in viniculture status.
Et pourquoi donc la Californie (et tous les autres états producteurs) se fendent-ils le cul pour définir des crus et des différences de terroirs! Avant il n'y avait que Napa maintenant il y a Howell Mountain, St. Helena, Oakville, Los Carneros...

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Message par Don Max » mer. 05 mars 2008 22:47

Un autre article simpliste sur le sujet pour mon ami Croc... grrr!!! :;-):

Don Max






Myths of minerality
Wines & Vines, Dec, 2006 by Tim Patterson


Fruit and oak have their place in great wine, but the top prize among wine attributes probably goes to minerality--the expression of rocks and soil in the aromas and flavors that end up in the glass. But for all its desirability and status, minerality is only vaguely defined and not well understood. In fact, the one thing we do know is that it has very little to do with minerals.

The great Rieslings of Germany's Mosel Valley are almost always described in terms of the slate soils they come from; for Sauvignon Blanc from Sancerre and Pouilly-Fume from France's Loire, it's "flint" that shows up in most every tasting note. New World wine regions aiming to match the Old World benchmarks--the Finger Lakes or New Zealand--often feel they have arrived when they, too, can boast of mineral character. Even some reds bask in the warm, stony glow.

Expressing minerality is not exactly the same thing as revealing terroir, but the two concepts are certainly intertwined. Distinctive terroir can show up as peaches or eucalyptus or creosote, not rocks. But claims that a particular wine captures the taste of a place--the gout de terroir--often revolve around vineyard geology and the subtle differences in soil composition between neighboring plots.

One would expect that an attribute this celebrated would be well documented, but one would be wrong. I started my research by whipping out my handy Wine Aroma Wheel, only to discover to my genuine surprise that no trace of "mineral" can be found therein. I fired off a quick e-mail to Dr. Ann Noble, creator and keeper of the wheel, asking how that could be, and she responded, "Minerality is a concept which could never be consistently defined in words or physical standards. If someone could come up with a stone or metallic solution that had an aroma that could be used to define minerality, it could be on the wheel. But the criterion for being on the wheel is that it is objective, analytical and nonsubjective, nonevaluative, nonhedonic."

She also put her personal view a little more bluntly: "Sucking on stones doesn't give any sensation akin to wine flavor."

The same concern about the slipperiness of the descriptor came from UC Davis flavor chemist Dr. Sue Ebeler: "As far as I know, there are no clear correlations of any specific compounds with a 'mineral' aroma. It is likely a complex mixture of compounds which we associate with the smell of soils or rocky areas. To really understand the use of this term, we would have to carefully define it with the use of some reference aroma/taste compounds that we could all agree on. Otherwise, two individuals may be describing the same physical or chemical stimulus with very different descriptive terms--your 'mineral' may be my 'salty.' Maybe then, once we've agreed upon a sensory descriptive reference and terminology, we could begin to identify the chemical compounds associated with the aroma or taste."

Part of the difficulty in finding a reliable, standard mineral reference is that, by and large, minerals don't have much smell at all. The scent of a rock-strewn patch of the great outdoors may be memorable; a single, clean rock in your hand is almost guaranteed to be odor-free. Deposits of individual minerals and agglomerations of minerals into rocks rarely contain volatile aromatic compounds. This helps explain why, when I Googled the phrase "mineral aroma," the results all had to do with body lotions and spa treatments, not rocks.

Devotees of minerality may admit that dry rocks have little smell, but go on to clarify the sensory concept as the aroma that rises when rain falls on thirsty stone. Turns out there is even a word for this phenomenon--petrichor--coined by two Australian researchers in 1964. The source of the smell, they determined, is that water liberates aromatics contained in complex, multi-compound oils that are given off by vegetation during dry spells and find their way onto the soil. (I happened across the term on Robin Garr's Wine Lovers Page; for more information, go to worldwidewords.org.) In other words, the smell of rain on stone is the smell of plants.

Assuming we could all agree on a definition of minerality in wine, we would still need to figure out how it is produced. What Master of Wine and popular wine-science writer Jamie Goode calls the "literalist" school holds that minerality comes more or less directly from the vineyard soils: slate in the vineyard produces slatey-type mineral character in the bottle. The implicit mechanism is that little molecules of slate journey from the soil through the roots and the xylem into the berries, and somehow manage not to fall out during fermentation. This, alas, is not how grapevine physiology works.

Even though chunks of slate (or clay or sandy loam) don't make their way into the grapes, some elementary minerals and mineral compounds do get taken up from the ground and end up in the juice. They arrive in small quantities, not enough to independently influence flavor, one way or another. They do, however, play an important role in yeast nutrition and metabolism during fermentation. And they are not particularly glamorous minerals, not the stuff of lyrical tasting notes: potassium, magnesium, sodium and calcium are the major players, none of them with noteworthy aromatic properties, particulary in such low concentrations. Wine flavors and aromas overwhelmingly come from compounds created either inside the berries during maturation or in the cellar during processing, not from substances transported from the soil.

The leading candidate in ongoing research for an explanation of minerality is, in fact, part of the mineral kingdom, one of the few downright famous for its odor: sulfur. In his recent book, The Science of Wine (University of California Press, 2005), Jamie Goode pulls together the findings and hypotheses from a number of European researchers suggesting that what is called minerality is likely related to low levels of a number of sulfur-based compounds, especially likely to occur in reductive (highly oxygen-restricted) winemaking or under conditions of nutrient stress in yeast during fermentation.

Another line of explanation links the perception of minerality with high acidity. Besides thinking minerality has little to do with "sucking on stones," Ann Noble suspects acidity may be involved: "I personally think it (minerality) implies 'austere.' Flavor with 'tight fruit,' high acid. Temporally, the aroma and taste are sharp, quick in onset and do not linger."

It seems hardly coincidental that Germany, known for high acid wines, reductive winemaking and chronic nutrient deficiencies in wine musts, should also be the source of so many wines identified by those who love them as highly mineral.

Without an agreed-upon standard, theories about where minerality comes from are bound to remain speculative. But the possibility that minerality stems not from the fixed characteristics of the vineyard but from compounds that can be controlled in the cellar should be cause for optimism. If emanations of slate can only be derived from slate soils, most of the winegrowing world is out of luck. But if this desirable property is due to the level of acidity or the presence of one or another sulfur compound that can be encouraged or discouraged, so much the better.

The prospect: less romance, more minerality.

HIGHLIGHTS

* The desirable wine characteristic of minerality is only vaguely defined and not well understood. In fact, the one thing we do know is that it has very little to do with minerals.

* Part of the difficulty in finding a reliable, standard mineral reference is that, by and large, minerals don't have much smell at all. The scent of a rock-strewn patch of the great outdoors may be memorable; a single, clean rock in your hand is almost guaranteed to be odor-free.

* Another line of explanation links the perception of minerality with high acidity. Besides thinking minerality has little to do with "sucking on stones," Dr. Ann Noble suspects acidity may be involved.

(Tim Patterson writes for a cuvee of publications about adult beverages--and makes his own--in Berkeley, Calif., where the wine country meets what's left of the '60s. He may be contacted through [email protected].)

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pango
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Message par pango » mer. 05 mars 2008 23:10

Cros Parantoux a écrit :Je trouve cet article vraiment simpliste. Comme si les apôtres du terroir ne tenaient qu'à boire de la roche et que les auteurs sont des génies pour avoir affirmés que le terroir est plus que la géologie, mais aussi le micro-climat ou la micro-biologie ou les levures (naturelles?)... bravo ! je suis persuadé que les grands vignerons de bourgogne n'y avaient jamais pensé !!!! Well duh!
Cros,

Il ne faut pas oublier que plusieurs amateurs et vignerons associent le terroir uniquement à la minéralité. En ce sens, l'article corrige le tir. J'ai surtout apprécié cet article au sujet de la minéralité et nom sur le concept de terroir.
"Les hommes boivent et ils ne sont pas heureux." Albert Camus (variation)

Cros Parantoux
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Message par Cros Parantoux » jeu. 06 mars 2008 7:20

Un autre article simpliste sur le sujet pour mon ami Croc... grrr!!! clin d'oeil
Baveux va! :twisted:

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