Tag Archives: minerality

On the Semantics of Minerality

09 Thursday Jan 2020

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mineralityIf you have been wondering about the state of research into minerality in wine, Alex Maltman in Decanter has you covered. He summarizes all the latest theories about minerality and supporting scientific evidence for them and ends up concluding—well, we still don’t know what it is or where it comes from

But as I read through the article it became clear to me that one reason the science is inconclusive is because there is no agreement on what we mean by “minerality” and the disagreement seems to largely stem from cultural differences.

Another illustration of the communication problem is the different word associations reported by research groups at Lincoln University in New Zealand and at California’s UC Davis. While both teams noted positive correlations between minerality and words like citrus, fresh, zingy, flinty, and smoky, the Lincoln researchers differed from those at Davis in finding no correspondence with acidity or reductive notes.

One study showed that minerality represented different things to Swiss and French wine consumers, and that the Swiss group used a markedly broader vocabulary.

When Professor Maltman turns to the question of where minerality comes from, it seems the science is hampered by that lack of agreement on what the term “minerality” refers to:

A later investigation, from UC Davis, reported that professional tasters found minerality in wines with greater malic and tartaric acidity and, to a lesser extent, free and total sulphur dioxide. However, a New Zealand study, while supporting a role for sulphur dioxide, found no correlation between acidity and perceived minerality, nor with reductive notes.

Here is what stood out to me. The New Zealand study found no correlation between acidity or reductive notes as the cause of minerality. But notice in the first quote, the New Zealand team found no correlation between minerality and word associations indicating acidity and reductive notes. In other words, for New Zealanders, high acid or sulfur compounds were not viewed as the cause of minerality because they don’t refer to high acid or sulfurous wines as “minerally”.

The basic problem is that there are cultural differences in the words used to describe wines. Thus, cross-cultural analyses of causal connections between compounds in the wine and our perceptions will be influenced by how we talk about those perceptions.

This is not unusual. Obviously in our language use we are deeply influenced by the people we interact with and there are often significant cultural differences between language groups even if they nominally speak the same language. There is little reason to think New Zealanders and Americans or the French and the Swiss would share all linguistic references despite the overlap in their official languages.

People have different names for things. That doesn’t necessarily mean we disagree about the underlying non-linguistic phenomenon.

What there does seem to be agreement on is that “minerality” doesn’t come directly from soil or rocks. Despite the tendency to talk as if there are such connections the science seems conclusive.

The Myth of the Myth of Minerality

13 Monday May 2019

Posted by in Food Science

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rocks in the vineyardVicki Denig writes a balanced article on minerality despite an ambiguous headline and a misleading introduction. Entitled “Nailing the Myth of Minerality”, she introduces the post by asserting “Minerality is perhaps the wine industry’s most overused, underwhelming, and misunderstood descriptors of them all.”

What’s wrong with this? For starters, “minerality” isn’t a myth; it’s a metaphor. And it’s neither overused nor underwhelming. She gets the “misunderstood” right but it’s misunderstood in part because of headlines like this. Happily she interviews enough somms and winemakers who routinely use the term and find it useful, so in the end the post leaves the impression that minerality is “a thing” as she calls it.

“Minerality” is a general term we use to describe wines that exude aromas such as flint, crushed rock, wet stone, or sea breeze or that have textures of chalk, hard stone, gravel or a kind of electrical snap on the finish. Since it is clear from tasting notes that many, many wines have these features, and they are highly prized among some wine critics and winemakers,  I don’t see what is “overused” or “underwhelming” about the descriptor.

The whole controversy really comes from some scientists talking out of school. Scientists have definitively shown that minerals in the soil do not transfer to the vines or fruit, and many (although not all) scientists use that fact to berate wine writers who use the term to describe wine. But although the fact that soil characteristics are not transferred to the wine is an important and interesting scientific claim, it is entirely irrelevant to the question of whether the term “minerality” is a useful or accurate descriptor.

We are not literally tasting rocks in the wine anymore than we are literally tasting cherry, peach, or barnyard soil in the wine. Most wine descriptors are metaphorical. Wine literally tastes like grapes; there are no cherries, peaches, or soil in your wine. These are all metaphors. But that fact has little to do with whether these descriptors are useful or accurate.

No doubt there isn’t a precisely established definition of “minerality”—it’s a metaphor!  (Sorry for screaming) While still “living”, a metaphor will not have a precise definition. That is why metaphors are useful—they flexibly and creatively pick out properties for which there is no literal description.

Denig quotes geologist Brenna Quigley who, to her credit, actually does seem to understand the usefulness of the term.

The science is quite clear that the vine is not literally picking up minerals from the soil and transferring them into the wine,” she explains, adding that this does not mean that experiences that tasters may have and describe as minerality do not exist.

This is exactly right.

This “controversy” would go away if a few more scientists had paid attention during English class. We should listen to scientists when they talk about science. When it comes to language we should listen to people who write and talk for a living.

(I suspect, by the way that Denig’s headline, is deliberately ambiguous. Is it the association of minerality with mythology that is being nailed or the allegedly inappropriate use of the term “minerality”? It is a clever headline. Apparently, Ms. Denig paid attention in English class.)

Randall Grahm, Vitality, and the Next Phase of the Doon

25 Thursday Oct 2018

Posted by in Philosophy of Food and Wine, Wine Culture, Winemaker Interviews

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popelouchum

Hilltop overlooking the Popelouchum Vineyard

For the past few years I’ve been obsessed with the idea of vitality in wine which, in tasting, is expressed via the number, type, velocity, and quality of phases the wine goes through as it evolves on the palate. Some wines feel alive. They vibrate with an electric intensity that is more than just big flavor. Others are static and moribund. Vitality is a dimension of quality that is too often ignored in wine assessment. And of course some wines age gracefully, another indicator of vitality.

When there is something new and exciting in the wine world, it’s probably a good idea to ask Randall Grahm of Bonny Doon Vineyards about it since he is usually out in front of the issue. In fact, a couple years ago I heard him say he was interested in discovering the “qi” of wine, a concept from Chinese philosophy which roughly translates as “vitality”. So when passing through Santa Cruz last summer I reached out to Randall to get his views on the matter.

popelouchum2As we motored about the hillsides of his new vineyard project, Popelouchum in San Juan Bautista, the issue of vitality was woven with descriptions of this fascinating exercise in creative viticulture. Plots of Furmint, Timorasso, Ruché and Rossese, old European varieties seldom grown in the U.S., are being dry farmed and head trained to test their drought tolerance and flavor potential. New rootstock from wild vitis berlandieri seeds are showing potential; some vines are grown from seed to take advantage of genetic instability and they’re experimenting with self-pollinating vines in search of recessive genetic characteristics better adapted to this specific vineyard site; and conventional vines are used to develop new varietals bred for disease resistance and drought tolerance. Biodynamic farming practices and the use of bio-char (a carbon-based soil enhancment) to encourage mycorrhizal populations are all part of the mix.

All this in addition to growing the conventional Rhone varietals that will make up Bonny Doon’s lineup going forward. The vineyard is almost ready to generate production-level yields which means there are big changes afoot for Bonny Doon. The iconic Le Cigare Volant, which has been the backbone premium wine for Bonny Doon since 1984, will no longer be a premium GSM. Beginning with the 2018 vintage it will be a Cinsault/Syrah blend designed to be consumed when young and sold for under $20. Going forward, as the Popelouchum Vineyard begins to produce, the premium wines will be from this vineyard expressing the terroir of this unique site—an event that will hopefully rock the wine world.

Oh. What was I saying? Ah, vitality, vitality that was the topic.

Randall began his discussion of vitality with a disclaimer. “The idea of life force is tricky, but minerality is connected, although even that is fraught with disagreement since there is no physical presence of minerals in the grapes.” Yep. Some people think this kind of talk is nuts. By “vitality” I don’t mean anything too metaphysical and by “minerality” we don’t mean that you’re actually tasting rock residue in the wine. It’s a stony, chalky, steely, or saline character that makes a wine more than fruit juice.

“It’s correlated with soils and the available minerals in the soils and the available microflora that can help plants extract minerals”, he notes, which makes his efforts to encourage fungi in his soils directly relevant

“Reduction is correlated too.” Reduction refers to the state of wine that has not been exposed to sufficient oxygen. This creates stinky aromas, especially sulfurous notes like cabbage, garlic, or burnt rubber but also more appealing aromas such as gunflint. Reductive aromas are a natural by product of yeast metabolism and for many winemakers this is a necessary stage in the wine making process because it protects the fresh fruit from early oxidation. “Stinky aromas when young often indicate that the wine will live long”, insists Randall. Obviously, you want these aromas to dissipate when the wine is exposed to oxygen as it ages. “But screwtops intensify reduction and that’s a challenge for super-reductive wines”, he laments.

Acidity is connected. Lower PH wines seem to have more life. So are suspended solids. “Unfiltered wine takes longer to saturate with oxygen”, again protecting the fruit from oxidation.

And finally, vitality requires persistence on the palate which is created by acidity and tannins. “You need some green tannins or hard tannins to drive evolution on the palate”, he says. New world wines tend to have soft tannins and no green tannins, the implication being that perhaps new world wines need a bit more vitality.

As for vitality, “The best wines have it”, referencing especially Domaine Romanée-Conti and Côte-Rôtie.

“In the end, if there is a secret to greatness, it’s using impeccable grapes, ripe and intense, but extracting gently…When you don’t punch down you are allowing subtle nuances to emerge.”

This is a complex topic. Notice Randall speaks of correlation, not causation when discussing the factors contributing to vitality.  There is a lot we don’t know. I’m a bit surprised by the connection to reductive wine making. Orange wine, barrel fermented Chardonnay and the vins jaunes of Jura are oxidative wine making styles and some of these wines have vitality. Many red wines, especially Cabernet Sauvignon, need oxygen to facilitate polymerization and color stabilization so the wine making for some varietals is less reductive. So there are lot of factors involved. As with so much of wine making, it is a matter of how much oxygen and when it is introduced.

Thanks to Randall for taking the time to show us his inspiring vineyard and validating my obsession with vitality. For more on how wine expresses vitality see my monthly column at Three Quarks Daily.

The Controversy Over Minerality

28 Wednesday Sep 2016

Posted by in Food Science, Wine Culture

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soilOne of the most interesting debates in the wine world today is the debate over minerality. Does it exist? What is it? and Where does it come from?

The term “minerality” is relatively new to the wine world. It does not appear in Ann Noble’s influential flavor wheel developed at UC Davis in 1984. It does not appear in any of the canonical wine manuals that have formed our modern wine tasting practices such as Peynaud or Broadbent. It appears in the Oxford Companion to Wine only in the most recent edition. Yet it now appears routinely in the Wine Spectator’s tasting notes.

I find it to be one of the more useful terms for describing wine although I think it refers to many different taste experiences. The burnt matchstick flavors of Chablis, the aromas of wet stone in a good Riesling, the crushed rock aromas of a Willamette Valley Pinot Noir, and the iron filing notes of a Left Bank Bordeaux all can be described as falling under the general category of “mineral”.

But many people, especially wine scientists, dismiss the term as romantic nonsense, in part because, when the term gained currency, it was thought those mineral flavors in wine were the direct result of minerals in the soil being transferred to the wine. And indeed there is no evidence of that. Most minerals in soil have no flavor and although the roots of grapevines take up trace minerals from the soil, these do not appear to be transferred to the grapes. Wine also contains minerals such as potassium, calcium, and magnesium but these are not transferred from the soil and they also may not directly influence flavor. So there is skepticism about whether what we’re tasting has anything to do with actual minerals. On the other hand, we know soil has significant impact on flavor and we cannot rule out an indirect impact on flavor.

Despite this skepticism there is evidence that what we are tasting is real and rooted in features of the wine. Two studies described in this paper by Palacios and Molina are especially interesting. Researchers gathered two tasting panels of professional wine tasters and winemakers to taste wines selected for their minerality. After assessing the wines for their degree of minerality, the wines with the highest levels were analyzed for chemical compounds and the statistical analysis showed that high levels of perceived minerality were correlated with higher levels of free sulfur dioxide, low PH, and high total acidity with a variety of other compounds playing a less decisive, contributory role.

In a followup study, two tasting panels were given synthetic “wines” containing a variety of the previously identified compounds that seemed to effect minerality. In blind tastings using discrimination tests, the tasters were first asked to simply describe the “wines” with no knowledge of the purpose of the experiment. Then, in a second tasting, there were asked to specifically look for minerality. The purpose was to see which compounds produced the most significant perceptions of minerality.

The results:

…the presence of Succinic acid and a low pH combined with high levels of free sulfur dioxide are directly related to the use of the term minerality with a probability of 95%. The presence of Ethylphenols, m-Cresol and metals obtained a significance of 99% to relate as minerality in wine. Finally, with the same probability appears the compound Geosmin. Also the presence of Isoamyl acetate and Thiols is directly related in 99.9% with the emergence of the term minerality for the panel of producers winemakers…

Apparently there are many sources of what we call “minerality” and its perception is the result of the synergistic effect of many compounds as well as the absence of fruitiness which can cover up minerality.

At our session on minerality at the SWE conference conducted by Roger Bohmrich MW there was widespread agreement that wine such as Domaine Patrick Baudouin Anjou “Effusion”, Fritsch Grüner Veltliner “Steinberg”, and Christian Moreau Père & Fils Chablis all exhibited minerality.

Minerality may not be a direct transfer of flavor from soil to wine but there appears to be a consensus emerging that it is a useful descriptor with a foundation in the chemistry of the wine.

The Science of Wine: Some New Data

19 Wednesday Jun 2013

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wine science A couple recent developments in the science of wine are noteworthy. In the never ending debates about terroir and minerality, studies by geologist Andrew Maltman confirm that what we wine yakkers call “minerality” is not “the taste of the soil”. As reported to Decanter’s Andrew Jefford, Maltman claims:

Any mineral solutes present in wine, he says, exist at levels well below the threshold for detection, and if they could be tasted would taste unpleasant anyway; furthermore, as far as flavour creation in wine grapes is concerned, “the real action is up on the vine”, via photosynthetic processes, rather than down in the roots

So references to minerality, stone, or slate in describing the sensory impressions of a wine are metaphorical and not to be taken as literal descriptions of wine components.

Wines do take up minerals, geology does matter in determining how a wine tastes, and minerality is a detectable flavor note in many wines, but there is no direct causal connection between the minerals taken up and the flavor of the wine.

But there is new evidence that the shape of the glass does influence the taste and aroma of wine. Palate Press has a comprehensive discussion of this issue. In this experiment:

The sensory team poured the same Gewürtztraminer into five “glasses”: a Zweisel Bordeaux glass, an IKEA white wine glass, an IKEA red wine glass, a standard INAO tasting glass, and an Erlenmeyer flask. Each of these, after sitting for zero or five or ten minutes, was held up against the upper lip of a blindfolded panelist for twenty-five seconds. Panelists then ranked the strength of the aroma by fruity, floral, chemical, alcohol/hot, and total aroma intensity; no resmells. Generally speaking, the Bordeaux glass and the INAO glass tended to emphasize the fruity and floral elements of the Gewürtztraminer, while the IKEA red wine glass emphasized hot and chemical qualities. The IKEA white wine glass ended up somewhere in the middle, and the Erlenmeyer flask data was tossed out (for sniffing, not for the chemical analysis), because the panelists could tell the difference between the thick, rolled rim of the Erlenmeyer and the thin rim of the wine glasses; they couldn’t distinguish between the feel of the other wine glasses by upper-lip touch alone. Likewise, chemical analysis showed significant differences in the concentration of multiple aromatic molecules in the glass headspace; in other words, glass shape alone caused different aroma compounds to emerge into the air (thereby becoming smellable) in different ways.

So the next time your friends think you’re being too fussy about wine glasses you can now show them that effete, geeky, snobbish behavior is sanctioned by science. Which will just make you seem more effete, geeky, and snobbish.