There Is No Such Thing as Minerality

Or if there is, the Seminar on Minerality organized by the Institute of Masters of Wine failed to find it. The seminar had a great format: first three speakers presented views of minerality from geological and sensory perspectives; then there was a tasting to assess minerality.

I thought it had long been established absolutely beyond contradiction that, whatever minerality might be in wine, it is not due to uptake of minerals from the soil, but geologist Alex Maltman presented several amazing examples from supposedly respectable sources, such as textbooks, where minerality was attributed to soil elements. So it’s maybe worth repeating that this cannot be: measured quantities of trace elements in wine are far below the threshold for taste. Any effects they have on taste must be indirect.

Debunking another myth, Alex pointed out that insofar as soil might influence any uptake by the plant, it’s the surface that is important: deep roots basically take up water, but it’s the roots towards the surface (or at least in the top meter) that take up nutrients. So all those efforts to drive roots deeper, all that pride in the deep roots of old vines, if not misplaced is at least misunderstood. Deep roots may be important in ensuring water supply, obviously this may have a big effect on ripening and therefore quality, but if nutrient uptake were to have any effect on character, it would come from the surface. (And if there were any such thing as microbial terroir, which I take leave to doubt, it would be superficial.)

You might even question whether minerality relates to the actual character of wine (that is, some chemical or physical property) or is due to some form of association (think of Proust’s madeleine). Wendy Parr’s experiments show that it’s associated with people’s descriptions of other properties in the wine, and so does at least appear to result from what they actually smell and taste.

But there is the most extraordinary range of characteristics associated with “minerality.” Jordi Ballester finds that people who call Chardonnay mineral fall into three groups, loosely characterized as: flint/seashore, oaky/smoky/wet dog, and floral/apple/banana. Personally I’m pretty much in the first group, I can understand the second group (sort of), but the third leaves me totally mystified as to what people mean by minerality. However, Jordi points out that whereas producers in Chablis have a relatively clear idea of what they mean by minerality, consumers show little agreement, to the point at which he is not working with consumers any more.

We blind tasted 5 Chablis and 10 Sauvignon Blancs and were asked to assess minerality for each wine on a scale from 1 to 10. I got a completely different view from participating in the survey from reading papers on the subject, and at the least a much better idea of the limitations. Here was a group of around a hundred professionals, but the assessment of which wine was the most mineral was totally dispersed in each set, not quite equally, but certainly showing no consensus.

I wondered whether this was because none of the wines (to my palate) actually showed strong minerality. I use minerality as a descriptor quite often, but I wouldn’t actually have applied it to any of these wines. I also wonder whether Sauvignon Blanc is a good variety to test, because its varietal typicity can be so strong. I was surprised that there wasn’t an internal control, that is, the same wine included twice: at a minimum, in a research setting I would not accept the validity of any study that didn’t show that individual tasters rated the same wine reliably—otherwise all we’re looking at is scatter in the data.

So is minerality at all useful as a descriptor? I know what I mean by it, but evidently this is not necessarily the same as anyone else means by it. There is an amazing panoply of components that have absolutely no taste but that are used to describe the flavors or smells of wine: graphite, flint, rocks, iodine just to start with. Where a smell is ascribed to an odorless compound, it may come from association—the solvent used in tincture of iodine, or the aromatics released by sparking flint, for example. I don’t think it would matter particularly if iodine was used as a descriptor, even though the smell is not actually of iodine, if it was a reliable descriptor.

The problem is that minerality is anything but reliable. There is a cynical view (people were too polite to express it directly) that minerality is nothing more than a marketing ploy. I don’t accept that, because I do find it useful in my tasting notes, although maybe what I really mean is gunflint or smoky. I guess we end up with the old philosophical question of how we know whether any two people smell and taste the same thing, which of course implies that tasting notes are useful only for the person who wrote them.

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15 thoughts on “There Is No Such Thing as Minerality

  1. I agree with most of what you write. The aroma I most associate with minerality is the smell of a running water over stones, say in a babbling brook, or the smell of wet pavements after a brief rain shower on a hot day, But again it’s the agent (in this case water) that releases these aromas not the stone itself, which would have an all but neutral aroma.

  2. Thank you for this. I no longer have to be ashamed that I have no clue what this elusive “minerality” actually is, since it’s applied to so many different wines.

    • The connection with reduction is elusive. I have always thought that reduction is associated with minerality (and certainly a wine in oxidative style does not show minerality). But the paper you refer to by Denis Dubourdieu was a one-off: it’s never been followed up on, there’s never been any subsequent validation. The mercaptan he implicated seems to be associated with smoky aromas, so I suppose it might be regarded as involved with minerality to the extent that you regard smokiness as part of minerality, but that seems a bit tenuous. So there really is no scientific basis for minerality at the present, assuming of course that you can define it to begin with.

  3. Perhaps minerality for some people is associated with sulfur compounds; and a lack of other flavors in the wine accentuates it? For some people, they seem to find this characteristic in red burgundies from the top of the slope with poor thin soils. A winemaker friend once commented that, to him, whites with this characteristic seems to age better. Perhaps these wines tend to be more austere so maybe the sulfur used would be more noticeable? With Chablis in the old days, the excessive amount of sulfur used gave it a gun flint smell, and I associated this with minerals. I believe mercaptans are also mostly volatile sulfur compounds, perhaps this is why some people find minerals in reductive wines?
    Many years ago, I went to a tasting of whites of Germany imported by Therry Theise. He had a group of wines which he labeled as “terroir or “minerals”, and I swear I felt as if I was sucking on stones. Perhaps they reminded me of a brief rain on a hot pavement, as another commenter mentioned. Needless to say, it made quite an impression on me. I wish I could taste them again.

  4. I’ve always found Clark Smith’s views on minerality interesting and have yet to come across anyone else talking about minerality in the same way. This is a brief snippet of what he says in his book Postmodern Winemaking:

    “Just as titratable acidity is sensed on the palate as a flow of protons discharging from binding sites on weak acids, minerality may very well be a flow of electrons released from various metallic elements of the periodic table as they move to higher valences.”

    Of course this only deals with how minerality tastes not how it smells. Are they two different things?

    • In my opinion, the disagreement on what minerality means makes it impossible to approach any scientific basis for it. Clark Smith’s position involves an assumption that what we perceive as minerality in fact relates to metal ions in the wine. I think that is unlikely as there isn’t any evidence for significant differences in metal ion contents that affect flavor; at all events it is premature.

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  6. My lil opinion is that somehow, certain chemical elements in the water uptake, generate certain flavors post fermentation that mimic those things we call minerals, or more accurately, chemical elements. Since we know only a little as to why fermentation creates the esters and phenols etc that we perceive in our senses, there is stuff going on, but we just don’t know the pieces of matter that are involved.

    • Even if this were true, the effects on flavor of anything taken up by the roots must be indirect, so if they do change the behavior of yeast and affect the compounds that are made by fermentation, why should they resemble what we think of as minerality? It’s a conundrum.

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