Minerality in wine

Various online wine forums were buzzing with discussions on minerality a few weeks ago.  I have taken part in the discussions on the UK Wine Forum and WLDG, and Jancis Robinson also joined in with a contribution in the FT on the subject.  What sparked it all off was a survey designed by Graham Reddel for the WSET Diploma.  If you think you might want to take part in the survey, it is probably best if you click on one of the forum links above to get Graham’s introduction as well as the link to the actual survey.  If you are going to, please do it now – before your mind is polluted by what I have to say on the matter!

I found the discussions fascinating, and after it all died down I felt a strong need to pull together my own thoughts on this broad-ranging subject.  This is the result…

A bit of history

I find it interesting that the use of the word minerality in tasting notes, is a relatively recent phenomenon.  The chart below shows its rise in usage in CellarTracker notes.  Before 1999 there were only 3 usages: 1 in 1989 and 2 in 1998.  I did not include those in the chart because they were early days for CellarTracker, and too few notes to draw conclusions.  After 1999 the trend is clear – the term was used very little before 2002, and then between 2002 and 2004 it really took off.  It seems as though the increase in usage is perhaps now tapering off, with the first 4 months of 2012 showing a slight drop.

Mentions of the word minerality per 1,000 CellarTracker tasting notes

A search in the wine literature, mainly books in my “library”, also leads one to the conclusion that minerality is a new descriptor.  I have checked in all of the following to a greater or lesser extent, using an electronic search in some cases, indexes and thumbing through pages in others:

Peynaud, The Taste of Wine, 1983
Noble, Aroma Wheel, 1984
Robinson (Ed), Oxford Companion to Wine 2nd Edition, 1999
Schuster, Essential Winetasting, 2000
Robinson, Wine Tasting Workbook, revised 2000
Broadbent, Winetasting, revised 2002
Broadbent, Vintage Wine, 2002
Jackson, Wine Tasting – A Professional Handbook, 2002
Lehrer, Wine and Conversation, 2009
Stevenson, Sotherby’s Wine Encyclopedia 5th Edition, 2011

In all these sources, here is what I could find on minerality.  Michael Schuster mentions it only in his glossary: “Suggestions to both nose and palate of stones: slate, granite, chalk, schist and so on, Especially in wines from the Loire, N Rhône, Bordeaux, Burgundy, Douro, Mosel, Tokay etc.  Fanciful?  Maybe, but real enough to many wine tasters; see TERROIR, p 129”.   And Jancis Robinson has an entry for “minerally”, also in the glossary only: “Smell of assorted minerals and a common component of fine Cabernet and Riesling”.  She put an asterisk by the word to indicate it is her own descriptor and not commonly accepted.  And that is it!  OK, earthy, sulphurous and petroleum notes are widely discussed, but those in my view are different to how most people use the term minerality.

I would hope that any modern book on winetasting, or wine in general, would discuss the concept of minerality as the term is now used so widely.  Goode and Harrop’s book of 2011, Authentic Wine,  has a section of 4 pages devoted to minerality, and it gets several other mentions in the book.

So what happened at the start of this century to kick-start the concept of minerality?  It seems Michael Schuster was literally ahead of the curve (as defined by CellarTracker) with his description in 2000.  Jancis Robinson too, albeit with a slight variant on the word, particularly if the same glossary also appeared in the  Wine Tasting Workbook’s precursor of 1983.  My guess is that a number of professional tasters started referring to minerality around 2000 and it took off from there, but I would love to know more precisely how it happened.

What does the recent conversion to minerality mean?  That’s another difficult question.  Have people suddenly discovered an aspect of wine they previously were oblivious to?  That seems unlikely to me.  A much more likely explanation is that they are giving a new name to the same nose and palate experiences.  Or the idea of minerality is perhaps one of the more fanciful wine descriptors that does not mean anything very precise when you analyse it, and it is mere fashion that dictates that modern tasters write about minerality – rather than, for example, a wine being like a pretty girl with a white dress dancing in a meadow.  I think its rise is linked with another concept gaining traction with wine writers: terroir.  When asked most people will say that it is naive to made a direct link between minerality and terroir, but when enthusing about a wine it seems it is all to easy to be able to taste the slate in which the vines were grown.  However it happened, once the concept of minerality was established it took on a new air of reality.  The question for many people now is not “what does minerality mean?”, but rather “does this wine have minerality?” and “what type of minerality does it have?”.

But personally I am stuck at the “what does it mean?” stage, and I think it is an important question – one I am going to address in the rest of this essay, er… I mean, blog post.  Please indulge me.

Definitions and facts

Leaving aside for a moment the sensations they invoke on the nose and palate, what exactly are minerals?  In common winespeak, my impression is that there is a loose definition and a tight one.  The loose definition includes pretty much everything that is not animal or vegetable, e.g. sulphur, petrol, salt, steel and graphite.  The tight one includes only rock-like materials: pebbles, slate, granite schist and chalk.  Neither of these corresponds particularly well to any of the definitions accepted by scientific bodies, but let’s not get too hung up on that.

Old vine growing in Douro schist

If we are talking about rocks only, we should be aware that very few rocks taste of anything.  The main common exception is halite – rock salt.  Geologists commonly stick rocks in their mouth to identify them, mainly by texture and hardness, so they should know.  But many people insist that rocks do have flavour, and I would not deny anyone’s experience.  I would just suggest that it may be some organic matter on the surface of the rock that they are smelling or tasting – geologists doubtless lick newly broken surfaces.  In a sense it does not matter.  But in another sense it does, because if it is organic matter on the surface of the rock, what they perceive as granite could be actually totally unrelated to the stone itself – if a bit of slate were found in the same environment it might taste the same.

Another possible explanation for the claimed taste of rocks might be synaesthesia caused by their texture and temperature.  I know of no firm evidence for this particular type of synaesthesia but from everything I have read about synaesthesia and taste, particularly the work of Charles Spence who has recently published a few articles in The World of Fine Wine, it would not seem at all surprising.

Finally, a few random facts:  1) Broadening things out from a consideration of rocks, metallic smells are now known not to derive directly from the metals, but from interaction with oils from the human body.  2) Pencil lead contains clay as well as graphite, so if your wine tastes like pencil lead it is quite possible that it is the clay you are thinking of.  Medical grade charcoal tablets are probably a better model for how carbon tastes, and as I remember them they are very neutral in flavour.  3) The chalk sticks you use to write on blackboards are not chalk, but gypsum.   All this may not be hugely important, but I think it does show that we need to be a bit careful about the words we use as not everyone will have the same associations, and certainly the link between the words we use and the actual rocks and minerals is not at all straightforward.

Another thing worth noting is that wine does contain metal ions, which count as minerals for some people.  Indeed, one can go further and demonstrate that the metal ions found correlate with the vineyards in which they were grown.  Here is one study that has shown that, and I am sure there are more.  But this seems to be a bit of a red herring when it comes to the perception of minerality in wine, as the concentrations of metal ions are so low as to be undetectable, at least at the conscious level.  And if you could detect them you would expect a salty sensation, which is rarely ever reported in wine.  Just under 0.3% of notes in CellarTracker use the words salt, salty or saltiness.  I understand there is some doubt as to how these metal ions get into the wine.  Through the vine roots is certainly one possibility, but another plausible explanation is that it is through dust on the surface of the grapes.  So if this is the cause of minerality in wine, and I doubt it very much, there is a possibility it can be easily manipulated!  Also, before we get too excited by metal ions in wine, and wanting more of them, we should remember that heavy metals (which include some of the minerals in the study linked to above) are poisonous, and a few years ago heavy metals in wine raised health concerns in some quarters.

What minerality means as a tasting descriptor

In this section we move beyond fact, but it is not really opinion either.  It contains assertions – not my assertions, but those I have heard from other people.  Most of them came from online wine forums, and some can be found in the forum links at the top of this post.

Some people seem to use minerality as a general class, implying that with experience and discrimination different types of minerality within the class can be identified.  I think the types of minerality within the class are implicitly specific rock types, but you only rarely see these figuring in tasting notes. Often, however, minerality itself, rather than as a general class, seems to mean something specific to tasters .  But that specific something varies a lot from person to person.

For some it is more of a texture than a smell or taste.  I find it easy to relate to that idea.  Some wines have a chalky texture, which I would attribute to a type of astringency.

Some compare minerality to sucking pebbles, which seems to me to imply a taste or tactile sensation rather than aroma, though you can get minerality on the nose as well.  Others claim to get a taste from licking rocks that is akin to minerality in wine.  I think that must be due to surface contamination or synaesthesia as mentioned above.

The taste of iron is another thing often referred to when discussing minerality.  This seems to be a real phenomenon, mentioned above in the context of metallic smells (see the link in that bit), but it seems to me to be unrelated to other types and explanations of minerality.  Perhaps iron would be a more straightforward descriptor.

A specific example of minerality is flint, often used to characterise Pouilly Fumé.  More correctly it is gunflint, or struck flint, that is associated with the wine, and that predominantly has the smell of sulphur, also technically a mineral.  That brings me on to the theory espoused by some, that minerality in wine is mainly due to reductive sulphur-like odours.  I am not sure how much evidence there is for this, but it is certainly an interesting idea.  The sulphur explanation certainly seems to be a better explanation for the gunflint character of Pouilly Fumé than bits of flint in the vineyard.

Then there are the fanciful descriptions of minerality like “a stream running over wet pebbles”, or “rocks at the seaside”, or “hot rocks in the desert”.  I can relate to some of those ideas, but would hesitate to use them as examples of minerality – I have never inhaled country smells and thought I was sensing minerality.  I also rarely, if ever, get those impressions on a wine – but maybe that is just me.

Others are convinced that minerality is an obvious and well-defined property of a wine – one that is even more obvious than acidity for example.  I find that very difficult to accept.  Acidity can be measured scientifically and that measurement correlates, albeit imperfectly, with our perceptions.  The same can be said of many other descriptors used in winetasting, like the various fruit aromas for example.  But minerality has no clear physical or chemical basis as far as I know.

In some cases people say they can taste slate or chalk because the vines grew in terroir comprising that rock.  I am never quite sure what they mean by that.  Is it that they literally think the wine tastes of slate, or is it rather that it tastes like other wines derived from vines grown in slate?  I am not even sure they always care to distinguish between the two.

How I might describe minerality

The concept of minerality is not something I particularly relate to, and I use it only rarely in tasting notes when I think I can identify something of the nature that other people talk and write of.  So, assuming that I do not have an inability to smell and taste minerality, I started to wonder how I describe what other people call minerality.

Looking at the list of wines that are supposed to show good minerality, the first thing that springs to mind is acidity.  Now I know many say acidity is very different, but nevertheless the correlation between the two seems strong.  I am wondering if some are reluctant to say a wine is acidic because that sounds negative, so minerality is almost a euphemism.

Another thing I was wondering about was whether minerality describes a wine that lacks of other things, namely fruit, but which is still good and fresh, and has subtle qualities that are difficult to describe.  In these case I would probably comment on the lack of fruit or say the wine was lean or austere, but otherwise give the wine a good score.

I also tend to describe some good wines as angular, edgy, or having hard edges.  I see wines more in these geometrical terms, than in terms of minerality, but I suspect the two are related.

Well-delineated is another possibility.  For me this is a very positive term, and a sign of real class.  Cheap wines are often soupy, in my terminology, where all the flavours merge into each other. Well-delineated wines have a few, or several, very distinct flavours.

To the extent that it is true that minerality is caused by sulphur-like odours, the chances are that I would condemn them as sulphurous, rubbery or reductive.  I think I am quite sensitive to these odours and usually find them quite unpleasant – I object to them a lot more readily than other tasters.

Note that I am not claiming my terms are any better than minerality.  Indeed, I am a little embarrassed by some of them, but they are meaningful to me.  Am I getting at all close to understanding minerality, I wonder?

Conclusion

You can doubtless detect a strong note of scepticism here, and I am indeed sceptical.  But more important than my scepticism, is my overall observation that people mean very different things by the term minerality.  So even if the term is meaningful to an individual, it serves little purpose when used in a tasting note designed to communicate an impression of the wine.  Writer and reader may feel that communication is taking place, but often they will be wrong.  If you don’t want communication, but think of tasting notes as a prose art form, that is of course a different matter, and I will leave to your own literary devices.

I must also admit that sometimes my scepticism slips into cynicism.  I don’t doubt that many tasting notes are well-intentioned, and their writers are earnestly trying to express their perceptions, but equally I fear there are unfortunately a lot of pseuds in the wine world, and those who are out there to follow fashion, impress, and sell.

As with many other vinous issues, my mission with minerality is to understand the earnest and well-intentioned – and to flush out the pseuds and quacks.  I also don’t want to rush to judge in particular instances, and definitely don’t want to upset the good guys.  If you have made it to the end of this post, you are definitely a good guy, and have nothing to fear 🙂

Author: Steve Slatcher

Wine enthusiast

3 thoughts on “Minerality in wine”

  1. I thought I should fess up that I was in a bit of a hurry when I calculated the CellarTracker statistics and could have done it better. For each year, the rate I plotted was the number of tasting notes mentioning the word “minerality” divided by the number of notes for vintages between 1900 and 2011. If I had done a better job and included non-vintage wines in the divisor, the rate would have been slightly lower for all years – but the overall trend would doubtless be the same.

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