Have you ever gone out for a walk in the forest, and bent down to lick a rock? No, neither have we. And that’s why minerality is such a fascinating topic. Why do we seem to love wines that convey austere, ‘landscape’ flavours? – characters that would be entirely undesirable, except in the prism of a wine glass.
You may have enjoyed our occasional blogs that answer our customers’ ‘Most Asked Questions at Caro’s’. But this is not part of that series because, strangely, nobody ever asks what minerality means. Perhaps our customers are already clued up. Or perhaps they are too shy (or polite) to query us, as we follow a very recent fashion and proclaim the ‘chalky minerality’ of this and the ‘mineral freshness’ of that.
For industry and wine lovers the term seems useful and meaningful – even pleasurable. But for the more scrupulous it is suspiciously vague: here it means a particular effect of the vineyard soil, while there it can resemble a generic wine fault. One moment it means a narrow set of flavours, while the next it’s like a catch-all phrase for any character that is neither fruit nor oak.
That’s why science is fervently dismantling the traditional idea of minerality – and reconstructing it in new, more complex forms. Meanwhile the term continues to swirl and evolve in wine circles…
So to keep us all abreast, this discussion (Part One) is an introduction to the idea of ‘minerality’: what it refers to, how it influences wine experiences and which wines are involved. For those who want to go deeper into this surprisingly controversial topic, please subscribe to this blog – because in a few weeks you’ll be notified of ‘Minerality, Part Two’. In the later piece we’ll dive into the details and, somewhat tragically for wine lovers, take a look at the compelling, combative science.
The term minerality is most often used where a wine has ‘raciness’ and acid ‘zing’ – refreshing acidity, essentially. Qualities of acid are traditionally seen as similar but distinct from the mineral effects. But the impression of bracing, stoney freshness – especially in cool climate whites – means the sourness and cutting feel of acids may seem inseparable from what might be called the wine’s ‘minerality’. In flavour terms, such whites may be mineral because of a smack of licked-steel or licked-stone freshness ‘streaking’ through the nose and palate.
Mineral ‘tension’ might be another way to describe this – an effect in which austere flavours and ‘prickly’ or ‘nervy’ acidity contrasts sharply with the fruit. The term ‘tension’ can also apply because the effect can seem to hold the wine on its feet, preventing the drinker’s palate from, as it were, flopping into the softer armchair of the wine’s ripeness and body.
But while many whites are ‘mineral’ because they’re lean and clean, others can be the opposite – mineral because of certain kinds of richness, weight or presence. An oily texture can feel ‘mineral’, for example, especially if accompanied by metallic or kerosene notes.
As we have seen, the foremost qualifiers of minerality are often geological terms like chalk, slate, steel, salt, and wet stone. But it also extends to a diversity of related terms often associated with minerality – such as earth, oyster shell, kerosene/petrol, oil, and licorice.
We have already touched on the lightest and most traditional – effects that resemble the purity of licked metal or stones. New Zealand Sauvignon and Riesling can have it, along with their French archetypes. But it also has complex and nuanced forms in the steely, stoney and/or flinty minerality of many white Burgundies (for example the gorgeously serious Rully from Bouchard).
It can be strangely exciting and ‘bracing’ to taste such licked-stone characters. (Perhaps the drinker’s body goes into a subtle state of shock, the nervous system unsettled about why the tongue is touching sword-steel, or why the taste buds are apparently buried in the bedrock.) What a strange pleasure – to taste the most unyielding, cold and flavourless objects in the world!
But whatever the origin, wines with licked-stone characters can also carry specific flavours and textures – imaginary or not – of the actual vineyard geology. An example of such ‘direct’ minerality would be the perceived mineral nuances of chalk or lime noted in Burgundy’s coolest sub-region, Chablis (such as the delicious William Fevre Chablis).
Indeed Chablis is perhaps the most classic example of minerality. Legend has it that chalky, flinty and/or oyster-shell characters are consistently detected in its Chardonnay wines. These characters are supposed to be a ‘terroir effect’ of the limey Kimmeridgian soils – the region’s ancient sea-shell soils, literally chalky and mineral-rich, which Chablis shares with Champagne and the Loire Valley. Compounds from the bedrock and deep subsoil are supposedly taken in by the vine’s deep roots to find their way up through the plant into the fruit – and the finished wine.
Other whites too can share this chalkiness. In some it can be both a flavour and a chalky texture – like the superb Argyros wines from Santorini, or the elegant Felici Verdicchio from Italy. Or it can sometimes be solely a texture, with no obvious flavour – like the fine chalk-dust, barely perceptible granularity in wines such as the Cotes du Rhone Blanc from Janasse.
In addition to flinty/chalky notes, whites from Chablis and the Loire Valley might present a slight salty or ‘oyster shell’ minerality. This enhances their natural kinship with seafood, as you can imagine. But the classical restraint of many French wines mean they are rarely as maritime or salty as, for example, coastal dry Sherry from Spain (such as Lustau’s Manzanilla), or even less so the rather unwashed evocation of seaside smells found in some of Europe’s other distinctive regionals such as Falanghina from Italy’s Campania.
A salty mineral character from a more land-based source is said to be emitted by the volcanic soils of Sicily’s Mount Etna. (Readers of Part Two will learn why our own Etna wines are, however, rather cleaner and less ‘volcanic’ examples). Mount Vulture in Campania seems to have much the same sulphuric effects on the local wines – notably the mineral and savoury Aglianico Del Vulture red, the complexities of which have earned the nickname ‘Barolo of the South’.
Vaguely saline characters take us on a further side-step toward licorice – whether salty or perhaps slatey licorice (i.e. derived from slate soils). Slate licorice character is often associated with red wines from black slate soils of Spain’s Priorat region. But a similar licorice minerality can seem to touch many wines, including occasional Rieslings from Germany’s steep hillsides – where both slate and volcanic soils are common.
To complete the survey of sulphur/salty notes we arrive back at something we referred to earlier as ‘flint’. Most often appearing as something between ‘struck-match’ and salty rubber, many wine experts consider such whiffs to be a subtle – and sometimes celebrated – effect. But if too strong it is nonetheless labelled a wine fault. ‘Reduction’ is caused by lack of oxygen during wine-making, probably due to vessels that are too air-tight (in a way that old oak barrels usually aren’t, but many modern vessels are). Sceptics of minerality will enjoy reading Part Two, where claims of flintiness in wine are made to seem rather…questionable. But traditional wine culture considers struck-match flintiness to be a classical form of ‘terroir’ minerality, associated with vineyard soils containing flint (aka silica or silex).
With flint we have circled back to the beginning – from stoney to salty and back to flinty – so let’s pause and notice that types of minerality can be closely related, sharing characteristics and blurred boundaries. By nature quite indefinable, the metaphors of minerality often touch and merge. So tasting minerality is about spectrums or constellations of characters, incremental distinctions across terms. In other words, you have to be flexible. (There go the scrupulous ones, getting anxious again).
We started with the light and fresh, classical forms of geological minerality. But to complete this journey we must step up through a couple of further, slightly more ‘grey-zone’ types.
The idea of ‘earthiness’ forms a constellation with minerality in wine. It is occasional in whites but often in reds – notably red Burgundy and other Pinot Noir. A wonderful example might be the elegant Waimanu Pinot Noir from The Boneline – beautifully ethereal, earthy-mineral layers support the fruit and make it an expression of the best in Waipara Pinot. In many such wines, the character of earthiness can seem quite subtle. But from a chemical point of view it is deceptively so – which may explain how it is frequently picked up and talked about by non-experts. Because as Part Two will explain, science tells us that one compound that produces earthiness is extremely aromatic, being perceptible even at very tiny trace quantities.
In addition, earthy qualities in certain wines may seem amplified because the effect shares blurry distinctions not only with other mineral characters, but with organic and ‘savoury’ flavours also present – like ‘forest floor’, truffle or mushroom, oak, and leather. These flavours are different but similar to minerality.
In less fastidiously clean wines there may also an earthy funk caused by Brettanomyces or ‘brett’ infection. Brett dulls the fruit impression while introducing mouldy cardboard or ‘barnyard’ (i.e. faecal) aromas. Love it or hate it, such ‘dirty’ wines may be called ‘earthy’ by some – but this is not to be confused with clean, defined, ‘mineral’ earthiness.
Texture too can play a role here. We often hear the term ‘earthy tannins’ because the bitter, drying, granular effect of tannins can augment an earthy impression (almost as if there were some actual earth dissolved in the glass). Indeed the tannins of some wines invite mineral descriptors that are geologically specific. Gamay Noir in Beaujolais reds, for example, have a prized dusty-mineral finish that may manifest as firm, granite-feeling back palate in some sub-regions, or a softer and more chalky texture in others.
Finally the most overbearing mineral association in wine is the heady kerosene-like overtone of some aged whites. This character can add a peculiar sense of power and dignity to wines from more more acidic varieties, like Chenin Blanc, some Semillon, and most of all Rieslings – especially those from Australia’s Clare Valley. While the relevant compound can be increased or decreased by certain conditions, it is usually understood as an effect of bottle aging rather than minerals in the vineyard soil. In fact, kerosene notes may be called ‘mineral’ simply because there is no more accurate term for such a peculiar, petro-chemical smell.
So the notion of minerality is broad – oh yes! But most forms have at their core a ‘myth’ about the importance of soil.
Why do we enjoy the smells and tastes of a bare landscape? Actually, only a philosopher could answer that one – and even then only by leaning on metaphors. But this connection between subsoil and flavour is a key element in wine tradition, and specifically in the very French/European culture of ‘terroir’ – the wonderful idea that wines preserve a sensory record of the time and place in which they were produced.
Science has burst this bubble on multiple points, dismissing the old idea of minerality as simplistic and literal – nothing but a romantic tale, or venerable folklore. (Or a culture, if you prefer.) The details of this destruction are in Part Two. But on the positive side, science has also shown that our perception of minerality (what we’re referring to and what we taste) is consistent and predictable. In other words, ‘minerality’ does indeed mean something – it’s just not clear what or why. All we know is that these ephemeral and obscure characters have became a source of much refreshment, character and interest in wine.
So for now let’s just say that minerality is real and, to the continued health of the idea, let’s raise a glass of Chablis or Awatere Sauvignon Blanc. For we may not know what it is – but we know we like it!