Nelson's special Moutere Clay provides some of New Zealand's only dry grown chardonnay and pinot noir. Photo: Michael Glover.

'Minerality’ is a made-up word. A faint feign of fake falsity and fraud. Forged in the fires of flamboyant wine writing as only (relatively) recently as the late-1980s. Indeed, the term was popularised even more recently, over the past decade or so. It is an artificial word that is often used – or, perhaps, more to the point, misused – exhaustively, and almost exclusively by sommeliers and wine writers to help describe a wine that is, supposedly, instilled with a perceived sense or feeling of … well, minerals. And yet, according to the science, this is literally impossible. Rocks don’t have a taste. Moreover, the constituent geological minerals that bond together to form rocks don’t taste like anything either.

“Rocks don’t taste. I mean, it’s a scientific fact. It’s demonstrable. And there are a great many reasons why they don’t taste,” says Dr Alex Maltman, Emeritus Professor of earth sciences at Aberystwyth University, in Wales. “For starters, for things to have a taste they need to be dissolved. They need to be liquid. This means they need to be extremely soluble, like salt or sugar.

“Rocks will dissolve, eventually. But, even limestone, which is really soluble, takes centuries, millennia even, to start dissolving.”

It’s disappointing, isn’t it? I should know; I’m one of those wine writers.

The Wait Vineyard.

“You can test it for yourself,” Professor Maltman continues. “Try licking the fresh surface of a rock. It must be fresh, which means you’ve got to smash the rock so that you get a new, un-weathered, unadulterated fresh surface of the rock itself. Lick it and you’ll see that is doesn’t taste like anything.”

Picking up some pebble from the garden won’t do, either. Its surface will have a taste, though not of the rock. What you would taste is organic matter; the substance that is veneered onto the surface of the rock. Microbial stuff, like bacteria and faint traces of mould or algae. Not the literal rock.

“I’m arguing that minerality cannot literally be the taste of the soil, of the rocks and their minerals, because vines are very selective regarding which positively charged elements they take up,” Professor Maltman explains. “These elements are called ‘cations’, and they’re made up of certain metals – potassium, calcium, magnesium, and iodine.

“These are the nutrients that the vine needs in order to grow. Vines are actively selective in taking up the optimal amount of these particular cations,” he says.

A 2018 journal article, co-authored by Professor Maltman, explained that a vine’s nutrient minerals come largely not from the vineyard geology, but from the soil’s organic component, humus. Humus is the dark material that forms in soil when plant and animal matter decays. It exists right at the surface, where most of the fine feeder roots reside, rather than within the strata of weathered rock and bedrock found below.

Oh dear. It’s not looking good for advocates of any literal interpretation of the made-up term minerality.

Vignerons Schmölzer & Brown.

“I don’t have an issue with the current scientific standpoint, which asserts that it’s impossible to observe or quantify the passage of certain minerals from a soil or rock type through the vine’s tissues and hence into the subsequent wines made,” says Beechworth viticulturist Tessa Brown, of Vignerons Schmölzer & Brown. “And I don’t find the tenant particularly threatening to the validity of the concept of terroir. Insofar as a group of wines made in one area can express a commonality of taste. Thankfully, science, at its core, holds space for what it doesn’t yet know.”

UK Master of Wine Alex Hunt agrees with Brown. “Minerality is something different, which, I think you can arguably taste in wine, but which Maltman concludes is not actually caused by the literal presence of minerals in the liquid.

“With this, I agree wholeheartedly. More likely is that minerality is an emergent property of low pH and/or high acidity, a certain profile of tannin (even in whites), perhaps a handful of reductive/mercaptan aroma compounds, too, as well as a whole host of other things to which we haven’t yet cottoned onto.”

When a winemaker, a sommelier, or indeed a wine writer writes down the word ‘minerality’ in their tasting notes, they don’t mean the literal taste of rocks or their essential mineral ions.

More often than not, minerality is used – just like most, if not all wine tasting terms – as a descriptive metaphor to help articulate certain sensations one notices. These are aromas, flavours and textures that a particular wine may be composed of. Just as there is literally no strawberry or cherry, melon or peach, florals or blossoms added to a wine ferment, of course there are no bits of slate or flint or chalk or stone added either.

A wine may be described as ‘crunchy’ or ‘chewy’, but it isn’t either of those things. You can’t really taste ‘elegance’, ‘freshness’ or ‘finesse’. Nonetheless, you can feel the notion of these qualities within a wine.

Alex Hunt.

“I regard minerality as a presence; a feeling or sensation that usually accentuates a sense of tension in a wine,” says Vanguardist winemaker, Michael Corbett. “Minerality adds another layer to a wine’s quality. I’d go as far as to say that for a wine to make it to the next level, to be considered a great wine, it would need to have a degree of minerality present.”

Could this just be the acid talking? Oftentimes, a wine that possesses a sense of tension or vibrancy tends to also have a good amount of natural acidity – an idea that can be referred to interchangeably with minerality.

“The chardonnays I made while at Bannockburn were, I think, interesting examples of minerality,” Mammoth Wines winemaker Michael Glover explains. “I worked very hard to bring some restraint to the style, which involved changing the cooperage, and also picking a lot earlier. I noticed that as I picked earlier and earlier, the flavour spectrum of varietal chardonnay changed from ripe peach and mango to leaner characters, such as citrus fruits, like lemon. There was a point around 20˚ Brix (11 Baume) that the varietal aspect almost disappeared.”

See what I mean?

“The fruit was not unripe, but it wasn’t ripe either,” Glover continues. “There seemed to be a window, just after unripe that had these characters of oyster shell and river stone, right before the more familiar varietal characters kicked in.”

Acidity is the illumination of all food and wine. Perhaps, minerality is just acidity in disguise? It wouldn’t be the first time a synonym was used or applied to describe or detail the sensation or feeling of tasting a wine.

“The sensation can feel quite different, depending on the wine,” Corbett adds. “In white varieties, it feels like another layer that sits between acidity and the fruit. Chablis is an obvious one, with its chalky, oyster shell characters. That, to me, feels like minerality. In reds, I see it in wines that have a lot less primary fruit, with lower alcohols.”

Or perhaps minerality is just a lack, or absence of fruit? Jancis Robinson MW said as much in a discussion on minerality with fellow wine writer Jamie Goode MW, in his excellent book Wine Science: “In general, I try to use [minerality] as little as possible and be a bit more specific. ‘Wet stones’ is a favourite tasting note of mine.

“But, when a wine definitely doesn’t smell of anything fruity, vegetal, or animal, I might use it.”

Winemaker Michael Corbett (pictured) agrees the meaning is hard to pin down.

Me too, to be honest. Oftentimes, the less I perceive fruit, the more I perceive minerality; although, I don’t always term it that way.

Glover says he gets around the problem like this: “There are a number of descriptors I use that I would classify as having minerality. Like ‘flint’, ‘oyster shell’, ‘chalk’, even ‘saline’ springs to mind. There are also certain textural qualities that seem to sit well within a note about minerality, such as ‘lean’, ‘restrained’, ‘subtle’ and ‘tight’.”

How about ‘gunflint’, ‘wet stone’, ‘hot stone’, ‘chalky’, ‘citrus’, ‘tension’, ‘sourness’, ‘reductive’, even ‘bitter’? All are metaphorical synonyms attempting to define much the same thing; minerality.

“Minerality, on its own, is not especially pleasant or interesting. It shines in counterpoint to other characteristics,” says Alex Hunt MW.

“It supplies all sorts of enlivening contrasts to other characters in wine, especially ripe and concentrated fine wines. I think of minerality as a counterpoint to fruit, to opulence, to heft in a wine. It is another layer of complexity. I think, therefore, it contributes both to refreshment and interest, which ultimately are the underlying components of quality.”

Minerality as an indicator of quality? Now, there’s a notion…

Perhaps we’ll never get to the bottom of this most nebulous of wine concepts; minerality. Maybe we should just chalk it up – pun intended – to being best considered as among the ever-expanding family of other obscurely related terms used to define the myriad sensations we all love to write and talk about, endlessly, devotedly, in relationship to wine?

I could think of worse things to spend my time on.