Why I still can’t quite put my finger on ‘minerality’…

Peter Ranscombe goes into full ‘wine geek’ mode with an exploration of what ‘minerality’ might mean when it comes to wine.

FLICK through the tasting notes for bottles of wine and it’s not long before you start to spot patterns emerging.

Pinot noir tends to taste of red fruits like strawberry, raspberry and red cherry, while shiraz or syrah centres around darker flavours like blackcurrant, blackberry and black cherry.

Red wines from Italy are invariably described as having “high tannins”, the same substance found in tea that makes you suck in your cheeks, while decent riesling is rarely found without a comment about its “high acidity”.

Yet there’s one word that’s perhaps a little harder to lay a finger on – “minerality”.

Used most frequently – but by no means solely – to describe white wines, it’s often linked to “stony”, “flinty” or “chalky” flavours.

But what do winemakers and wine writers mean when they mention “minerality” in their tasting notes?

That was the question posed during a discussion in London last week hosted by wine writer Jamie Goode and Steve Daniel, head of buying at wine importer Hallgarten & Novum.

Getting the science right

Goode began by pointing to the difficulties involved in communicating about the “taste” of wine, including how much our perceptions of wine are affected by the words we use to describe it.

He acknowledged criticisms of the term minerality, especially by Alex Maltman, emeritus professor of earth sciences at Aberystwyth University, who has explained that any minerals that have gone from the soil through the vine to its grapes and then survived the fermentation process to end up in wine are present in such small quantities that they cannot be detected by human taste buds.

“Part of the problem is this confusion between the notion of ‘mineral’ – like a rock – and the 14 or so dissolved ‘mineral ions’ that plants need, which are taken up by the roots from the soil,” said Goode.

“Here, we’re talking about two very different things, which have got confused together.”

He quoted soil microbiologist Lydia Bourguignon as saying: “Minerality is the perception of the rocks in the soil by the palate”.

Goode added: “If you take that literally then it’s impossible for that to happen, but people assume that – when we’re talking about a ‘mineral taste’ in wine – we’re being literal, yet if we talk about a wine being ‘leathery’ or having ‘cherries in it’ then we’re not literally saying that the wine has cherries or leather in it – so why can’t we use ‘minerality’ as a sort of picture language?”

For me, Bourguignon’s inclusion of the word “perception” is key – most winemakers or wine writers aren’t claiming that particles of limestone or flint or gravel have made their way into the glass, but instead are coming across a taste or a texture that they’re describing as “minerality”.

‘Reductive’ reasoning

With those definitions out the way, we can begin to explore the deeper question – where does that “minerality” taste or sensation come from?

That’s a more difficult question than it sounds; a wine’s aromas and flavours are described as strawberry or blackcurrant or peach because it contains the same chemical compounds as those fruits, shown by experiments such as those carried out by the Australian Wine Research Institute to isolate “rotundone”, the spicy black pepper note found in much of the country’s cool-climate shiraz.

With “minerality”, it’s a much more complex picture, with Goode and Daniel kicking round concepts such as acidity and reduction as they tasted their way through samples of 11 wines from Hallgarten’s portfolio, which were selected to show different aspects of minerality.

Daniel pointed to one school of thought suggesting that reductive wine making – in which the wine is exposed to as little oxygen as possible during the production process – and the associated build-up of sulphide compounds could lead to the perception of “minerality”.

His examples included the 2018 Idaia Dafnes Vidiano (£15.05, Drinks & Co) (2017: £11.24, Novel Wines; 2016: £13.95, The Whisky Exchange) from Crete – with Daniel highlighting the high limestone content in many Greek islands’ soils – and the 2018 Al-Cantàra Luci-Luci Etna Bianco (£25.79, All About Wine) from Sicily.

Both wines really appealed to me, including the lime-laced indigenous vidiano variety, which definitely had a “stony” character, and the peach, lime and watermelon-esque Luci-Luci, made from the carricante variety, which I scribbled in my notes as having a “bit of stainless steel tanky” note, which could be seen as “flinty” or simply reductive.

Daniel labelled the vidiano as tasting of “calcium” – and highlighted research showing humans could detect calcium in low concentrations – while Goode said it had “salinity”, which he described as a mouthfeel he often gets from wines with minerality; Daniel believed he could identify the volcanic nature of the Sicilian soils in which the Luci-Luci grew, promoting Goode to reflect on the “brightness” he observed in wines made on granitic soils.

Fermenting ideas

“I’m sure to many people that this idea of being able to taste the influence of the soil is absolute heresy, but we’re not positing that there’s translocation of flavour elements through the roots and into the grapes and then survives the winemaking process and produces flavours in the wines; but there’s a plausible scientific explanation, not just through soil-water relations, but through soil chemistry that could affect gene expression in the grapes indirectly, which would then alter the flavour precursors produced in the grapes, which are then transformed by the yeasts into the flavour compounds we taste in the wine,” Goode added.

Goode pointed to research into the sap content of vines grown in different types of soils and suggested there could be a mechanism by which different soil chemistries could affect what goes into the glass.

“The fashion for what people want to taste is changing – delicate wine will come more to the fore, so the word ‘mineral’ will become more apparent,” Daniel added.

“If you have big oaky wines then you don’t see minerality, if you have big aromatic wines you don’t see minerality – instead, you see it in these more modern wines.”

Two of my favourite wines from the tasting certainly highlighted more modern techniques being used in the vineyard and in the winery.

The vineyards on Tenerife in the Canary Islands in which the listán grapes – better known as palomino fino, one of the grapes used to make sherry – are grown for the 2017 Viñátigo Listán Blanco (£16.86, Corking Wines) are farmed sustainably, an important trend as farmers try to reduce the use of pesticides, with the wine showing delicious lime notes and a flinty element, with a touch of asparagus and lemon rind.

My favourite wine of the day was the 2018 Feudi di San Gregorio Fiano di Avellino Pietracalda (£24.90, Connaught Cellars), a top winery that always draws my attention on a wine list or shop shelf, and this combination of stony – almost marble-like – texture with pear, apricot and lemon rind to match its crisp acidity was stunning.

Keeping it succinct

Daniel also highlighted research from South Africa and Australia into the build-up in wine of the naturally-occurring succinic acid, which produces a salty or bitter aftertaste that certain commentators have suggested could be the origin of some “mineral” notes, especially in wines that have been aged on their lees, the dead yeast cells left over after the fermentation has finished.

Whether it’s coming from succinic or another form of acid, there’s a definite tang to the acidity in the 2018 Gaia Thalassitis Assyrtiko (£24.70, Exel Wines), which is nicely balanced by lime and peach flavours, with both Daniel and Goode commenting on its “saltiness”, pointing out that the skins of the grapes pick up salt from coastal breezes on the Greek island of Santorini.

Two of the wines that, for me, expressed much more acidic characteristics than minerality were the 2018 Gerard Bertrand Château la Sauvageonne (£25.91, GP Brands) – a blend of grenache blanc, roussanne, viognier and vermentino from the Languedoc in the South of France that offered slightly confected pear and floral aromas that led into more complex and concentrated mandarin, lemon rind and pear flavours – and the 2015 Xosé Lois Sebio, Salvaxe (£27.99, All About Wine), which showed high acidity plus plenty of aromatic peach, honeysuckle, lemon and lime aromas and flavours.

The influence of the vessels in which a wine is made was highlighted by the 2017 Matias Riccitelli Blanco de la Casa (£19.84, Corking Wines), which was fermented in egg-shaped concrete vats in Argentina, and the 2018 Herdade do Rocim Fresh from Amphora – Nat’Cool (1 litre: RRP £20.49), created in traditional clay amphora or “tahla” in Portugal.

Riccitelli’s white brings together 40% each of sauvignon blanc and semillon blended with chardonnay to produce pronounced peach, grape and honeysuckle aromas on the nose and then more sauvignon-focused green pepper, asparagus and lemon on the palate, alongside crisp acidity, which – for me – only had a passing nod to stoniness.

The three indigenous red varieties in the Portuguese example – 40% moreto and 30% each of tinta grossa and trincadeira – offered up blueberry, blackcurrant and raspberry aromas, plus those tell-tale low-intervention crunchy red apple textures and flavours on the palate, and certainly stonier in nature to me.

Goode reflected on the influence that concrete tanks – of whatever shape – have on a wine’s texture, as opposed to the use of oak or stainless-steel vessels.

Reds and beyond

Continuing with the final two reds, Daniel admitted he found it harder to detect minerality in red wines, with Goode suggesting the flavour or texture was masked by other factors, such as increased use of oak.

My favourite red of the afternoon was the 2017 Zorzal Eggo Tinto de Tiza (£17.05, Exel Wines) – it was fragrant, floral, fresh and fruity and, although not demonstrating “minerality” per se for me, those floral notes have been attributed by some to the region’s chalky soils; either way, a truly excellent wine.

On the other hand, the 2018 Clos Troteligotte K-nom (£12.64, Great Wines Direct) from Cahors in France didn’t quite hit the spot for me, with its roast meat aromas verging into more rancid territory.

Yet I recognise Goode’s comment on the blood-like iron tang he got from the wine and from certain other reds.

Looking further afield, Daniel also admitted to not finding minerality in wines from Chablis, the area north of Burgundy that’s often associated with wines that have a mineral note, alongside Sancerre, Pouilly-Fume and other villages further north in the Loire valley.

He mused over whether it was due to higher temperatures in Chablis and the Loire, which have led to riper grapes, while Goode thought that winemakers in the Jura region were still capturing minerality by making fewer interventions in the winemaking process.

For anyone looking for extra homework, I recommend exploring wines from Alsace – which has few rivals when it comes to the complexity of its soils – and the Crozes-Hermitage part of the Rhone, where syrah expresses its terroir.

Read more of Peter’s articles about whisky, wine, and other drinks on his drinks blog, The Grape & The Grain