Minerality – The Great Debate

“Wet stone. Matchstick. Vibrancy. Slate. Exclusively textural. Alcohol sensitive. Schist. Possibly the only true measure of greatness in wine.”

The popular definitions for the term ‘minerality’ are many and varied. It is a term that means different things to different people – winemakers and critics included. Inherently personal, inherently nebulous.

But where does the term ‘minerality’ come from?Wet stones

Most wine professionals old enough to remember and/or care, agree that the term ‘minerality’ didn’t exist as part of the wine tasting lexicon until the 1980s.

I believe it’s no coincidence that the birth of the term coincided with the rise of New World wine imports into the UK market. The highly aromatic, fruit-forward wines made by ‘technical’ New World producers were so different from the subdued, earthy Old World wine styles. The trade needed a catchall aromatic descriptor to differentiate between the two, and minerality stepped up to bat for the Old World.

From that point on, the concept of minerality not only played an important role in defining the two opposing styles, it was also an attractive and suggestive term that – from the very first moment it was whispered in between swirls – was destined to be widely accepted by wine professionals and consumers alike.

When I moved to the UK in the mid 1990s, minerality had become a regular addition to the industry vocabulary. I noted that it seemed to be used exclusively as an aromatic descriptor and also a neutral one, i.e. there were no strong associations with quality. There were poor and excellent mineral wines – complexity and balance were all important, as they are today.

This ‘aromatic’ mineral expression could be traced back to a diverse group of highly pungent winemaking-derived compounds, best described as volatile sulphur compounds or ‘sulphides.’ Gunflint, struck match, wet wool and even onion skin are some of the evocative terms used to describe the character of different sulphides in wine.

As a young winemaker I was rather perplexed to encounter such a wide acceptance of the very characters my New Zealand university lecturers regarded as a mark of poor winemaking. Their view was absolute: Anything that gets in the way of fruit is a fault.

Over time, I’ve grown to appreciate certain sulphides – as long as they work within the context of the wine. When they are in balance with other sensory qualities and do not dominate, they behave almost like a seasoning – providing intrigue and enhancing complexity. In addition, they are a fairly reliable indicator of a wine’s longevity.

So what of the minerality discussion today? In the last ten years or so, the term has morphed into a broader, more complex and arguably more confused one. Most fine wine professionals agree that minerality is not exclusively aromatic but also has a textural persona that enhances wine quality and longevity. This is where the consensus begins and ends. Some believe that it is a saline character on the palate. Others talk of an important relationship and association with acidity, in particular malic and succinic acids. One more enlightened professional even likened it to an electrical current on the palate!

The term’s recent link to texture is likely to have emerged out of the biodynamic viticulture movement, which has grown over the last 15-25 years.

One of the cornerstones of biodynamics in wine growing is the management of soil, and in particular the microbial load of the soil. It has been suggested by the proponents of biodynamics, that with more micro-organisms in the soil there is more mineral expression in the wine. This is a great marketing hook, but the problem is: Concentrations of minerals, even in biodynamic wines, are well below the level required for detection on the palate.

So what do we know for certain about the term minerality?Three piles of different types of salt on measurement spoons

– It has never had an agreed definition but nonetheless remains a widely used term in wine tasting.

– It can be used to describe both aromatic and textural qualities in wine.

– It may indicate greater wine longevity and is generally a positive term.

– Claims about a real and direct relationship between minerals in the vineyard soil and the aroma or textural profile of a wine are not backed up by science.

– Until science can prove otherwise, we have to consider it a ‘metaphorical tasting term.’

I personally believe minerality expresses itself in both an aromatic and textural manner. Flint and struck match are the most common mineral aromatic descriptors I encounter. On the palate I believe it to be exclusively linked to acid complexity: The more acids present in the wine, the more minerality in the wine.  Thus wines that have completed malo-lactic fermentation will show less mineral nuances than those that have gone through partial malo-lactic fermentation. I detect minerality on the palate as both a saline and green apple acid freshness that provides lift and length of flavour. I believe that the acids that make a wine mineral don’t come exclusively from the vineyard. Succinic acid (a winemaking derived acid with a salty expression) may well be the most important factor in this debate. Only time will tell.

In any case, if – like me – you are intrigued to see where the minerality discussion will go next, you can download the latest research by Molina and Palacios (two dynamic Spanish researchers who arguably know more about this subject than any one else on the planet!)

Do you have a new definition to add? Send me your thoughts.