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Minerality: Describing What You Can’t Describe

I have written confidently about many wine topics, but the subject of minerality gives me the heebie-jeebies. Although the heebie-jeebies can refer to an after effect of excessive alcohol intake, in this case the reference is to a type of anxiety or nervousness. As a physician, I have a scientific background and I love to deal in facts and proofs, not in a vague metaphor, (some would say simile), like minerality.

Over the past few months, I have attended seminars on minerality at the World of Pinot Noir in Shell Beach, California, and Pinot Paradise in the Santa Cruz Mountains. In addition, I spent some time with Kevin Harvey, proprietor of Rhys Vineyards in the Santa Cruz Mountains, who is a proponent of the role of minerality in fine wine. I have heard from wine writers, winemakers, winegrowers, professors and wine drinkers, and one conclusion stands out: minerality is a misused descriptor that is controversial and esoteric to say the least.

Minerality is a descriptive word for wine which has no common definition and is supported by no scientific proof that minerality from the soil can influence wine aroma and flavor. Here are but a few attempts at defining minerality I have heard or read recently:

“A descriptor that reflects our struggle to find what we are experiencing.” (Winemaker James Cahill)


“An effort to connect wine to the place it is grown.” (Winemaker Fintan du Fresne)


“A way to describe the non-fruit components of wine. A word used to describe what one can’t describe plainly.” (Winemaker Jason Jardine)


“A lack of fruit character in wine.” (Winemaker Mike Waller)


“The lack of something rather than the presence of something (ie fruit) in wine.” (Consumer)


“A soil-based characteristic in wine.” (Winemaker Jason Jardine)


“Perception of geology in wine.” (Dr. James Kennedy UC Fresno)


“Being able to actually taste the vineyard geology in the wine....in any literal way is scientifically impossible. Whatever minerality is, it is not the taste of vineyard minerals.” (Alex Maltman Institute of Geography and Earth Science, Wales)


“Minerality is a complex mixture of compounds in wine which we associate with the smell of soils or rocky area.” (Dr. Sue Ebeler, UC Davis)


“Something that exists but is not explainable: I know it when I taste it.” (Writer Karen MacNeil)


“I can’t define minerality, but I know it when I feel it.” (Writer Steve Heimoff)


“Wines richer in minerals present way differently. There is a suppression of obvious fruit...the wines seem to have a sort of nucleus or density around their ether, they are gathered, focused, cohered the way a laser coheres light.” (Winemaker Randall Grahm)


“Minerality is a concept which could never be consistently defined in words or physical standards.” (Sensory chemist Dr. Ann Noble)


“No one specific, precise detail can recognizably define minerality; it is a combination of many attributes.” (Sensory chemist Dr. Ann Noble)


“The minerality of a wine is experienced like a generation of tension in the mouth that is innately refreshing and energizing.” (Winemaker Jason Lett)


“Minerality is more of a sensation than a flavor that predominantly appears in an elusive finish.” (Winemaker Steve Matthiasson)


“The aroma, taste and tactile sensation in wine when grapes are grown on rocks.” (Winegrower Kevin Harvey)


“A sense of mineral-ness in the wine, flavors of slate, schist, silex, etc.” (Wikipedia)

Most agree with Dr. James Kennedy, who says, “It is not whether it (minerality) is there, but what is it.” Still, there are some naysayers when it comes to minerality. Mike Waller, the winemaker at Calera Wine Co., who appeared at both the World of Pinot Noir and Pinot Paradise seminars on minerality, said, “I don’t get much minerality in red wines. I am an “atheist of minerality,” preferring to ascribe minerality to the “lack of fruit expression.”

Winemaker Greg Saunders of White Rose Vineyards in the Willamette Valley is another skeptic. He told me the following. “When we use language to convey meaning, a basic premise is that we are using commonly defined terms. With minerality, we are not using a commonly defined term. If I say something tastes like blackberry, people can agree or disagree, but they can understand the reference. Minerality has no reference. My problem is with ambiguity. I am a dirt-eating farmer with a palate preference for calcerous clay. Where I come from, if you cannot have a common definition, we usually say the word is BS.”

Winemaker Fintan de Fresne believes that wine critics should abandon completely the use of the word “minerality.” He feels it is much too vague, and encouraged writers instead to try to use more specific descriptors.

As ambiguous as the term minerality is, there are some reasonably firm ideas to hang your hat on.

1. The word “minerality” is a relatively new term in common use today. Karen MacNeil pointed out that historically the word was not used, and first began to appear in the wine lexicon about 45 years ago. The word “minerality” is absent from Emile Peynaud’s The Taste of Wine (1983) and Ann Noble’s Wine Aroma Wheel (1984).

2. It is unlikely that minerals in the soil of a vineyard can travel up the roots and xylem into grapes and survive fermentation in large enough concentrations to produce identifiable mineral flavors. Most smart wine people believe this does not happen. Take calcium carbonate in limestone soil as an example. Fintan du Fresne points out that in such an alkaline soil, if that mineral compound was taken up by the vine, the resulting wine would have a high pH, but the resulting wines are instead high in acid. Dr. James Kennedy, speaking from the viewpoint of a chemist, does not see how calcium carbonate would be brought into wine and there is not evidence to support this. Some winemakers (Jason Jardine as an example) argue that the vine’s sap is a conduit and the vine uptakes soil-based mineral components such as iron that are reflected in the wine. Fintan du Fresne believes that the vine does uptake minerals but there is no direct correlation between minerals in the soil and flavors in wine. He argues that wines that are perceived as having minerality are often from rocky vineyards, but points out that rockier soils should provide less take up of minerals since “The vine can’t take up minerals from rocks.” However, Dr. James Kennedy would point out that it is possible that microorganisms can cause minerals in the bed rock to dissolve in the moisture in the soil and the vine may express the result. Clark Smith (Vinovation and winemaker) does not believe that grapes can take up complex nutrients. Do you understand how talk of minerality drives me crazy?

3. There are no clear correlations of any specific mineral compounds in wine with a “mineral” aroma or taste.

4. It is generally accepted that minerals such as potassium, magnesium, sodium and calcium are present in wine as mineral acids, but some have declared their concentration to be so low as to be tasteless and non-aromatic. Others, such as John Casey (wineanorak.com), have argued that, although minerals are not contributing to the perception of minerality, the inorganic cations and their salts contribute to the wine’s acidity and affect the taste of wine. Clark Smith (Vinovation, winemaker) agrees, pointing out that potassium levels are high enough in wine to contribute to the perception of body and flavor persistence in the finish. He is a proponent of negatively charged electrons as the driving force in minerality.

5. Of the five taste sensations, salt, sweet, acid, bitter, and umami, both salt and umami seem to be most related to the awareness of minerality. Minerality has been perceived as salty, briny or like soy sauce. Other aroma descriptors for minerality include flint, slate, metal, iron, wet rocks or stone (petrichor), chalk and smoke. A related aroma is earthiness.

6. Minerality is similar to, but not the same as acidity. Acidity is measurable, and as Steve Harvey points out, one can add more acid to a wine without changing the underlying perception of minerality. However, there appears to be an association. Mineral scientist David Killilea (Wine Business Monthly April 2013) said, “Minerality....is associated with a complex of other things, the most important of which is likely acidity.”

7. Whether minerality is more evident in younger (Dr. Kennedy) or older wines (Fintan du Fresne) is controversial. Some believe that clonal expression is more evident in young vines while there is more expression of site in older wines.

8. Minerality can be a euphemism for sulfur--based compounds due to reduction. Stressed fermentations can lead to aromas of onion, garlic, match stick and rotten eggs which at low levels can be interpreted as mineral. Fintan du Fresne points out that the perception of flint in wines from Chablis is due to a stylistic decision of the winemaker to incorporate reductive winemaking.

9. Another explanation for minerality is the volatile esters and thiols that occur during fermentation from the interaction of alcohol with organic acids leading to a wet stone aroma.

10. Most agree that minerality has an aroma, flavor and tactile component, but aroma is often the most prominent gauge of minerality.

11. Minerality is perceived more in white wines than red wines. Of the four winemakers who participated in the minerality seminar at the World of Pinot Noir, three said that minerality was more evident in white wine and one felt it was perceived equally in both white and red wines. I looked at several hundred reviews of Pinot Noir & Chardonnay from North America and France published in a recent issue of the Wine Spectator, the Wine Enthusiast, and The World of Fine Wine. The word “minerality” or variations thereof were used overwhelmingly more often with Chardonnay than Pinot Noir. The term was also used much more frequently for French Chardonnay than North American Chardonnay. Terminology included: mineral, mineral stamp, mineral vein, mineral nose, mineral depth, mineral punch, mineral finish, citrus-mineral nose, mineral-toned fruit, mineral apricot nose, mineral grip, mineral streak, mineral core, sense of mineral place, mineral-imbued fruit, mineral character, saline minerals, salty minerals, grippy mineral structure, mouthwatering mineral quality, minerality, fine minerality, stony minerality, streak of minerality, minerally finish, mineral fruit, mineral strength, minerally texture, minerally structure, minerally acidity, stony minerality. Stone, stony, crushed rock, wet stone, sense of rocks and stones, iron, steely character, steely grip, and salty were rarely used.

Dr. Kennedy summarized his talk at Pinot Paradise in the Santa Cruz Mountains, “Minerality in Wine: Searching for Common Elements,” with three possible explanations for minerality:

1. The existence of unique volatile chemistry associated within a site. Volatile compounds that arise from the soil can reach the grape and appear in the vine. Soil ecosystems provide a continuous cycle of life and death and decomposing matter releases volatile compounds. An example of this effect is the volatile oils released from the leaves of the eucalyptus tree that fall on the ground and decompose. The resulting camphor that appears in the wine from nearby vineyards is not something produced by the grape.

2. Fruit development. Terroir determines the composition of fruit and minerality is associated with specific fruit chemistries resulting from interaction of molecules.

3. Reductive winemaking and packaging (screwcaps for example).

The time I spent recently with Kevin Harvey and winemaker Jeff Brinkman of Rhys Vineyards tasting their 2011 Chardonnays and Pinot Noirs was very enlightening. I tried to pin Kevin down about minerality since he is very knowledgeable on this subject and has based his entire winegrowing venture on seeking out sites, rootstocks, and clones and selections that reveal minerality. He believes, “The Santa Cruz Mountains are the most mineral-driven wines in the New World.” Kevin has a laid back drawl and manner about him that reflects his Texas upbringing, but he is a very smart guy who has studied the geology of the Santa Cruz Mountains in depth. He is a student of viticulture, has a full grasp of the wines of Burgundy, and is a devotee of terroir. Spend an hour with him and his wines and you will come away a believer in the gospel of minerality.

Kevin has an unshakable faith in the ability of rocky soils to express minerality in contrast to deep, more fertile soils which produce wines lacking in this character. Rocky soils drive roots deeper and deep rooted vines express more minerality. Kevin realizes that soil nutrients cannot pass directly into grapes but feels there are many other ways for minerals to be expressed in wine. One example would be through water stress and availability but there are so many factors involved that minerality is far too complicated to explain or understand. He told me, “Wine is just too complex and the incentives too small to justify the type of research that is necessary to fully understand the interplay of soil and wine.” Kevin had a cousin from Massachusetts Institute of Technology come to the winery with scientists from that prestigious school. When tasting the Rhys minerality, but they could appreciate the differences among wines from different sites and the various expressions of minerality, but they could not explain it.

For Kevin, minerality is expressed on the nose, through taste, and by tactile sensation in the mouth. Wines from his Horsehoe Vineyard always reveal a wet rock perfume both in Chardonnay and Pinot Noir. On the palate, minerality is expressed as an “electric current.” From the standpoint of tactile sensation, minerality is a “digitization,” or a sensation of fine particles that leads to an extra dimension on the finish, a sense of fine-grain texture to tannins for example. He notes, “In French wine, a lot of what is attributed to acidity is actually minerality.”

The discussion of minerality can be best summarized by Kevin’s view. “Whether it is the scorched earth of Haut Brion, the Asian spice of La Tache, the rusty iron of Nuits St. Georges, or the seashells of Chablis, site-derived attributes are what make wine endlessly fascinating and not just a simple fruit drink. Distinctive site expression, of which minerality is a subset, is what causes all the world’s greatest wines to rise above the pack. It is the key to real, lasting complexity and interest and it is what causes wine to improve and become more complex with age as opposed to just mellowing. It is my belief that the mineral and nutrient composition of soil along with the specific resident biology and the physical properties of the soil combine to create a unique site expression in wine. I hope science can one day explain all of this, but while current science places too much emphasis and faith on an incomplete and undoubtedly inaccurate understanding, the everyday reality of minerality can be best experienced through a glass of wine.”

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