Marl: The Most Misused and Misunderstood Word in Burgundy Literature?

Mud, Clay, Marl, Silt? photo borrowed from the excellent
Mud, Clay, Marl, Silt? photo borrowed from the excellent

In trying to understand the effect of ‘terroir’ on the wines of Burgundy, only ‘clay’ has been a keener form of frustration than ‘marl’. But that isn’t because marl is a difficult concept to grasp, but rather because few wine writers seem to really know what marl is. The word is thrown around, even by people regarded as experts, with such seeming abandon, that almost anyone who attempts to understand the word can be hopelessly confused.

Marl is generally defined as a mix of clay and limestone. When they refer to limestone in this fashion, they don’t mean solid stone, they mean that has been mechanically eroded, of varying sizes (from a fine sand to fairly large stones) that are mixed into the soil.  The ratio of these two major elements of marl can be a range of 35% of one, to 65% of the other.(1)  This would be fairly simple, but Wikipedia lists marl as a calcium carbonate-rich mud with varying amounts of clay and silt.

Marl table. With one extreme being all clay and the other being all limestone, marl is a mix of both. Courtesy of wikipedia.
Marl table. With one extreme being all clay and the other being all limestone, marl is a mix of both. Courtesy of Wikipedia

Deep into researching vineyards, I began to realize that much of the information I was reading on soils, (and particularly about marl) was sounding borrowed, shallow and canned. I’ve seen marl written of in myriad ways including that a vineyard had “a mix of limestone and marl” or the vineyard is made up of “Marly clay.”  This one, from one of the more definitive of Burgundy reference books, stated that the soils of Mazis-Chambertin have “a lot of marl mixed in the with the clay and limestone.” But the prize of goes to this gem that spoke of “clayey marly limestone soils”, written by an authority on the subject.

Chardonnay prefers more clayey marly limestone soils from which it can develop sophisticated, elegant aromas in the future wine.”unnamed author

Since we already know that marl is a mix primarily of clay and limestone, you don’t have to think very long and hard to see this statement is contradictory at its core. A soil can be a clay-heavy marl or a limestone-dominate marl, but it can not be a “clayey marly limestone soil.”  All this kind of language does is confuse a difficult subject, and make Burgundy more inaccessible to students of this already arcane subject.

I am not alone in this criticism. On researching marl and clay, I found this article “On marls and marlstones” by geologists Stephen K. Donovan and Ron K. Pickerill that confirmed I wasn’t going completely off base.

“As enthusiastic editors, we cringe whenever we trip over lax use
of terminology and language that authors make, repeatedly, in the
geological literature. We have over 50 years editorial experience
between us and present this note as a brief suggestion for wider
consideration. We have commented on the subject of this paper before
(Pickerill et al., 1998), but, sadly, identifying the disease hasn’t
facilitated the cure, at least so far.”

I could go on and on, and in fact I have. Visit my long 2600 word post: Preface to my upcoming article: “Understanding the Terroir of Burgundy”) for more. Some of the above is excerpted from that post.


(1)  The fact that mud/mudstone (and this is substance is sometimes referred to as shale) is introduced as a term by wikipedia, see table certainly confuses the issue, but they also indicate that this mud is a clay element.


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Diary of a Winebuyer

About Me: Thirty years ago, I graduated with a degree in political science from the College of Letters and Science at the University of California at Berkeley. Having grown up at the height of the Cold War, I still have vivid remembrances of being instructed to hide under our elementary school desk, covering our heads. The young, white, female teacher, training us without explanation, to face away from the windows. I suppose it is not all that surprising that I had a particular interest in the realpolitik of international relations. My fascination grew with the discovery that certain conditions almost uniformly exist where all revolutions ferment. Did this mean that the revolutions which had occurred in the first half century were revolutions which had been usurped by Marxists who were in the right place at the right time? Probably. A favorite professor was A. J. Gregor. This was a man who, while rakishly wearing a Gestapo-styled black leather motorcycle jacket, exuded expertise on fascism (which he looked the part) and Marxism. Improbably, he did it with a significant swagger. Then in my last semester, I had the blind luck to take a class on Asian Marxist revolution, and the professor, who just happened to be visiting that year while he worked on some unnamed project, was Chalmers Johnson. In retrospect, I should have known his name, as he was a luminary in the political science community but at that time, I did not. It was a remarkable opportunity to experience the ivory tower, but I seem to remember being anxious to get on with life. After college, I drifted through a few of jobs that were of interest to me. One of my former high school teachers said to me. "If I were in your shoes, I'd get a job as a flight attendant." So in order to be young while I could still afford to, I accepted a job serving chicken or beef at Pan American. With that airline losing money faster than it could sell its routes, I got a job doing cellar work at David Bruce Winery. This was the beginning of my wine career. All during this period, I wrote a still unpublished novel about homegrown terrorists the U.C. Berkeley campus, attempting to use some of what I learned in school, weaving in the Vietnamese political and military strategies of Dau Tranh as professor Johnson had lectured years before. Since the early 1990's, I have been involved in the wine industry, selling fine wine in both the retail and wholesale arenas. I have approached learning about wine, by always challenging myself to question how I know what I think I know? And in an effort to try to find answers I've turned, with varying degrees of success to wine books. Overall, I've not been happy with the quality of most wine writing, finding the authors either to lack any deep knowledge, or unable to move much past what I consider to be superficial information. I recognize that wine writers have to monetize their work, but I believe this has dramatically held back our knowledge and understanding of wine. I have set out to add to our industry's base of knowledge where I can. My first series, 'The Terroir of Burgundy' (which I should probably re-edit and complete some kind of conclusion, but I got involved in this project), can be viewed here. I currently work as a sales and marketing manager for a Burgundy and Bordeaux importer based in Atherton, California.

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