Preface to my upcoming article: “Understanding the Terroir of Burgundy”

(Opinion) and the ensuing quest for answers.

Wine literature champions the one half of one percent of the top vineyards, and the very top producers. What about the wine for the rest of us?

Despite the scores of books written about Burgundy, if you really break down what is being written specifically about each climate, the information can be pretty sparse. For a handful of the greatest vineyards, extraordinary efforts are made to explore the grandness of these few plots.(1)  However, these vineyards probably represent less than one half of one percent of Burgundy. Little coverage is given to the physicality of the rest of Burgundy’s sites, including many highly-regarded premier crus. Beyond listing most vineyard’s size, what the name means in French, sometimes an inane fact (like some wild bush used to grow in that spot) and who the top producers are, most crus don’t seem to warrant the effort. How does Puligny’s Les Combettes differ from Les Champs-Canet, which sits directly above it? It is not likely you find the answer by reading a book about Burgundy.

Of these vineyard entries, writers typically ignore the soil makeup and limestone below; the most primary elements of terroir. Perhaps this is due to a lack of information. (2) However, I have no doubt that if as much effort was given to researching these appellations as is given to tasting Armand Rousseau’s latest barrel samples, we’d have a lot more understanding about Burgundy than we do today. Typically when a comment regarding a particular vineyard’s soil is made by a wine writer, it is simply as a notation, with no connection to the style of wine that comes out of that vineyard. It sits there like a pregnant pause, as though it were quite important, but no explanation follows.  And that explanation is what I hope to supply by my upcoming article. I can’t do what the top wine writers can: go to Burgundy and walk the vineyards with the winemakers, talk to the professors at Lycée Viticole de Beaune. But I wanted these answers for myself; what it all that means the limestone and “marl” and clay, and what did for the wine. If I could. Did I dare?

While I am critical of the much of the wine writing produced – for its lack of deeper educational and intellectual content, I understand that wine writers must produce what consumers are willing to pay for. We are a consumer-driven society, and readers are really looking for buying guides wrapped up in a little bow of information. The capitals of 19th century Europe were famed for their starving intelligentsia, but no one wants to scrape-by in a land of plenty, regardless of how romantic. Wine writers write what the public wants.

The beginning

Way Too Geeky!

After more than a year of researching Burgundy vineyard information for the marketing part of my job, I thought I could do a quick write-up about the terroir of Burgundy. I had come to some interesting conclusions and felt I could write a piece with a unique perspective on vineyard orientation, slope, the general soil types determined by that, and how it all relates to a wine style.

It was all going along quickly and easily until I wanted to clarify a couple of points about geology. What had initially looked like a weekend project, has taken 9 months of daily work. This article has become something of a Leviathan, but the exploration has taken me to uncover some enlightening information, as the pieces started falling into place. The original piece first became two parts, and ironically, now it is four parts, each divided into articles of a more manageable size of 2,000 to 4,000 words. The result of this is untold hours of research and writing.

Unfortunately, sections of Part One have ended up being so technical that I no longer really know who will want to read it. Any hope of an audience is slim. Most wine professionals are so burnt by the end of the week, that they would rather paint their house than read about wine. However, this is a unique article that looks at the breadth of the factors that influence vine growth in Burgundy and ultimately influence wine character.

An example of a map I developed, showing the vineyards I’m highlighting, as well as the soil and limestone base it sits upon.

A Path of Discovery and Frustration

One of the first surprises was difficulty justifying the satellite images with some of the vineyard maps that I had been so diligently studying. Sometimes they just didn’t look like the same place. The vineyard maps often gave little sense of topography of the hillsides, despite paying particular attention to the elevation lines. I believe that the amount of slope in vineyards that are not terraced, like in Burgundy, is critically important to the profile of a wine.

What looked like roads on a map, at times were not, and in many places, there were entire sections which were shown as vineyard were actually unplanted, inhabited only by trees, scrub or rock. This I found to be very illuminating information regarding adjacent vineyard land, and how that might define a wine’s character. At times, the shapes and sizes of vineyards depicted on maps appeared to be different from the photos, perhaps changed to fit the artist’s needs.  After a while, I started making my own maps using Google Maps’ satellite images and adding the information that I found relevant to the needs of my job. Perhaps the most telling visual information has come by utilizing Google Maps’ street view, to see a vineyard and its slope, the topsoil, quickly and easily, and often from multiple angles. It is an amazing tool, I highly recommend using it in addition to maps when studying wine regions.

Am I a Skeptic or Just Paranoid?

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

I noticed that the information I was reading, from multiple sources, wine writers, importers, etc, was all starting to seem repetitive, using similar wording, ideas, phrasing. Increasingly, the information seemed more and more borrowed, shallow and canned. For instance, it is common for a writer to state that a vineyard is “a mix of limestone and marl” or the vineyard is made up of “marly clay.” And then there was this from one of the definitive Burgundy reference books regarding the soils of Mazy-Chambertin: “there is a lot of marl mixed in the with the clay and limestone.”

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 rock 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. (3) The more I read, the more I question what I am reading. (4)

Below is an example kind of “soil information” that I’m talking about. At first blush, the passage below sounded like I’d found the holy grail of explaining what kind of soils for which Pinot and Chardonnay were best suited, but later I realized it was anything but.  The following was written by an authority on the subject.

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“• Pinot Noir flourishes on marl soils that are more yielding and porous, that tend towards limestone and which offer good drainage. It will produce light and sophisticated or powerful and full-bodied wines, depending on the proportion of limestone, stone content, and clay on the plot where it grows.”
“• Chardonnay prefers more clayey marly limestone soils from which it can develop sophisticated, elegant aromas in the future wine. The clay helps produce breadth in the mouth, characteristic of the Bourgogne region’s great white wines.”

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With the Pinot, he starts off well. Marl (a combination of clay and limestone in varying percentages) with very high levels of calcium carbonate (limestone) is has a correspondingly high-rate of infiltration by rainwater. And he is right again as he writes that the weight of the wine is dictated by the “proportion of limestone, stone content, and clay on the plot where it grows.” 

The problem occurs when he tries to differentiate the conditions in which Chardonnay thrives. “Chardonnay,” he writes, “prefers more clayey marly limestone soils from which it can develop sophisticated, elegant aromas in the future wine.” If we compare the soils and bedrocks of the finest Pinot and Chardonnay vineyards, there are tremendous commonalities, and both varietals seem to flourish on the same soils. Every aspect of what he said about Pinot equally applies to Chardonnay.  Second, as marls increase in their clay content (which is what he was trying to say with the utterly confusing description of “clayey marly limestone soils“), these denser soils, which typically occur at the curb of the slope, are still capable of excellent drainage. We will look at this in depth later, but for an immediate explanation see below (6),

 

To make this passage more accurate, he should have led with drainage. The porosity of the soil allows drainage: in other words, it has a causal effect of good drainage. It is not an axillary attribute as he suggests when he writes “and which offer good drainage.”

Secondly, it seems that the writer is suggesting that Chardonnay does not do as well as Pinot Noir in porous limestone dominated soils, and vice-versa. I believe vineyards like Les Perrières in Meursault, that have very poor, and very porous, limestone soils, with little clay content, contradicts that notion. Additionally, in Chassagne Montrachet, Chardonnay has replaced much of the  Pinot Noir on the upper slopes of the appellation, while Pinot Noir has remained in the heavier, clay-infused soils lower on the slope.

“Now every piece of information had to pass the smell test, and preferably it needed to be corroborated by another source, that clearly wasn’t of the same origin.”

Skeptical, now everything must pass the smell test.

I plodded on with my inquiry. Now every piece of information had to pass the smell test, and preferably it needed to be corroborated by another source, that clearly wasn’t of the same origin. I had read enough to identify “family trees” of bad information, and I often believed that I could often identify the original source.  Just how easy it is to pass on incorrect information is illustrated by this next example. I found an error (in my opinion) in one Master of Wine’s book on Burgundy, saying that the “white marl” of a vineyard was found on the upper slope, producing a richer, fuller wine, and while the calcareous (limestone) soils were down below, and produced a lighter wine. It was an obvious mistake if you just thought about it for a second, as the forces of gravity and subsequent erosion drive clay to the lower-slopes where it reforms via flocculation. Later I would find the same information, but in more detail, in another Master of Wine’s article, again containing the same error.(6)  The source of the error was either a mistranslation of a conversation with a vigneron or a typo. While this is a simple mistake, having two of our most revered Master of Wines citing the same information can only confuse an already misunderstood subject, even further. I can envision a whole generation of Sommeliers reciting that the upper-slope of Les Caillerets produces heavier, more powerful wine than sections of Caillerets farther down the slope.

It was clear I wasn’t going to find the answers I was looking for in the English language Burgundy books I had access to. Ultimately my questions would become more and more specific, pushing my inquiry of terroir to an elemental level – delving into the construction of the earth and stone, and how it breaks down, and how it might influence the wine we ultimately drink. I still have a tremendous number of questions that will simply go unanswered for quite some time,(7) either due to the lack of research, or that this information is not available in an accessible, English-language format.(8) 

Part One of the article is the result of searching out, reading, and trying to understand small, maybe inconsequential details.  Since I’m putting it out there on the internet, I have made a concerted effort to attempt to get it right. Obviously not a geologist, so despite reading about clay and clay formation dozens of times, from dozens of sources, the complexity of the science makes it easy to over-simplify, to misunderstand it, and definitely, easy to misrepresent. Making this process more difficult, I could find no articles that (for instance) were specific to the clay and clay formations of Burgundy. (9)

It’s not sexy reading, but I’ve done my best to pull it all together into one place.  If nothing else, I hope this can be a jumping off point for others to research, and expand our cumulative understanding of terroir. 

 

 

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ADDITIONAL NOTES

(1) Even with the top vineyards, publications heavily link the greatness of the wine to the producer, rather than the vineyard. The mantra for the past 30 years has been: producer, producer, producer. While there is a historical reason for this producer-driven focus, I feel the vast improvements in viticulture and winemaking knowledge over the past two decades, coupled with the concurrent global warming, has changed the paradigm and significantly leveled the playing field between producers. There are now much smaller differentials in quality from the top producers and the lower level producers. I feel that the focus should now return to the vineyards of Burgundy, each with a distinct set of characteristics due to its orientation, slope, and soils. Nowhere else in the world is this kind of classification so rigorously defined. And because of that, nowhere else in the world is this kind of ‘study’ possible.

(2) The mapping of Limestone has never really been done before the geologist Francoise Vannier-Petit began her work a number of years ago. She has now mapped Pommard, Gevrey, Marsannay, and Maranges, for the trade associations that have been willing to pay for her services.

(3)  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.

(4) To give credit where credit is due: When I first started doing an overview of our producers, I had summarized this idea, (Pinot liked preferred limestone soils and Chardonnay preferred more clay-rich soils.) My boss, Dr. George Derbalian (with his background in failure analysis) looked at the statement and said, “I don’t know about that.” He asked where I had obtained this information, and when I couldn’t immediately produce the source, he warned: “You have to be very, very, careful about these things. As an importer, we have to be completely sure we are right when we say something. I would like to remove this sentence.” I thought he was being over-reactive at the time, and 100% accuracy wasn’t important for the marketing piece I was working on, but later, with much more research under my belt, I would revisit his words with far more respect.

(5) The word marl has a very poorly defined meaning because it is a very old word that was used somewhat indiscriminately. Wikipedia lists marl as a calcium carbonate-rich mud with varying amounts of clay and silt in their of the definition. To make matters more confusing Wikipedia’s definition of mud says it has clay in it. Is mud part of marl? Is clay part of mud? Does it really matter?

6) This is for two reasons: first, because of the shards limestone, in the soil, weathering of that material by rainwater produces an abundance of freed calcium. This is sometimes referred to as “active” limestone. This calcium, which is mixed by plowing with the clay, misaligns the platelets in clay causing the clay to lose its plasticity. This misalignment greatly increases the infiltration rate (IR) of water through the clay. So while clay alone has very poor IR’s, clay that has been mixed with calcium has much-improved drainage. The second reason that these richer marls, meaning an equal or higher percentage of clay than limestone in the mix, produces richer wines is there is more root space in the vineyards which our author is writing about, (ie le Montrachet and Batard-Montrachet). This occurs because of the location in which clay increases in the soil, happens in places where the slope is leveling off. These locations are where gravity has sent the hills colluvium. Here is where the hillside’s scree, sliding down, due to erosion or from man’s working the land, sits, and upon it, water runoff and gravity have sent the clay, eroded from the hillside above, to this same spot. This convergence of higher proportion of clay in the topsoil and limestone colluvium, together, provide a deep, rich soil that has excellent drainage for the level of slope. Of course, we will get into the science of this in much greater detail, later.

(7) The quote from the second Master of Wine’s write up of Les Cailleret. I have added the (er) to here to make the passage more clear. “Up at the top of the slope, there are outcrops of bare rock. He(re) we find mainly a white marl. This will give the wine weight. Lower down there is more surface soil and it is calcareous, producing a wine of steely elegance. A blend of the two, everyone says, makes the best wine.”

(8) The list of questions I have that don’t have answers seems limitless.  Here are my top questions with no answers at the present: 1) How pervasive is is the fracturing of limestone in the top crus, 2) what kind of limestone is it?  3) does the limestone there to fracture and is thus friable? 4) how much water do these limestones hold?  5) how much groundwater is available to the vines? 6) How does the groundwater circulate, and 7) how quickly through different types of soil?  8) Where are the faults in the various top climates, 8) are the faults often at the boundaries dividing limestone types? 9)  how deep are the drop-offs (covered by the topsoil) created by the various faultlines?

(9) The University, Lycée Viticole de Beaune is likely to be active in this kind of research, but so far I have not been able to access what might be available, and correct translation from French to English can be problematic if it isn’t done by the author who wrote it, and many times more so if using a translating program (software).

(10) Therefore I’m unable to discuss the types of primary clays, called kaolins which may have formed there, in situ, instead focusing on transported clay that has been derived from the erosion of limestone of the vineyards, called Chlorites.