Tom, I will agree that Tablas is relatively restrained for the area. Even so, in any vintage try comparing the Esprit to Beaucastel Coudoulet, and you’ll certainly note the difference (and that’s not even bringing the big brother CdP into the equation) - though even CdP has edged into riper territory in many recent years. As for Alban, I have no idea what the viticultural and picking strategies are there, but the very fact that he can make such ripe, high alcohol wines tells me it’s not optimum for the variety. I subscribe to the theory that the best wines are made in locations which are near the borderline of producing acceptably ripe fruit (a subjective definition, for sure).
Cheers
Thanks for the question, I have struggled to understand the weather’s varying impact on this “region” (the Northern Rhone through the Saone valley). Basically I come back to what Kevin said. He is just much better at articulating it. Gamay does and Syrah presumably can grow in Beaune, but the nature of the wine isn’t as interesting as it is on more acidic and less fertile granite and schist. I can think of a number of Pinot examples from Switzerland grown on granite which are not as aromatic and graceful.
Great topic and tremendous quality of comments. I am enjoying this thread. Thanks to Tom for originating.
Paul, I don’t think the soil is the primary driving factor in this case. Syrah needs warmer temps than Pinot to ripen properly (properly, of course is a subjective metric, see Alban comments above, but we can probably get everyone to agree that there is a minimum threshold somewhere, say 20-22 brix). So I don’t believe that Syrah can regularly ripen properly in Beaune. We have good examples here in California of vineyard locations where both Pinot and Syrah are grown (Rhys and Peay are two that I’m familiar with), and Syrah in those places is always picked several weeks after Pinot, and definitely struggles to get ripe at the end of most growing seasons. So given that Pinot is close to the edge of being viable in Burgundy in most vintages, I think it’s safe to say that Syrah cannot be grown successfully there, and why I argue that climate is the most important factor, and soil next.
I was waiting for this comment to chime in on the soil chemistry part of it, and expand a little bit with no oenological knowledge, but that of clay chemistry. There are several reasons that the clay derived from weathered limestone is so important. Let’s first start with the genesis of clay in limestone soils, the type of derived material is dependent primarily on the proportions of cations (Ca, Mg, K, Na, etc), and the pH. Limestone is high in Ca and also high in ph, and is also the result of marine deposition of various organics, primarily organisms, which results in a high proportion of Si, or silica, and also an abundance of trace minerals. This promotes the formation of clay minerals (which are of various crystalline forms of Si) that have a high CEC because the basic silica tetrahedra is of the arrangement Si4O10 which has a net negative 4 charge, which must be balanced by cation replacement or bonding to other silica sheets with net positive charge. The CEC is due to the clay minerals overwhelmingly negative charge that attracts both H20 and then of course also soluble cations (hence CEC). These are contained in a diffuse double layer (DDL), of water around individual clay particles that physically holds water, and hence soluble minerals. With a shallow rock profile in young weathering stages, the result is an abundance of trace clays and minerals that are available to the vine through the presence of unoxidized soil horizons (low amounts of leeching, climatically speaking). The soils are fertile, but only in the sense that a well developed root structure can exploit the nutrient load over several years of establishment, unlike typical agricultural loam soils that provide nutrients with high nitrate content to plants with temporary root structures.
To summarize: Limestone weathers to favorable clay elements that retain water and soluble cations and are the most favorable to CEC, contains tons of Ca to raise pH, the DDL of clay particles retains moisture through periods where no precipitation is present, contains lots of trace minerals from it’s organic origins to provide further nutrient support, promotes root formation and decreased vigor as opposed to loam soils. As previously mentioned it is also well drained.
^^^
that guy knows dirt
Alan, I did a non blind comparison of 2003 Tablas Esprit and 2000 Beaucastel (big brother) recently. The Tablas did not come across as hot and showed far better in comparison than any of us would have expected. Tablas is also imho the only vineyard in Paso where the wines might actually improve with a little age (yes, I’m not much of a fan of Paso an is becoming less so with every year that passes.)
Peter, that’s interesting. In all honesty, I think even CdP has gotten too ripe in some recent vintages (notably 2007 and 2009), and is probably on par with Paso in that respect.
Great stuff Kenny.
I would be interested to hear a contrast of clay derived from limestone with clay derived from diatomaceous shales (also created by the deposition of organics). Two of our vineyards are located on clay soils above diatomaceous shales.
I’m more ignorant of the science behind it than I’d like to be (I’ll defer to Kenny) by I know the practice. I moved to Monterey in part because of the preponderance of limestone and calcareous soils in the area. Compared with the loams that dominate most of CA vineyards, these vineyards produce fruit with smaller berries, thicker skins, more intense flavors, and better balance. I make Grenache, Mourvedre, petite sirah and albarino from limestone or calcareous shale vineyards in the area. I’ve yet to find a local Pinot vineyard in a cool enough place with the soils but I’d like to. To that end, climate is important in that balanced ripening allows you to get to the soils. Too hot or too cold, the fruit gets in the way.
I’m of the opinion that limestone and syrah results in a very pretty but overly simple wine. I think granite lends grit and heft, which is important for syrah but often too much for Pinot. I use some syrah off limestone for blending every year.
There’s also a way that skin tannins ripen on limestone that is distinct. You lose the bitter tannin early without moving to simple fruity overripe skins. I find that a lot of loamy vineyards go from bitter to unidimensional real quick --and require things like oak and enzymes to get ‘there’.
Great discussion. Keep it up you guys–I suspect a lot of us are “lurking”.
Fair point. Lyon is only +/-4° warmer than Dijon between mid-March and mid-Oct but Lyon gets +2 weeks additional days +50° during the same time period. Warm weather is more stable in Ampuis even if it isn’t much warmer than Dijon. Touché.
Interesting comments on the Syrah grown on limestone in CA. Similar to a lot of the comments from growers in Rhone.
Yes, I have very little interest in Southern Rhone these days as well. Hard to believe given how much I used to buy. Must be getting old.
This question is much more difficult than it would appear! My knowledge continues more into engineering properties than the chemistry itself. But the genesis and parent material would be the more important consideration here because ultimately what you want to know is what clay particles did you end up with? For that I have to bust out my copy of Fundamentals of Soil Behavior by JK Mitchell of Cal Berkeley and do some brief research.
Since the dependence is primarily on the specific proportion and type of clay mineral that is formed in the weathering process(since we’re primarily concerned with CEC), and that is so heavily influenced by environmental factors, it can be difficult to generalize. But in general you end up with smectites, illite, montmorillonite, and vermiculites, (clay minerals) with varying pH and cation composition (guessing based on the California environment).
Shale is of various forms, even limestone. The key to diatomaceous shale is the resultant of high organic content in the depositional phase (diatoms). So really the primary difference in parent material is that claystone shale is of a more highly weathered phase than limestone (since it already contains clay with added organic content). Limestone does not and weathered forms are new silicates. My guess is that this would result in a lower proportion of Ca silicates than limestone in shales, and thus more alumina silicates(lower CEC).
A comment on the importance of Ca in CEC. The valence is important in replaceability of cations(higher is less motive). A typical replacement series would be as follows
Na>K>Mg>Ca>Al>Fe>Th
However it is possible to increase CEC to remove higher trivalent cations such as Al if the concentration of a lower valence ion is higher in solution.
So for common soil compositions Ca is least replaceable in relation to Na,K,Mg but more replaceable than Al. But it is not possible to predict these based on soil type alone due to environmental factors.
So we are left with knowing what the clay fractions are. The clay minerals of higher CEC are montmorillonite and vermiculite. Lower would be hydrous mica (illite with strong K component see above), saponite, and chlorite (Al substitutions). These can be measured in the lab with Xray diffraction techniques.
So the soils that derive from diatomaceous shales and limestone could end up being very similar since one has existing clay of unknown origin and one makes it’s own, and both have Ca. But certainly limestone will have the greater Ca providing the higher pH, which is known to have a positive effect on CEC. All things equal (ha!), I’ll take the limestone residual, but if the shale has favorable native clay and high diatomaceous content, they could end up with similar CECs. The shale CEC could be augmented by artificially raising the pH of the native shale soil with common agricultural additives.
Wow…great stuff Kenny/Kevin/Ian. Thanks for contributing here…though much of it is waaaay over the head of a simple little ole rocket scientist.
There actually seems to be much more Science behind the subject than I originally suspected.
Tom
Kevin I would be interested to hear what your actual findings have been at the various sites (CECs and pH). Either to validate, or throw cold water on my theories. If you have clay chemistry data that would be super juicy.
Kenny,
We do find our highest CEC clays on the shale-y vineyards. Our highest CEC is at Skyline which also has higher pH and some limestone in the melange of bedrock. Horseshoe and Alpine (diatomaceous shales) are a just a bit lower CEC and pH but still fairly high CEC overall. As you predicted, we usually do see lower CEC in the more acidic, lower pH soils.
On the Syrah and limestone topic, Jean Louis Chave has separate parcels of Hermitage on limestone, schist, conglomerate and sandstone. His favorite is the schist (metamorphic shale) not the limestone.
Thanks Kevin. It would be cool at some point if you could go full geek and task UC Davis with some clay composition analysis.
Something that came to mind after I had made some gross generalizations on CEC, is the prosaic, yet actually more applicable, concept of “total amount of stuff that matters”. Or in an engineering sense, unit analysis. Certain materials, limestone, shale, etc, may result in components that individually are of higher CEC, but that doesn’t necessarily mean they end up with a higher CEC per unit volume of soil. Claystone shales will inevitably result in a higher amount of free clay minerals on a shorter timeframe, although various proportions may or may not result in higher CEC per volume than others such as limestone, schist, etc. A young soil horizon of weathered limestone does not necessarily contain a high unit volume of high CEC clay mineral, for example, since erosion or time may not be in its’ favor for total clay formation. Which is to say, the fundamentals of the chemistry are important, but the big picture is more important, and is site specific. That includes morphology and also depositional history, and can explain why in some cases a weathered schist horizon may be better than a limestone horizon. The optimum level, and cation composition, of CEC soils is fleeting. Site specific evaluation is necessary, and the quickest way for a grower to that is simply CEC and pH. Although it seems a focus on total Ca composition is also important. Think we have it covered at this point.
Thanks for all the fine technical discussion. As a minor addition, the large grain size of the sub-clay limestone clay layers, and tendency toward flocculation, in addition to promoting rapid drainage, should maintain tiny, well-distributed air pockets within the soil, providing oxygen for cellular respiration, which should promote root maintenance and propagation - though soil shallowness would tend to constrain root depth, of course.
On the tangential point of minerals moving from soil to fruit, if even small mineral concentrations exist in the water taken up through the roots, when microscopic bits of soil are dissolved by rainwater, why wouldn’t those components not removed for nutritional purposes create corresponding mineral concentrations in the fruit? Or does gravity alone keep the non-water, non-cation-exchanged molecules from rising in the plant.
Because plants absorb cations through the root cell wall, they don’t absorb minerals, and plants use those cations to form molecules that are used in metabolism and to form complex molecules, not as flavoring. There are proteins in the root hair cell walls that to some extent regulate cation entry that are expressed by genes based to some extent on nutrient and water status of the vine. But you have to look at the total availability interaction of cations and relative charges because they tend to displace others in the soil solution and affect availability which is one of the key aspects of selecting rootstocks. Cation displacement is one of the reasons cations like calcium with two charges can be beneficial because they tend to displace single charge cations for example decreasing the availability of potassium in the soil solution and have the effect of devigorating vines. Also decreasing potassium affects juice and wine because it forms a precipitable salt with tartaric acid and raises pH. You tend to get a greater perception of minerality in wines that have lower pH because that perception is to some if not not mostly a tactile sensation on mucosal tissue in the mouth rather than a flavor. Calcium is magic stuff. From how it affects the availability of other cations to the physical effect it has on clay particles of causing them to clump together (flocculation) so instead of a dense, matrix that is anearobic and easily water logged, it becomes porous and drains, yet still has high cation exchange because of the number of small particles with electrostatic surfaces to hold cations ie. high nutrient retention. That is clearly visible when you look at the effect of the vein of dolomite running through the Côte de Nuits on the clay soils and argilo calcaire. Terroir is real, but its not flavor of soils, its the effect of soil chemistry and physics on the genetic expression of the vine, which translates into vine physical characteristics which translates into flavor.
Nice picture, but this isn’t limestone.