Wednesday, June 26, 2013

Earthiness in wine is unrelated to the soil

I have previously reported on Alex Maltman's view of the inapplicability of geologic terms as wine descriptors because geologic minerals have not been scientifically shown to transit from the soil into the grape berry and the resulting wine. I have also shown that "chalky minerality" is a tannin effect rather than a "mineral taste." In this post I will explore the source of another putative minerality term -- earthiness.

Joe Janish (wineweekly.com, Wine Term: Earthy) describes earthy wines as having " aromas and flavors of soil, minerals, vegetation, and or wet leaves." Voicing a widely held belief, Joe states "... it is believed that the earthiness comes from the soil in which the vine is planted."

Wine chemists beg to differ with this characterization. They see the earthiness in wine as an off-odor caused by geosmin (trans-1, 10-dimethyl-trans-9-decalal), a secondary metabolite (compound produced by an organism that is not required by that organism for growth, development, or reproduction) produced by the fungus species Penicillium expansum (M.H. Siddique, Study of the biosynthesis pathway of the geosmin in Penicillum expansum, Doctoral Thesis submitted to the University of Toulouse, 5/11/12; Lisanti et al., Oenological treatments for the removal of geosmin, responsible for earthy off-flavors, in wine, Paper prepared for the XXX1st World Symposium of Vine and Wine, Verona (Italy), 15-20 June, 2008; Florence Kennel, Bordeaux Boffin solves geosmin connundrum, Decanter.com, 1/14/05; R.R.M. Paterson et al., Why do food and drink smell like earth, Communicating Current Research and Education Topics and Trends in Applied Microbiology, 2007) or geosmin in combination with another earthy/musty-smelling secondary metabolite 2-MIB ( methyl-isoborneol) which is produced by the fungus Botrytis cinera (Siddique, Laguerche in Kennel, and Paterson et al.).

Geosmin, the name is a combination of two Greek words which translate to earth odor, exists as both (+) and (-) isomers and is responsible for a freshly plowed-earth odor in a wide variety of foodstuff to include drinking water, bottom-feeding fish, grape juice, and wine. Humans have a very low odor and taste sensitivity to the compound and, while deemd desirable at low levels, it is viewed as off-putting at higher concentrations. Siddique perceives the presence of geosmin to be "highly detrimental to the aromatic quality of wines due to its low olfactory perception threshold and stability during aging." Higher concentrations of the compound are generally attributed to the (-) isomer which is 10 times more potent than its (+) counterpart.

The source of geosmin appears to be the fungus Penicillum expansum which is found on rotten grapes. In a gas chromotography-mass spectrometry study of rotten Bordeaux grapes, 48 Penicillum-related species were examined and all of the geosmin-producing strains belonged to the P. expansum species (Siddique). The presence of geosmin in juice obtained from rotting grapes would seem to indicate that the P. expansum that developed on the grapes contributed to the geosmin in the wine (Siddique). According to Kennel, two to five clusters in a hundred are enough to contaminate a wine, requiring long-term barrel maturation (two years in the case of Pinot Noir) for dispersal. Lisanti et al., examined six treatments for decreasing the concentrattion of geosmin and found that treatment with grape seed oil appeared to be effective in reducing the earthy flavors in both red and white wines.

In many of the studies that have been done to date, geosmin is found in association with MIB, a product of Botrytis cinera. It is not clear exactly how they work together but scientists are willing to concede that the earthy smell could be a result of their collaborative work (Siddique, Laguerche in Kennel, and Paterson et al).

So, when confronted with odors such as mushroom, camphor, mossy, moldy, or earthy, think of grape selection, or judicious application of grape seed oil. Do not think soil.

©Wine -- Mise en abyme

Friday, June 21, 2013

Myths and legends: the "taste" of "chalky minerality" in wine

In my most recent post, I presented Alex Maltman's arguments against what he perceived as the myth of minerality in wines as evidenced by the frequency of geologic terms in tasting notes. In a comment on my post, reader Themeperks stated "We've all had wines with chalky, flinty, steely, earthy or other "mineral" characteristics. Putting those things in a wine wouldn't make it taste that way, so it's likely those characteristics arose in complex ways, and not necessarily from the soil being chalky, flinty, steely or earthy." The question here is, basically, if these "tastes" are not mineral, what are they and where are they from? The first term mentioned by Themeperks was chalky and that is the concept that I will address in this post.

Based on the work done by an Australian and French research team (S. Vidal et al., Use of an experimental design approach for evaluation of key wine components on mouth-feel perception, Food Quality and Preference 15, 2004) and reported on in Wine Business Monthly (Bibiana Guerra, Key Wine Components in Mouthfeel Perception, November 2011), we learn that chalkiness is an astringency categorization (along with pucker, adhesive, dry, medium-surface smoothness, and coarse-surface smoothness).

According to sensorysociety.org (and Richard Gawel, Secret of the Spit Bucket Revealed, aromadictionary.com), astringency is a tactile sensation, rather than a taste, and is primarily caused by polyphenolic compounds contained in certain foods (including wine) but can also be caused by acids, metal salts (such as alum), and alcohols. A key characteristic of astringency is the fact that it is difficult to clear from the mouth and, as such, builds in intensity on repeated exposure to the source.

The source of astringency in wines is tannins, "a heterogeneous group of phenolic compounds" with properties to include: astringency (caused when the tannin binds with protein in saliva; evidenced by mouth pucker and a bitter aftertaste); bitterness; the ability to react with ferric chloride; and the ability to bind with proteins (Dr. Bruce Zoecklin, Enology Note #16). 

There are two main types of tannins: hydrolizable and condensed (more properly called proanthocyanidins). Hydrolizable tannins are found in the bark of oak and other plants and are formed in the growing tree for the purpose of food storage. These tannins are called hydrolizable because they can be broken down into smaller components in the presence of an acid or water. Condensed tannins are insoluble and are found in tea, pomegranates, and the seed, skins, and stems of grapes.

Grape tannins are a combination of compounds (cathecin, epicathecin, epigallocathecin) which link up in chains and of which at least two need to be present for the compound to be termed a tannin. Seed tannins weigh, on average, 3.5 - 5mg per berry while skin tannins weigh in between 0.5 and 0.9 mg. Seed tannin polymers are shorter than skin tannin polymers (the longer the tannin chain the higher the astringency) yet seed tannins are perceived by winemakers to be harsher, greener, and more astringent than skin tannins and that is evidenced in the way that the berry is handled once it enters the winery. Oak tannins are astringent in tree matter and need to be seasoned and toasted -- as a part of the barrel treatment -- in order to increase their usefulness.

Grape tannins accumulate during the first period of berry growth with skin tannin synthesis beginning earlier than seed tannin synthesis and then ending with the conclusion of the first phase of growth. Seed tannin synthesis continues into the early period of berry ripening before concluding. Both skin and seed tannins continue to mature during the berry ripening phase.

Tannin release is a function of how the grapes are handled in the winery. Tannins are not desirable in white wines so white wine grapes are pressed lightly and there is no contact between the juice and skin. In the case of red wines, tannins are desirable for color, mouthfeel, and aging and there is extensive skin contact. The amount of tannins released are a function of skin thickness (Cabernet Sauvignon, Nebbiolo, and Syrah are thick-skinned and thus release more tannins than do thin-skinned varieties like Pinot Noir, Gamay, and Cabernet Franc), the length of maceration, and the number of cap punch-downs to which the must is subjected. Skin tannins release early and easily but then plateau. Seed tannin release is slow, steady, and long and requires alcohol as a solvent. Tannin extraction will continue throughout fermentation with the ratio tilting in favor of seed tannin at some time during the process (James A. Kennedy, Grape and wine phenolics: Observations and recent findings, Ciencia e Investigacion Agraria 35, 2008).

Once grape tannins are in solution, 80% undergo one or the other of the structural changes listed below:
  • Tannin-tannin linkages
  • Oxidative change
  • Acid-catalyzed reactions
  • Bind with anthocyanins (color compounds) to form polymeric pigments that ensure long-term color stability
  • Formations that provide structure and mouthfeel to wines.
Grape tannins provide color, flavor, structure, and texture to the wine and serve a preservative function. Oak tannins play an essential role in wine maturation in that they: (i) promote oxidation products (react with oxygen in the presence of a transitional metal to release activated oxygen which, in turn, oxidizes alcohol to acetaldehyde); (ii) produce astringency; and (iii) aid in the removal of off-notes. Tannin-anthocyanin complexes sediment out of wines as they age resulting in browner, less tannic wines.

There are two theories as to how astringency presents in the mouth (sensorysociety.org). (i) Polyphenols bind with the proteins in saliva and the resultant proline-rich proteins precipitate out (Gawel sees these precipitates as being reflected in the "stringy" salivary material that we spit into the buckets at wine tastings), thus reducing the ability of saliva to lubricate the mouth (this loss of "lubricity" is perceived as an increase in oral friction). (ii) The astringents directly effect the oral epithelium with a sensation of harshness presenting when the gums brush against the insides of the mouth. According to both Gawel and sensorysociety.org, individuals with high saliva secretion rates will experience lower levels of astringency.

Gawel alludes to three types of astringency:

  1. The feeling of having fine particles on the surface of the mouth; referred to by terms such as Powdery, Chalky (our key word), and Grainy
  2. Roughness of feeling inside the mouth; referred to by words such as Silky, Emery, Velvety, and Furry
  3. Causing the mouth to move; referred to by words such as Pucker, Chewy, Grippy, and Adhesive.

The foregoing has shown a berry rather than a mineral origin for the astringency type which manifests as a chalkiness on the palate. According to Guerra, this chalky sensation will increase with the addition of tannin and in the presence of anthocyanin and will be reduced with an increase in ethanol and in the presence of acidic polysaccharides.

So you are justified in talking about chalkiness in a wine but will be off-base when describing this sensation as "chalky minerality."


©Wine -- Mise en abyme

Tuesday, June 18, 2013

Minerality in wine? Fuggedaboudit

Or so says Alex Maltman of the Institute of Geography and Earth Sciences, Aberystwyth University, Wales.

In a previous post, I outlined a battle revolving around the role of soils in wine quality/typicity. Alex Maltman (Role of Vineyard Geology in Wine Typicity, Journal of Wine Research 19 (1), 2008) noted that it had become de riguer, when describing a vineyard, to specify its geology and this, coupled with the geological indications common in tasting notes, has served to infer "... a direct link between the vineyard substrate and the resulting wine." According to Maltman:
Such perceptions bolster a valuable tactic for the wine trade, as, being one of the few aspects of wine production that cannot be translocated or easily replicated elsewhere, a vineyard's geology is something that can be invoked to promote a wine's typicity, to give it a marketable uniqueness.
In a follow-up article (Minerality in Wine: A geological perspective, Journal of Wine Research, 2013), Maltman has honed in on minerality, a thoroughly modern (according to him) invention which had received no mention in the works of the "masters" (Peynaud 1987, and Vine 1997, for example) or the science-based tasting schemes (Jackson 2009 and Noble et al., Aroma Wheel 1987, for example). Maltman's 2008 and 2013 articles are built around a similar core argument but in the 2013 article, in addition to focusing on minerality, he advances explanations as to what tasters could be confusing with minerality. The latter aspect of his research will be dealt with in a later post.

There is, in general, a lack of understanding of the differences between minerals in foodstuff (of which wine is a part) and geological minerals (Maltman).


While it is true that the vine plant needs a variety of mineral nutrients, and that weathered bedrock is the source of much of these nutrients, the path from geological mineral to nutrient mineral is a protracted, rocky, and time-variant road.



To illustrate the latter point, Maltman uses the example of feldspar, the most commen geological mineral resident in modern vineyards. Feldspar is a family of minerals containing various combinations of minerals that are "ionically and covalently bonded into a crystalline lattice that gives a grain of feldspar strength and rigidity." This feldspar particle is bound together with a number of other mineral grains to form the aggregate we call rock or, in its fractured form, stone. The minerals contained in feldspar are not directly accessible by the vine plant. To be accessible by the plant the minerals have to be ionic and in solution. The process of transformation from the geological mineral feldspar to vine-accessible mineral nutrients is illustrated below.

Source: geology.csupomona.edu

Source: letslearngeology.com
The gulf between the vineyard chemical profile and that of the wine is further widened as a result of vine activity. The amount of nutrient ions absorbed by the vine roots is not directly related to the amount of nutrient ions in the soil. Rather, it is dependent on the transportation proteins and cell wall hydrophobic deposits among other factors. Further, once in the xylem, differential amounts of ions are directed to the various components of the vine architecture. Even within the berries there is a differential allocation of ions between, skin, seeds, and juice (Maltman 2013).

The disconnect grows even wider once cellar activities commence (shown below) and, as a result, the "proportion of mineral nutrients in finished wine bears only a complex, indirect, and distant relationship with geological minerals in the vineyard" (Maltman 2013).


After establishing a less-than-tenuous relationship between vineyard minerals and the mineral-nutrient signature of the finished wine, Maltman goes on to argue that minerality, as such, cannot be tasted in a wine. First, he argues, the concentration of inorganic material, in general, and mineral elements, in particular, in wine is miniscule -- between 0.15 and 0.4% for inorganics and very low levels for the mineral elements. Of the minerals, potassium has the largest concentration at 577 ppm (.06%) while calcium ranges between 30 and 200 ppm and magnesium registers at .005 ppm. Of the 50 organic elements identified in wine, 25 are trace elements (1 - 100 ppm) while 20 are ultra-trace (parts/trillion).

Compounding their relative scarcity in wine, these mineral elements have no flavor, a situation that also holds for geological minerals which are both solid and insoluble. Flavor-detecting organs in the mouth can only deal with solutions thus only sodium chloride, of all the geological minerals, registers a flavor in the mouth (Maltman).

So mineral nutrients resident in wine occurs in small amounts and are lacking in flavor. Vineyard geological minerals are flavor-free and would not register a taste in the human mouth. Aroma, the other component of flavor, requires volatilization in order to register on the organs on the olfactory bulb but neither rocks nor minerals possess this capability. Minerality as a taste descriptor, then, requires a leap of faith on the part of the taster.

How about texture, you ask? The geological minerals that existed at the beginning of the journey have been transformed beyond recognition in that they now exist as ions, rather than compounds, and in extremely small quantities. Any minerality imbuing capability would have to survive the journey detailed above and still have enough "surviving energy" in order to "infect" the completed wine in such a way that it exhibits "minerality" in a uniform manner.

Does Maltman's analysis consign minerality to the scrap heap of taste descriptors? Let me know your thoughts.

©Wine -- Mise en abyme

Wednesday, June 12, 2013

Battle over the role of geology in wine typicity

According to Christopher Bargman (Geology and wine in South Africa, Geoscientist 15(4), April 2005), soil is the major influence on the growth of the vine plant. It provides: (i) a supply of water; (ii) anchorage in the ground; and (iii) a source of nutrition. According to education.mhusa.com, " soil is more than just dirt." It is, instead, "... a complex system of decomposed rocks that have been enriched over time by decomposed organic matter." The classic soil profile is shown below.

Source: westone.wa.gov.au


According to Wolf and Boyer (Vineyard Site Selection, Virginia Cooperative Extension), the best vineyard soils "permit deep and spreading root growth" and provide a moderate supply of water year-round. Mark Chien (Soil and Site Selection Considerations for Wine Grape Vineyards, Pennsylvania State University) posits that wine grapes do best in moderately fertile soils that are unsupportive of vigorous vine growth. What are the soil characteristics that will permit "deep and spreading root growth" and year-round access to water? Those characteristics are presented in descending order of importance in the table below.


But to many in the business of wine production and wine marketing, these "rudimentary" roles for soils do not tell the full story of its contribution to the finished product. According to champagne.fr (the website maintained by The Comité Champagne, the trade association that represents the interests of Champagne Growers and Houses):
The subsoil of Champagne is predominantly limestone. So too are the outcrops of sedimentary rock (75% limestone), composed of chalk, marl, and limestone proper. This type of subsoil provides good drainage and also imparts the particular mineral flavor found in certain Champagne wines.
The official Burgundy wine website (bourgogne-wines.com) stipulates:
In Bourgogne, Terroir is a broad concept which includes both natural and human factors. ... The basis of Terroir is above all the sub-soil and soil from which the vine draws its nutrients and which create a secret alchemy of colour, aromas and flavours.
In a Wine & Spirits article (Life in the Dirt: Claude and Lydia Bourguignon interviewed by Carson Demmond, www.wineandspirits.com), the subjects extolled the virtues of minerality, its relationship with the soil, and the capability of detecting it through mouthfeel. Lydia -- an Agri-Food Scientist and an Enologist -- characterized minerality as "... the perception of the rocks in the soil, by the palate." Further, "with a properly managed soil, the roots will dig deep into the subsoil, and it's the subsoil that determines the gôut de terroir. Without deep roots, all you taste is the grape variety and the cellar technology." Claude (an Agricultural Engineer with a Ph.D in Soil Microbiology) agrees that the minerality has to be based on tactile sensations because minerals are scent-free: "When you have ... different elements, the mouthfeel of the wine will be different. We can taste it and say 'this vine grows on clay' when we've never even seen the terrain.

Jennifer Huggett (Geology and Wine: A Review, Proceedings of the Geologists Association, 2006) and Alex Maltman (Role of Vineyard Geology in Wine Typicity, Journal of Wine Research 19 (1), 2008) are not as accepting of this central role of soils as is broadly presented. Maltman says that it has become de riguer when describing a vineyard to specify its geology and this, coupled with the geological indications common in tasting notes, has served to infer "... a direct link between the vineyard substrate and the resulting wine." According to Maltman:
Such perceptions bolster a valuable tactic for the wine trade, as, being one of the few aspects of wine production that cannot be translocated or easily replicated elsewhere, a vineyard's geology is something that can be invoked to promote a wine's typicity, to give it a marketable uniqueness.
Huggett uses two examples to knock back this idea of geology impacting wine quality/typicity. First she mentions the oft-noted "flinty" character of Chablis but wonders how such a material, being insoluble in normal groundwater, would contribute to the flavor of any wine. Further, she does not know what the flavor of something so hard and insoluble would be.

Her second push-back relates to Chablis and Kimmeridgian soil. Chablis is the "big island" in the Kimmeridgian chain and is home to some of the finest Chardonnay known. The defined region was recognized in 1923 by the Wine Tribunals as being grown on a sub-soil of Kimmeridgian limestone while wine grown anywhere else in Chablis would be classed Petit Chablis. The mid-slope in Chablis maps almost perfectly to the Kimmeridgian outcrop with the soft, carbonate-rich mud rock being capped by Portlandian Barrios limestone and supported by Calcares à Astarte, itself a limestone . This south-facing Kimmeridgian slope has significant sun exposure and is home to the Chablis Grand Cru vineyards (Wilson (Terroir) notes that geologic conditions identical to those experienced by the Grand Cru slope extend both northeast and southwest but that the vineyards on those sites are classed as Premiers Crus. That is an indication that Kimmeridgian soil is not the key ingredient in the making of a Grand Cru Chablis.). As a matter of fact, the reference to Kimmeridgian limestone in the definition of Chablis was discontinued in 1976, a tacit admission, according to Huggett, that "slope and orientation are of greater importance to wine quality in Chablis.

What do you think? Is soil a support mechanism or is it a key player in wine quality and typicity. I will explore the arguments of these two contrarians in upcoming posts.


©Wine -- Mise en abyme

Friday, June 7, 2013

Guild of Sommeliers Alto Adige Master Class: The red wines

On Thursday, May 16th, Master Sommelier Geoff Kruth led a Guild of Sommeliers Master Class on wines from the Alto Adige (Südtirol) region. The tasting component of the class was divided into white and red flights of five wines each. I covered the white-wine tasting in a prior post and will discuss the red wine tasting herein.

First up for the red wines was the 2011 Cantina Bolzano Santa Maddalena Classico Huck am Bach. Cantina Bolzano is the result of a 2001 merger between the producers of Gries (in business since 1908) and Santa Maddalena (a going concern since 1930). The Co-op has one location in Gries and one in St. Magdalena and draws upon 320 ha -- at elevations ranging between 240 and 800 m -- in eight vineyards for its fruit. The grapes for the subject wine is sourced from the Huck am Bach vineyard which is located on a south-facing hill at 330 m on ice-age moraine and sandy soils. The wine is made from 90% Schiava and 10% Lagrein, with the selected grapes subjected to "traditional" red wine fermentation and aged in large wooden barrels.

Notes: Low color concentration. Floral and expressive. Light-bodied. Low tannin. Tame red fruit. Unusual texture. Clean and elegant. Andrew McNamara found this wine to be "muskier and funkier" when he went back to it and the end of the tasting. $18 SRP.

Consolidation appears to be the rage in Alto Adige. Nals Margried, producer of the 2011 Schiava Galea, is a 140-grower Cooperative which resulted from the 1985 merger of The Cellars Nalles (in business since 1932) and Magre-Niclara (1954). Growers farm 150 ha of vines at 200 - 900 m elevation using natural methods and Pergola and Guyot training. The philosophy of the winemaker (Harald Schraffl) is to preserve the characteristics of the soil and variety as embodied in the fruit brought to his cellar door. This wine is 100% Schiava made from hand-harvested, rigorously selected grapes that were produced by 100-year-old vines resident in the Galea Vineyard. The grapes were macerated for 6 days in cement tanks prior to fermentation with cultured yeasts. The wine underwent 100% malolactic fermentation and then spent 5 months on the fine lees. The wine is aged for 5 months in large oak barrels and then spends a further 2 months in bottle. A total of 35,000 bottles were produced in this vintage.

Notes: Different color and flavor profile than the Cantina Bolzano. Red fruit with some pungency. Freshness. Appealing finish. SRP $22.99.

Cantina Andriano (2011 Cantina Andriano Pinot Nero) was founded in 1893 as the first wine Cooperative in Alto Adige and was purchased in 2008  by Cantina Terlano. The Andriano vineyards are protected to the west by Mt. Gantleopl and eroded sedimentary rock from this dolomite peak has been deposited at the base of the winery's valley providing excellent soil for vine-growing.  Grapes for the subject wine are sourced from the Mazzan Vineyard, a 500-meter altitude vineyard which, as a result of its height, gains access to a lot of sunlight. The vineyard has a northeast-southeast exposure and sits on red clay and lime soils which are seeded with calcareous dolomite stones. Yield is 90 hl/ha. The grapes are fermented in stainless steel tanks and undergo malolactic fermentation. The wine is aged in large oak barrels.

Notes: Smokiness on the nose. Dark, brooding, spicy character. Non-complex. Rhubarb, sour red fruit, cranberry. One taster compared it to an Oregon Pinot of 20 - 30 years ago. SRP $23.

The 2011 Elena Walch Lagrein Selezione is sourced from vineyards that sit at 300-m elevation on limestone soil high over Lake Caldaro. In addition to the Lagrein, Chardonnay and Sauvignon Blanc are also grown here. The wine is 100% Lagrein and was fermented over 10 days in stainless steel tanks. Malolactic fermentation occured in large wooden oak barrels with aging in barriques.

Notes: Color concentration. Violets on the nose along with a spiciness. Full-bodied. Dark fruits. Medium tannin and acidity. Good texture. SRP $15.


The 2010 Manincor Lagrein Rubatsch is sourced from a 400-year-old estate currently owned by Count Michael Göess Enzenberg. The biodynamic estate covers 463 ha of orchards, vineyards (five), woodlands, and meadows. The Lagrein is a blend of grapes from the Rubatsch (two-thirds) and Seehof (one-third) vineyards. Rubatsch is located in Terlano, is southwest-facing, and sits at 250 meters elevation on sand mixed with eroded porphyry soil. Seehof is located in Kaltern and sits at the same elevation as Rubatsch but its soil is sand and clay mixed with limestone gravel. The grapes are fermented (two weeks) with natural yeasts in open-top oak vats during which process the cap is punched down to ensure full capture of color and flavor. The wine is aged for 14 months in 1/10 new oak barriques.

Notes: Extracted color. Over-the-top vanilla. Dill. Rioja-like oak. Pure fruit. Unbalanced with dominance of acid, oak, and tannin. Long-lived. Will pair well with heartier dishes. SRP $39.




©Wine -- Mise en abyme

Wednesday, June 5, 2013

Loire Valley wine region soils: Origins and characteristics

Winegeeks has identified Kimmeridgian as the top vineyard soil in the world but has erroneously attributed that soil type to the totality of vineyards in Burgundy, Champagne, and the Loire Valley. I have set the record straight by, first, identifying the locations where Kimmeridgian soils can actually be found and, second, clarifying what soil types are to be found in Champagne, Burgundy, and the Loire. In this, my final post in the series, I discuss the origin and identity of the soils of the Loire Valley.

The Loire Valley wine region is an agglomeration of appellations located on the slopes and plateaus that line the river's 620-mile course and associated areas of its many tributaries. In the course of its passage, the Loire River transits varied climates and soil types and, as a result, the region is characterized by a diversity of wine styles. While not as famous as other French wine regions (Bordeaux, Burgundy, Rhone), the Loire is understood to produce the definitive expressions of Sauvignon Blanc, Chenin Blanc, and Cabernet Franc.

The broader Loire Valley wine region is further divided into five sub-regions which are, from east to west: Central Vineyards; Touraine; Saumur; Anjou; and Pays Nantais.


The figure immediately following is a high-level geological map of France. The second figure below shows a more detailed geology of the Paris Basin but also shows the course of the Loire River from its origin deep in the "old rocks" of the Massif Central, through the Jurassic and Cretaceous strata surrounding the Paris Basin, through the Tertiary strata of the Paris Basin, then again into the outlying strata of the Upper Cretaceous, and, finally, into the old rocks of the Massif Armoricain at Anjou. I will follow this geological course in describing the soils associated with the region.


Central Vineyards

I have previously discussed the formation of the Kimmeridgian chain and identified Pouilly, Sancerre, and Menetou-Salon of the Central Vineyards sub-region of the Loire Valley as components of that chain.

Lower Loire

The overarching geology of the Lower Loire is as follows: Cretaceous of Paris Basin overlaying Jurassic strata for Touraine; Cretaceous of Paris Basin over Jurassic for Anjou-Saumur until southeast of Angier and "old rocks" of the Massif Armoricain over Jurassic thereafter; and, old rocks of Massif Armoricain over Jurassic for Pays Nantais.

Touraine to Anjou

Soil formation in this zone has benefited from a number of contributory events. (i)The receding seas of the Late Cretaceous left deposits of sand and flinty clays in their wake (Wilson). These deposits have proven to be less-than-perfect as vineyard soils but they help in the aeration of the underlying chalk soils. (ii) During the Eocene period (Early Tertiary), rivers deposited sandy gravel which cemented into "flights of steps."

The Loire transits the Paris Basin through the soft rocks of the Cretaceous and the surroundings present as rounded hills -- with varying degrees of steepness -- topped by cap rocks formed from cemented Tertiary gravel. The composition of the slopes are shown in the figure below and are expanded upon in the table following.



Anjou and Pays Nantais

Southeast of Angiers, we see a clear soil delineation which the locals refer to as "Black Anjou" and "White Anjou." White Anjou refers to the white, chalky limestone of the Paris Basin while Black Anjou refers to the dark slate and stones of the Massif Armoricain -- the "old rocks."

The old rocks of the Massif Armoricain are the surviving elements of a once-mighty mountain range called the Hercynian whose origins extend back into the Cambrian Age of the Paleozoic Period. The material of this mountain range included schists, graywackes, limestone, lavas, tuff, granite, and puddingstones, among others, formed during the Paleozoic. These materials had, in turn, been deposited on remnants of the eroded Caledonian mountain range which had itself been formed in the Proterozoic Period.The Massif Armoricain was subjected to erosion and weathering during the Mesozoic such that its southern portion became a plain into which the seas of the Paris Basin advanced during the Upper Cretaceous.

In addition to the indignity of erosion to a plain in the south, the old rocks of the Massif Armoricain underwent a number of physical changes (Wilson):
  • The original thick shale deposits metamorphosed into schists and slates
  • Sandstones became hard quartzites
  • Limestones became compacted or marbelized
  • Granites and old volcanic rocks also metamorphosed.
The hardest of the old rocks survived the weathering and became ridges while others became excellent soils. These rocks contain biotite mica, serpentine, and other dark minerals which release valuable mineral nutrients when weathered to clay (Wilson).

In addition to the soils created by weathering/erosion and the intrusion of the Cretaceous Seas, the Pays Nantais region was affected by Mid-Miocene Atlantic Ocean intrusions which deposited fossiliferrous sands and pebbles in the region.

The geological map of the Massif Armoricain is shown below.


A summary of the soils distribution in the Loire Valley region resulting from the activities described in the foregoing is provided in the following three figures.

Soils of Central Vineyards, Loire Valley (Sources: Data -- Wilson (Terroir);
base map --  Guildsomm)

Soils of Touraine, Loire Valley (Sources: Data -- Wilson (Terroir);
base map -- Guildsomm)

Soils of Anjou and Pays Nantais, Loire Valley (Sources: Data -- Wilson (Terroir);
base map -- Guildsomm)

A discussion of the soils of the Loire Valley wine region would be incomplete without mention of tuffeau, the porous, chalky limestone which is held in high regard from Touraine to Saumur. This soil-type is generally found in tabular deposits containing fragments of mica and sand and adds valuable chemical and physical properties to the soil profile (Wilson). It is noted for its ability to retain heat (thus helping in ripening) and is well-drained. It is widely used as a building material in the region and winemakers generally carve their underground cellars out of tuffeau deposits.

This then concludes the series on defining in full the soils of Champagne, Burgundy, and The Loire Valley, soils which had been mis-characterized as Kimmeridgian. I have shown that Kimmeridgian represents only a small portion of the soils of each of these regions and that a wide diversity of soils exists within and between said regions.


©Wine -- Mise en abyme

Sunday, June 2, 2013

Guild of Sommeliers Alto Adige Master Class: The white wines

On Thursday, May 16th, Master Sommelier Geoff Kruth led a Guild of Sommeliers Master Class on wines from the Alto Adige (Südtirol) region. I described the wine region component of the Master Class in a prior post. The tasting component was divided into white and red flights of five wines each. I cover the white-wine tasting herein.

The tasting was held at Khong River House in Miami Beach and was open to Guild members who had registered to attend the event. I am very familiar with the Miami Beach area but was unfamiliar with the establishment where the event was being held. The tasting was scheduled to begin at 11:00 am and I arrived at around 10:45 am. The restaurant is located at the corner of Meridian Avenue and 16th Lane North and when I checked in at the Hostess stand I was directed to a stair at the back of the restaurant which took me to the second floor room in which the tasting was to be held. The low-ceilinged room was furnished with white-tablecloth-clad tables separating inward facing chairs all fronted by a large screen and projection equipment. Each seating position was equipped with glasses, spittoons, and sundry event documents. The wines to be tasted were resident on a bar to the right side of the room as you entered. As an early arrival, I was invited to take a seat wherever I desired.


Geoff Kruth was joined in this endeavor by Andrew McNamara MS, the freshly minted Director of Fine Wine, Premier Beverage and Augustan Wine Imports.

 

The first white tasted was the 2011 Erste + Neue Pinot Grigio. Ernst + Neue is the wine cooperative resulting from the 1986 merger of Erste (first) wine cooperative -- founded in 1900 -- and Neue (new) wine cooperative -- founded in 1925. The wine is from the Oltradige region and the appellation is Alto Adige DOC. The grapes for the wine were grown in limestone-endowed moraine deposits on Pergola-trained vines. Yield was 85 hl/ha. The wine was fermented and matured in stainless steel tanks and was kept in close contact with the fine lees for an extended period.

Notes: This wine had a lemon rind character on the nose and tart fruit, waxiness, and a "kiss of lees" on the palate. It was light and delicious with more apparent acidity and less grey color than is characteristic for Pinot Grigio. The finish was thin and short. Suggested retail price for this wine is $15.

The second wine tasted was the 2011 Peter Zemmer Pinot Bianco. Peter Zemmer was established in 1928 in Cortina s.s.d.v in Alto Adige and has been making wine from grapes sourced from the best vineyards on the valley floor and steep slopes near the estate since then. Vineyard soils are stony, sandy, and chalky and yields -- at 60 hl/ha -- are tightly controlled. Grapes are hand-picked and brought into the cellar where they are pressed and then clarified through natural settling of the sediments. Alcoholic fermentation is conducted in temperature-controlled stainless steel tanks using pure yeast strains. The wine is subjected to extended lees contact and mature in both large and small barriques.

Notes: This wine had a hint of sweet white flowers and green apples on the nose. Exploded on the palate with vibrant acidity and nectarine notes. Great texture and weight. This wine retails for $16.99.

The next wine up was the 2010 Cantina Terlano Sauvignon Blanc Quarz. Cantina Terlano (located in the municipality of the same name) is a Cooperative (143 growers, 165 ha of vines, 1.2 million bottles/year production) that is noted for long-lived wines holding, as it does, 20,000 bottles with vintages ranging from 1955 to the present. Grapes are sourced from seven different sites and the resulting wines (70% red, 30% white; all DOC) are marketed in three different Quality lines (Selections, Vineyards, Classics) and an annual Rarity (must mature in cellar for 10 years prior to release). Quarz is grown in Terlano at altitudes ranging between 250 and 500 meters on slopes with SSE exposures and gradients of between 5 and 35%. Yields are 42 hl/ha. The grapes are manually harvested and those selected are subjected to whole cluster fermentation. After naturally settling, the juice is fermented slowly in temperature controlled containers and are aged on the lees for 9 months (50% stainless steel tanks, 50% large wooden barrels). Blending occurs 3 months prior to bottling.

Notes: The wine was intensely aromatic with citrus, green papaya, papaya skin, sweet basil, and a rusticity on the nose. Weighty on the palate with vibrant fruit and mineral notes. A long, gritty finish. An excellent wine. Retails for $60.

The 2011 Abbazia di Novacella Kerner Praepositus is produced by an Augustinian Order of monks whose Abbey was founded in 1142 and whose reigning Abbot has responsibility for all aspects of life on the property. The Abbey is located in Alto Adige's Isarco Valley and is Italy's northernmost winery. The Abbey has three major wine production areas: one in the surrounding valley and the remaining two in southern Alto Adige. The soil around the Abbey is granitic schist. Wines are produced as either Classic or Premium (Praepositus). The Kerner (a cross of Schiava and Riesling) is produced from grapes grown at elevations of 600 meters in the municipalities of Bressanone and Varna on SSW exposures and 25 - 40% gradients. The vines are Guyot-trained with planting densities of 6000 vines/ha and yields of 50 hl/ha. The wines were fermented in stainless steel containers using natural yeasts and spend 3 months in bottle prior to release.

Notes: Citrus, apricot, and peach with some oiliness on the nose. Andrew id'd some Gruner and Riesling elements. Sweet citrus on the palate. Weighty with a long finish. Retails for $30.

The final white wine tasted was a 2011 Tenuta Klaus Lentsch Gewürztraminer Fuchslan. The Hemberg Farm, with a pedigree that stretches back to its first mention in a 12th-century document, is located at the beginning of Alto Adige's Isarco Valley. This 27-ha farm was purchased by Klaus Lentz and he has dedicated the 3 ha of plantable land to single-vineyard offerings: Eichberg for Veltliner; Fuchstan for Gewürztraminer; and Bachgart for Pinot Noir.  Vineyard soils are clay-gravel at elevations ranging between 400 and 600 meters. Vines are trained both Pergola and Guyot. After harvesting, the wines are cold-macerated and then gently pressed and fermented. The wine is racked off the lees after two weeks and placed in steel barrels for maturation on the fine lies. Bottling occurs in June of the year following harvest.

Notes: Complex aromatics. Rose and lychee, floral palette. On the palate, fruit complex, weightiness, elevated alcohol, and phenolic bitterness. Fermented completely dry. The MSs felt that the complexity of fruit would work well with strong cheeses and complex dishes. This wine retails for $30.


I will cover the red wines in a future post.


©Wine -- Mise en abyme