Monday, May 28, 2018

The Mt. Etna viticultural environment

The Etna Consorzio has decreed that Etna DOC wine should meet the following varietal requirements:
  • Etna DOC Rosso (and Rosso Riserva) -- to be made from the indigenous varieties Nerello Mascalese (> 80%) and Nerello Cappuccio (< 20%) plus up to 10% of other non-aromatic grape varieties (red or white)
  • Etna DOC Rosato -- same as for Rosso
  • Etna DOC Spumante -- minimum 60% Nerello Mascalese and maximum 40% of other Sicilian grape varietals
  • Etna DOC Bianco -- to be made from Carricante (> 60%), Catarratto (< 40%), and up to 15% of other non-aromatic grapes such as Minella or Trebbiano
  • Etna DOC Bianco Superiore -- to be made from Carricante (> 80%) and Trebbiano, Minnella, or other non-aromatic Sicilian grape variety (< 20%). All grapes to be sourced exclusively from the area of Milo on the eastern side of the volcano;
and should be made from grapes grown in the delimited area illustrated in the map below (Wines not adhering to these requirements are free to employ the IGT Terre Siciliana designation.).

Etna growing zones

In this post I describe the viticultural environment -- a mix of physical and built environments -- that has been deployed in order to allow winegrowers to effectively meet Consorzio and consumer demands.

Climate
At 3,350 m (10,991 feet), Mt. Etna is the highest mountain in Sicily. Marco Perciabobco of the Department of Agriculture, Sicily Region, describes the region's climate as "mesotermic humid sub-tropical with dry summers." He sees it as a typical Mediterranean climate characterized by an average temperature (coldest month < 18℃, in warmest month > 22℃) and a rainy period mostly concentrated in the autumn and winter months. Rainfall in the region is distributed as follows: between 1.000 and 1.200 mm/yr on the northern, eastern, and southeastern slopes and 500 mm/yr on the southwest slopes.

According to Nesto and di Savino (The World of Sicilian Wine), at the highest elevations for viticulture, the climate is similar to North Italy's, becoming more Sicilian as you proceed downslope. As a result, growing environments differ depending on altitude and aspect.

Etna elevation map. Source: mmsolucoesweb.com.br
The chart below shows the impact of altitude on the grape-growing environment. According to Nesto and di Savino, conditions at the highest elevations are particularly helpful for white and rosato wines and grapes used in their production can be found growing as high as 1300 m (4265 feet). These high-elevation climatic conditions also reduce the incidence of vine pests and diseases and naturally limits vine yield. Below 900 m, conditions become more suitable for red wine production.


As shown on the below chart, growing conditions are also significantly impacted by aspect.

Data from Nesto and di Savino

The Nebrodi Mountains offer some protection to the north slope of Mt Etna but some wind does make it over the top, bringing rain in the autumn and winter and moisture year-round. There are some benefits to this moisture though. The runoff, unlike the case for the runoff on the eastern and southeastern slopes, proceeds downhill at a moderate pace and is absorbed by the lava beneath the soil, This water store then becomes available to the vine roots during the growing season. The major beneficiary of this process is the area between the towns of Solicchiata and Randazzo. The wind from the northeast blows steam from the vents to the southeast creating a shadow which serves to reduce evaporation.

The southeast and eastern slopes are unprotected from the autumn and winter rains but the combination of rapid runoff and early morning sun contribute to their attractiveness as growing regions (especially for whites). The Foti Aeris vineyard is located on the east slope and, as explained by Salvo, lies between the mountain and the sea and the warm air from the latter meets with the cold air from the former over Milo with the result being significant rainfall over the entire growing area.

In addition to the rain, growers have to contend with year-round winds which can attain speeds of as much as 50 miles/hour. There are beneficial aspects to the winds, however. Moisture dries out rapidly, keeping vine diseases at bay and making it easier to farm organically. As a result, the vineyard makes it through the growing season with only sulfur and copper sprays. In addition, the sea and wind combine to imbue the Carricante grown on this side of the mountain with a saltiness that is not evident in Carricantes grown on the north face.

Terra Costantino is a winery located on the southeastern slope of the mountain and experiences markedly different climatic conditions than do north-slope-resident wineries. For example, it is warmer in the southeast than in the north; 4 to 7 degrees warmer, as a matter of fact. 

The west slopes are generally the worst for quality wine production because of the late arriving sun.

Soils
"All Etna soil rests on, or directly derives from, lava that flowed and hardened for thousands of years, along with ejected pumice, lapilli, and windblown volcanic ash" (Nesto and di Savino).

Historically, eruptive events at Mt Etna have been of the Strombolian style but occasional Hawaiian-style eruptions generate considerable lapilli fall on the flanks (The Strombolian and Hawaiian styles are described in the table below.). Large active volcanoes with the Etna eruptive style present some of the most complex soil-forming environments on earth (James, et al.).

Source: http://www.geology.sdsu.edu/how_volcanoes_work
Factors such as diversity in age and characteristics of volcanic materials, land surface morphology, local climate, vegetation, and land-use history all contribute to complex soil spatial patterns. In the profile dimension, complex soils result from intermittent tephra deposition, anthropogenic disturbance (in the case of Mt Etna, over 70% of the vineyards are terraced), erosion and subsequent deposition. According to James, et al., "soil profiles may reflect the amount and frequency of tephra deposition as much as 'normal' profile-forming soil processes operating on stable surfaces."

Landscape Formation
Volcanism in the Etna region began during the middle Pleistocene, at around 600 ka. The peak today stands at 3350 m elevation and the base is 40 km across. At elevations below 1100 m, lava varies in age from the 2014/2015 flow to the 500,000-year-old tholeitic basalts of a small area on the lower part of the southern flank (James, et al.). The terrain of historical (12th century to today) flows, as well as some pre-historic flows, is dominated by aa lava (basaltic lava with a rough surface, pahoehoe (basaltic lava with a smooth or billowy surface), and toothpaste (transition between aa and pahoehoe) morphology (James, et al.).

On Etna, depositive explosive activity from the summit crater is frequent with less frequent eruptions, often with higher effusive rates, from the flank vents and Strombolian activity from vents high on the volcano. The tephra varies in deposition rate and particle size with distance and direction from the source and accumulates unevenly on rugged lava surfaces. As an example, areas on the western and northwestern slopes of Mt Etna are barren rockscapes due to insufficient topsoil for significant vineyard development.

Soil Formation
As described above, volcanic activity on Mt Etna is both effusive (lava flows) and explosive (airborne ejection of pyroclastics). According to Nesto and di Savino, the lava flows create a patchwork of terroirs that is pertinent to any discussion of Etna contradas. Initial flows are barren rock pasteurized by heat which, after cooling, require hundreds of years to erode into soil and develop hummus, and, in so doing, become suitable for vines. The erosion product is sand rich in potassium and other minerals. Organic matter, created initially by the growth of micro-organisms (and later by plants and animals), results in rich, fertile soil.

But, according to Marco Perciabobco (Department of Agriculture, Sicily Region), soil parent material in the Etna environment is primarily pyroclastic (My post on volcanic soils detail the weathering of these materials). Weathering of this coarse-textured parent material, according to Marco, produces soils with an "aerated hypogeal (underground) environment and the following characteristics:
  • Extremely well suited for the growth and development of vine roots
  • Soil water stagnations are rare
  • They warm easily (this generates stable conditions for the occurrence of the chemical reactions required for the weathering of the finest materials).


    Soil Distribution
    According to Perciabobco, the Department of Agriculture's soil survey dataset shows five different landscape systems in Etna: northern; northwestern; eastern; southeastern; and southern. The soils of these environments differ in the degree of weathering of the primary clay minerals. From north to south wetness decreases and so does weathering of the volcanic constituents. The soils of the northern landscape, when compared to the soils of the south, are finer textured, have a higher organic matter content, and a have a higher value of cation-exchange capability.

    Tenuta di Fessina's main vineyard is located in Contrada Moscamento (Muscamento in the dialect) in the commune of Rovitello on the north face of the mountain. The vineyard soils date back to between 4000 and 15,000 years ago, and is comprised of pumice and light sand enriched with iron, copper, manganese, and potassium. Soil depth ranges between 10 and 12 meters.

    Barone di Villagrande (Milo on the eastern face) was the beneficiary of the formation of the valle del bove, the result of the collapse of a dormant volcano. The collapse resulted in landslides that carried debris as far as the coast. The Villagrande soil is rich in iron and copper and has adequate amounts of potassium, phosphorous and magnesium. It is poor in nitrogen and calcium-free.

    Communes and Contradas
    A ministerial decree dated September 27, 2011 has updated the requirements of the 1968 decree as regards production zones and labeling requirements. The decree lists 20 communes and 133 contrade with defined borders within the DOC and allows for placement of contrada names on the label if all the grapes used in the wine were sourced from the subject contrada.

    "The production area of the appellation of origin covers part of the territory of the municipalities of Aci, Sant'Antonio, Acireale, Belpaso, Biancavilla, Castiglione di Sicilia, Giarre, Linguaglossa, Mascali, Milo, Nicolosi, Paterno, Pedara, Piedimonte Etneo, Randazzo, Sant'Alfio, Santa Maria di Licodia, Santa Venerina, Trecastagni, Viagrande and Zafferana Etnea, on the slopes of Etna, in the province of Catania" (www.enotecaregionalesiciliana.it/listings/vino-etna-doc/).

    In their explanation of the formation of contrade, Nesto and di Savino state thusly:
    Lava flows radiate down from Etna's summit, more or less, like the spokes of a wheel from a hub ... All Etna soil rests on or directly derives from lava that has flowed and hardened for thousands of years, along with ejected pumice, lapilli, and windblown volcanic ash. There are lava flows upon lava flows upon lava flows. The hardened flows on the surface each have a different age and different soil constituents.
    Vinifranchetti.com describes the same process a little more colorfully and, further, relating it to territories and wine:
    Thousands of mouths across a fifty-kilometer diameter on Mount Etna have spit lava from every different depth under the earth, covering the surface of the volcano where vines take root. Flowing lava -- descending sometimes dense and slow, at times fast as water - eventually stops, spreading and hardening at various altitudes. After cooling for many years, these flatter areas over the centuries become established properties, each one producing a different taste of wine because of the different mineral origin of their soils and, more importantly, because of the grain that the lava had broken into during its cooling process: sand, gravel, powder, or rock. Under the same old names the properties became territorial subdivisions called contrade, and, with regards to wine, they represent Etna's own version of a cru.
    Contrade as territorial designations have gone the way of the dodo bird but not so its relevance for wine. According to Nesto and di Savino, of the cadre of new winemakers to breach the Etna walls in the early 2000s, Marc de Grazia was the first to "promote the connection between Burgundy Crus and Etna contradas and between contradas and lava flows." Further, say the authors, "Certain Etna producers support contrada labeling because it connects Etna to the concept of terroir and, from a marketing standpoint, models Etna on Burgundy, the wine zone with which the concept of terroir is most closely associated."

    Salvatore Giuffrida, the consulting agronomist for Valentini, Gambino and the IRW, cautions against this focus on the mineral content in the lava flows. Speaking to Nesto and di Savino, he indicated that exposure, soil depth, and elevation had greater impacts on vines and wine flavor than did the mineral differences between lava flows.

    Winemakers across the region have hearkened to the practice and advice of early adapters such as de Graci and Franchetti and are producing contrada/cru wines in greater numbers.

    The map below is a recent addition to the literature and attempts to capture the contradas in the communes on the north face of the mountain.


    While a noble first step, I have a number of issues with the effort:
    • It only captures the northern slope of the mountain
    • It does not clearly delimit the Communes
    • It is not clear which Contradas are associated with which Communes
    • It is not clear where the boundaries fall between the various Contradas.
    Grape Varieties
    Carricante
    Carricante is an ancient white variety -- prevalent on Mt Etna's eastern face -- that yields low-potassium, low-pH, high acidity wines (benanti.it). The bunches are of average length at ripening, with medium-sized berries of a green-yellowish color.

    Carricante (tenutaterrenere.com)
    Frank Cornelissen, one of the leading winemakers on the mountain, has historically viewed the variety as too acidic to produce world-class wine. Ian d'Agata, author of Native Wine Grapes of Italy, on the other hand, is quoted in Szabo's Volcanic Wines thusly: "potentially one of Italy's greatest cultivars ..." that "... when properly tended to, yields wines of great longevity and intense mineral character."

    According to Salvo Foti, long-famed viticulturist, Carricante vines have to be somewhere between 10- and 15-years old in order to begin giving great concentration. Salvo said that both his father and grandfather worked Carricante and the wine's high acidity was extremely important in the days before widespread access to refrigeration. The wine is also great for raw fish, the main dish in the area.

    There are some 100% Carricante wines on the market but the grape is usually the primary varietal in an Etna DOC wine. It is also used, at lower elevations, to lighten the color and body of Nerello Mascalese and Nerello Cappucchio blends.

    Catarratto
    Catarratto is a high-yielding, low-acidity Sicilian white grape variety. It is the main grape used in the production of Marsala but on Etna is primarily blended with Carricante. There are two clones -- Commune and Lucido -- with the former having more acid and less sugar than the latter as well as being the clone of choice on the mountain.

    Catarratto (etnawine.it)
    Catarratto does not engender as much discussion on the mountain as does Carricante.

    Minnella
    Minnella is a white-berry vine that is indigenous to Etna where it is mostly found in old vineyards interplanted with Nerello Mascalese and Carricante. This is an early ripening variety.

    Nerello Mascalese
    Nerello Mascalese is the most important variety on Mt Etna. In older vineyards in can be found interplanted with Nerello Cappucchio while newer plantings position these varieties into separate rows or blocks to facilitate cellar rather than field blends.

    Nerello Mascalese (tenutaterrenere.com)
    The vine is vigorous and is readily affected by:
    • Vintage conditions
    • Cultivation area
    • Training system
    • Density
    • Cultural practices.
    The wines from the variety are mildly sweet and "distinctively tannic." Szabo compares it to Pinot Noir and Nebbiolo both in color and the ability to reflect even minor variations in terroir.

    Nerello Cappuccio
    This variety's medium-to-small-sized bunches and medium-sized grapes produce wines with good acid and tannin levels. The variety buds and ripens earlier than Nerello Mascalese with the former characteristic bringing the negative effects of late spring frosts into play.

    Used primarily in a blend with Nerello Mascalese, this grape brings color and perfume to the blend as well as serving to soften up some of the harder edges of its partner.

    Vineyard Management
    For most of it lengthy vinous history, the Mt Etna region had utilized the albarello training system as the foundation of its viticultural regime.

    As was the case for Algeria and Spain, Phylloxera did eventually invade Etna but the impact was most felt at altitudes of 400 m and below where sedimentary soils dominated. According to Nesto and di Savino, the decimated vineyards at those altitudes were replaced with citrus fruit trees and new vineyards were planted at higher altitudes where the soils had greater proportions of lava rock and volcanic sand and were resistant to the depradations of the aphid. According to the authors, these new vineyards joined an existing belt of vineyards resident on the northern slope between Solicchiata and Randazzo.

    The remnants of that belt of vineyards are today's pre-Phylloxera vineyards of which Ian D'Agata speaks so highly.

    Pre-phylloxra vine. Source: tenutaterrenere.com

    And these pre-Phylloxera vineyards had all been albarello-trained (As were all vines planted prior to the introduction of the Guyot training system.). Albarello training was well suited to the Etna environment. According to Nesto and di Savino:
    • Its free-standing configuration aids in withstanding the high winds to which the mountain is prone
    • The 360-degree exposure to light aids in the ripening of the fruit
    • The black soil readily absorbs radiation from the sun and warms up. The low training of the vines allow them to take advantage of that heat and ripen the grapes faster than would other training systems
    • This low training also allows for more rapid evaporation of water through the skin of the ripe fruit, resulting in greater sugar concentration in the fruit (and higher alcohol in the wine)
    • The vine conserves the humidity arising from the ground, a plus in dry growing conditions.
    Albarello-trained vines in Etna are planted at densities of 8000 to 10,000 vines/ha dictating costly manual labor for vineyard work. Many of the old vineyards have lost their uniformity due to the practice of replacing damaged vines by sticking one of the branches into the ground where it takes root.

    The Albarello system was dominant on the mountain until growers turned first to the Guyot system -- the first half of the 20th century -- and  the cordon-spur system -- beginning in the 1950s -- for new vineyard plantings.

    As explained to me by Salvo Foti, if you went back 20 years, most new plantings were Guyot, as growers pursued the perceived benefits of mechanization and increased yields. But now things are looking up, he continued, as small producers are going back to albarello for new plantings. Viticulture on the mountain is a mix of the traditional and these "newer" training systems and associated practices.

    There is no fiercer proponent and advocate of the traditional approach than the aforementioned Salvo Foti. In his writings (Foti has written a couple of books and a number of pamphlets on wine-related topics), Foti draws a sharp contrast between "producing Etna wines" and "making wine on Etna." Producing an Etna wine results in a product that "captures the essence of the land, the environment, and the people;" requires a winemaker who is "committed to improving and preserving the land where she or he operates," and a vineyard that is ...
    in harmony with the terroir, is naturally integrated with the Etna volcano and is expressed in vertical: lives and grows upwards (leaves and shoots to the sky, in lavic stone terraces) and down in the depth (roots), in opposite directions but complementary between them (Salvo Foti, Applied Viticulture, Book 4, The Etnean Palmento: the traditional vinification).
    Foti's core mission (Nesto and di Savino), is:
    • Protection of the land
    • Preservation of albarello viticulture
    • Cultivation of indigenous vine varieties
    • Emphasizing the humanity of the grower
    • Conservation of Sicilian culture.
    His key viticultural principles are:
    • The use of the albarello training system
    • Dense vine spacing
    • Avoidance of systemic sprays and synthetic soil additives
    • Chestnut poles for vine support.
    Foti's key principles on display at Aeris Vineyard

    Foti is not a big fan of non-albarello training systems (Foti, The Verticality of Etna):
    In the Etna, the vineyard cultivated in the horizontal way (destruction of the terraces to make flat the land, cultivation of the vineyards in the espalier system) is a forcing system for the vine, intended only for the mechanization and for the quantity. 
    Foti has formed an organization called iVignieri wherein participants farm their land according to his principles and also serve as resources to work on farms of potential adherents.

    Foti with his son Simone

    Foti works the Aeris vineyard according to I Vigneri principles. The vines are planted high-density in a quincunx formation with chestnut staves for support. The Quincunx planting system is, essentially, a square planting system with a fifth plant in the center.

    Quincunx planting system (http://e-tesda.gov.ph/)
    As described in quincunx.it:
    In viticulture, the quincunx is a planting pattern: the vines, trained as bushes, are arranged in staggered rows that repeat the lines hinted at in the quincunx. It was the favorite system of the ancient era, because at the same time it met the requirements of order, efficient use of the space and aesthetics: the vineyard looks symmetric regardless of the terrains shape.
    It is a way of doing viticulture that is very expensive in terms of energy and economic resources: machinery, in fact, can only be employed to a limited extent. Furthermnore, to grow and maintain a healthy bush vineyard planted in the quincunx pattern, it is essential that the growers have a long experience in the area where they operate. 
    According to Salvo, in the original system there was a middle plant (in the Sicilian dialect called "o francisco"). They no longer place a plant in the middle but still mark the spot when they make the alignment. So, essentially, they have a square planting system with a marker in the middle for esthetic purposes. The diagram below, provided by Salvo, illustrates this point.


    The field is worked by hand on the slopes while a small tractor aids in the process on the flatter portions. Lavic stone terraces have been built to ensure that the soils are not washed away by rainfall.

    In contrast, Terra Costantino, an organically farmed estate on the southeast flank of the mountain, has 60% of its vines planted cordone speranato and the remaining Albarello. Rootstocks are Ruggieri and Paulson. Average vine age ranges between 15 and 35 years.



    The farm is not a monoculture. Chestnut, olive, and cherry trees are planted all around the estate. Legumes are planted between the rows to aid in nitrogen fixing.

    Calabretta (Randazzo) adheres to a sustainable, noninterventionist approach in both its grape-growing and winemaking activities. The grape vines are grown among olive trees and fruit orchards and never see chemical pesticides or herbicides (small quantities of copper sulphate and sulphurum are used to combat powdery and downy mildew). Old vineyards are head pruned while newer vineyards are trained Guyot.

    Pietradolce (Solicchiata) also farms organically. Vine training is a mix of albarello (legacy and youngest vines) and espalier. Albarello is cropped shorter here than on other Etna estates. The estate’s position is that albarello affords the best expression of Etna wines in that it forces the roots to dig deep in search of nutrients and water.

    Barone di Villagrande (Milo) was certified biologic in 1989 and uses nature to combat vineyard pests and diseases. Strategically positioned bushes on the margins and at transition points in the vineyard provide a natural habitat for flora and fauna. Forests to the southeast and east provide protection from offshore winds. Trees from these forests are used as sources for chestnut barrels with the wood dried for 4 to 5 years at Villagrande before being sent off to Trapani in Marsala to be finished. Some sulfur is used from time to time to combat mildew.

    The foundation of the Frank Cornelissen style is non-intervention and this philosophy permeates every aspect of the estate's grape-growing and winemaking activities. The figure below attempts to capture the Cornelissen viticultural environment in a single place and, in the areas of fertilization and pest management, we see that philosophy clearly demonstrated.


    Frank is so committed to letting nature take its course that he has sworn off the broadly accepted Mt Etna practices of monoculture and high planting density to interplant local fruit trees with vines in pursuit of a more complex ecosystem.

    The core objective of Frank's viticultural regime is the production of grapes that lead to profound wines. The practices to promote this goal include: crop management through pruning; tailoring of bunches to concentrate sugar; handpicking of defective grapes; late harvests; and multiple passes through the vineyards to ensure harvesting of fully ripened grapes.

    Challenges
    One of the challenges facing the producers is getting the consumers (and even some growers) on board with the Contrada scheme and demonstrably showing (i) the differences between contrade wines and (ii) that any such differences are soil-related rather than aspect or elevation. And that challenge can only be met with greater clarification of the contrade. As I have mentioned previously, there is a need for the following types of data in order to allow quality comparative analyses:
    • Delimited Contradas by Commune (with explanation if a Contrada spans multiple Communes)
    • Size (ha) of each Contrada
    • Exposition of each Contrada
    • Elevation range of each Contrada
    • Soil types for each Contrada
    • Variety percentage by Contrada.

    ©Wine -- Mise en abyme

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