Thursday, December 8, 2011

The Carso DOC of Friuli-Venezia Giulia, Italy

Between Trieste and Collio Goriziano, and running from the Gulf of Trieste over the border into Slovenia, lies a rocky strip of land called the Karst (German; Carso in Italian and Kras in Slovenian) Plateau, an area whose name, according to Gams (Origin of the term "karst," and the transformation of the classical karst (Kras), Environmental Geology 21(3), pp. 110-114), derives from a pre-Indo-European word "karra" which means stony.  And stony it is.

A karst landscape forms when water interacts with soluble bedrock, such as limestone or dolostone, to create an environment that is riven with unique landscape shapes and underground rivers and caverns. This condition arises when falling rain picks up carbon dioxide (either from the atmosphere or ground) and forms carbonic acid.  This mildly acidic solution dissolves the surface of the soluble bedrock and, over time, creates distinct surface shapes and underground cavities and drainage systems.

The characteristics of a karst landscape are :
  • Absence of a surface water web
  • Partial or total lack of soil
  • Irregular plateau
  • Closed depressions
  • Rocky, stony surface which reflects a higher degree of the sun's radiation than say a gneiss surface
  • Limited vegetation cover due to a lack of soil and surface water
Karst landscapes exist in many parts of the world but the area in the Slovene-Italian region was the first to be subjected to rigorous scientific study and, as a result, is called Classical Karst.

And it is in this area that we find the Carso DOC of the Friuli-Venezia Giulia region.  Bounded by the Gulf of Trieste, the border with Slovenia, Vipacco River, the Gorizia-Monfalcone Railway Line, and the A4 Autostrade, this land is a testament to man's perserverance, patience, and ingenuity.  Cultivating land here is a hard, intense, expensive process.

The Carso climate is maritime Mediterranean at the coast and continental approaching the Julian Alps.  A sea breeze -- Yugo -- during the day time keeps the vineyard dry while a nightime breeze --Tramate -- brings the temperatures down at night.  A strong northeast winter wind called Bora-- named after the Greek mythological figure Boreas (the North Wind) -- pummels the area in the winter time with gusts that can reach up to 120 km/hr.

I have just described the karst landscape and it is not vine-friendly in its native state because of a lack of surface soil.  Vineyards are prepared by cutting away any vegetation and then digging down into the limestone to take away the roots of the old vegetation.  Yellow soil from Trieste is then trucked in and laid to a depth of 3 meters.  This soil levels the ground as well as retains some humidity in the environment.  One-half meter of Carso red soil is overlain on the base Trieste soil.  This red (terra rossa) soil is found in collapsed caves called Dolina and is both hard to find and expensive.  This soil is rich in iron and lime but poor in organic components.  This soil is the result of the mixing of calcium carbonate solutions from the bedrock with blown sand from the Sahara and Sahel regions of Africa.

Vineyards reside on stone terraces and vines are Albaretto-trained.  In the Cante vineyard, the density is 8500 vines/hectare, a situation necessitated by the expense associated with creating each acre of vineyard.

Grapes are hand-harvested.  DOC wines must contain 85% of the stated variety with the remainder from permitted varieites of the same color.  The permitted varieties are the major internationals plus two indigenous whites -- Vitovska and Malvasia -- and one indigenous red -- a strain of Refosco called Terrano. The Vitovska is a cross between the Malvasia and Prosecco varieties.  A Rosso is also produced from 70% Terrano and the remainder from other permitted red grapes.

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