The wearing down of the Alpine ridges, which were created by the collision of the European and African tectonic plates, has resulted in the formation of a morainic amphitheater at the foot of which, with the passage of the millennia, glacial and riverine erosion has deposited gravel and sand. The terrains of the plain of Friuli largely consist of such material.
Within that plain are situated the territories of two different Denominazioni di Origine Controllata wines, one with a name derived from the Grave del Friuli and the other from the river, the Isonzo.
All the principal varieties of the region are cultivated in the plain, with Merlot in the lead, followed by Tocai friulano, Pinot bianco, Pinot grigio, Refosco and Verduzzo friulano.