Back when Ornellaia was established in 1981, world-renowned oenologist Andre Tchelitscheff discovered something interesting on the estate.  While much of the vineyards were clay-dominant, ideal for Bordeaux varietals, one hill in particular was nearly entirely composed of blue and gray clay, much like Petrus' blue clay on the Right Bank of Bordeaux.  Historically this hill was already highly valued for its clay - the density of the soils made for great brick-building quality in Bolgheri's castles. But in wine terms, it was a gold mine. Densely packed so that it maintained a rock-like hardness, the staff bagan to call the hill Masseto ("massi" in Italian means rock), and suggested planting Merlot alone on the hill, a la Petrus. Initially blended into the Ornellaia releases, by the early 1990s they found the grapes so exceptional that they used all of the fruit for Masseto's production alone, and later even built Masseto its own winery to distinguish it from anything else they made.  In the estate's eyes, "Ornellaia is the maximum expression of Bolgheri and its Bordeaux blends, Masseto represents the ultimate expression of a single vineyard".