Bolgheri DOC the territory
Geography and climate
The production area runs parallel to the beaches of northern Maremma, located in the province of Livorno, in the town of Castagneto Carducci. To the east, a chain of hills runs between Bibbona and Castagneto, protecting the vineyards and olive groves from the cold winds from the north, which often provoke lethal freezes during the winter. In the summer, on the other hand, this corridor is swept by cool winds that are generated between the valleys of the Cecina river to the north, and the Cornia stream to the south.
The elders used to say that you couldn't make great wines close to the sea. For this reason, the first Sassicaia vineyard was planted in 1944 in Castiglioncello di Bolgheri, facing east at an altitude of 400 m. above sea level. Today, it has been shown that vicinity to the sea is precisely what makes great wines. The highest-quality vineyards are all at the feet of the hills and in the plane between Bolgheri and the southern part of Castagneto. The cool winds which come from the sea, and the moderate temperature range in August and September provoke slow and regular maturation of all of the qualitative components of the grapes: sugars, polyphenols and fragrances, and contribute to keeping the acidity high, which is necessary in order to give balance to the wines.
The Bolgheri microclimate receives a great deal of light: in addition to direct sunlight, the land benefits from the effects of the reflection of light from the stretch of sea located to the west. The average annual temperature is approximately 14°C, with 18.6°C from April to September, 7.5°C from December to January, and 24°C in August. Average annual rainfall is approximately 600mm, with rain that is well-distributed statistically: more abundant during the vegetative growth, less frequent during the period of maturation of the fruit, and then abundant again after the harvest. The driest month is July.
Geology
The zonation research carried out by Prof. Attilio Scienza in cooperation with the University of Milan has shown that the soils in Bolgheri have a great variety in a relatively limited area. There are alluvial soils, of fluvial origin, with round pebbles deposited by the ancient waterways. The name Sassicaia (sasso=stone) comes precisely from this characteristic. There are soils which originated from the sea, with Aeolian sands, limestone and clay. And also volcanic rock which comes from the Metalliferous Hills to the east.
Thus, we find soil which is clayey, clayey-sandy or sandy-clayey, clayey-muddy, or completely sandy. As a result, the water reserves and nutritive elements vary significantly from one area to another. These soils are found on terraces at different levels, such that on average, the general structure succeeds in maintaining the humidity at a deep level, and returning it during the dry periods. 
According to the research of Lizio-Bruno, three major areas can be found: the hills, the intermediate area, and the area close to the sea. On the hills we find the oldest alluvial deposits. The pebbly alluvion on which the Sassicaia vineyard is found is also characterized by a significant presence of iron oxide. Further down, the fluvial deposits are younger, and to the west, they mix with the marine deposits.
Vineyard and vines
The density of cultivation in the vineyards is very variable. The oldest have a density of 5,500-6,000 grapevines per hectare, while some of the most recent reach the level of 10,000 grapevines per hectare, and require the use of long arm tractors. Most of the new cultivation systems have a density of approximately 7,000 grapevines per hectare.
The predominant cultivation system is the cordon spur system, but there are also examples of guyot, and even free-standing systems(gobelet).
The most important varieties, obviously, are those whose vocation was amply demonstrated by Sassicaia first, and other historical varieties later, such as Ornellaia, Grattamacco, Macchiole, Guado al Tasso, and Satta.
This means Cabernet Sauvignon, Cabernet Franc, and Merlot. The experimentation which has now been taking place for almost twenty years, has shown the great potential of other varieties such as Syrah and Petit Verdot. And Sangiovese continues to have a hard core of supporters. For white wines, Vermentino is currently the most planted. Sauvignon Blanc, after changing fortunes, is recovering a highly-qualitative dimension, and is often accompanied by Viognier.
Zoning