Spain's most famous and important wine estate is located at Valbuena del Duero, 30 km east of the ancient university town of Valladolid. The northern boundary of the estate is marked by the main road that runs along the left bank of the Duero (Douro) river between the river bank and the hilltops are some of Spain's most prized vineyards, on north-facing slopes at altitudes of 750-800m above sea level. Care begins in the vineyards. Neither chemical fertilizers nor herbicides are used, but organic compost will be added if the vines are suffering unduly. This way, the high average age of the vineyards is maintained. The combination of old vines and severe pruning limits yields, which are further reduced by strict selection at harvest time. The altitude and cold nights delay ripening, and Vega Sicilia only harvest when the grapes are truly ready, which means late October or even November on occasion. Picking is by hand, and the crop is transported to the bodega in small plastic boxes so as to arrive in perfect condition.