Wine composition is determined by various conditions:
grape variety, rootstock, soil type, cultivation techniques,
and climatic characteristics (Gladstones 1992, Wilson
1998, van Leeuwen et al. 2004). The first three conditions
are generally constant, particularly variety and rootstock
because of the control exercised by regulating councils
(Rodo and Comin 2000). Cultivation techniques, at times
labeled “human factors,” are most often responsible for
long-term variability since modification in production
methods may require a long period for adoption by grapegrowers.
Regulating councils may also be responsible for
a limited and controlled introduction of innovation techniques
(Rodo and Comin 2000). Climatic variables are the