Grape dehydration is a pre-fermentation process which extends
the ripening process; however, it differs from physiological matu-
rity as metabolic changes in the grape berry can occur during the
dehydration process, such as the expression of genes related to the
protection mechanisms and those that regulate secondary meta-
bolism, for instance, phenols and volatile compounds (Cirilli et al.,
2012). When dehydration is carried out under controlled condi-
tions, changes in the chemical composition of the grapes are
influenced by factors such as temperature, relative humidity and air
flow. Temperature plays the most important role because it affects
the water evaporation rate and also the main metabolic pathway,
and the reduction in the relative humidity associated with the air
flow in the dehydration process accelerates the water loss (Cirilli
et al., 2012; Mencarelli et al., 2010).