Composition of grape grown on different Homogenous Terroir Units (HTU)

This paper was based on the soil maps units from Ribera de Duero viticulture and wine Denomination of Origin that defined different Homogeneous “Terroir” Units (HTU) with potentially diverse oenological qualities. The main aim of this study was the study of possible correlations between HTU categories and the development and quality of the wine grapes cultivated on specified HTUs. Five vineyards from three different optimum HTUs were selected for this study. Selection criteria were grape variety, clone, rootstocks, age, training systems and cultural practices, trying to select the most similar vineyards.
Samples of 25Kg were manually harvested, from each one of the 15 selected vineyards. The grapes were harvest at the degree of technological maturity as similar as it was possible. Technological maturity is correlated with adequate levels of sugar, acidity and phenolic content, so that good sanitary stages and even good levels of aroma precursor compounds. So, composition of grapes was evaluated considering all these parameters, however this paper showed only partial results, showing levels of sugar, acidity variables (pH, titrable or total acidity and content of malic acid), and phenolic compounds (several phenolic families were considered: total polyphenols, anthocyanins, catechin and flavanol levels). This work will be completed with future studies that will be carried out in future vintages.
Obtained data showed that, even having a large variance among vineyards of the studied Homogeneous Terroir Units, was possible to detect significant differences on the composition and oenological quality of the grapes of each UHT.