VALENCIA, 29 May. (EUROPA PRESS) -
A study published in the journal 'Frontiers in Plant Science' by the Center for Research on Desertification (CIDE) -a joint center of the Higher Council for Scientific Research (CSIC), the University of Valencia (UV) and the Generalitat Valenciana- has demonstrated that, through different adaptation strategies of the vineyard to global warming scenarios, the alcohol-acidity balance could be preserved and improved, which would give rise to wines for cava with a better structure and aromatic profile.
The increase in temperatures in the last 20 years has advanced the harvest date in the Mediterranean region by 6 days on average, altering the composition of the musts. In regions with a continental and semi-arid climate such as Requena, the grape quickly reaches high concentrations of sugars and high acidity values, while its content of phenolic compounds increases more slowly.
Additionally, high nighttime temperatures cause changes in varietal expression, which can result in low-quality wines. In the Utiel-Requena wine region, these effects could alter the typicity of its wines and specifically that of cava, compromising the sector's competitiveness.
Due to the loss of wine quality, CIDE researchers have evaluated in a Requena vineyard the agronomic efficacy of various cultivation techniques, such as shading of the vines, bud forcing (that is, severe pruning after flowering), late pruning and mulching (or padding), to improve the composition of the Macabeo grape, a variety used in the area, in order to make a better cava. Among the results, it has been observed that the forcing of buds improved the composition of the grape, with a higher alcohol-acidity ratio and a lower degree of the latter.
According to the CSIC scientist at CIDE Diego S. Intrigliolo, who has participated in the study, "the results have shown that through agronomic techniques it is possible to modify the composition of the grape and significantly influence the quality of the base wines for the subsequent elaboration of the cava".
All the techniques tested have served to improve the composition of the base wine with which to make cava. The effectiveness of shading will largely depend on weather conditions during the ripening period of the grapes, with more attention being paid to the health status of the grapes. In rainy and cool years, the application of the shading technique is not recommended, since it would be much more effective in the hottest and driest vintages. For its part, the bud-forcing technique is only recommended for the production of premium-type cava of high commercial value.
"In the edapho-climatic conditions of Requena, the main agronomic and oenological challenge faced by cava producers is the low acidity and high pH of the grape must. In this sense, the efficacy of techniques, given that they allow the microclimate of the cluster to be modified during the ripening period and decrease the alcohol-acidity ratio in base wines for cava", explains Diego S. Intrigliolo.
The research has been carried out in collaboration with the University of the Balearic Islands (UIB), the Valencian Institute for Agricultural Research (IVIA) and the Technological Institute of Viticulture and Oenology of Requena.