An Acidity‐Based Model Linking the Dryness Index to Grapevine Acidity Under Climate Change

Climate change increasingly threatens grape acidity, a key determinant of wine quality and stability, through intensified drought and warming. This study develops an acidity‐focused, climate‐based approach to characterise cultivar‐specific responses to climatic dryness in a Central European wine region. Long‐term observational data from the Eger Wine Region (Hungary) were used to quantify relationships between the dryness index (DI) and titratable acidity across seven Vitis vinifera cultivars through linear regression analysis. Two indicators are introduced: The dryness index for balanced acidity (DI_ACBal), which describes the climatic dryness at which balanced acidity, is maintained and the optimum water demand (OWD), a cultivar‐specific estimate of climatic water availability, is required for acidity preservation. Cultivars differed consistently in their responses to climatic dryness ( R 2 = 0.65–0.81), with low‐OWD varieties maintaining acidity under drier conditions, whereas high‐OWD cultivars required greater water availability. Scenario‐based DI projections indicate a declining probability of balanced acidity toward the late 21st century without adaptation. This approach supports cultivar selection and vineyard water management under a changing climate.