Vine water status modulates aroma composition and sensory quality of white wines cv. Pinela (Vitis vinifera L.)

Abstract

Vine water status affects grape ripening, metabolite accumulation, and wine quality. In the sub-Mediterranean climate of western Slovenia, terraced vineyards are increasingly exposed to summer droughts. This study evaluated the impact of regulated deficit irrigation on yield, aroma composition, phenolic profile, and sensory properties of autochthonous Pinela (Vitis vinifera L.) white wines produced in 2024 in a terraced vineyard in the Vipava Valley. A decision support system (DSS; Vintel®) was used to maintain three levels of predawn leaf water potential (ΨPD) from flowering to harvest: well-watered control (–0.10 to –0.30 MPa), mild-to-moderate deficit (–0.25 to –0.45 MPa), and moderate-to-severe deficit (–0.45 to –0.65 MPa). Vine water status was monitored using a Scholander pressure chamber. Grapes were harvested at technological maturity and microvinified in triplicate with commercial S. cerevisiae. Varietal and fermentative volatile compounds and phenolic compounds were analysed in five-month-old wines. At the same time wines were sensorially evaluated by a panel of experts using ranking test. Deficit irrigation reduced yield by 19 % (mild-to-moderate) and 34 % (moderate-to-severe) compared to the well-watered control. Mild-to-moderate deficit increased varietal thiols, esters, and higher alcohols, whereas moderate-to-severe deficit enhanced terpenes, fatty acids, C6 compounds, and volatile phenols. Flavan-3-ols were more abundant in well-watered wines. Sensory analysis revealed a preference for wines produced under mild-to-moderate deficit, which were rated highest in fullness and overall quality. Wines from the moderate-to-severe deficit exhibited greater bitterness, fruitiness and tropical and green apple notes. Well-watered wines received the lowest scores for most parameters but were characterized by higher perceived acidity. Vine water status modulates both chemical and sensory attributes of Pinela wines. Mild-to-moderate deficit irrigation proved to be the most sustainable water management strategy for producing Pinela wines in terraced vineyards, as the yield was not substantially affected while the quality was improved.