Impact of vine water status on sensory attributes of Cabernet Franc wines in the Niagara Peninsula of Ontario

Aim: To examine the impact of vine water status on sensory and chemical characteristics of Cabernet franc wines on non-irrigated sites in the Niagara Peninsula, Ontario, to assess whether vine water status might be a key factor in the determination of so-called terroir effects. Methods and results: The effects of vine water status on wine sensory characteristics were studied in Vitis vinifera L cv. Cabernet franc in the Niagara Peninsula (Ontario, Canada) in the 2005 and 2006 vintages. Vine water status was monitored throughout the growing season in ten vineyard blocks using midday leaf water potential (Ψ) values. Chemical and descriptive sensory analyses were performed on nine (2005) and eight (2006) pairs of experimental wines to elucidate differences between wines from high and low water status (HWS, LWS) zones in each vineyard. Twelve trained judges evaluated six aroma, six flavor and three mouthfeel/taste sensory attributes, as well as color intensity. In 2005, LWS wines had higher color intensity (four sites), black cherry flavor (one site), and red fruit aroma and flavor (two sites). Similar trends were observed in the 2006 vintage. No differences were found from one year to the next between the wines produced from the same vineyard, despite markedly different conditions in the 2005 and 2006 vintages. Conclusions: Measurement of midday leaf Ψ was successful in detecting differences among vine water status levels throughout the growing season. The range of leaf Ψ values were almost consistent at most sites in both 2005 and 2006 years. Differences in vine water status resulted in wines with different composition, aroma, flavor, and color intensity. Despite two different vintages of hot and dry (2005) and wet (2006) seasons, similar trends were observed in high and low water status wines. Significance and impact of study: The strong relationships between leaf Ψ and sensory attributes of Cabernet franc suggest that vine water status is a major basis for the terroir effect