Influence of Soil and Sur Lies Treatments on the Quality of Grillo and Chardonnay Wines Produced in Sicily

This study examines the effects of grape cultivar, soil type, and sur lies maturation on the chemical and physical–chemical properties of white wines. Chardonnay and Grillo were analyzed to identify cultivar-specific differences, while limestone and marlstone soils were compared for their impact on volatile and phenolic profiles. Multivariate analytical methods, including partial least squares-discriminant analysis (PLS-DA), were used to evaluate key chemical markers and their interactions. Significant cultivar-specific differences were observed, with Chardonnay wines containing higher levels of isoamyl acetate, hexyl acetate, phenylethyl acetate, 9-hydroxy-megastigm-7-en-3-one, 3-oxo-α-ionol, blumenol C, and vomifoliol compared to Grillo wines. Limestone soils yielded higher hexanoic and octanoic acids and their esters, whereas marlstone soil showed higher concentration of 9-hydroxy-megastigm-7-en-3-one and 3-oxo-α-ionol. Sur lies maturation increased ethyl esters (especially ethyl octanoate, ethyl decanoate, and ethyl dodecanoate) and linalool levels. Phenolic analysis indicated that Chardonnay wines contained higher levels of caftaric, coutaric, and fertaric acids than Grillo wines. Hydroxycinnamoyltartaric acids were not significantly affected by soil or sur lies treatment, whereas quercetin-3-glucoside was significantly higher in sur lies-treated wines than in the controls. Sur lies treatments significantly improved potassium bitartrate stability compared with control wines. Chemometric analysis successfully differentiated wines based on cultivar, soil, and treatment. These findings provide useful information for terroir characterization and for optimizing sur lies management in Sicilian white wine production.