Abstract Kevin UsherMike WatsonPat BowenDavid GregoryCarl BogdanoffKareen StanichMargaret Cliff

Timing of Leaf Removal Differentially Affects the Sensory Quality of Red and White Wines

Kevin Usher,* Mike Watson, Pat Bowen, David Gregory, Carl Bogdanoff, Kareen Stanich, and Margaret Cliff  
*Agriculture Canada, PO Box 5000, V0H 1Z0, Canada (kevin.usher@agr.gc.ca)

Riesling and Sauvignon blanc wines from the Okanagan Valley often have a crisp, fruit-forward style with attributes like stone fruit, tropical fruit, citrus, spice, floral, and honey. Characteristic descriptors for Shiraz wines of this region are dark fruit, black cherry, cooked fruit, pepper, and smooth tannins. Three experiments evaluated fruit maturation and quality and wine sensory quality with respect to timing and amount of leaf removal. The experiments were a randomized complete block design with five treatments and four blocks. Leaf removal treatments applied in the fruiting zone were: 100% at fruit set or veraison, 50% at fruit set or veraison, and no leaf removal. The vines had spur-pruned bilateral cordons with vertical shoot-positioning. Basic composition and phenolics were measured in fruit and wine. The blind sensory evaluations were by 16 judges who tasted 10 wines twice in a balanced, incomplete block design. In Shiraz, leaf removal at fruit set compared to at veraison and no leaf removal resulted in lower vegetative but higher dark fruit and pepper flavor and aroma in wines. Astringency and phenolics were higher with early and 100% leaf removal. In Riesling and Sauvignon blanc, the wines benefited from later leaf removal, showing more tropical and citrus fruit flavor and aroma when applied at veraison than at fruit set.

Funding Support: BC Wine Grape Council Agriculture and Agri-Food Canada