Glycosidic aroma precursors of Syrah and Chardonnay grapes after an oak extract application to the grapevines

► Application of oak extract to Syrah and Chardonnay grapevines at three different timings of the veraison. ► Grape assimilation of the compounds from oak extract and their storage as glycosidic aroma precursors. ► Differences on aroma composition of treated grapes in compounds not present within the oak extract. ► Oak extract treatments could be of great interest, since treated grapes may produce wines with a different aromatic quality.