Dynamic Changes in Volatile Compounds during Fermentation of Cabernet Sauvignon Grapes with and without Skins

Volatile compounds in wines arise from many sources: they may be extracted from the grapes during fermentation, formed by yeast during fermentation, and/or arise during postfermentation storage and processing. Factors influencing extraction of volatiles from grapes during fermentation have not been widely studied; an improved understanding of the processes and mechanisms involved in the formation or release of wine aroma compounds from grapes during fermentation could help winemakers to optimize or control wine composition and aroma. In this work, we studied the effects of different skin contact times on changes in concentrations of volatile aroma compounds during fermentation of Cabernet Sauvignon grapes. Headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry was used to monitor the volatile compounds produced during fermentation. Duration and timing of the skin contact during fermentation showed a measurable effect on volatile composition. Some compounds reached higher concentrations in fermentations performed with skins, while, in other cases, skins acted to "bind" or delay release of volatiles, particularly beta-damascenone.