Evolution of the aromatic profile in Garnacha Tintorera grapes during raisining and comparison with that of the naturally sweet wine obtained

► Free volatiles increase was for isoamyl alcohols, benzaldehyde and guaiacol. ► Bound volatiles increase of isoamyl alcohols, ethyl vanillate and benzoic acid. ► Raisins obtained were mainly caramelised, floral, phenolic and burned. ► Tropical and tree fruit odorants were predominant in the naturally sweet wine. ► Aroma of Garnacha raisins was close to Pedro Ximenez controlled-drying grapes. The postharvest dehydration is one of the most important steps in obtaining a high quality naturally sweet wine and it can play an important role in modulating the production and the release of volatile compounds. However, only a few studies have analysed the changes in the free and bound volatile compounds of grapes throughout the process. In this work, GC–MS was applied to determine the aromatic composition of Garnacha Tintorera grapes subjected to off-vine dehydration or raisining at several points during the process. The total water loss in 83days was about 62% and the sugar concentration rose from 225 to 464g/L. Within the free volatile compounds, isoamyl alcohols, benzaldehyde and guaiacol registered the largest increase above the concentration effect due to water loss; while within the bound volatile compounds were isoamyl alcohols, ethyl vanillate and benzoic acid. The aromatic profile of the raisins obtained were mainly caramelised, floral, phenolic and burned.