Evaluation of Oak Chips Treatment on Volatile Composition and Sensory Characteristics of Merlot Wine

Abstract

AbstractThe effect of treatment with different oak chips on the volatile composition and sensory characteristics of Merlot wine was evaluated. Seasoned and toasted oak chips from different geographical origins and species were tested: American (Quercus alba), French (Quercus petraea) and Rumanian (Quercus robur). Differences in the lactone content, volatile phenols (eugenol and 6‐methoxyeugenol) and derivatives of vanillin were found according to the different species used. The major differences were found in wines aged with toasted chips as the concentrations of lignin derivatives increased while furan compounds appeared. The treatment with nontoasted chips increased the flavor complexity of wine due to the pleasant attributes imparted by oak wood. Rumanian chips imparted the lowest intensity of aged flavor into the wines. Meanwhile, wines treated with toasted oak chips were negatively assessed by the tasters due to the strong perception of smoke or tobacco attributes that masked the rest of the notes.Practical ApplicationsThe use of oak chips is a new alternative to barrels used in red wine aging. The oak treatments with seasoned American, French and Rumanian oak chips improved and enhanced the volatile profile of Merlot red wines. However, the chemical composition of aged wines varied in relationship to the chips use. This fact implied different sensory characteristics in the resulting Merlot wines.The toasting process is a common treatment applied to oak barrels to improve their aromatic potential. However, the toasting treatment applied to chips must be dealt carefully by winemakers. It was observed that the use of medium toasted chips produced strong intensities of smoke and tobacco impressions that masked the rest of the notes detected in aged wine. Therefore, these aspects must be taken into account by the winemakers in the choice of the type of oak chips to guarantee the success of the wine obtained.