Effect of Grain Type and Toasting Conditions of Barrels on the Concentration of the Volatile Substances Released by the Wood and on the Sensory Characteristics of Montepulciano d'Abruzzo

Abstract

We report the results of an aging trial of Montepulciano d'Abruzzo D.O.C. wine in commercially available oak barrels that differed in the type of wood grain (extra fine and fine) and cooperage toasting conditions: medium (EVM), light (EVL), medium for a shorter time (CM), and, finally, a single short-time pretoasting stage at high temperature (ExpT). The chemical-physical composition, the volatile substances released by the wood, and the sensory characteristics of wines after 6 and 12 mo of aging were monitored. The differences observed were mainly in the concentration of volatile substances and the olfactory characteristics of the wines. The volatile compounds that could distinguish among the wines were the cis isomer of beta-methyl-gamma-octalactone, the ratio between cis and trans octalactone, vanillin, cyclotene, maltol, 5-methyl guaiacol, and the furfuryl compounds. The concentration of cis octalactone was influenced by the type of grain of the wood, while the cis/trans octalactones ratio varied depending on the toasting conditions used in the production of the barrels (the highest concentration was in EVL). In particular, the length of time (EVM compared with CM) and the temperature (EVM compared with EVL) of the toasting process influenced the concentration of vanillin, furfuryl alcohols, cis octalactone, and 5 methyl guaiacol. Among the olfactory descriptors, statistically significant differences were detected in the notes of caramel, toasty, spicy, green pepper, coconut, and wood.