Accelerated aging of wine vinegars with oak chips: evaluation of wood flavour compounds

Assays of accelerated aging in wine vinegars were performed with 2% w/v of oak chips and different pretreatments (toasted at 180 °C, or boiled and toasted at 180 °C). An analytical method for determining volatile compounds from wood (volatile phenols, whisky–lactones, vanillin, etc.) in wine vinegars was set up. This method consisted of a solid phase extraction step followed by gas chromatography. When traditional aging for 180 days (oak barrels) and accelerated aging for 15 days were compared, the results showed that the biggest difference was the rate of extraction for vanillin. Oak-chip aging increased the concentration of this compound 20-fold. Levels of oak-lactone isomers were higher when only toasted oak chips were used. Other factors such as ethanol content or the use of barrels have also been considered. We conclude that oak chips (only toasted) are a valuable alternative to oak barrels for obtaining, in a short period of time (15 days), wine vinegars with the peculiar characteristics given by oak wood.