Using electronic odor sensors to discriminate among oak barrel toasting levels.

Toasting changes both the quantity and the quality of the extractable substances in oak wood of barrels used for the aging of fine wines and spirits. Mastery and repeatability of toasting are vital in the production of quality barrels to be used for aging wines and spirits. Toasted wood components, which can be extracted by the wines or spirits during the aging process, are normally analyzed by maceration in standard alcohol solutions at concentrations adapted to the various products and can be used to control the intensity of the wood toasting. These kinds of analyses are accurate but time-consuming and need specialized laboratories. In this work, the feasibility of monitoring barrel toasting levels using an electronic nose with a metal oxide odor sensor array (MOS) was studied. The results of oak toasting level differentiation obtained via the MOS network were identical to those obtained by analyzing extractable compounds in liquid or gas phase as described in a previous paper. The results presented in this work at the laboratory scale could be used to implement a nondestructive monitoring system based on the analysis of headspace of barrels under industrial conditions.