What is the effect of toasting on oak aroma?
Toasting during barrel processing modifies the structure and chemical properties of the oak. This influences the wood aroma composition and consequently, the release of aroma compounds into the wine. Increased toasting diminishes the fresh oak aromas generally attributed to oak lactones. Simultaneously, vanilla and caramel aromas associated with vanillin, furfural and 5-methylfurfural increase. At higher toast levels these compounds decrease and are replaced by spicy (eugenol, isoeugenol, 4-methylguaiacol) and smoky characters (guaiacol, 4-methylguaiacol).
