Toasting Oak Barrels

Toasting is one operation in the barrel-making process that has a very direct effect on the taste of the wine. During toasting, furanic aldehydes (responsible for “roasted” aromas) reach their maximum concentration, the vanilla aroma of vanillin is heightened, and various phenols, such as eugenol add a smoky, spicy touch to the complexity of oak aromas in wine.

There are three degrees of toasting: light, medium, and heavy. A light toasting is used by winemakers who seek the most natural oak character (although it is not as neutral as using staves that have been bent with steam); medium varies between a true medium, which suits most red wine demands, and the so-called medium-plus, which is the favorite for fermenting white wines; the third, a heavy toast, dramatically reduces the coconuttylactones and leaves a distinctly charred-smoke character that can be overpowering unless used only as a small component in a blend.