What chemical reaction during bourbon aging can improve flavour?

The process of oxidization during bourbon aging plays a significant role in enhancing the flavor profile of the spirit. As bourbon is aged in charred oak barrels, it undergoes a slow oxidation process. This occurs when the bourbon interacts with oxygen that seeps into the barrel through the wood.

Oxidization helps to mellow harsh flavors and can transform the character of the bourbon, resulting in a complexity that evolves over time. Through this interaction, various esters and aldehydes are formed, which can contribute to fruity or nutty notes. Additionally, oxidization allows for the extraction of flavors from the wood, such as vanillin, which adds sweetness and richness, and tannins that provide structure.

In summary, oxidization is a critical chemical reaction in bourbon aging, making it essential for developing the nuanced and layered flavors that bourbon enthusiasts appreciate.