Sources of variation in bourbon whiskey barrels: a review

Abstract

Oak barrels serve two purposes in the production of distilled spirits: storage containers and reaction vessels. It is the latter function which bestows barrel aged spirits with their unique and highly sought after flavour profiles. However, achieving consistent flavour profiles between barrels is notoriously difficult as no two barrels are comprised of the same source of oak. Source variation is due to a range of factors, beginning with the genetic and topographical background of the oak tree from which the barrel staves originate, the spatial region of the tree from which the stave was taken and continuing through each step of the barrel production process. In this review, we detail each source of variation and highlight how this variation affects the reactants present in the barrel stave