The inner liner of this Cobalt ring is made from a genuine used Jack Daniels Whiskey white oak barrel. Almost as much work goes into perfecting the Jack Daniels barrel as does perfecting the iconic American whiskey. Carefully selected American White Oak is slowly dried outdoors for nearly a year. After being exposed to the rain & sun, it is kiln dried, assembled, & then charred to release the naturally occurring flavors that will be imparted to the whiskey. Though the blanks reek of whiskey, the final products (sadly, from an authenticity perspective) have no odor, having been sealed with finish. I have a few other barrel wood options besides Jack Daniels®, including Jim Beam, Maker’s Mark, Woodford Reserve, Stranahan’s, Buffalo Trace, Four Roses, Angel’s Envy, Pappy & Old Rip Van Winkle, the Macallan, The Yamazaki, The Hakushu, & Hibiki. Please see this blog post to see what I mean Cobalt Wooden Ring Lined With Bourbon Barrel White Oak Wood