Bourbon By Nino Marchetti / November 26, 2014 It has been a long time coming, but the fabled Buffalo Trace Single Oak Project, which explores how different aspects of individually selected American oak trees interact with different bourbons, is nearing the end. It was started back in 1999 when the trees were first picked, and now the next to last 15th release has just been announced.For round 15 of this four year study after years of aging, the folks at the Buffalo Trace distillery decided to focus upon differences in the top and bottom of the tree cut using, in their own words,bourbons which were all aged in barrels with the same entry proof (105), same stave seasoning, aged in the same warehouse (concrete floor), and same char level (number three). All other variables, recipe (wheat or rye), grain size, and tree cut (top or bottom of the tree) vary. “There are many variables to consider in this project but one of the most interesting to learn more about has been tree cut,” explained Harlen Wheatley, Buffalo Trace master distiller, in a statement. “There are four direct components that are related to wood that contribute to our bourbon flavor; hemicellulose, lignin, tannins, and the char layer.“There are two major considerations when it comes to tree composition and location, and those are lignins and tannins. The top half of the tree tends to have more lignin, which contributes to the formulation of vanilla and vanilla flavor. The bottom half of the tree tends to have more tannins, which contributes to the formation of ellagic acids and tannic flavor. Tannic flavor leaves your mouth dry and delivers complexity or richness in texture.”If you are curious to the specific nuances more complete history of the Single Oak Project, it is explained more in depth in a previous post. If you want a fun way to influence how a distillery picks a bourbon, you should grab a bottle from one of the releases to take part in online voting. As for the release of this round of bourbons it is made up of barrel numbers 21, 22, 53, 54, 85, 86, 117, 118, 149, 150, 181 and 182. Each one comes in a 375 ml bottle and prices around $35.