Is the 13th Colony 15th Anniversary Bourbon 15 years old?
No. The whiskey is aged eight years and nine months. The name marks 13th Colony's fifteenth anniversary as a distillery — the company was founded in Americus, Georgia in 2009 — not the age of the bourbon in the bottle. It is a point worth stating plainly, because "15th Anniversary" on the label invites the assumption, and reviewers have flagged the same confusion.
What proof is the 13th Colony 15th Anniversary Bourbon?
It is bottled at 139.2 proof, or 69.6% ABV, at cask strength with no water added. As a single-batch release, that figure is fixed for every bottle — Master Distiller Graham Arthur selected the barrels for one release and bottled them uncut, so the strength reports the barrels rather than a house target. That places it well above the 100-to-120-proof band most cask-strength bourbons occupy.
What is the mash bill of the 13th Colony 15th Anniversary Bourbon?
13th Colony did not disclose the mash bill for this specific release, and this page does not guess one. The distillery's flagship Southern Bourbon is built from corn, rye and malted barley, and 13th Colony both distills its own whiskey and sources to a specified recipe — but the barrels chosen for the anniversary batch were not tied to a published grain bill, so the honest answer is that it is undisclosed for this bottling.