Bourbon must be aged in a "new, charred oak container." But the oak itself can come from anywhere. And since that oak gives bourbon nearly three-fourths of its flavor, using a different type is bound to have a significant impact on the final product. Buffalo Trace started to experiment with this over a decade ago, and this is the first release in a new line dubbed Old Charter Oak. The initial offering features their tried and true Mash #1 bourbon aged in Mongolian Oak barrels for ten years. And as you'd expect, the result is much different than one that was aged in traditional oak barrels. Packaged in a glass bottle with an oak medallion on the front and available in limited quantities.