Single Barrel, Bottled at Proof, Powerfully Complex, Distinctly Unique From Anything We’ve Done Before. Stupendous. On the rare occasion that Dave Pickerell’s five promises are realized, we release a whiskey that epitomizes WhistlePig’s odyssey to unlock the potential of Rye Whiskey. The Boss Hog Edition 六 is the first American Whiskey finished using Japanese Umeshu, the result of a true collaboration between WhistlePig and Kitaya brewery on Japan’s Kyushu island. This well aged Straight Rye Whiskey was created using koji fermentation. Each bottle is adorned with The Samurai Scientist – Jōkichi Takamine – who pioneered koji fermentation in the American whisky industry over a century ago. Each bottle barrel is bottled at strength, between 120 – 122 proof.