Four Roses OBSK Single Barrel is a Kentucky Straight Bourbon Whiskey bottled at 100 proof (50% ABV) in a 750ml bottle. The "OBSK" recipe code identifies both the mash bill and yeast strain used: "B" denotes Four Roses' high-rye mash bill (approximately 60% corn, 35% rye, and 5% malted barley), while "K" refers to the distillery's proprietary K yeast strain. Each bottle comes from a single, individually selected barrel, meaning no two releases are exactly alike.

OBSK is considered the spiciest of Four Roses' ten distinct bourbon recipes and is a favorite among bourbon enthusiasts who prefer intense, bold flavors. The nose is dominated by rich, clean rye aromas with hints of lighter baking spices. On the palate, assertive rye tones lead before seamlessly transitioning into flavors of allspice, nutmeg, and cinnamon. As this recipe matures, the robust, bright flavors mellow into deeper and richer notes of oak, caramel, and vanilla. Despite its spicy presentation on the front and mid-palate, OBSK finishes with a notably soft and mellow character.

Four Roses Distillery is located in Lawrenceburg, Kentucky, and is known for its unique approach of using two mash bills and five proprietary yeast strains to craft ten distinct bourbon recipes. The Single Barrel line showcases the character of each individual barrel, offering collectors and enthusiasts the opportunity to experience the nuance of a single cask expression at 100 proof.