Straight from the barrel to the bottle at 108 to 114 proof, Makers Mark Cask Strength retains the signature front-of-the-palate flavors of Makers Mark, while intensifying the oak, caramel, vanilla and spice to create a wonderful new bourbon. Although Makers Mark goes into barrels at a consistent entry proof of 110, the proof of Makers Mark Cask Strength will vary. As water evaporates from the barrels as the spirit rests, the proof increases. Due to the fluctuating summer temperatures in Kentucky, the rate at which the bourbon becomes the “angel’s share” also differs.