Buffalo Trace Distillery uses two primary mash bills for their bourbons. While the exact recipe is kept secret, there are sources that discuss the composition of the mash bills. Here are some details: Mash Bill #1: Known as the “low-rye mash bill,” it contains 10% or less rye. Used in Buffalo Trace Bourbon and Eagle Rare, among others. Mash Bill #2: Referred to as the “high-rye mash bill,” it has 12-15% rye. Brands like Blanton’s Single Barrel and Elmer T. Lee use this mash bill12.