There are many distilled spirits terms that don’t have official TTB definitions and this is one of them. It’s similar to barrel strength yet it’s not. Full proof is actually the barrel entry proof or original proof recorded when the white dog whiskey entered the barrel. W.L. Weller Bourbon ia 114° proof (57% ABV) and non-chill filtered. Buffalo Trace Distillery fills their wheated bourbon barrels at 114 proof. This bourbon completely skips chill filtration to preserve all the naturally occurring residual oils and flavors which means it may appear cloudy when cold. The company says by offering this high proof non-chill filtered version, Weller’s signature wheated bourbon flavor and mouthfeel are showcased.