BB1 typically refers to a specific batch or barrel identification number used by a distillery to label their whiskies. In the context of "First Fill Bourbon Casks," it suggests that the whisky has been aged in bourbon casks for the first time.
"First fill" indicates that the cask has been used for maturing whisky for the first time after being used to mature bourbon. First fill bourbon casks are highly prized in the whisky industry because they impart strong bourbon flavours to the whisky, including notes of vanilla, caramel, and oak, while also allowing the unique characteristics of the whisky itself to develop. This aging process can result in a rich and complex flavours profile in the final whisky product.
