what is sour mash

Sour mash is a process used in the distilling industry that involves using material from an older batch of mash to start the fermentation of a new batch, similar to the way sourdough bread is made with a starter. The term can also refer to the type of mash used in this process, and bourbon made using this method can be called sour mash bourbon. The use of sour mash helps control the growth of bacteria, improves consistency, and enhances the quality of the liquor. It is also used in the production of sour beer and can contribute to the sweeter and more robust flavor of the bourbon