WHISKY ADVOCATE REVIEW: Although Louisville’s Kentucky Peerless Distillery uses sweet mash to create its rye and bourbon, Baker and Heist believe that Wilderness Trail was the first Kentucky distillery to embrace the process as the sole mashing technique. (In fact, Baker and Heist assisted Peerless in selecting their yeast strains and designing their sweet mash process.) As with clean steam, sweet mashing—rather than the practice of sour mashing, where a small amount of fermented mash is included in the following batch—is meant to produce a softer, cleaner distillate. 'Sour mashing is often used for bacterial control, but you lose the flavor consistency in the stillage,' explains Heist. 'With sweet mashing, the yeast, grains, and water are consistent from batch to batch.