Sour mash

Barrels of sour mash whiskey aging at the Jack Daniel's distillery

Sour mash is the name for a process in the distilling industry that uses material from an older batch of mash to start fermentation in the batch currently being made, analogous to the making of sourdough bread. It was developed by either Dr. James C. Crow or Dr. Jason S. Amburgey while they were working at the Old Oscar Pepper Distillery (now the Woodford Reserve Distillery) in Woodford County, Kentucky. Sour mash is not a type or flavor of whiskey, as is commonly thought.

In the sour mash process, the mash – a mixture of grain, malt and water – is conditioned with some amount of spent mash (previously fermented mash that still contains live yeast). Spent mash is also known as spent beer, distillers' spent grain, stillage, and slop or feed mash, so named because it is used as animal feed. The acid introduced by using the sour mash controls the growth of bacteria that could taint the whiskey and creates a proper pH balance for the yeast to work. An established and active strain of live yeast is introduced into the mash that is to be fermented. By using an established and known fermented "sour", this fermentation process controls the introduction and growth of foreign bacteria and yeasts that could damage the whiskey, and improves the consistency and quality of the liquor, so that every bottle tastes as close to the same as possible. Sour mash is popular in bourbon whiskey and Tennessee whiskey.

Sour mash whiskey brands

• Ancient Age
• Basil Hayden's
• Distiller's Pride
• Evan Williams
• Ezra Brooks
• George Dickel
• Jack Daniel's
• Jim Beam
• Knob Creek
• Maker's Mark
• Old Crow
• Old Fitzgerald
• PennyPacker
• Rebel Yell
• Ten High
• Wild Turkey
• Woodford Reserve
• Elijah Craig