What is the purpose of using sour mash in bourbon distillation?

The purpose of using sour mash in bourbon distillation primarily relates to maintaining consistency and quality in the fermenting process. Sour mash is a mixture that includes a portion of mash from a previous distillation, which contains not only the yeast but also lactic acid bacteria.

When sour mash is added to the new mash, it helps to adjust the pH of the mash, providing an acidic environment that is beneficial for yeast fermentation. This acidity can inhibit the growth of undesirable bacteria and ensures that the yeast can thrive, which contributes to a more consistent fermentation process. Additionally, the nutrients from the sour mash help in supporting yeast health and activity, leading to a more efficient fermentation cycle.

This use of sour mash is crucial for bourbon production as it assists in producing a cleaner, more reliable fermentation, which ultimately results in higher quality bourbon.