sour mash

noun

1. a blended grain mash used in the distilling of some whiskeys, consisting of new mash and a portion of mash from a preceding run and yielding a high rate of lactic acid.

sour mash

noun

1. a grain mash for use in distilling certain whiskeys, consisting of a mixture of new and old mash
2. any whiskey distilled from such a mash

Word History and Origins

Origin of sour mash¹

An Americanism dating back to 1880–85