sour mash


noun

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.

Origin of sour mash

An Americanism dating back to 1880–85

British Dictionary definitions for sour mash

sour mash

noun US

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