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
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for sour mash
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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012