The mixture of 70% corn, with the remainder being wheat and/or rye, and malted barley is fermented and distilled, typically between 65% and 80% alcohol, to ensure a consistent pH across batches. What mix are we talking about?

Bourbon whiskey must be made from at least 51% corn by law, and a mash bill of 70% corn with wheat, rye, and malted barley fits within bourbon requirements. The mixture is fermented and distilled to between 65-80% alcohol (130-160 proof), which helps ensure consistent pH. Rice vinegars and wines are not distilled to these high alcohol levels.