He is loosely credited as the perfecter of the sour mash process used in creating bourbon whiskey. There are no historical records pin pointing him as the creator. Earliest records, in fact, cite Catherine Carpenter of Casey County, KY in 1818 as the first documented user of the sour mash method at her families' distillery.
Dr. Crow, a Scottish chemist-physician, graduated in medicine from Edinburgh University in 1822. He moved from Philadelphia to Kentucky in 1823 and began working for a distiller, bringing his scientific and medical training to the process.
According to The Kentucky Encyclopedia, Crow began experimenting in 1835 at his Glenn's Creek Distillery in Woodford County Kentucky with a saccharimeter to measure sugar content. This litmus paper test to determine the mash acidity resulted in Crow's decision to age his "Old Crow" whiskey before selling it.
Crow moved to the town of Millville and for the next twenty years he was in charge of the Old Oscar Pepper Distillery, now known as Woodford Reserve. Later he went to work for the Johnson Distillery. That distillery eventually became Old Taylor. He worked there until his death in 1856. He was buried in Versailles Cemetery in Versailles, Woodford County, Kentucky.