Charting a Chemical Roadmap of Terroir in Corn—Tools for Selection of Novel Varieties for Whiskey

Abstract

Corn is a vital ingredient to the whiskey industry, most notably as the main ingredient in bourbon whiskey. However, little research exists that explores how genetic, environment, and gene-environment interaction effects (collectively, terroir) impact corn chemistry and ultimately flavor and alcohol yield in whiskey. Here, the impact of terroir on new-make bourbon whiskey, as well as how it can be leveraged for the selection of flavor and alcohol yield in corn, was determined. A novel lab-scale distillation process, high performance liquid chromatography, gas chromatography-mass spectrometry, and quantitative sensory analyses allowed for the identification and quantification of those flavor compounds, aromas, and yield-related metrics that are impacted by terroir. We report for the first time that alcohol yield, a variety of flavor compounds, and ultimately aroma are indeed impacted by terroir in new-make bourbon whiskey. Certain metabolites in corn, mash, and beer were identified as significant predictors for alcohol yield and flavor chemistry in new-make bourbon whiskey, providing chemical makers that can be implemented in a breeding program. Notably, it appears that benzaldehyde in corn, ferulic/coumaric acid in mash, and total sugar concentration in mash can serve as markers for various flavor compounds and alcohol yield in new-make bourbon whiskey