Molecular Dynamics Study of Flavor Molecules Diffusion in Ethanol–Water Mixtures: A Key to Unlocking the Secrets of Whisky’s Flavor

The flavor perception of whisky arises from the intricate interactions among ethanol, water, and diverse flavor molecules. However, the molecular scale mechanisms governing flavor release under different alcohol concentrations remain poorly understood. In this study, molecular dynamics (MD) simulations combined with density functional theory (DFT) calculations were employed to investigate the diffusion behaviors and interaction mechanisms of 11 representative whisky flavor compounds in ethanol–water mixtures. Furthermore, we developed a theoretical model that links microscopic molecular dynamics parameters to flavor perception, which provides a theoretical foundation for the molecular simulations. We reveal the transition from water dominated to ethanol dominated microstructures with increasing ethanol content. Diffusion coefficients of individual flavor molecules exhibited a non monotonic dependence on alcohol concentration, strongly modulated by molecular polarity, size, and functional groups. These findings provide molecular level insights into the interplay between ethanol concentration and flavor molecule properties.