EXPRESS: Spectroscopic Decoding of Ethanol–Water Clusters in Alcoholic Beverages

Recent advances in spectroscopic techniques have provided molecular insights into the supramolecular structures of ethanol-water clusters (EWC) in alcoholic beverages. Sensory quality of these beverages is not only governed by trace flavor compounds but is fundamentally influenced by the dynamic, hydrogen-bonded networks formed between ethanol and water molecules. This review summarizes progress in elucidating the structural characteristics, stability, and transformation mechanisms of EWC across different alcoholic matrices, with a particular emphasis on contributions from multiscale spectroscopic methods including infrared (IR), Raman, nuclear magnetic resonance (NMR), and fluorescence spectroscopy, often coupled with two-dimensional correlation analysis. We further examine how external factors (temperature, electric fields) and endogenous components (acids, esters) modulate EWC architecture and, consequently, perceived taste and mouthfeel. By integrating spectroscopy with computational modeling and artificial intelligence, a more predictive understanding of EWC behavior is emerging, offering a robust scientific foundation for real-time quality monitoring, process optimization, and tailored sensory design in the beverage industry.