Influence of alcohol level and temperature on rice wine metabolite changes during 200-day storage

Rice wine is typically freshly consumed, but its quality during long-term storage depends on storage conditions. The relative impacts of alcohol concentration and storage temperature on the long-term quality of rice wine have not been quantitatively evaluated. In this study, rice wine adjusted to 6%, 9%, or 12% alcohol was stored at 4 °C or −2 °C for 200 days, and its physicochemical, microbial, and metabolite profiles were examined. Yeast viability decreased over time but was better maintained at higher alcohol levels and under sub-zero storage, while lactic acid bacteria showed greater cold sensitivity. Principal component analysis (PCA) indicated that alcohol concentration primarily determined compositional differences, whereas temperature governed the magnitude of temporal change; the rate of metabolic change, defined as accumulated Euclidean distance divided by elapsed days, was up to threefold higher at 4 °C. Higher alcohol levels retained more organic acids and polyols, whereas lower alcohol favored γ-aminobutyric acid (GABA) accumulation. Three metabolites—GABA, malic acid, and sorbitol—were identified as condition-specific markers based on fold change (≥2) and statistical significance ( q < 0.05). These findings demonstrate that alcohol content and storage temperature exert complementary influences on microbial survival and metabolic dynamics, providing insights for optimizing rice wine storage. • Storage temperature and alcohol concentration collectively altered the metabolic profiles of rice wine during 200-day storage. • Alcohol concentration defined compositional differences, while temperature determined the rate of metabolic change. • Sub-zero storage suppressed metabolic drift and maintained microbial stability. • Refrigerated storage promoted dynamic metabolite shifts, including GABA accumulation. • Condition-specific metabolites (GABA, tyrosine, malic acid, trehalose, sorbitol) were identified as quality markers for rice wine.