Abstract:Solid-state fermentation is the core process in the production of traditional Chinese Baijiu. However, traditional pit fermentation faces limitations such as high labor intensity, imprecise temperature and humidity control, large land footprint, and safety hazards during grain discharge. In this study, a modular fermentation vessel was designed and developed for solid-state fermentation. Using Nongxiangxing Bajiu as the research subject, comparative experiments were conducted between the modular vessel and traditional pit fermentation. The differences in fermentation temperature stability, physicochemical properties of the fermented grains, flavor compounds in the liquor, sensory quality, and production efficiency were systematically evaluated. The results demonstrated that the modular fermentation vessel maintained temperature fluctuations within ±2°C, thereby optimizing the micro-ecological environment of the fermentation system. The synergistic enrichment of Clostridium sensu stricto 1 and Lactobacillus promotes the production of key aroma compounds such as ethyl caproate, while the reduced abundance of Acetobacter, Pediococcus, and Bacillus helps minimize the accumulation of by-products like fusel oils. The hexyl caproate content in the liquor reached 242.5 mg/100 mL, an 8.4% increase compared to traditional pit fermentation, while fusel oil content decreased by 38.7%. The comprehensive sensory evaluation score was 88 points, and the land area required per unit fermentation volume was reduced by 41.3% compared to traditional pits. This study provides equipment support and theoretical basis for the modernization and standardization upgrade of solid-state fermentation technology.