The fermentation of Baijiu is profoundly influenced by environmental microbiota, but the exact origins and the specific impacts of these microbes are not entirely understood. To address this issue, we used reverse-analysis to comprehensively map the environmental sources and reveal their pivotal role in shaping microbial succession and metabolic variations across three workshops of different ages. We initially discovered that these workshops exhibited unique microbial succession and metabolic profiles in baijiu fermentation. Further investigation revealed that environmental microbiota associated with Baijiu fermentation showed a distinct separation between outdoor and indoor settings, especially in the 70-year-old workshop (workshop 70y). The unique distribution of environmental microbes in workshop 70y did not only accelerate microbial succession 5 days earlier, but also significantly enhanced ester production, with an increase from 60.63 μg/mL to 155.31 μg/mL. Source tracking revealed that the rich indoor environmental microbes in the workshop 70y dominated the whole fermentation, while the 2-year-old workshop (workshop 2y) and the 20-year-old workshop (workshop 20y) initially relied on Raw Materials (RM) and Daqu (DQ) microbes, but the control gradually shifted to indoor environment. These findings might offer valuable implications for Baijiu quality control, and enhance our understanding of the functional roles of the environmental microbiome.

Environmental Microbiota and Its Influence on Microbial Succession and Metabolic Profiles in Baijiu Fermentation Across Three Distinct-age Workshops