Precipitation and temperature drive microbial community changes affecting flavor quality of Nongxiangxing Daqu

<i>Nongxiangxing Baijiu</i> is the most famous <i>Baijiu</i> flavor in China, and its characteristic style is closely related to <i>Nongxiangxing Daqu</i> used in fermentation. However, there are few reports about the difference of <i>Daqu</i> quality between seasonal variations. In this study, precipitation and temperature drove changes in microbial communities that resulted in differences in the flavor of <i>Daqu</i> produced in different seasons. For example, the average daily temperature in summer was as high as 27.29 ± 2.24 °C, which was significantly higher than other seasons (<i>p</i> < 0.01). <i>Bacillus</i> was abundant in the <i>Daqu</i> produced in this season, while tetramethylpyrazine flavor was more prominent, up to 1556.95 ± 153.92 μg/kg. Metabolomics studies identified major pathways associated with the weak flavor of spring_<i>Daqu</i>. In addition, LEFSe analysis revealed the marked microorganisms in different seasons. These results revealed the differences in seasonal <i>Daqu</i>, thus contributing to the scientific and rational use of <i>Daqu</i>.