Environmental factors at different scales: a review of their effects on spontaneous fermentation Chinese Baijiu and related mechanisms

Environment serves as the pivotal medium to produce fermented food, with fluctuations in environmental factors exerting a profound impact on the modulation of fermentation microbial communities. Such shifts are crucial for the distinctiveness of fermented food flavor and the variability in quality. Chinese liquor (Baijiu) is one of the typical representatives of spontaneous fermented food. In this review, the multifaceted relationship between regional environmental attributes and the fermentation dynamics of Baijiu was examined, with a spotlight on the strong-flavor, sauce-flavor, and light-flavor varieties. It reveals the influence of regional environmental factors and brewing environmental factors on microbial function and metabolism, which results in the formation of unique flavor characteristics of Baijiu. The 9 main factors affecting the microecology of Baijiu fermentation were further explored, including environmental sensitivity, microbial interactions, biogeographic patterns, and key abiotic factors such as temperature and humidity. Environmental factor management is crucial for controlling microbial community in fermentation. Intelligent detection of the fermentation system is combined with artificial intelligence to realize the digitalization of Baijiu fermentation, with a view to further studying the environmental mechanism or quantitative control relationship of natural fermentation, improving the environmental stability of natural fermentation, and promoting the mechanization and intelligence of fermentation production.