Long-term batch brewing accumulates adaptive microbes, which comprehensively produce more flavorful Chinese liquors

The strong aromatic Chinese liquors are batch-brewed in mud cellars, but the changes in the brewing microflora and their effects on the production of flavors are mostly unclear. In the liquor brewing industry, it is a mystery that older cellars produce better tasting liquors. In this study, by pyrosequencing the 16S rRNA gene, we found that the microflora in a 10-year-old cellar and a 1-year-old cellar significantly reduced the differences of microbial communities between the top, middle and bottom mud layers, but became surprisingly more diverse in the old cellar than that in the new cellar. Gas chromatography-mass spectrometry assays indicated that the liquors produced in the old cellar contained higher concentrations of certain ester ingredients that are important for the liquor flavor. We further demonstrated that different bacterial isolates from cellar mud were all able to produce diverse organic compounds. These results indicate that long-term spontaneous batch-fermentation accumulates diverse adaptive microbes, which comprehensively produce more flavorful Chinese liquors. (C) 2014 Elsevier Ltd. All rights reserved.