Mystery behind Chinese liquor fermentation

•Traditional Chinese liquor fermentation faces industrial challenge of modernisation.•Traditional liquor fermentation is a treasure to explore for quality of life today.•Hidden knowledge is valuable to study and apply in food and biotechnology sectors.•Multidisciplinary approach will accomplish innovation and improvement.

BackgroundChinese liquor, a very popular fermented alcoholic beverage with thousands of years' history in China, though its flavour formation and microbial process have only been partly explored, is facing the industrial challenge of modernisation and standardisation for food quality and safety as well as sustainability. Meanwhile, the hidden knowledge behind the complicated and somehow empirical solid-state fermentation process of Chinese liquor can enrich the food sector to improve our quality of life, and benefit other industrial sectors in the modern biomass-based technology, economy and society.Scope and approachThis review reveals the traditional fermentation process and characteristics of Chinese liquor, summarises the current study progress of flavour chemistry and responsible microbial process, and addresses future improvement and research needs. We provide here a detailed, systematic and critical review on Chinese liquor to improve the current industrial practice and serve the modern society with yet incompletely explored but useful principles.Key findings and conclusionsThe hidden knowledge behind the traditional Chinese liquor production is rich in useful principles including flavour chemistry, microbial growth, solid-state fermentation, enzyme production, biocatalysis, microbial community metabolism and process engineering. Studies in a more in-depth, systematic and practical way on this look-like empirical process to explore the scientific principles behind will definitely benefit the liquor industry in particular, and the (food) biotechnology sector in general.