Why does distilled liquor (Baijiu) have a yellowish color: A comprehensive analysis

Elucidating the mechanisms underlying Baijiu production is a shared aspiration among academic groups specializing in the field of Baijiu research. This study comprehensively examined the mechanisms underlying the yellowish coloration of Baijiu through a synergistic application of chromatographic, spectroscopic, and physical methodologies. Aging of Baijiu in earthenware pots involves the infiltration of mineral ions such as iron, aluminum, and calcium; however, these ions are detected at extremely low concentrations and are therefore not linked to the development of Baijiu's yellowish color. Instead, the yellowish coloration is attributed to the diverse colorants generated during the high-temperature fermentation of small-molecule sugars derived from the saccharification of grain materials. Although these colorants exist in minimal quantities and exhibit spectral absorption peaks ranging from 300 to 450 nm, their overlapping spectra collectively contribute to the light-absorbing properties of Baijiu across a broad wavelength range, ultimately accounting for its characteristic yellowish color.