Preserved 800-Year-Old Liquid Beer in a Jin Dynasty Vase: Evidence of Malted Sorghum–Wheat Fermentation in Xi’an, China

This study investigates a rare case of liquid alcohol preserved in a glazed ceramic vase from the tomb of Li Jurou (AD 1226), Jin dynasty, Xi’an, China, to provide new insights into medieval brewing traditions. We employed a multi-proxy approach combining microfossil and isotopic analysis, experimental brewing with sorghum, and incorporated previously published proteomic data to illuminate its origin. Microfossil analysis revealed yeast cells and starch granules with damage patterns diagnostic of enzymatic saccharification and mashing, indicating the use of malted sorghum and wheat, alongside cooked rice and foxnut. The starch damage features observed in the archaeological sample are consistent with patterns documented in experimental beer brewing with sorghum and wheat/barley. Stable isotope analysis yielded a δ¹³C value of –18.5‰, consistent with mixed C₃ and C₄ inputs. Two-component isotopic modeling revealed that C₄ plant (likely sorghum) contributed 40–50% of the ingredients, with C₃ plants such as wheat, rice, and foxnut making up the remainder. These findings align with proteomic results identifying sorghum proteins in the liquid. The combined evidence distinguishes this beverage from qu-based fermentation and links it instead to li-type brewing, rooted in malted cereals and associated with ritual practices. This represents the earliest direct archaeological evidence of sorghum beer in China, highlighting both technological innovation and cultural adaptation in historical alcohol production.