Photo: People's Daily Online

Chinese archaeologists have identified traces of a 2,300-year-old grain-based alcoholic beverage from the Warring States Period (475BC-221BC) in Northwest China's Ningxia Hui Autonomous Region, offering new insights into ancient Chinese brewing technology.

The discovery was made at the Shanjiabao cemetery near the Qin section of the Great Wall dating to the Warring States Period, located in Guyuan, the Ningxia Hui Autonomous Region, according to Ningxia's department of culture and tourism, In 2024, archaeologists excavated 183 tombs from the period at the site and recovered liquid residue from a bronze garlic-head-shaped pot, a distinctive vessel from the Qin.

Through archaeological research and advanced scientific analysis, researchers determined that the 3,740 milliliters of liquid extracted from the vessel was a grain-based alcoholic beverage produced during the Warring States Period.

The sample is believed to be the currently known best-preserved liquid alcohol from the era to date, filling a gap in archaeological research on ancient brewing in Ningxia, according to the Xinhua News Agency.

The bronze vessel adopted a dual sealing structure lined with textile fabrics and coated with organic mud. The sophisticated sealing isolated external contaminants, allowing the ancient liquor to survive with minimal volatilization after more than two millennia, archaeologists noted.

To uncover the drink's ingredients and brewing process, a joint research team from the Ningxia Institute of Cultural Relics and Archaeology and the School of Cultural Heritage at Northwest University conducted detailed tests using technologies such as infrared spectroscopy, ultra-high-performance liquid chromatography-mass spectrometry, and microscopic analysis of starch grains, phytoliths and yeast microfossils.

The analysis identified 24 categories of compounds, including organic acids, amino acids and carbohydrates. Researchers found that the organic acid profile matched that of artificially aged rice liquor, confirming the liquid is a fermented grain-based alcohol.

Further examination showed that wheat and barley starch grains in the sample had been processed through methods such as grinding, heating and microbial degradation.

The findings indicate that the Qin people had already mastered the use of grain-based fermentation starters, allowing saccharification and fermentation to occur simultaneously, a sign of advanced brewing skills for the time.

Researchers said the discovery provides physical evidence of the sophistication of ancient Chinese grain fermentation and offers valuable clues for studying the agriculture, food culture and craftsmanship before the Qin Dynasty (221BC-206BC).