2,000-year-old alcohol discovered in Ningxia tomb

A cereal-based alcoholic residue, dating back to the Warring States Period (475-221 BC), unearthed by archaeologists at a cemetery in the Ningxia Hui autonomous region, is expected to shed new light on cereal processing, grain utilization and brewing techniques among the Qin people.

Experts said the discovery not only represents the best-preserved liquid alcoholic beverage sample from the Warring States Period ever reported in China, but also provides rare physical evidence of how the Qin people brewed grain-based alcohol more than 2,000 years ago.

The findings were published in the June edition of the Journal of Archaeological Science: Reports.

According to the study, the residue was discovered at the Shanjiabao cemetery in the southwest of Yuanzhou district, Guyuan. The cemetery, surrounded by a series of frontier defense facilities, lies about 2 kilometers south of the Qin Great Wall dating to the Warring States Period.

Chinese archaeologists excavated 183 tombs at the site, 179 of which belonged to the Qin people. Tomb M39, located at the northernmost edge of the cemetery, yielded a bronze bottle with a garlic-shaped mouth.

The bottle was sealed with textile on the inside and organic-tempered daub on the outside. After removing the seal with a sterile scalpel and forceps, researchers extracted about 3,740 milliliters of clear, light blue-green, odorless liquid, along with a small amount of sediment.

Wang Xiaoyang, who led the archaeological project at the Shanjiabao cemetery, said the bottle's multilayer seal effectively minimized evaporation and contamination, allowing the liquid to remain largely intact for more than 2,000 years.

To identify the beverage's composition and brewing techniques, a research team led by Wen Rui, a professor at Northwest University's School of Cultural Heritage, used a range of analytical methods, including Fourier transform infrared spectroscopy, or FTIR, as well as analyses of starch grains, phytoliths and yeast microfossils.

The analyses revealed characteristic flavor compounds, diagnostic organic acids, starches, phytoliths and yeast, providing multiple lines of evidence to identify the beverage's ingredients and reconstruct its brewing process, according to the study.

Microfossil analysis confirmed that the primary brewing ingredients were broomcorn millet and grains from the Triticeae tribe, including wheat and barley. Wang said the finding may reflect the development of the subsistence economy during the period. "Alcohol production was only possible when grain harvests generated a surplus."

Zhang Hongying, deputy director of the Ningxia Institute of Cultural Relics and Archaeology, said the findings demonstrate that the Qin people had mastered the use of cereal-based qu, a traditional fermentation starter that enabled simultaneous saccharification and fermentation.

Wen said the study fills a gap in research on alcoholic beverage production by the Qin people during the Warring States Period in Ningxia and helps reconstruct how they brewed grain-based alcohol.

The findings provide further evidence of China's long-standing tradition of cereal-based fermentation and offer new material evidence for research on agriculture in the pre-Qin era (before 221 BC), ancient dietary culture and the evolution of handicraft techniques, he said.

Contact the writers at huqing@chinadaily.com.cn