Technology Unlocks Flavor Code: Guizhou’s Qiandongnan Sour Soup Goes National

GUIYANG, April 20 — “Three days without sour food, and you’ll stumble while walking.” A local doggerel in Qiandongnan Miao and Dong Autonomous Prefecture, Guizhou Province, vividly reflects the local people’s love for sour soup. In this region, from towns to villages, every household keeps earthen jars and masters traditional methods to make this beloved delicacy.

The traditional process involves washing tomatoes, wild cherry tomatoes and red peppers, removing their stems, chopping them, and adding galangal, garlic, litsea cubeba, glutinous rice and liquor in a certain proportion, without any oil contamination. Sealed and fermented in jars for 3 to 6 months, the result is a pot of spicy and sour red sour soup, a staple of local cuisine. China Food News reports that sour soup is one of Guizhou’s most distinctive ethnic traditional foods, and its industry has become a new force in the province’s food condiment sector.

In the past, most sour soup producers relied on traditional brewing methods, making sour soup based solely on experience, which made it hard to taste authentic flavor outside Guizhou. In 2021, the Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, launched technological assistance in Taijiang County. “We evaluated many industries; some were small-scale, others high-cost, and none could give full play to technological strength. Finally, we settled on the sour soup industry,” said Li Shuying, a researcher at the institute.

Li noted that the sour soup industry had a solid foundation, involved a variety of raw materials, and could drive the industrial chain extension, with great market potential but insufficient production capacity. To help sour soup get out of the mountains, Li’s team focused on promoting standardized and large-scale production of Hmong sour soup. They visited 18 villages in 5 towns of Taijiang County, sampling 26 sour soup samples to identify the key microbial flora.

“The flavor code lies in the microbial strains,” Li explained. The team domesticated 463 microbial strains from the samples, narrowed them down to 78 through genetic identification, then locked 11 strains, and finally obtained 3 core fermentation strains, developing a second-generation strain suitable for large-scale production. This shortened the fermentation period to 7 days, ensuring stable quality and controllable flavor.

With the technology in place, industrial transformation became the key. With the help of various parties, Guoquan Food (Shanghai) Co., Ltd. conducted research in Taijiang and cooperated with the institute. In June 2024, they co-founded Taijiang Miaomiao Sour Soup Food Co., Ltd. and built an automatic production line with an annual output of 6,000 tons. “Experts from the academy provided full follow-up guidance, from workshop planning to equipment procurement,” said Guo Feng, deputy general manager of the company.

After 5 months of hundreds of tests, the flavor was highly restored. The company has signed cooperation agreements with surrounding villages, purchasing tomatoes, peppers and other raw materials from at least 2,000 mu of farmland annually. In March 2025, it officially achieved standardized, stable and digital production, selling products nationwide. Last year, the total output value of Qiandongnan’s sour soup industry exceeded 8 billion yuan, with more sour soup products reaching the national market with the help of technology.