Dou Zhi is the ultimate acquired taste of Beijing cuisine. Made from fermented mung bean liquid, it has a gray-green color and a sour, slightly funky flavor that locals adore and visitors often struggle with. It's traditionally served hot with jiaoquan (crispy fried rings) and pickled vegetables. The fermentation process gives it a complex, tangy profile similar to a very mild cheese. Lao Beijing (Old Beijingers) swear by it as a breakfast staple.
Dou Zhi originated over 1,000 years ago, mentioned in Song Dynasty texts. It was historically a drink of the common people, served at street stalls throughout Beijing.