"Pure sage and turbid sage" is another name for wine. At the end of the Han Dynasty, wine making was strictly prohibited due to famine. Drinkers kept secret of wine, saying that those with clear wine were saints and those with turbid wine were sages.
"Biography of Xu Miao, Wei Zhi, annals of the Three Kingdoms": "on weekdays, the guest said that those with clear wine were saints and those with turbid wine were sages."
When the three kingdoms were first built, Cao Cao was strict in prohibition. People had to steal their drinking in private, but they kept silent about the word "wine". So they used "sage" as the "Baijiu" (or "Turbid wine") and used "sage" as a metaphor for "sake". Qingsheng and Zhuo Xian evolved into an allusion. There is also an idiom "Qingzhou is engaged in business, Pingyuan supervises post", which is also a metaphor for good wine and bad wine.
Liu Yiqing of the Southern Dynasty recorded in Shi Shuo Xin Yu that one of Huan Wen's assistants was good at distinguishing between good and bad wine. He called good wine "Qingzhou engaged". Qingzhou is a place name. There is a place under the jurisdiction of Qingzhou called Qi County, "Qi" means "navel", and good wine is called "Qingzhou engaged", because after drinking good wine, the spirit of wine can reach the navel; He called bad wine "Pingyuan Duyou" because there was a place in the jurisdiction of the plain called Xi county. "Xi" means "diaphragm", which means that if bad wine is drunk, the wine can only reach the diaphragm.