English: "Doogh" in an Iranian Azeri restaurant in Ankara. Other than the excessive amount of dried mint leaves on it, this "sour ayran" is not to the general taste of Turkish people. I spoke to the restaurant owner and he told me that they get the drink sour and gasified by leaving it under the sun. (Kind of fermentation?) Sorry, next time I go there I will eat their tasty food with Turkish ayran. This experience served me to realize that "doogh" is not the Iranian name of ayran but quiet a different beverage. Hope to try "tan" some day.