Pu-erh tea

„Pu'er traditionally begins as a raw product known as "rough" Mao Cha (毛茶) and can be sold in this form or pressed into a number of shapes and sold as "raw" Sheng Cha (生茶). Both of these forms then undergo the complex process of gradual fermentation and maturation with time.“

„Sourness in Raw Puer is due mostly to inadequate airing after the rolling process or, after pressing tea into cakes, they have been immediately exposed to the sun. The tea soup will likely be turbid.“