Pu-erh tea

„The process used to convert máochá into ripened pu'er is a recent invention that manipulates conditions to approximate the result of the aging process by prolonged bacterial and fungal fermentation in a warm humid environment under controlled conditions, a technique called Wò Dūi (渥堆, "wet piling" in English), which involves piling, dampening, and turning the tea leaves in a manner much akin to composting.“

„bing; 饼 - cake. Something shaped like a cake. 茶饼; cha bing - tea cake. This is a cake of tea that has been pressed by hand or machine into a compact form. Easy for transporting and storage. The more tightly pressed it is, the slower the tea will age. They can range in size from 100 gms to several kilograms.“