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.“

„Mushroom shaped tea appeared in 1912. It was invented at that time in order to prevent the tea from going mouldy during the transportation. It was produced in Xia-Guan and Fo-Hai (two cities in south China) with the trademark "Bao-Yan". The production was then stopped in 1966. In 1986, the production was resumed due to the request of Buddhists in Tibet.“