Pu-erh tea

„Once dry, maocha can be sent directly to the factory to be pressed into raw pu'er, or to undergo further processing to make ripened pu'er. Sometimes Mao Cha is sold directly as loose-leaf "raw" Sheng Cha or it can be matured for 2–3 years in loose leaf form due to the faster rate of natural fermentation in an uncompressed state. This product is then pressed into numerous shapes and sold as "raw" Sheng Cha as a more matured final product.“

„Yunnan Tea Company standardized the trade number for Pu Erh Tea in 1976 for the purpose of export. Each bingcha has 4 digits: the first 2 digits indicate the manufacturing year, the third digit indicates the leaf grade, the last digit indicates the tea factory (e.g. Kun-Ming 1, Meng-Hai 2, Xia-Guan 3, Pu Erh 4). The loose-leaf tea has 5 digits with the third and fourth indicating the class level of raw materials. Examples of early trade numbers for Puerh Tea are 7452, 7562, 7572, 75671, 76563.“