text: The fermentation is carried out primarily by molds. Aspergillus niger was implicated as the main microbial organism in the  process, but that species identification has been challenged by comprehensive PCR-DGGE analysis, which points to Aspergillus luchuensis as the primary agent of fermentation.
  Most varieties of fermented teas are produced in China, its country of origin, with several varieties also produced in Korea and Japan. In Myanmar, lahpet is a form of fermented tea that is eaten as a vegetable, and similar pickled teas are also eaten or chewed in northern Thailand and southern Yunnan.
  History
  The early history of dark tea is unclear, but there are several legends and some credible theories.
  For example, one legend holds that dark tea was first produced accidentally, on the Silk Road and Tea Road by tea caravans in the rainy season. When the tea was soaked in rain, the tea transporters abandoned it for fear of contamination. The next year, nearby villages suffered from dysentery, and decided to drink the abandoned mildewed tea in desperation. The legend concludes that the tea cured those suffering, and quickly became popular.
  Other historical accounts attribute the first production of dark tea to the Ming dynasty in the 15th and 16th centuries. It may have been first traded by tea merchants much earlier than the legends state, across the historical borders of Han and Tibetan cultural areas.