text: Many fermented teas do not arrive on the market ready for consumption. Instead, they may start as green teas or partially oxidized oolong-like teas, which are then allowed to slowly oxidize and undergo microbial fermentation over many years (comparable to wines that are sold to be aged in a cellar). Alternatively, fermented teas can be created quickly through a ripening process spanning several months, as with Shu Pu'er. This ripening is done through a controlled process similar to composting, where the moisture and temperature of the tea are carefully monitored. The product is "finished" fermented tea.
  Fermented teas are commonly sold as compressed tea of various shapes, including bricks, discs, bowls, or mushrooms. Ripened  teas are ripened while loose, then compressed. Fermented teas can be aged for many years to improve their flavor, again comparable to wines. Raw  tea can be aged up to 50 years in some cases without diminishing in quality, and ripened  can be aged up to 10 or 15 years. Experts and aficionados disagree about the optimal age.
  Many Tibetans and Central Asians use  or other fermented teas as a caloric and micronutrient food, boiled with yak butter, sugar and salt to make yak butter tea.
  Ageing and storage
  Post-fermented tea usually gets more valuable with age. Dark tea is often aged in bamboo baskets, bamboo-leaf coverings, or in its original packaging.
  Many varieties of dark tea are purposely aged in humid environments to promote the growth of certain fungi, often called "golden flowers" or  () because of the bright yellow color.