Just like exceptional wines, pu-erh tea improves over time owing to the specific type of fermentation that affects the tannins.
Pu-erh tea cakes
By the dawn of the 9th century the Chinese had introduced tea to Tibet. Tea became so popular there and the surrounding areas that it was used as a form of currency. Compressed tea was a common form of payment for almost anything, and workers were routinely paid this way.
For centuries, villagers from all over the Yunnan Province followed the Ancient Tea Horse Road to reach Central Tibet and Beijing with countless caravans of mules laden with bamboo-leaf-wrapped stacks of pressed pu-erh tea. More than 2.500 km of treacherous mountains separated muleteers from their trade-off: furs, leather, musk, medicinal plants, and horses for the Chinese army.