"Unlike other varieties of tea, Pu-Erh Tea is traditionally made with older
leaves (not the first flush or budding leaves) from tall and old trees.
These trees are of a type only found in Yunnan Province, known as broad leaf
tea. The leaves are covered with fine hairs, are larger than other tea
leaves, and have a different chemical composition. The leaves are then left
green or moderately fermented before being dried. Often times the tea is
then formed into cakes or bricks, wrapped in paper or pomello rinds, and
stored outside exposed to moisture, air, and heat for order to further
mature. Then the tea is stored underground for several years before taking
on the darker, mellower characteristics that make Pu'erh tea. This type of
tea originated from the natural aging process that happened along the
ancient caravan routes, and the tea bricks were at times used as a form of
currency. The tea bricks developed a unique flavor that was then refined by
aficionados. One of the most expensive and rare Pu'erh teas is made from the
droppings of worms that eat stored Pu'erh bricks."

http://www.reference.com/browse/wiki/Pu-erh_tea

Well, is it true? I don't see worm dropping puerh actually brewing into tea,
just sludge...