A sun - dried, 'post-fermented' tea made in Yunnan Province from camelia sinensis assamica.
Puer or Pu'erh is the name of a city that was on the the 'Ancient Tea Horse Route' in the south of Yunnan, China. Subsequently, it is a name that has come to refer to a particular kind of tea; a post-fermented, aged tea produced in Yunnan Province in the south west of China.
Puer tea can be divided into two main categories; a green or 'raw' Puer tea (sheng cha) which can be aged, much like a good red wine, and 'cooked' Puer (shou or shu cha), sometimes misnamed 'Black' tea. Raw Puer is sometimes mistakenly considered a form of green tea which it is not, as the processes are slightly different.
Both of these types of tea are named Puer tea though factory fermented shou Puer is a relatively recent form of tea, having first been made in the 1970's.
Of all Chinese teas, Puer is no doubt the most illusive, difficult to define, but this too is part of its intrigue.