Pu'er or pu-erh is a variety of fermented tea produced in the Yunnan province made from large-leaf varietal of Camellia Sinensis. Fermentation in the context of tea production involves microbial fermentation and oxidation of the tea leaves, after they have been dried and rolled. This process is a Chinese specialty and produces tea known as 黑茶 hēichá (literally, 'black tea') commonly translated as 'dark tea'. This type of tea is different from what is known as black tea in English, which in Chinese is called 红茶 hóngchá (literally, 'red tea').

Pu-erh is particularly special because it can be aged for decades or longer, always changing and (in most cases) developing more depth and texture.

Pu'er traditionally begins as a raw product known as "rough" máochá (毛茶, literally "fuzzy/furry tea") and can be sold in this form or pressed into a number of shapes and sold as "raw" shēngchá (生茶, literally "raw tea"). Both of these forms then undergo the complex process of gradual fermentation and maturation with time. Raw Pu-erh (生茶) is sun-dried and compressed.

Ripe Pu-erh (熟茶) is fermented during a 40-50 day period under-going a mellowing fermentation process that changes the tea into something dark red-brown in color. The wòduī (渥堆) fermentation process developed in 1973 by the Kunming Tea Factory created a new type of pu'er tea. This process involves an accelerated fermentation into "ripe" shúchá (熟茶, literally "ripe tea") which is then stored loose or pressed into various shapes. The fermentation process was adopted at the Menghai Tea Factory shortly after and technically developed there.[5] The legitimacy of shúchá is disputed by some traditionalists in contrast to aged teas. All types of pu'er can be stored to mature before consumption, which is why it is commonly labeled with the year and region of production.

Aside from vintage year, pu'er tea can be classified in a variety of ways: by shape, processing method, region, cultivation, grade, and season.

Pu'er tea is typically compressed into a variety of shapes: Brick/ Zhuan cha, Square/ fang cha, Dragon Pearl/ long zhu, Bing/Beeng/Cake/ Disc/Bing cha, Tuocha. Other lesser seen forms include: stacked golden melon pagodas/ jin gua, Mushroom/ Jin cha, pillars, calabashes, yuan bao/Ingot, and small tea bricks (2–5 cm in width), Bowl, or Nest, . Pu'er is also compressed into the hollow centers of bamboo stems or packed and bound into a ball inside the peel of various citrus fruits.