Editing Tea (section)

=== Processing and classification ===

{{main|Tea processing}}

[[File:Tea in different grade of fermentation.jpg|thumb|Teas of different levels of oxidation (L to R): green, yellow, oolong, and black]]

Tea is divided into categories based on how it is processed.<ref name="LiuTong">{{cite book |author=Liu Tong |title=Chinese tea |publisher= China Intercontinental Press|location=Beijing|year=2005|page=137 |isbn=978-7-5085-0835-1}}</ref> At least six different types are produced:
* [[white tea|White]]: wilted and unoxidized;
* [[yellow tea|Yellow]]: unwilted and unoxidized but allowed to yellow;
* [[green tea|Green]]: unwilted and unoxidized;
* [[Oolong]]: wilted, bruised, and partially oxidized;
* [[Black tea|Black]]: wilted, sometimes crushed, and fully oxidized (called {{lang|zh|紅茶}} [''hóngchá''], "red tea" in Chinese and other East Asian tea culture);
* [[Fermented tea|Post-fermented (Dark)]]: green tea that has been allowed to ferment/compost (called [[Pu'er tea|''Pu'er'']] if from the Yunnan district of South-Western China or {{lang|zh|黑茶}} [''hēichá''] "black tea" in [[Chinese tea culture]]).

After picking, the leaves of ''C. sinensis'' soon begin to [[Wilting|wilt]] and [[Redox|oxidize]] unless immediately dried. An [[Food browning|enzymatic oxidation]] process triggered by the plant's intracellular [[enzyme]]s causes the leaves to turn progressively darker as their [[chlorophyll]] breaks down and tannins are released. This darkening is stopped at a predetermined stage by heating, which deactivates the enzymes responsible. In the production of black teas, halting by heating is carried out simultaneously with drying. Without careful moisture and temperature control during manufacture and packaging, growth of undesired molds and bacteria may make tea unfit for consumption.