Oolong (simplified Chinese: wūlóng) is a traditional Chinese tea (Camellia sinensis) somewhere between green and black in oxidation. It ranges from 10% to 70% oxidation. It is among the most popular types of teas served in typical Chinese restaurants.

Oolong tea leaves are processed in two different ways. Some teas are rolled into long curly leaves, while some are pressed into a ball-like form

Possible origins

There are three widely accepted explanations on how the Chinese name came about. According to the "tribute tea" theory, oolong tea was a direct descendant of Dragon-Phoenix Tea Cake tribute tea. Oolong tea replaced it when loose tea came into fashion. Since it was dark, long and curly, it was called the Black Dragon tea.
According to the "Wuyi" theory, oolong tea first existed in Wuyi Mountain. This is evidenced by Qing dynasty poems such as Wuyi Tea Song (Wuyi Chage) and Tea Tale (Chashuo). It was said that oolong tea was named after the part of Wuyi mountain where it was originally produced.

Varieties of Oolong Tea

Wuyi Huang Guan Yin tea leaves

Wuyi Qi Lan Oolong tea leaves

The most famous and expensive oolong teas are made here, but the production is still usually accredited as organic. A lot of Shuǐ Xiān is grown elsewhere in Fujian. Some of the better known cliff teas are:
Dà Hóng Páo: Big Red Robe in Chinese, a highly prized tea and a Si Da Ming Cong (四大名樅, literally: The Four Great Bushes). This tea is also one of the two oolongs that make it to the list of Chinese famous teas.
Shuǐ Jīn Guī : Golden Water Turtle in Chinese, a Si Da Ming Cong.
Tiě Luóhàn : Iron Arhat in Chinese, a Si Da Ming Cong tea
Bái Jī Guān : White Cockscomb in Chinese, a Si Da Ming Cong tea. A light tea with light, yellowish leaves.
Ròu Guì : Cinnamon in Chinese, a dark tea with a spicy aroma.
Shuǐ Xiān : Water Sprite in Chinese, a very dark tea, often grown elsewhere.

Fújiàn province

Tiě Guānyīn or Ti Kuan Yin : Iron Guanyin in Chinese, this is a tea from Anxi in South Fujian. It is very famous, in fact a 'Chinese famous tea' and very popular.

Guangdong province

Dān Cōng: A family of stripe-style oolong teas from Guangdong Province. The doppelganger of teas, Dancong teas are noted for their ability to naturally imitate the flavors and fragrances of various flowers and fruits, such as orange blossom, orchid, grapefruit, almond, ginger flower, etc.

The name dan cong is often misinterpreted as meaning the tea is all picked

from a single bush, grove, or clone. This is not correct. Dan cong is a botanical term that refers to the morphology of the tea plant. Most tea bushes emerge from the ground as a cluster of branches, however, the uncommon dan cong variety emerges as a single trunk that branches off higher up the stem.

It is commonly brewed to be strong, with the bitterness leaving a sweet aftertaste. Several sub-varieties of oolong, including those produced in the Wuyi Mountains of northern Fujian and in the central mountains of Taiwan, are among the most famous Chinese teas. In Chinese tea culture, semi-oxidized oolong teas are collectively grouped as qīngchá (Chinese: "clear tea"). Oolong has a taste more akin to green tea than to black tea: it has neither the rosy, sweet aroma of black tea, nor the stridently grassy vegetal notes that typify green tea.