Oolong (, ; ;, "black dragon" tea) is a traditional semi-oxidized Chinese tea (Camellia sinensis) produced through a process that includes withering the leaves under strong sun and allowing some oxidation to occur before curling and twisting. Most oolong teas, especially those of fine quality, involve unique tea plant cultivars that are exclusively used for particular varieties. The degree of oxidation, which is controlled by the length of time between picking and final drying, can range from 8% to 85% depending on the variety and production style. Oolong is especially popular in southeastern China and among ethnic Chinese in Southeast Asia, as is the Fujian preparation process known as the gongfu tea ceremony. Different styles of oolong tea can vary widely in flavor. They can be sweet and fruity with honey aromas, woody and thick with roasted aromas, or green and fresh with complex aromas, all depending on the horticulture and style of production. Several types of oolong tea, including those produced in the Wuyi Mountains, Nanping of northern Fujian, such as Da Hong Pao, are among the most famous Chinese teas. Different varieties of oolong are processed differently, but the leaves are usually formed into one of two distinct styles. Some are rolled into long curly leaves, while others are "wrap-curled" into small beads, each with a tail. The former style is the more traditional. The Chinese term wulong (oolong) was first used to describe a tea in the 1857 text Miscellaneous Notes on Fujian by Shi Hongbao. In Taiwan, oolong teas are also known as or "dark green teas" since early 2000. The term "blue tea" in French is used to refer to oolong tea. Oolong teas share some characteristics with both green and black teas – they have light flavour notes but are often more complex in taste than green teas, and not as strong as black teas. The manufacturing of oolong tea involves repeating stages to achieve the desired amount of bruising and browning of leaves. Withering, rolling, shaping, and firing are similar to the process for black tea, but much more attention to timing and temperature is necessary.

Possible origins

There are three widely espoused explanations of the origin of the name of Oolong tea. According to the "tribute tea" theory, oolong tea came directly from Dragon-Phoenix Tea Cake tribute tea. The name oolong tea replaced the old title when loose tea came into fashion. Since it was dark, long, and curly, it was called "Black Dragon" tea, leading to the Oolong name.

Varieties

Fujian

Tea production in Fujian is concentrated in two regions: the Wuyi Mountains and Anxi County, Quanzhou. Both are major historical centers of oolong tea production in China.

Wuyi Mountains

The most famous and expensive oolong teas are made here, and the production is still usually accredited as being organic. Some of the better known cliff teas are:

Anxi

Guangdong

Single Bush Dancong (单 枞**) ("Phoenix oolong")** refers to a family of strip-style oolong teas from Guangdong Province. They 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 term dancong originally meant phoenix teas all picked from one tree. In recent times, though, it has become a generic term for all Phoenix Mountain oolongs. True dancongs are still produced, but are not common outside China.

Taiwan

Tea cultivation in Taiwan began in the 18th century. Since then, many of the teas which are grown in Fujian province have also been grown in Taiwan. Since the 1970s, the tea industry in Taiwan has expanded at a rapid rate, in line with the rest of the economy. Due to high domestic demand and a strong tea culture, most Taiwanese tea is bought and consumed in Taiwan. As the weather in Taiwan is highly variable, tea quality may differ from season to season. Although the island is not particularly large, it is geographically varied, with high, steep mountains rising abruptly from low-lying coastal plains. The different weather patterns, temperatures, altitudes, and soil ultimately result in differences in the appearance, aroma, and flavour of the tea grown in Taiwan. In some mountainous areas, teas have been cultivated at ever higher elevations to produce a unique, sweet taste that fetches a premium price.

Other varieties

Preparation

Recommended brewing techniques for oolong tea vary widely. One common method is to use a small steeping vessel, such as a gaiwan or Yixing clay teapot, with a higher than usual leaf to water ratio. Such vessels are used in the gongfu method of tea preparation, which involves multiple short steepings. For a single infusion, 1- to 5-minute steepings are recommended, depending on personal preference. The recommended water temperature ranges from 180-205 F.

Characteristics

Caffeine

Oolong contains caffeine, although the caffeine content in tea will vary based on terroir, when the leaf is plucked, and the production processes.

Teaghrelins

Some semi-oxidized oolong teas contain acylated flavonoid tetraglycosides, named teaghrelins due to their ability to bind to ghrelin receptors. Teaghrelins were isolated from Chin-shin oolong tea and Shy‐jih‐chuen oolong tea and recently from other oolong tea varieties.