The name oolong (also called wulong or wu long, sometimes "blue tea") refers to a semi-oxidized type of tea that fills the gap between green (non-oxidized) and black (fully oxidized) tea. Typical oxidation levels of oolong tea range from roughly 10% (very green) to 70% (heavily oxidized). Oolong teas are generally considered to be the most complex type of tea, combining qualities of both green and black teas, creating a very different experience.
While the finest green and black teas are made from young, tender buds and one or two leaves, oolong teas undergo more mechanical stress during processing and more mature leaves are often used (3 or 4 leaves and a bud).
The processing of oolong tea consists of 5 main steps:
- Withering & bruising: The withering is often done in the form of spreading the leaves out in the sun. Gentle bruising is induced by turning the leaves over or by shaking them in baskets. Since the leaf edges and stems are most susceptible for bruising, oolongs often feature a reddish-brown (i.e. oxidized) edge and/or stem on an otherwise green leaf. These processes start oxidation of the leaves which continues until the desired level is reached (short oxidation: greenish oolong, longer oxidation: darker, more reddish tea). This stage takes a number of hours during which the leaf is considered to be still alive.
- First Firing (Roasting): To stop oxidation, the leaves are fired in large pans or mechanical roasters at very high temperatures. This heating process inactivates most enzymes and kills the leaf. Roasting usually takes a few minutes, the duration having an important effect on the flavour and aroma of the resulting tea.
- Rolling: To give tea leaves their desired shape, they are rolled. Leaves for oolong tea are often wrapped in large pieces of cloth for rolling and can undergo multiple rounds of rolling.
- Second Firing (Drying): The shaped leaves are heated to around 100°C to reduce moisture content to the storage level and completely stop enzyme activity.
- Sorting & Grading: Finally, the leaves are sorted according to size & shape, then graded into quality classes.
Name and history of oolong tea
The origins of oolong tea date back to the end of the Ming Dynasty (1368 - 1644) or beginning of the Qing Dynasty (1644 - 1911), shortly after the discovery of black tea. Like black tea, it was first produced in Wuyi Shan, Fujian Province, China.
The beginnings of oolong tea were more discovery than invention since coincidence played a major role in its inception.
As with most Chinese teas, there are multiple legends about how exactly oolong manufacturing originated. There are two general stories (and many variations thereof) that offer different explanations for the source of the name oolong (the Chinese name wu long literally translates to "black dragon" or "black snake").
According to one legend, a tea farmer picked leaves off a tea bush to make them into tea. He was scared away by the approach of a black snake and left the picked leaves behind. When he came back the next morning to collect the leaves, they had changed colour and were brownish-green. He took the tea home and processed the leaves into tea. He enjoyed this different tea very much and decided to name it after the black snake that had led to its creation.
Another legend tells the story of Wu Liang as the discoverer of oolong tea after whom the tea was named. The story goes that Wu Liang was on his way home with a large bundle of fresh tea leaves after picking all day when he saw a deer. He went hunting after the deer and brought it home. He was so absorbed in the preparation of this unexpected feast that he forgot about the tea he had carried. When he returned to his bundle the next day, he discovered that the leaves had changed colour and turned half-way brown. Worried about losing his harvest, he started processing the tea immediately like he usually would. When he tried a cup of his finished tea, he was amazed by the unique flavour and aroma of his tea. He shared it with his friends and neighbours and the word quickly spread about his unusual tea which eventually became known as Wu Long cha.
While oolong processing was a specialty of mainland China (and Fujian Province in specific) for almost two centuries, tea farmers brought the knowledge with them to Taiwan (then known as Formosa) at the beginning of the 19th century. Today, Taiwan is world-famous for its fragrant high-mountain (gao shan) oolongs.
In recent years, other tea-producing regions like Darjeeling and Vietnam have begun to produce oolong teas but the teas from China and Taiwan are considered to be superior.