Processing Green Wulong Teas

Processing Green Wulong Teas

As previously noted, it is the process of oxidation that determines which of the six families a tea belongs to. The wulong family of teas consists of semi-oxidized teas that can be categorized somewhere between green teas and black teas. This family of teas, which is less well-known in the West, is widely grown in China (Fujian, Guangdong) and in Taiwan, where it is something of a specialty. A wulong tea can be closer to a green tea or a black tea depending its degree of oxidation. This is why we distinguish between green wulong teas, which generally undergo 30 percent to 50 percent oxidation, and black wulong teas, which can be up to 70 percent oxidized. Of course, these different degrees of oxidation develop very different aromas. It is easy to tell the vegetal and floral bouquet of a green wulong from the sweet, woody notes of a black wulong tea.

The processing of black wulong teas is described h the section on China, and below is a description of how green wulong teas are processed.


On the first day, as soon as the freshly picked leaves arrive at the factory, skilled workers concentrate on the oxidation process, which will take up the better part of the day.


Although most of the first picking takes place in April, some growing areas on the plains at an altitude of 330 feet (100 m) can be harvested as early as mid-February. If the factory is producing a wulong tea, the buds need to have reached a certain stage of maturity. The final bud must have opened before it can be picked, along with the three following leaves. Picking is done manually by women, especially at plantations in and on steep slopes. On the plains, machines are often used.


Once the leaves have been picked, they are spread out on large sheets, usually outside, to undergo the first stage of processing: withering. This stage consists of drying the leaves slightly so the moisture they contain does not damage them. Depending on the weather conditions, they may be left to stand for 30 minutes to two hours. If the sun is tod strong, light canopies are placed over the leaves to protect them.


The next stage of processing, oxidation, is an extremely delicate step, as it largely determines the final flavor of the tea. It is during oxidation that aromas are released and begin to stabilize on the leaves. The leaves are spread out on woven bamboo trays about 3 feet (1 m) in diameter in an environment where the temperature is maintained at 68 to 77°F (20to 25°C) and the humidity at 60 percent to 85 percent. The leaves are lightly stirred at regular one- to four-hour intervals. This stirring action is very important, as the friction of the leaves against the bamboo trays breaks down the cellular structure of the leaves and releases oils that contain aromatic substances, thus triggering the process of oxidation. This stage can last from 10 to 18 hours.

This process is instinctive, as only the experience of the grower, who touches and sniffs the leaves, tells him when it is exactly the right time to stop the oxidation process.


Next, the leaves are fired. This process, as with green teas, is intended to stop oxidation by destroying the enzymes that causes it. Once the leaves have reached the required degree of oxidation, they are placed in a heated rotating cylinder that looks like a large clothes dryer, where they undergo a preliminary heating/stirring. The leaves will be heated to about 572°F (300°C) for five to seven minutes.


As soon as they are taken out of the rotating cylinder; the still-warm leaves are rolled for the first time. A mechanical arm attached to a rounded dome rotates swiftly, causing the leaves to brush against the walls of the machine and release their fragrance. This first rolling lasts three to five minutes.


Drying stabilizes the aromas of the leaves. It also prevents excessive residual moisture from damaging the leaves. Drying starts at about 158°F (70°C), for five or six minutes, and then continues for 20 to 30 minutes at 212°F (100°C).

Finally, the leaves are spread out on large bamboo trays and left to stand for six to eight hours.


On the second day the leaves undergo three basic stages, which will be repeated several dozen times: heating/stirring, rolling and compression.


The leaves are first placed in a rotating cylinder for a few minutes to soften them.


Next, the leaves are formed into a 44-pound (20 kg) package and wrapped in a special fabric. This mass of leaves is placed in a machine equipped with four rotating rollers that compress it into a round shape.


Still wrapped in the fabric the leaves are then placed in another machine, where they will be turned and pressurized for about 10 minutes while being compressed.

These three steps are repeated 10 to 20 times with a rotating cylinder that is full of air heated to 140 to 392°F (60 to 200°C) and 30 to 40 times with a non-heated cylinder. This is how, after a great deal of work, the distinctive wulong bead shape is obtained.


Later, the final drying will stabilize the aromas on the leaves and allow the grower to ensure that no more than 2 percent to 3 percent moisture remains in the leaves. This drying phase lasts five to ten minutes at a temperature ranging from 212 to 248°F (100 to 120°C).


At the sorting stage, the leaves are separated from the small stems that are still attached. Although there are machines that can do this work, sorting is usually done by hand. It is an extremely tedious process that does nothing to enhance the flavor of the tea according to some growers; however; it remains Important to those who want their tea to look perfect. After the sorting, the processing is done.


In Taiwan, current practice is to leave the tea intact, without roasting it. However, at the request of customers, many producers heat the leaves one last time. It is often tea merchants who carry out this last step. With the help of an electric oven or bamboo baskets placed over a heated base, the leaves are heated at temperatures ranging from 167 to 320°F (75 to 160°C) for two to 60 hours, depending on the intensity required. There is no need to rotate the leaves in a convection oven, but if a bamboo basket on an electric heater is used, the leaves must be stirred at 20- to 30-minute intervals in order to ensure an even firing. Firing plays an important role in the taste and color of a tea. It can add woody, sweet, even caramelized aromas. In addition, it gives the liquid more balance, reducing the astringency as well as the level of caffeine. At the request of some older customers, who claim that roasted wulong teas "eliminate moisture" from the body, several growers fire their teas in the fall. This type of wulong gives that impression because, by reducing the "greenness" of the tea, firing makes it easier to drink and to digest.

Although it may look like a simple operation at first glance, roasting is an art in itself, as it involves adding heat-induced notes without overpowering the other aromatic accents present in wulong tea.


Just as there are aged Pu er teas, there are also wulong teas that are called "aged" after several years of maturing. The creation of this type of wulong tea is probably a direct Result of the humid climate of the island. Because of the climate, unsold harvests had a tendency to become saturated with moisture and to deteriorate. It is likely that certain growers, seeking to remedy this situation, cane up with the idea of firing in order to conserve their teas. Combined with the effect of the aging of the leaves, the annual roasting gives rise to new flavors quite different from those that were present at the outset.


The process of aging wulong teas consists of subjecting them to firing annually or every two to three years. As a skilled worker decides instinctively for how long and at what temperature the firing should take place, it is difficult to make any connection between the age of the tea and the intensity of the roast. However; after 20 to 25 years of aging, mineral notes begin to appear, creating similarities with aged Pu er teas. Further aging progressively confirms the mineral notes.

Today, the production of aged wulong teas is quite rare and unfortunately, due to economic factors, this tradition could disappear entirely in few years. The high demand for wulong teas leaves producers with very little surplus. Harvests are now vacuum-stoned, further reducing the risk of deterioration. In addition, as the price of aged teas is relatively low, growers no longer see any advantage in conserving and processing a small quantity over a long period of time to finally obtain a price only slightly higher than that of fresh tea. However; as tea enthusiasts, let us hope that this unique tradition, rich in gustatory pleasure, will be continued.


The literal translation of wulong is "black dragon," and it refers to the black snakes that were sometimes found wrapped around the branches of tea trees. It is said that adults would try to comfort children who were afraid of the snakes by telling them that the snakes were little black dragons.


It takes one person no fewer than 10 hours to remove the stems from 26 1/2 pounds (12 kg) of tea. Once the stems have been removed, only 20% pounds (9.4 kg) of tea remain.


In the past, small pieces of coal were used for roasting. Today, few growers still resort to this method; however, it is sometimes possible to discover teas fired in this way in specialty stores.