How Oolongs Are Made
Of all the tea-making processes, the process to create oolong is one of the most complicated and time consuming in the tea world. In addition to having additional steps not found in the production of other tea types, making an oolong is a nuanced process with each manufacturer developing their own styles and methods of creating their perfect oolong. The process is labor intensive with some oolongs taking up to four days to produce, but like any work of art, the result is a masterpiece worth the wait.
Note: The following steps in the production of oolong mentioned below are general steps taken to create oolong teas. The steps and order may vary depending on the variety of oolong being created.
Harvest: Beginning at the Tea Bush
Oolong production begins like any true tea: at the tea bush.
Harvested all year long, tea leaves used for oolong can have different flavors depending on the time of year a harvest occurs: leaves harvested during the warming temperatures of late spring or early summer tend to have a flowery, light flavor, and leaves harvested when the weather is getting colder (such as in autumn or early winter) produce a flavorful cup.
However, leaves harvested during late summer and early autumn tend to have less flavor. Some oolongs, like Wu Yi Shan, are only harvested one a year in the spring. Tea connoisseurs tend to favor Chinese oolongs harvested in spring and fall, while spring and winter harvests produce some of the best oolongs in Taiwan.
While most teas are made with the bud and first two leaves on a branch, oolongs can use more leaves off the tea bush, with one to four leaves making up the oolong leaf set. Large leaves are favored in oolong production, and depending on the oolong variety, the entire intact leaf set or individual leaves are plucked off the bush. The entire leaf set is usually used to make rolled oolongs while individual leaves are ideal for twisted oolongs.
The leaves for oolongs can be either hand picked or harvested by machine: Chinese farmers prefer harvesting tea by hand while Taiwanese farmers use both hand harvesting and machine harvesting. Hand harvested oolongs tend to be finer and more expensive due to the time and care taken to pick the leaves.
Wither, Rest, and Repeat
Once a leaf is picked off the bush, chemical reactions come into play as it begins to wilt. Oolong manufacturers control those chemical reactions during the withering process, which makes the leaves soft and malleable for shaping. During withering, tea leaves laid out on trays or screens and exposed to air, whether outside in the sun (called Solar Withering) or stacked inside. The leaves are tossed (or bruised) for even oxidation. During the production of some oolongs, the leaves are allowed to rest and cool down in between bruising and withering sessions where they continue to wilt and flatten.
Oolongs can have anywhere between 12% and 80% oxidation (for reference, green teas aren’t oxidized at all while black teas are fully oxidized). Because of this wide range, some oolongs are closer to green tea with a light flavor and yellow color while heavily oxidized oolongs, with a bolder flavor and reddish brown color, will resemble black tea.
The steps in the withering process are repeated as many times as the tea manufacturer wishes, and each manufacturer has their own withering processes and techniques. At the end of the withering process, the moisture content of the tea leaves is reduced by about a third. Darker oolongs will take the most time to wither (anywhere from twelve to twenty hours).
After the leaves have been withered and have achieved the appropriate oxidation level, the oxidation process is halted by heating the tea leaves; this destroys an enzyme in the tea leaves that causes oxidation. There are two methods to do this in oolong production: tumble drying or pan frying. In tumble drying, the leaves are put into drying cylinders (not unlike drying machines for laundry) where they are heated and tossed. In pan frying (a technique also popular in Chinese green tea production), the leaves are put into a giant pan and tossed.
Shaping and Drying
Once the tea leaves are malleable, they are either rolled or twisted. This process can take up to twelve hours. Either style can be achieved by hand or machine.
For machine rolling, the leaves are put into cloth bags and put on a rolling machine that continuously twists the bag tighter and tighter (this causes the leaves to form into a ball inside the bag); then they are emptied onto a belt for drying before repeating the process to make the leaves even tighter. For twisting, the leaves are placed on a heated base as the machine rolls over the leaves in a circular motion which twists the leaves.
RoastingWhile most greener oolongs are left unroasted, some heavier oxidized oolongs are roasted before they are packaged. This final roasting creates a nice toasty flavor in the tea which many find very pleasing. Traditionally, the more oxidized an oolong is, the more it’s roasted. Outside of the production process, some tea merchants purchase greener oolongs and roast the leaves to further dry out the leaves; this is a technique called “dry roasting” and is often done to extend the shelf life of the tea.
Once roasting is completed, the teas are packaged into vacuum-sealed packages and shipped, ready to find a teapot to call home.