If you’ve never tried or heard of oolong tea, you might have wondered how oolong tea is different from other types of tea. The primary differences are the oxidation level of the tea leaves and how the leaves are shaped after the oxidation process.
Oxidation of Tea Leaves
Oxidation is sometimes confused with fermentation. Generally, oxidation is a chemical reaction involving oxygen. It occurs in tea leaves when they are picked. After tea leaves are harvested from the Camellia sinensis var. sinensis plant, they undergo physical trauma (aka bruising) to promote oxidation when the natural enzymes in the leaves are exposed to oxygen. Fermentation, on the other hand, generally occurs when a microorganism such as bacteria, yeast, or mold undergo a chemical reaction when there is no oxygen present.
The oxidation level of tea leaves is how several true teas are differentiated. True teas range from unoxidized green teas to black teas, which have the most oxidation. Oolong tea leaves are partially oxidized and the various levels of oxidation of those leaves fall between green tea and black tea. Like most true teas, the leaves used to make oolong tea are heated to slow down the oxidation process.
Final Stages of Processing Oolong Tea Leaves
The final steps in producing oolong tea involve hindering oxidation and shaping the leaves. The tea leaves are heated to cease oxidation and then rolled into a ball shape or twisted into strands. Once shaped, some varieties of oolong tea require additional heating. The additional heating involves baking or roasting, which is commonly used interchangeably, but are not the same. The last stage of processing is eliminating as much oxygen by vacuum sealing the tea leaves to prevent further oxidation. Vacuum sealing tea helps extend its shelf life, in addition to storing it in a dry place.
The assortment of oxidation levels, amount of heat treatment, and shaping has created a wide variety of oolong tea flavors. Hwa Gung Tea produces several distinct varieties of high-mountain oolong tea to choose from. The best way to understand the differences is to taste and compare all the different varieties.