What is Concubine Oolong Tea?
Concubine Oolong is a relatively new classification of tea that came about as a result of the 9/21/99 earthquake in Taiwan. The establishment of this unique character of oolong tea is indebted primarily to the Green Leaf Hopper ( Jacobiasca formosana). This is a tiny grasshopper-type bug that feeds on the sap of young tea leaves. The result is that the leaf is slightly "injured" by the insect, and the natural immune system response in the plant evidently causes subtle changes in the leaf's chemistry, along with the slight oxidation of the leaf caused by the minuscule insect bites while the leaf is growing. The effect is an enhanced substance and distinct flavor that these leaves brew when they are properly cured. Concubine tea can typically undergo many more infusions than a conventional Oolong. The most pronounced quality is a honey-like fragrance and flavor that is unlike anything else in the world of Oolong Tea. It is a tell-tale quality that is unique effect of the Green Leaf Hopper. Incidentally, this also indicates the absence of pesticides that would otherwise deter this bug from feeding on the leaves.
The idea of this Concubine Oolong had been conceived prior to the earthquake however, according to a colleague at the Lugu Farmers' Association. A year or so prior to the earthquake, the farmers' association organized a group of local Dong Ding Oolong tea artisans from Central Taiwan to visit the factories where Oriental Beauty Oolong is made in the North, mostly Hsinchu County. Acknowledging the scarcity of this unique type of Oolong, and the high value it warrants as a result, Oriental Beauty was worth learning about. Oriental Beauty, aka Dong Fang Mei Ren, also called "Bai Hao" and "Pom Feng" Oolong is the traditional Oolong that has been cultivated in Northern Taiwan for over a century. It is purposely cultivated without the use of pesticides so that it will be affected by the Green Leaf Hopper during the growing season. (This begs the question of how many variations of this tea existed in pre-modern times, before pesticides existed.)
Oriental Beauty is a heavily oxidized Oolong - on its way to resembling a Black Tea, but still with enough green in the leaf to keep it within the Oolong category. Oriental Beauty is not roasted post-production, and the leaves are only curled as they are dried, which is the more traditional way of curing tea leaves. Concubine is less oxidized (about 40-50%) and the leaves are tightly rolled in the manner of Dong Ding Oolong or High Mountain Tea. This is a relatively modern innovation that was adopted in Taiwan in the 1980's. Tightly rolling the leaves protects the integrity of the leaves (prevents crumbling) and preserves the freshness, which prolongs shelf life. Concubine is also roasted after curing the leaves, similar to Dong Ding Oolong, although usually Concubine is roasted to a lesser degree. In recent years, we have observed the research done by artisan friends on roasting "bug-bitten tea leaves" in order to make Concubine Oolong. It proves to be a particularly unpredictable type of tea to roast, and the leaves will change in character over time when stored without being vacuum-sealed. This factor lends to the traditional artisan quality of producing this type of tea. Not only do the leaves need to be affected just the right amount by the Green Leaf Hopper at the right time in their growth cycle, but they also need to be masterfully roasted and stored to attain the optimal results. We feel that Concubine Oolong is the most prominent representative of a traditionally made Oolong in the 21st Century, along with is predecessor, Oriental Beauty.
A standard Guefei Oolong should be closer to medium oxidation. This is partially due to the fact that the leaves are already slightly oxidized before they are picked as a result of the the Green Leaf Hopper that "makes" Concubine Tea and Oriental Beauty Tea. Secondly, the leaves are intentionally oxidized more than, say a Gaoshan/High Mountain Tea. Guifei/Concubine Oolong is also typically roasted to varying degrees, integrating Dong Ding Oolong processing methods with Oriental Beauty methods. To achieve optimal results, roasting requires a certain degree of oxidation in the processing of the leaves. So this is why Guifei Oolong is typically a medium oxidation.
Having said this, there is the occasional phenomenon of "bug bitten tea" being processed as a High Mountain Tea. This is because the "bug bitten effect" is a natural, unregulated occurrence that may or may not happen when little or no pesticides are used. So if a high elevation tea garden is not sprayed, or minimally sprayed, the Green Leaf Hopper may affect a crop. Many High Mountain Tea farmers do not want to venture into Concubine tea processing and will simply process the leaves as a High Mountain Tea. In this case, you may find a batch of lightly oxidized tea that is called Guifei tea because of its honey-like character that results from the Green Leaf Hopper effect.