Oolong tea is a special tea category from Fujian Province. Its initial processing is meticulous, resulting in many quality factors, making tea leaves evaluation relatively complex. Currently, sensory evaluation of Oolong tea remains an important method for judging tea quality, divided into rough tea evaluation and refined tea evaluation. Rough tea refers to the primary product formed after initial processing of fresh leaves. Minnan (Southern Fujian) Oolong rough tea refers to tea leaves initially made through ten major processes including withering & shaking, fixation, rolling & baking, etc.
Oolong rough tea evaluation involves both dry and wet inspection. Dry inspection focuses primarily on strip shape and color, appropriately combined with cleanliness; wet inspection focuses primarily on aroma and taste, appropriately combined with the degree of "withering & shaking" and "softness" in the brewed leaves.
Dry Evaluation of Oolong Tea: Tightly Rolled Strips with a "Treasure Color" are Premium
Strip shape refers to the specific external specifications of various dry teas. Minnan Oolong tea requires a tightly rolled strip shape, primarily formed during the wrapping and rolling process. Currently, most is done manually, though machine shaping also exists. Besides breaking leaf cells to make the rough tea glossy and increase brewing aesthetics, wrapping and rolling also creates the curled strip shape, enhancing the visual appeal of the tea's appearance, which is the traditional style of Minnan Oolong tea. Due to different production techniques, strip shapes vary, including curled, flat-straight, spiral, etc.
Various colored substances exist in the fresh leaves of Oolong rough tea, such as chlorophyll, carotene, xanthophyll, anthocyanins, etc. Due to different contents and processing degrees, rough tea colors are diverse, like banana yellow, ivory, greenish-brown, black and glossy, green, dark brown, etc. Among them, banana-yellow tea has high aroma, while black and glossy tea has mellow flavor and good infusibility; these two are premium tea colors.
Minnan Oolong tea's spring, summer/heat, and autumn harvests have noticeably different colors. In spring, temperatures gradually rise, sunlight is moderate, and moisture is suitable. Tea plants accumulate nutrients over a long period; the tenderness of new shoots' upper and lower leaves is similar, with good flexibility. Protein and flavonoid content is high. Spring tea colors are generally glossy, and the taste is relatively mellow.
Summer/heat tea experiences high temperatures, strong sunlight, fast growth, easy aging, small buds, and significant tenderness differences between upper and lower leaves of new shoots. Polyphenol and anthocyanin content is high, while protein and flavonoid content is low. Therefore, summer tea colors are generally dull, with a strong bitter and astringent taste.
In the autumn growth season, temperatures gradually drop, days are shorter, rainfall is scarce, and the weather is dry. Tea plant growth is hindered, easily forming "flushing pairs" (对夹叶). Rough tea colors are grayish and mixed, with many reddish flakes. Autumn tea with appropriate tenderness shows a "mung bean green" color. Autumn tea aroma is relatively high, slightly grassy, and not very infusible.
Oolong tea with bright red spots, glossy and bright color, showing a "treasure color" (meaning a color like a treasure, pleasing to the eye, mainly referring to Oolong tea's sandy green, oily luster with a vivid sense of brightness) is premium tea; conversely, it is of lower grade.
Wet Evaluation of Oolong Tea: Three Infusions to Smell Aroma, Taste Leans Towards Mellow and Thick
Aromatic substances in fresh leaves are the material basis for aroma formation. The main aromatic substances in fresh leaves are essential oils, but changes in proteins, amino acids, and polyphenols during tea processing also significantly impact aroma.
Each variety of Oolong tea has a special aroma. Even the same variety can have different aromas due to geographical environment, plucking standards, fertilization and cultivation management, and season. This is related to the different proportions and contents of various aromatic substance components in the fresh leaves.
The aroma of Oolong tea is most related to the degree of withering & shaking fermentation. Fixation and baking also greatly influence aroma. When distinguishing aroma, we mainly compare purity vs. oddness, intensity, and longevity.
When evaluating Oolong tea aroma, we mainly smell the aroma on the lid of the brewing cup. The first infusion assesses aroma intensity and the presence of any odd odors; the second infusion identifies the aroma type, analyzing the broad category or varietal scent, noting aroma characteristics, coarseness/fineness, length, freshness, and any odd odors; the third infusion assesses aroma persistence.
The Minnan Oolong tea production area has many varieties, each with a special aroma and taste. Even the same variety grown in high mountains versus flatlands will have different aroma and taste characteristics due to climate and soil differences. Therefore, only by being familiar with the local variety distribution and the aroma/taste characteristics of each variety can one further understand the "terroir aroma." For example, Huangdan (黄旦) grown in Luoyan, Chengguan, Changkeng, and Jiandou different places will have differences in the style of its rough tea color, aroma, and taste. Tieguanyin grown in Tiger Hill's Shipikeng and Xianghua will not have exactly the same style.
Tea is a beverage; the superiority of its taste reflects the economic value of the tea. Oolong tea has distinctions like strong/light, mellow/bitter, refreshing/astringent. Different tastes are related, on one hand, to the content and ratio of flavorful substances in the fresh leaves, and on the other hand, to whether the changes in leaf substances during initial processing are appropriate. Among these, withering & shaking is the key process forming Oolong tea's aroma and taste.
Oolong tea taste is described as mellow and thick, mellow and strong, sweet and mellow, fresh and mellow, mellow and harmonious, light, bitter and astringent, green and turbid, red and turbid, etc. Premium tea requires mellow thickness, sweet mellowness, and good infusibility.
Tieguanyin has a unique style. Tieguanyin's unique varietal taste is commonly called "Yin Yun" (音韵, literally "rhyme"), usually expressed as "pronounced, clear." Premium Tieguanyin requires pronounced Yin Yun, with a slight initial bitterness upon entry followed by a sweet, refreshing aftertaste.
The aroma and taste of Oolong tea cannot be fully described by terminology to indicate quality. Therefore, adverbs like "slightly, somewhat, a little, relatively, lacking, fairly" are often used to express different degrees.
Oolong tea liquor color should be golden, bright, and clear, avoiding turbidity.
Oolong tea brewed leaves should be soft and bright. Pouring the leaves into a water-filled leaf observation tray allows analysis of many reasons in manual processing based on leaf tenderness, uniformity, leaf substance thinness/plumpness, color brightness/dullness, red edge depth, leaf state shape, and degree of leaf expansion. It can also show variety purity and the situation of grade classification during purchase and factory acceptance. This is an indispensable evaluation factor.