The fragrance of Tieguanyin comes from three indispensable factors: nature, terroir and craftsmanship.
• Nature: Favourable weather conditions; sunny days with north wind are ideal.
• Terroir: The exclusive Tieguanyin tea cultivar plus unique growing conditions including local soil and altitude in Anxi County.
• Craftsmanship: The most decisive factor, represented by its one-of-a-kind processing techniques, especially leaf manipulation (zuoqing).
We will break down step by step how fine craftsmanship builds the wonderful aroma of Tieguanyin:
Core Procedure: Leaf Manipulation - The Birthplace of Aroma Leaf manipulation is the heart of oolong tea production for Tieguanyin. It consists of repeated rounds of shaking and spreading leaves alternately. This stage determines semi-fermentation and lays the foundation for the type and depth of the tea's fragrance.
1. Leaf Shaking (Cell Disruption) Tea leaves collide with one another inside the shaking machine. The edges of tea leaves get slightly and partially bruised by friction. Purpose: Internal sap and substances ooze out and react with enzymes and oxygen in the air to start enzymatic oxidation. It also creates precursors for all aromatic compounds.
2. Leaf Spreading & Resting Shaken leaves are spread thinly on bamboo sieves to rest and recover. Purposes:
• Moisture evaporation: Leaves shrink from water loss. Water and soluble nutrients from stems and veins flow into leaf tissues, a process known as water transportation.
• Gentle oxidation: Enzymatic oxidation takes place slowly and thoroughly along the damaged leaf edges during resting. Shaking and spreading are repeated three to four times with changing intensity and duration, following the rule of light-heavy-light or light-heavy-heavy. Inside the tea leaves, dramatic chemical changes take place:
• Grass-like low-boiling compounds evaporate: Substances such as leaf alcohol that bring raw green odour fade away gradually during repeated shaking and resting. • High-boiling aromatic compounds are generated: With the effect of enzymes and oxygen, proteins and glycosides break down and transform into hundreds of different aroma substances:
✦ Nerolidol: The key compound forming the distinctive Guanyin rhyme and elegant orchid note, featuring long-lasting fragrance.
✦ Indole and jasmolactone: Create fresh sweet jasmine flavour.
✦ Various esters and alcohols: Combine to produce rich fruity notes and sweet honey aroma. • Formation of the classic feature: Green leaves with reddened edges. Leaf edges damaged by shaking are fully oxidised and turn red, while the centre of leaves remains green, forming the iconic mark of oolong tea.
