Tea withering refers to the process of dispersing moisture in tea leaves before they are subjected to heat Fixation, allowing for more chemical changes to occur. Traditionally, methods of withering include solar withering (sun-drying), natural indoor withering (spreading out to air-dry), and a combination of both. Nowadays, semi-mechanized withering equipment that is artificially controlled—the withering trough—is also used.
The Main Purpose of Withering
The primary purpose is to reduce the Water content in fresh leaves and stems, promoting complex chemical changes due to enzymes. The chemical reactions during withering and Fermentation have a broad range of effects, which directly relate to the tea's aroma, taste, and liquor color.
Proper and effective withering allows the grassy smell of fresh leaves to dissipate and be replaced by a fragrant scent, often accompanied by fruity or floral aromas. The resulting tea has a smooth and fragrant taste without bitterness or astringency. Withering requires suitable temperature, humidity, and air circulation conditions.
The Degree of Withering for the Six Types of Tea
Generally, green tea does not undergo withering or fermentation; yellow tea does not wither but undergoes a yellowing process after heat fixation followed by additional fermentation; dark tea does not wither and undergoes post-fermentation; white tea undergoes heavy withering but no fermentation; and Oolong tea undergoes withering and partial fermentation.
Oolong tea has the lightest degree of withering, requiring a moisture content between 68% and 70%; black tea has a moderately heavy degree of withering, reducing moisture content to around 60%; and white tea has the heaviest degree of withering, requiring the fresh Leaf moisture content to be reduced to below 40%.
Withering is a term used for a step in the tea-making process. The master spreads out freshly picked leaves at a certain thickness evenly. Through air-drying, when the leaves become wilted, this process is called withering. The first step in making white tea, black tea, oolong tea, and other types involves withering, though the degree varies. White tea has the heaviest degree of withering, requiring the fresh leaf moisture content to be reduced to below 40%. Black tea has a moderately heavy degree of withering, reducing moisture content to around 60%, while oolong tea has the lightest degree of withering, requiring a moisture content between 68-70%.