Hubei Karn Tea Co., Ltd.
Detailed explanation of black tea fermentation process
Published Time：
2025-06-27
In the world of tea, black tea stands out with its rich taste and strong aroma, all thanks to its core process - fermentation. Fermentation is a key step in the formation of black tea's quality. Through a series of complex biochemical changes, it gives black tea its unique color, aroma, and taste.
In the world of tea, black tea stands out with its rich taste and strong aroma, all thanks to its core process—fermentation. Fermentation is a key step in the formation of black tea's quality. Through a series of complex biochemical changes, it gives black tea its unique color, aroma, and taste.
Black tea fermentation is essentially the process where, after tea cell damage, tea polyphenols are gradually oxidized and polymerized into colored substances such as theaflavins and thearubigins under the action of polyphenol oxidase. During this process, the grassy smell of fresh leaves gradually dissipates, transforming into floral, fruity, and sweet aromas. Simultaneously, the bitter tea polyphenols decrease, making the tea liquor richer and sweeter.
Black tea fermentation generally involves the following steps: First is withering, where the fresh leaves are spread out to reduce their water content, softening the leaves for subsequent rolling; then comes rolling, using external force to break down the tea cell structure and squeeze out the cell fluid, allowing the tea polyphenols and polyphenol oxidase to fully contact, creating conditions for fermentation; then the rolled tea leaves are placed in a suitable environment for fermentation. During fermentation, the environmental temperature, humidity, and oxygen content must be strictly controlled. Typically, the fermentation temperature is controlled between 25℃ and 30℃, the humidity is maintained at around 90%, and appropriate ventilation is ensured to promote the smooth progress of the oxidation reaction. The fermentation time varies depending on the tea variety, tenderness, and environmental conditions, generally ranging from 2 to 5 hours. After fermentation, drying must be carried out promptly, using high temperatures to quickly stop fermentation, fix the tea quality, and further develop the aroma.
Many factors affect black tea fermentation. If the temperature is too high, the oxidation reaction accelerates, potentially leading to over-fermentation, resulting in a dull aroma and dark liquor color; if the temperature is too low, fermentation will slow down or even stop, affecting the tea quality. Humidity is also crucial for fermentation. Insufficient humidity causes the tea leaves to lose water, resulting in incomplete fermentation; excessive humidity may breed mold, damaging the tea quality. In addition, the tenderness of the tea leaves, the degree of rolling, and the thickness of the spread leaves during fermentation all affect the fermentation effect.
Mastering the black tea fermentation process is like holding the key to unlocking the unique flavor of black tea. By precisely controlling various factors during the fermentation process, tea makers can transform fresh leaves into cup after cup of intoxicating black tea, allowing the charm of black tea to spread widely throughout the world.
Related Blog
Fermentation process of other teas
2025-06-19
Points to note when picking tea
2025-03-07
Bringing the authentic taste of Hubei's finest teas to the global market since 2023.
ADD:No. 87, Group 2, Heyexi Village, Wuyanquan Town, Yidu City, Hubei Province, China
E-mail:karntea@karntea.com
Quick Links
Get a Quote
If you are interested in our services, please fill out the form below and we will contact you as soon as possible.
Powered by 300.cn This website supports IPV6 access