Blog 21: The Roasting of Wu-Yi Oolong Rock Tea (Part I)

Updated: Oct 19, 2018

In the past few weeks, you and I have experienced Wu-Yi oolong tea season. We’ve discussed the harvest, the sun-drying, the shaking, the hot stirring and the rolling. At the end of the tea season, all fresh leaves are processed into a half-processed state (also called Mao-Cha, Chinese: 毛茶, meaning “fur-tea” or half-processed tea). The half-processed state allows tea makers to put some tea leaves in the storage while continue working on the next tea-making process. Today, we will discuss one of the most crucial processes in Wu-Yi oolong rock tea tea-making: the roasting.


The roasting, or Bei-Huo (Chinese: 焙火, meaning “baking/roasting fire”) is a unique process in oolong tea. Through different stages of roasting, oolong tea gains multiple layers of fragrances and flavors. Half-processed Wu-Yi oolong rock tea still tastes “grassy” like green tea, but after the roasting, it’d be stronger and more complex in both fragrances and flavors. Interestingly, the name “roasting” is somewhat misleading. Many tea lovers take the idea literally and think tea leaves are roasted/baked on open flame. The truth is, oolong leaves are roasted with the residual heat from charcoal ashes. Burning charcoals is also where we start to prepare for the roasting process.

Charcoal Burning

The charcoal burning is a surprisingly complicated procedure. All 45KG (99 pounds) of charcoals need to be burned to a white-ash state that there can be no sparkles or black thread anymore. This burning can take up to 10 hours to reach the ideal white-ash state. Once the burning is done, the residual heat from charcoal ashes can last about 12 days. In fact, the residual heat usually lasts more than 12 days, but experienced tea makers prefer to dump the ashes and start another burning after the 12-day mark. The intense heat from the charcoal ashes can heat the roasting room to at least 50℃ to 60℃ (122℉ to 140℉).

White Charcoal Ashes

After the charcoal burning, the roasting officially starts. Traditionally, tea makers use bamboo baskets (shown above) as the containers for tea leaves. Each batch holds about 5 pounds to 8 pounds of tea leaves. Since there’s quite a lot heat applied to the leaves, no batch should carry less than 5 pounds or more than 8 pounds of leaves. Then, the bamboo basket is put on top of the charcoal ashes and begins its first 10-hour to 12-hour roasting.

Tea Leaves in Bamboo Baskets

Now, if you wonder whether tea makers can rest during the roasting, just remember: tea-making is a cruel and harsh job. Every 30 minutes, tea makers need to flip a basket load of tea leaves bottom up to ensure that no leaves are overheated or under-heated. As you can imagine, the working environment in the roasting room is extremely hot and dry. After flipping multiple baskets of leaves, tea makers are exhausted and thirsty for water. In addition to the flipping, tea makers also need to constantly check on leaves by drinking and tasting them. The flavor tea makers look for during the roasting is the disappearance of the “grassy” taste.


Depends on the type of teas, there are different stages of roasting. Some teas can endure more roasting while other teas do not withstand multiple roasting very well. In our “Part II”, we will discuss what teas can be roasted more and why.

I hope you enjoyed today’s blog. As always, if you have any questions or suggestions, please leave a comment, tweet us @valleybrooktea or email us at contact@valleybrooktea.com. Please also follow us on Instagram @valleybrooktea and join our mailing list to get our daily tea updates and our latest promotions!