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Blog 29: Different Roasts and Heat Control of Wu-Yi Oolong (Yan Cha)

Updated: Oct 19, 2018

We hope you enjoyed our white tea blogs. If you haven’t read them, we highly recommend checking them out. After focusing on white tea for a month, we’d like to turn our attention back to oolong again. As you might remember, Wu-Yi oolong (yancha) has a tea season. Normally, Wu-Yi oolong tea season starts from around April 20th to around May 10th. During the 20-day tea season, tea makers worked 24 hours a day to process all fresh leaves into half-processed tea, also called Mao Cha(Chinese: 毛茶). After the tea season, it’s the roasting process. This process can last a year. We actually have multiple blogs discussing the roasting, and you can find them here. Today, let’s talk about different roasts and the heat control of Wu-Yi oolong roasting.

The roasting process is actually a combination of the second phase of Wu-Yi oolong tea-making. The purpose of the first phase, of course, is to process all fresh leaves into a half-processed state so that all harvests can be stored for further processing later. The second phase is to finalize all half-processed leaves into tea products. This 2-stage processing is similar to petroleum production. First, crude oil needs to be extracted, just like all fresh leaves need to be harvested. But as normal consumers, we need gasoline for our cars, not crude oil. That’s why all crude oil is further refined into gasoline. Oolong tea is the same. Half-processed tea needs to be refined(roasted) before it goes on sale.

The second phase has 4 steps. They’re selecting, sifting, winnowing and roasting. Among all, roasting is the most crucial and technical. Roasting gives oolong’s final flavor. Half-processed tea leaves still have a grassy note. Roasting clears the last bit “taste of green leaves”. Beside changes in the flavor and the aroma, roasting can also make leaves slimmer and tighter. During roasting, water content is lowered, thus allowing Wu-Yi oolong to oxidize much slower and maintaining its quality. Wu-Yi oolong borrows the power of fire to change the essence of tea leaves. After the roasting, the tender, soft and delicate feeling of a fresh leaf is gone; instead, a complex, strong, thick and resilient characteristic is developed.

Valley Brook Tea | Blog
Roasting is the Key to A Perfect Cup of Wu-Yi Oolong

In modern tea-making, there are many roasting methods. Traditional charcoal roasting is more common in Wu-Yi oolong tea-making. The use of roasting machine and electric roasting is exceedingly rare, but still exists. In Wu-Yi oolong tea-making, machine roasting and electric roasting can only make light roasted tea. If we want high quality, heavily roasted Wu-Yi oolong, traditional charcoal roasting is the only practical choice.

Charcoal Burning Before Roasting

In our previous blog, we’ve introduced the how the amount and the duration of roasting defines light, medium and heave roasts. Different roasts also have different requirement of roasting temperatures. Generally, temperature level depends on the type of fresh leaves. Earlier the harvest, lower the roasting temperature. For example, Huang Guan Yin (105) is one of the earliest harvested tea. The roasting temperature for Huang Guan Yin is between 140℉-194℉(60℃-90℃). Most other major Wu-Yi oolong teas, such as Rou-Gui and Shui-Xian, require a higher roasting temperature between 176℉-248℉(80℃-120℃). However, if the quality of fresh leaves is already inferior, it usually needs a much higher temperature to get rid of the messy taste. The starting temperature needs to be above 212℉(100℃). This type of low quality tea would have a nasty burned and overcooked taste.

We 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 Please also follow us on Instagram @valleybrooktea and join our mail list to get our daily tea updates and our latest promotions! Finally, this is the last week of our white tea sale!! Use code: whitetea186 and get a 10% off on all white tea products!


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