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Blog 122: What’s “Fan Qing/返青” in Wuyi Oolong (Yancha)?

In our last blog, we visited a term called “Fan Qing/返青”. Since it is quite a complicated subject, we’d like to dedicate this blog to help you better understand what’s “Fan Qing” and why it happens.

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Sorting newly processed leaves

In Chinese, the literal meaning of “Fan Qing/返青” is “going back to green”. In Wuyi oolong (Yancha), “Fan Qing” refers to the quality deterioration of the tea after a certain period of time.

If you are a regular oolong tea drinker or a tea business owner, you’ve probably noticed a strange “phenomenon”: the oolong tea you liked on the day of the purchase suddenly tastes strange after a few months or years. Some online posts even invented a conspiracy theory to explain how some dishonest businesses would let you taste a good tea but secretly sell you a lesser quality product.

As a matter of fact, this is not some shady business practices that tea producers intentionally do. This is the result of “Fan Qing/返青”.

Valley Brook Tea | Blog
Fan Qing/返青 means tea leaves "going back to green"

Interestingly, during our tea events, some of our customers raised a question that when they search “Fan Qing”, the result they get is totally different from our explanation. After a short conversation, we realized that this is actually a misunderstanding of the Chinese language.

In Chinese, the same term “Fan Qing/返青” is also used in agricultural production. Specifically, it refers to the spring growth of wheats, corns, and other farm-products. In this use, Fan Qing, or its literal meaning “going back to green”, describes that plants start to regrow for the season.

In tea, however, Fan Qing/返青 happens at the end of a tea’s life, not the beginning. When it happens, it’s a quality decline for sure.

In fact, when Fan Qing/返青 happens, it usually means that tea leaves are damp. If we taste a oolong tea with Fan Qing, we’ll discover the tea lacks aromas and tastes bitterer. In the most serious case, tea leaves would even go moldy in storage.

Valley Brook Tea | Blog
Heavily roasted leaves are less likely to face "Fan Qing"

There’re 2 major reasons why Fan Qing happens.

First, too much moisture in the storage environment. Getting rid of the water content in fresh leaves plays a crucial part in the overall tea-making. Fan Qing is exactly the opposite of that.

According to China’s national standard of Wuyi oolong (Yancha), a standard Wuyi oolong tea product should have a water content less than 6.5%. However, if dry leaves get in contact with too much air moisture, it’ll become damp. The extra water content makes tea leaves behave more like fresh leaves (“going back to green”). Thus, it “reverses” the tea-making as well as all tastes and aromas leaves acquired during the tea-making.

Another possibility of extra water content actually comes from tea leaves themselves. As previously introduced, finished tea products have an extremely low water content. Nonetheless, low water content is not the same as no water content. If oolong leaves are roasted to a level which no water content can be found, leaves would be carbonized and dead.

Heavily roasted Wuyi oolong (Yancha) are less likely to face “Fan Qing” because of the lower water content. As long as it’s properly stored in a dry, cool space, it should be fine. Lightly roasted Wuyi oolong have slightly higher water content, and it makes them more vulnerable to “Fan Qing”. If the temperature in the storage changes rapidly, the moisture inside tea leaves can slowly come up to the surface and cause a chain reaction that leads to “Fan Qing”.

Fan Qing is a situation that tea lovers should try to avoid at all cost. Although the consequences of “Fan Qing” are dire, it’s not impossible to stay away from. As long you get your oolong tea from a qualified tea producer who throughly roast all leaves, and store your tea products in a dry, cool, orderless environment, Fan Qing is a problem you’ll hardly have.

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

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