Recently, one interesting question from an online forum caught our attention. A tea store owner asked why her oolong tastes different after a one year’s storage and how come there are aged teas if it cannot last more than a year?
Under this topic, there were some tea lovers voiced their opinions, but none of which explained the real question: what caused a oolong “tasted different” after years and why?
In tea-making, we use a specific termed called “Fan Qing” (Chinese: 返青, meaning: returning to green) to describe the change of oolong (especially Wuyi Oolong/Yancha) during storage.
Fan Qing is the result of excessive water in the air that infiltrates tea leaves, causing tea leaves to have a grassy taste. This is often seen on teas that have a very light roast or badly sealed. Most unpleasant tastes and feelings of tea "going bad" in storage are indeed associated with Fan Qing.
In our previous blogs, we mentioned that oolong is a roasted half-fermented tea. Different oolongs have different roast levels. For example, Huang Guan Yin has a medium roast and Rou Gui has a heavy roast. Most authentic Wuyi oolong products are at least medium to heavy roast that are roasted in a closed, controlled roast room. Most Wuyi oolong can last two years in storage.
Generally, heavily roasted oolong teas, such as Rou Gui and Shui Xian, have little danger of getting Fan Qing because the water content in leaves are eliminated during multiple rounds of roasts. Lightly roasted oolong will unavoidably have Fan Qing.
Remember the tea store owner at the beginning of the blog? What she had, however, is a very lightly roasted Taiwan oolong tea, also commonly known as modern Tie Guan Yin or its close relatives. Very lightly roasted Tie Guan Yin is actually similar to green tea, which needs to be consumed within months after the harvest. Even when it claims to be a heavy roast, it’s still roasted in open air and considerably lighter than those Wuyi oolong roasted in-room.
Our Tea Master Mr. Xue Working in the Roasting Room
If we want a oolong to last longer in storage, we need to avoid water content in leaves. That means we need to choose a oolong tea with stronger roast and a dry storage environment. However, it doesn’t mean as long as we put a oolong in a good storage, it can be aged like a white tea or a pu’er tea. Not all tea can be aged, and not all teas are aged the same.
Aging Wuyi oolong is often a multi-year tea-making process. It cannot be simply aged like a cheese. Let’s say we want to age a Huang Guan Yin. After the harvest, processed into Mao Cha (Chinese: 毛茶, meaning: half-processed tea), and finally roasted, we put it into storage. Each year, we need to take the same tea out and re-roast it. For a 5-year aged Wuyi oolong, it’s most likely roasted at least once every year for 5 years. During the 5-year period, tea stays with the tea maker.
I’ve seen people call a jar of Wuyi oolong packaged in 1998 as a “20-year aged” tea. Not only is it wrong, but also it is possibly expired as a product. The date of packaging is not the guarantee of an aged tea; on the contrary, for Wuyi oolong, it’s probable that the date of packaging is a recent date.
Of course, since we can’t possibly get rid of all water in the air, it’s not possible to have a oolong that’s not going to have a Fan Qing situation. The best, also the laziest solution is to finish it as soon as possible.
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