26 October 2011

Oxidation Levels and Flavor Profiles

The process for making oolong involves more steps than other types of tea.  The most important steps for determining the fundamental taste and base of an oolong during its processing are in the oxidation.

Oolong oxidation will produce 4 major categories of flavor/aroma.  From light to heavy oxidation, those categories are:

1)  菜香 (Cai Xiang) - Vegetal, such as Baozhong.
2)  花香 (Hua Xiang) - Floral, such as Alishan high mountain tea.  This category is often further subdivided by the types of floral, such as 蘭貴 (Lan Gui - orchid) or 桂花 (Gui Hua - osmanthus).
3)  果香 (Guo Xiang) - Fruity, such as Dong Ding or Muzha Tieguanyin.  A traditional medium-high oxidized, medium-high roast Muzha TGY may even have notes of ripe fruit, 熟果香 (shu guo xiang).
4)  蜜香 (Mi Xiang) - Honey, such as Oriental Beauty.  A highly-oxidized oolong’s flavor is also said to sometimes resemble 焦糖 (Jiao Tang) or caramel.  I think that tea that has been over-roasted and allowed to rest a while will also infuse tea that is caramel in color and has sweet notes.

Several different leaf varietals are used in the production of Taiwan oolongs, the most prevalent of which is the Qingxin varietal (青心).  Nearly all high mountain oolong is produced with Qingxin leaf.  Dong Ding oolong is also produced with Qingxin, and often with Ruanzhi (軟支, soft stem). 

I greatly prefer medium-oxidation teas to light or high-oxidation ones.  General taste profiles are helpful to me (in addition to other info/experience) when identifying different types of high mountain oolong.  Lishan tends to have a higher-oxidation level than Alishan, for example, and also tends to taste more fruity than floral.  Shanlinxi usually has an oxidation level between Lishan and Alishan and has a uniquely fruity and floral profile. 


  1. Great information.
    Thanks Rich!

  2. How would you characterize a highly oxidized Wuyi oolong?

  3. Thanks Steve, let's have tea soon!

    Steph, you got me, I'm not sure how to characterize Wuyi. The taste profiles best apply to Taiwan oolongs. I admittedly know relatively little about Wuyi tea compared to my beloved Dong Ding and TGY.

    I've had some phenomenal aged Rou Gui/Shui Jin Gui/Da Hong Pao and they all tasted rich, deep and complex. All of them were traditional style high-oxidation, but I can't say that they had fruit or honey tastes. I've also tried some fantastic (but $$$) modern Wuyi teas from Essence of Tea this year, but I can't say they follow the oxidation trends, either.

    I have asked some various tea experts and several explained that the most important note to taste with Wuyi oolong is not the base flavor or aroma, but the unique cliff tea note, 岩韻. You got me again, that's a taste I can't describe, either :)

    What do you think?

  4. Hey Rich,
    Was hoping to run into you this week at the shop.I should be there this Wed around 4 if you are around.

    I have a few treats that should be in Mon or Tuesday's mail that I'm excited to taste!

    About the "unique cliff tea note" I describe it as minerally.

  5. Hey Steve, sorry, I just got back from vacation and won't be in this Weds. I may stop by later this week, but probably not.

    Sorry to miss your new treats...maybe next time?


  6. Hey, Rich - Thanks so much for the thoughtful response! I'll give this contemplation as I sip. I love Wuyi teas, so I'll be sipping plenty. ;)

  7. Hey Steph, sounds good, please share what you think about the different Wuyi teas - and let me know if you come across a good one that you think I should try!