Tuesday, October 02, 2007

To understand Oolong tea

(Note: this article follows Jim's comment asking me which Oolong varieties have which characteristics)

Many parameters influence the taste and smell of Oolong tea. Let's try to make a comprehensive list of all the information a drinker should have to understand exactly what Oolong he's drinking. (Also valid for other tea categories).

1. The tree variety
The first information an Oolong tea drinker needs is the name of the tea tree from which the leaves were harvested. Different tree varieties have different characteristics:
- luanze Oolong, also called Qingxin Oolong is the traditional 'soft stem' Oolong. Its emphasis is more on the yun, the aftertaste than on the fragrance.
- Si Ji Chun, Tsui Yu (Jade) Oolong, and Jinxuan Oolong are of a very fragrant type and have less aftertaste.
- Qingxin Da Pa is between these 2 groups with a balance of fragrance and aftertaste.

For the above teas, the fragrance itself will depend a lot on the process of the leaves, so it's difficult to make any general remarks in this regard. There are, however, Oolong varieties that have very distinctive fragrances:
- Tie Guan Yin, the iron goddess, comes to mind, or
- Bai Ji Guan as well as most varieties from Wu Yi.

Knowing the Oolong tree variety is the first step to understand your tea.

2. Where does it come from?

2 very common names around here in Taiwan are: Dong Ding Oolong or Gao Shan Cha (High Mountain tea). Such names don't mean very much if you can't get more precise information. Dong Ding Oolong has become a generic term for any kind of rolled Oolong that has been roasted. And Gao Shan Cha is a generic term for high mountain tea, because high altitude produces fresher and lighter Oolongs. But each mountain has a different soil and its own character. It even makes sense to know what part of the mountain the tea comes from and the elevation of the plantation.

For instance, my fresh Dong Ding Oolongs come from Feng Huang, one of the few locations close to the Dong Ding village that qualify as Dong Ding Oolong. And my Shan Lin Shi high mountain Oolong comes from the Long Feng Hsia district, the highest part of the mountain.

3. The season of the harvest

Each season has a different climate (temperature and sun/rain). This has an influence on the taste and smell of Oolong tea.
- Spring is more flowery and fragrant
- Summer has a cereal fragrance. Fragrances are often heavier (temperatures are higher),
- Winter season gives more dryness and long aftertaste to the tea. (It's the driest season)
- Fall is somewhere between winter and summer.

4. The year of the harvest

In the wine industry, this is one of the most basic information. Usually it stands right in the middle of the label. For Oolong, on the other hand, it is not always easy to get this information. The general assumption is that an Oolong needs to be young and fresh to be good. This is only true for low oxidation Oolongs, though, and those that are not (or just a little) roasted. Because they have a higher water content, these teas will deteriorate over time. However, thanks to modern air removing sealers, such Oolongs can be kept fresh for over 12 months if storage conditions are right.

Roasted Oolongs, on the other hand, need a few weeks or months (depends on the degree of roasting) of rest to taste very good again. Such Oolongs can make very good candidates for long term aging. After 20 years of right storage, they will evolve and gain new, complex fragrances.

5. Leaf grade

Sometimes, farmers harvest only a particular grade of leaves (the best or the rest) to make tea of different qualities. This can be the case when they prepare to attend a tea competition. Good teas will then also be processed manually to take away the stems. There is more grading going on for Baozhong than for rolled Oolong. This information is not critical as the leaves will speak for themselves once you make them.
(Article continued here)


Matthieu Weber said...

My Ti Guan Yin provider claims that the flowery taste of her tea comes from lilac flowers growing near the tea bushes and impregnating the tea leaves. Is this actually true? And is it the same with Taiwan wu longs?

Stephane said...


The surroundings do have an impact on the fragrance of very light teas: green teas and lightly oxidized Oolongs. However, the fragrance must be quite strong so that it can mix itself to the scent of the leaves themselves. When you scent tea with flowers, you need a very big amount of flowers to make an serious impact. If the flowers are just nearby, you will get hints, but it won't be the main fragrance. Therefore, it is more likely that the scent comes from the oxidized leaves.

VeeTea said...

Very informative! Thank you!

Out of curiosity, does the shape of the tea also influence the taste?

Stephane said...

I'll be talking about it next time. Basically, the way the tea processed, of course, has an influence on taste. A tightly rolled Oolong will need more time than a Baozhong (slightly curved shape) to release its flavors. So, yes, there is an impact.

Other indirect differences on taste: rolled Oolong is harder to break and allows less contact with air. So, it will evolve differently than a Baozhong that gets broken more easily and has more contact to air.

Julian said...


Another excellent post from you. Anything otherwise will be so untypical of you :)

Just a tiny note to add...

On seasonality, if you read the Chinese tea texts, it is widely accepted that spring tea tastes better, whereas winter tea (October harvest) is more fragrant.

This is backed up by some chemistry research (which unfortunately i haven't got hold of the papers).

The usual explanation is that spring tea contains higher concentration of theanine, whereas winter tea has more aromatic oils.

Theanine is often described as brothy, savoury or (maybe) qi...

It is for the same reasons that the best green tea gardens only harvest their teas once in spring.

A tea garden I work with in Xiping says the same thing about TGY as well.

Of course there are so many teas so it is always dangerous to generalise...

Just to add another twist to your excellent article.

Thank you and I look forward to the sequel!


Stephane said...

Thanks for your compliments Julian!

I'm a little (very!) surprised to read that the winter season is more fragrant than spring. Spring is the time when all the flowers blossom. Fall/Winter is the season when nature goes to sleep.
If winter were so fragrant, then I think it would be a great season for green tea?...

You are right, though, about the dangers of generalizations. That's why I tried not to say which season is best. I prefer to say that spring and then winter have more potential. A well made summer Oolong can be better than a badly made spring Oolong from the same plantation!

Julian said...


To add further to the discussion...

Green tea quality relies more on theanine than aromatic oils.

During spring, tea plants contain higher nutritions, and produce leaves with higher theanine content.

Hence green tea is more refreshing, purer.

Oolong tea quality relies more on polyphenol amount and aromatic oils.

Hence it is more fragrant, mellow.

It is often said that summer tea has the highest polyphenol, while autumn has the highest aromatic oils.

Hence the saying "spring for green and autumn for oolong".

I have heard that some tea gardens in Fujian uses oolong tea plants (the like of mao xie, huang dan etc) to produce green tea in the earlier part of the year, then oolong tea in the later part of the year...

...though I have yet to verify it.

All quite fascinating and yes, yes, yes, too dangerous to presume we know too much.


Sometimes I wonder tea gardens tend to oxidise their teas more in summer and winter, as these teas are supposed to contain higher polyphenol content...

I guess if I pop the question to the tea gardens they would just say NAY...

As for storage, generally speaking, the less oxidised the tea, the more easily it loses its quality.

Hence green tea can store for a shorter period of time than oolong tea.

Moisture content can be "dried" away, so it is not a direct cause.

The fact that is more unoxidised, means the it is more likely for the polyphenols to interact with moisture, oxygen.

At room temperature, this "natural oxidation" can result in rapid quality loss.

Sorry for the rambling... I hope I am not stealing too much of your thunder.

Thanks for your wonderful article and look forward to the sequel!


charles said...

What great info, very interesting!

Eddie Reyes said...

We have developed a new website Gourmet World Market that will offer a large variety of very fine teas. We would like to provide helpful background material on our teas so that consumers can make informed intelligent decisions on their selections and then advise about then how to best prepare them. We have several oolongs from JustTea and Hazo tea, and Tao of Tea all from Taiwan, and I have used your excellent blogs as part of my research. I have included quotes from your blogs for general information and in reviews of special teas, always with attributes to you and links to your site.
just want to make sure that you are OK with this, and that I can continue to refer to you excellent blog.


Stephane said...


It's OK to quote me if it's clear it's a quote and if you provide a link to my blog.
Good luck,