Friday, October 05, 2007

To understand Oolong tea (2)

(Continued from here)

6. Mention of special growing methods

'Organic tea' is heavily advertised nowadays. This is an information that sellers are eager to share if the plants are grown organically.
However, the concept of 'organic' is quite wide. We can distinguish between:
- Normal management of the field, but the farmer will use no pesticides and only natural fertilizer,
- Abandoned plantations which are still harvested. I call this semi-wild. An example is this 2007 Spring Wenshan Baozhong
- Wild grown trees. Extremely rare for Oolong (but less rare for puerh).

A word of caution: organic growth is just one of the many parameters that affects tea. It is, by far, not the only indicator of the quality of a tea. Proven organic Oolong often comes at a much higher cost than regular Oolong. In a large number of cases, I don't find that the taste/fragrance of Oolong is improved sufficiently to justify the higher cost. However, there are some teas like Oriental Beauty or the red tea based on Da Yeh Oolong that need to be grown without pesticides so that their leaves will be bitten by tea jassids. For them, organic growth is a necessity.

7. Harvesting methods

High quality Oolong is picked by hand. This way, the leaf is picked at the stem and not cut in pieces. Gao Shan Oolong plantations are mostly located on slopes of mountains and these places can't be accessed by mechanical cutting machines. So the only practical way to harvest the leaves is by hand. This increases the cost and also takes more time.

Mechanical harvesting takes place in the plains, where tea fields are large and located on flat land. It also has some advantages -besides a lower cost-: it can shorten the harvesting time to the best time of the day (around noon), when the leaves are the driest, which is also when it's hottest and the most difficult for people to work. This can make up for some of the quality lost due to the mechanical cut, so that mechanical harvesting does not have such a bad impact on teas that are of low/medium quality to begin with.

The way to recognize that a leaf has been picked by hand: the stem doesn't have a clear cut, but is like torn (See picture below).

On the other hand, a mechanically harvested leaf is cut by a blade. This leaves a red oxidation mark at the place where the metal cut the leaf. Also, you will notice that many leaves are cut in pieces instead of being whole.

8. Transformation process

After the leaves have been harvested, they go through a series of processes. The major decision of the farmers will be how strong to push the oxidation. What he will do with his tea leaves depend on several factors (customer demand, tea tree variety, season, humidity level during the harvesting...). One interesting example of how versatile tea can be: in Hsin Chu County, with Qingxin Da Pa, farmers make green tea (0% oxidation) in spring, then Oriental Beauty (50-70% oxidation) in June and red tea (100% oxidation) in summer. This changes the fragrance of the tea quite drastically.
How to recognize the oxidation level: the more red the open leaves, the stronger the oxidation. (picture shows a 100% oxidized tea).
A good description of an Oolong would try to characterize its oxidation level.

9. Roasting

This is the last transformation stage of Oolong. It is not necessarily made by the farmer. Traditionally, it is done by the tea merchants. They perform a light roasting to dry the leaves so that they keep their freshness longer or to refresh unsold leaves after one year. Slow and long roasting will also give Oolong more fruity and dark scents, as well as more body. A fully roasted Oolong is then called Shou (cooked) as opposed to 'green' Oolong, which is called Sheng (raw).
Good old Oolongs have necessarily gone through sufficient roasting to withstand years of storage.

(To learn more about the impact of roasting on Oolongs, you can order the following roasted Baozhongs and compare them to regular Baozhong:
- Qizhong Oolong, a medium roasted (30%) top grade Wenshan Baozhong of Spring 2006.
- Shou Cha, a strongly roasted (50%) top grade Wenshan Baozhong of Spring 2006.
Both are available in 50 gr packs

And to understand the impact of age on roasted Oolongs, you can check the old Taiwan Teas in my selection or you can come back to check on my blog as I plan to explore these teas in greater depth in the coming weeks.)

Conclusion: To make the most of the experience of drinking Oolong, you will need accurate data about its characteristics. And little by little you will be able to distinguish between Oolong varieties, between plantation locations, between seasons, between oxidation and roasting levels... But why bother learning? Because the more precisely you can describe the Oolong you love, the likelier you are to get it!

8 comments:

Anonymous said...

Steph,

I thought your 2 roasted Bao Zhong come in 30 gr pack?
So what's the current price for them as of now

Stephane said...

I changed so that most old/roasted Oolong has the same weight. As for the price, it slightly less than before -if you take the change of weight into account-.

Julian said...

Stephane

Bravo! You answer my hidden question from our last discussion on tea type and seasonality.

Now let me check up your tea store ...

Thank you :)

Julian

thomas said...

Bonjour,

les oolongs torréfiés de taiwan est une famille qui m'interesse de plus en plus, je suis donc assez heureux de voir qu'une bonne place leur est donnée dans les articles du blog. De mon point de vue, je trouve les thés torréfiés beaucoup plus digeste que les oolongs "verts", de plus ils développent des notes aromatiques très originales et plus surprenantes. Ces thés sont asolument excellents, c'est pour moi un mystère lorsque j'entends dire qu'ils ne sont plus au goût du jour et que les consommateurs préfèrent des oolongs plus "verts"...
Une petite question sur la conservation et la maturation de thés torréfiés: quelles sont les meilleures conditions pour les conserver et les laisser reposer? est ce qu'une boite métallique hermétique leur conviennent? faut il éviter les contact des feuilles avec l'air en conservant les feuilles dans l'emballlage en alu refermé par une pince et le placer dans une boite? Ces thés sont souvent vendu emballées sous vide d'air, le thé va t-il reposer en restant emballé de cette manière? Peuvent-il se conserver longtemps sans devoir subir une nouvelle torréfaction?
Encore un grand merci pour nous proposer ces maginifiques thés dans la sélection.

THOMAS

Stephane said...

Thomas,

L'air est l'ennemi du Oolong. Les boites en métal ne sont pas idéales. Mieux vaut garder le sac fermé comme tu l'indiques.

La ceramique est meilleure. Emaillée pour le long terme et en glaise poreuse pour le court/moyen terme.

Le sous-vide convient bien aux Oolongs très verts. Pour ce type d'Oolongs, c'est en faire un peu trop et ralentit un peu trop la postfermentation, d'après moi.

Le besoin de retorrefaction dépend du taux d'humidité du thé. Bien conservé, jamais ouvert, il n'a pas besoin d'être retorréfié. Taiwan est très humide et c'est pourquoi on (les marchands de thé, pas les consommateurs finaux) retorrefie relativement souvent ici. En Europe continentale, il y a surement moins besoin, surtout si le thé au départ est assez sec.

emmanuel said...

Bonjour Stéphane,

Merci pour le tip qui permettant de reconnaître un thé cueilli à la main d'un autre récolté à la machine.

Ce n'est pas quelque chose que j'ai l'habitude de regarder (contrairement au taux de fermentation par exemple). Habitude à changer!

Davka said...

Encore une chose qui n'est pas claire dans mon esprit:
Si je comprends bien, les thes subissent d'abord une oxydation (fermentation) par le fermier, et ensuite une torrefaction eventuelle par le marchand, qui l'adapte a sa clientele etc?
Mais comment stabiliser le degre d'oxydation? Est-ce que la torrefaction a une influence sur le degre d'oxydation une fois atteint a l'etape precedente?
Merci de clarifier cette question :)

David

Stephane said...

David,

Tu as bien compris.

Pour ta seconde question: Non, la torréfaction ne change pas le degré d'oxydation. On dirait, les feuilles perdent de leur couleur verte. Mais elles ne deviennent pas rouge (oxydation), mais brunes. Il sera difficile de dire avec précision le degré d'oxydation de départ si la torrefaction est très forte. Mais cela ne veut pas dire que les feuilles ont oxydés, juste qu'elles ont séché, grillé, torréfié quoi!