I have just launch on Thés du Japon a series of four very different traditional regional bancha (about these rare regional teas, please see this article). I will start here with the most puzzling of the four, the goishi-cha 碁石茶.
It is a tea produced in the mountainous town of Ôtoyo (Kôchi prefecture), in the heart of Shikoku Island. It is a post-fermented tea, sometimes called dark tea, ie a tea fermented under the effect of ferments (bacteria, molds), and not oxidized like black teas. In addition, the goishi-cha undergoes two successive fermentations.
Mid-June, the leaves are harvested directly from the branches, cut with a sickle. Leaves and branches are then steamed in a big barrel.
After a sorting phase, manual, the first fermentation takes place, inside but in contact with the air, the leaves stacked about fifty centimeters thick, then covered with a straw mat. Controlling the temperature during the fermentation is very important, when the temperature in the room increases too much, leaves are pressed down. This phase lasts about a week, the leaves are then covered with yellow mold. There are then 5 or 6 types of bacteria. Then the leaves are fermented in barrels. We add the juice from the steaming of fresh leaves, and we close the barrel with a lid, on which we put bricks to make weight. It is an anaerobic fermentation, without oxygen.
At the end of this fermentation, only the strongest bacteria remain; a single type of lactic acid bacteria of vegetal origin, which are very active on the intestinal regulation, much more than lactic acid bacteria of animal origin according to university studies. The leaves, fermented and compressed in the barrels for several weeks, are removed from it in early August and then cut into squares of 3-4 cm sides and dried for several days in the sun. The landscape offered by these small squares on the floor looks like go game pieces, which is the origin of the name of this tea.
Although this tea is fermented, I immediately cut short fantasies; tis taste and flavors are nothing like puerh shu or Chinese dark teas like fu-cha. Here, one is (probably) closer to Bulang’s suan cha or Burmese laphet-so.
Originally, goishi-cha was not consumed locally but was used as a bargain against salt in areas around the inland sea where it was used to prepare a rice porridge. It seems to be manufactured for about 400 years.
Nevertheless fifteen or so years ago, the producers started to become fewer and fewer. The quality of the goishi-cha was then very irregular, and overall it was very bad. Mr. Ogasawara then worked to fix his method of manufacture, mainly fermentation, to obtain a better, stable product rich in lactic acid bacteria. He then passed on the method to a handful of other producers while the goishi-cha has a renewed interest, to the point that production is no longer sufficient. It must be said that its mode of manufacture is difficult, requires a lot of time, nearly two months and is completely manual and particularly analog. Also, the question of bacteria is essential. At the station (let’s say the quay) of the small village of Ôtaguchi, 400 meters above sea level, it seems that the necessary bacteria do not develop enough, and it is higher in the mountain at 600m, that the conditions for fermentation are met.
What about the taste of this tea?
It really does not look like anything else and it’s very special, quite off-putting at first.
Dry, these little squares of fermented tea offer a sour and camphoric fragrance.
The question of preparation is delicate. Traditionally it is boiled, a square in 2 liters of water boiling for 5 to 10 minutes, then a few minutes fire extinguished (this broth was used to make a rice porridge, to try). The timing is not easy, but it can be surprisingly good (when I went to Ôtoyo, it was served like that, and it was excellent, so far the best I’ve drunk).
Otherwise the cooperative recommends in teapot of 350 ml, a square, infused five minutes in boiling water. Several infusions possible (I would say that for the first, 2 or 3 minutes will be sufficient).
But the two cases above have the defect of giving us a quantity of tea too important for consumption alone. I propose to infuse it with less water in a smaller pot, for very short periods, 20 to 30 seconds at the start.
In general, the first infusion is the one that will give the most acidity, it can even be thrown as a kind of big wash for those who really have trouble with this typical flavor. This acidity also comes out more when the infusion is hot, and less while cooling.
Initially, this smell (which nevertheless gives more in camphor and woody advancing in infusions) can almost evoke a cheese. However, on the palate, the goishicha does not present strong aromas, and remains somewhat light, like a bancha. The impressions in retro-olfaction remain particular.
In short, it is a tea that requires a phase of adaptation, which will repel many, but may also become accustomed to other.
Finally, to be able to enjoy better on many infusions, the solution would be to use half squares (cut in the slice), especially since this tea is rather expensive.
Another interesting thing: aging. Production currently below demand prevents the cooperative from experimenting on this issue for now, so all that remains is to do it at home !!
I have at home some squares bought 2 years ago, and I must say that it is very interesting! There is no doubt that this tea has a lot to gain …
The Cooperative of Goishicha de Ôtoyo controls the good production of the goishi-cha, whose name has been registered and protected. Their tea has been certified by the Japan Food Industry Association. Goishi-cha is applying for registration as Intangible Cultural Property of Japan. Nevertheless, it seems that the governmental office in charge of these classifications is thinking for the moment of designating the three fermented teas of Shikoku, goishicha, awa-bancha and Ishizuchi-kurocha together and not separately, while they come from three neighboring but different prefectures, and that their modes of manufacture are also different.
The goishi-cha is a unique taste experience, difficult perhaps, but it is also a traditional regional tea whose looks with some fermented teas of the Golden Triangle are fascinating, coming to bring elements on the history of Japanese tea very different from those in the official history of elite teas.