Keep your kyusu clean.

[Stentor]

(Some of what I am saying here has, to some extent, been discussed in another thread. Please excuse me for repeating myself in some instances. I figured it would be better to discuss this subject in more detail in its own thread.)

CLIFF NOTES:

- I noticed that water which went through my used Tokoname kyusu had a foul smell and taste to it.
- I could detect this taste in tea as well, albeit less apparent.
- The kyusu had been used regularly for about 6 months.
- I cleaned the kyusu, using a toothbrush and a paste of baking soda and water.
- Bad taste and smell gone.

I encourage you to taste the water from a kyusu that you've been using with sencha for months. Pour hot water in there, close the lid, let it sit for a minute, pour the water in a cup, smell it and taste it. Do you really like it? Compare with a new pot if you have one at hand.

LONG VERSION:

When it comes to teapots made of unglazed clay, it seems to be the general consensus that one should stick to one type of tea, if not one specific tea.
The idea is that the clay absorbs tea extracts and therefore some of the tea's aromas and flavors will be absorbed by the clay as well. From what I have read, this "seasoning" can have a positive impact on the tea with certain types of tea.
This thread is specifically about sencha and Tokoname clay tea pots. What I am saying may not apply to other types of teas or other types of clay, on which my knowledge is very limited.

When I was new to using clay teapots, this was the rule I followed.
I got two reduction fired Tokoname-yaki clay teapots by Sekiryu and used them strictly for Japanese green tea. To be exact, I used them for a lot of fukamushi and asamushi, some kabusecha and very little gyokuro (negligible amount) as well. Nothing flavored, scented, roasted or mixed with other ingredients, just plain sencha.

What I normally do to clean a kyusu is to remove the used tea leaves, rinse the pot with water a couple of times and use a toothbrush to make sure all leaf particles are gone from the teapot and from the filter. Then I use a small bottle brush to scrub the inside of the spout. Finally when the teapot is already "clean", I fill the pot with boiling water, let it sit for about a minute, and pour it out. Then I let the teapot dry with the lid off. I do all of this shortly after each use. I do not let the used leaves sit in the teapot for hours when I'm done drinking tea.
I think this is a pretty normal cleaning routine and it may even be more thorough than what some do for daily use.

So, after using these teapots very regularly (at least once a day) I noticed that the hot water I passed through the kyusu in order to preheat it had an unpleasant smell to it. I proceeded to taste this water and sure enough, the taste was unpleasant as well.
I am not talking about the "iron" taste that the water gets from the clay, which is not unpleasant at all, I am talking about a bad, kind of foul taste and smell. I figured that this must come from the tea residue or patina which accumulated on the surface of the teapot's inside.

Luckily I had a brand new Tokoname shiboridashi to compare these findings with. Sure enough, the water smelled better, it tasted better. More importantly, the tea tasted better. Don't get me wrong, it's not that the tea from the used kyusu tasted bad. Had I not noticed the smell in the water I used to preheat the kyusu, I had probably not noticed that there was anything "wrong". Still, that underlying smell and taste definitely had a noticeably negative impact on the tea that was brewed in the used kyusu.

So recently, I gave my my most frequently used Tokoname kyusu a thorough cleaning.
First, I soaked the kyusu in warm water for a couple of hours. I figured this could not be a bad idea. Now I think it's probably not a necessary step.
Then, I put about a tea spoon of baking soda (sodium hydrogen carbonate) inside the teapot, added a couple of drops of water to create a paste. After that, I thoroughly scrubbed the inside of the kyusu with a toothbrush, using the baking soda paste.
Shortly after I started scrubbing, the paste started to turn a brownish red and I realized the tea stains started to rub off.
When I was done scrubbing, I rinsed the teapot and proceeded to wipe the inside with a wet microfiber cloth. The cloth turned a brownish red as well so clearly, I wasn't done cleaning. I continued cleaning until nearly no more rusty red rubbed off on the cloth.
Then I rinsed the kyusu with boiling water and let it dry, curious to see how clean it would be when it was dry. I was quite impressed with the results.

Not only did the kyusu look significantly cleaner. After the cleaning, the "foul" taste and smell were gone, and the tea simply tasted better than before the cleaning.

Therefore, I have come to the conclusion that an unglazed clay kyusu that is being used for Japanese green tea needs a thorough cleaning from time to time.

Since a picture says more than a thousand words (I might be way over a thousand here?! , please forgive me), here's the...

BEFORE AND AFTER:

[jaderabbit]

Does this suggest that the theory of "seasoning" a pot is wrong then?? O.O

[Chip]

Interesting post and proposition, Stentor. Thank you for taking the time to post this experience.

Does this suggest that the theory of "seasoning" a pot is wrong then?? O.O

I think it suggests that seasoning a Tokoname kyusu given Stentor's set of variables would indicate this.

Everyone's unique variables could change this.

[karmaplace]

I finally went out and bought a toothbrush specifically for cleaning out the little tea bits from the obiami filter. I also noticed some brown staining along the bottom of my kyusu, so I tried to use the same toothbrush and a baking soda pasted to scrub it out, only to realize that the toothbrush head doesn't fit or bend well enough to scrub the bottom. I still got it cleaned out in the end.

It's looking much better. Not as dramatic as yours, Stentor, (I wasn't quite to the foul-smelling water stage) but there's definitely improvement. Thanks!

[Chasm]

I had a related experience recently.

I'd been doing cup comparisons with my morning sencha. One week I focused on two cups, similar in shape and size, one porcelain, the other banko-yaki. Both were given a thorough warm-water-and-finger-scrubbing after use, followed by a scalding rinse.

I used the two cups for about a week, same tea and pot each morning. At the beginning of the week I wasn't sure which cup I liked better, hence the ongoing experiment. By the end of the week, tea drunk from the banko cup was consistently bitter compared to the porcelain cup. It was quite noticeable.

[jaderabbit]

I had a related experience recently.

I'd been doing cup comparisons with my morning sencha. One week I focused on two cups, similar in shape and size, one porcelain, the other banko-yaki. Both were given a thorough warm-water-and-finger-scrubbing after use, followed by a scalding rinse.

I used the two cups for about a week, same tea and pot each morning. At the beginning of the week I wasn't sure which cup I liked better, hence the ongoing experiment. By the end of the week, tea drunk from the banko cup was consistently bitter compared to the porcelain cup. It was quite noticeable.

Very informative! Guess I shouldn't bother getting a banko kyusu. I like my teaware low maintenance.

[Tead Off]

I had a related experience recently.

I'd been doing cup comparisons with my morning sencha. One week I focused on two cups, similar in shape and size, one porcelain, the other banko-yaki. Both were given a thorough warm-water-and-finger-scrubbing after use, followed by a scalding rinse.

I used the two cups for about a week, same tea and pot each morning. At the beginning of the week I wasn't sure which cup I liked better, hence the ongoing experiment. By the end of the week, tea drunk from the banko cup was consistently bitter compared to the porcelain cup. It was quite noticeable.

Very informative! Guess I shouldn't bother getting a banko kyusu. I like my teaware low maintenance.

I prepare most of my Japanese teas in Bankoyaki and never have a bitter experience except if I mess up in brewing the tea. Why you are getting a bitter experience I cannot say. Not all clays are the same that go under the 'Banko' name. This can be said of every other clay, too.

[edkrueger]

There is really no reason to get a banko piece... unless you like the looks... or need it as a proof of membership for a cult. That said, I am a bit surprised about the bitterness. I differentiate between a good bitter and a bad bitter –I can't exactly but this into words. I find fine porcelain has some best good bitterness. Bad bitterness I usually attribute to bad teas, I can't think of any tea wares that brought more out, but that isn't to say they don't exist.

[solitude]

Does this suggest that the theory of "seasoning" a pot is wrong then?? O.O

good point, any comment to this?

[David R.]

I think Chip answered. We are talking specifically here about Tokoname pots, japanese green teas, and Stentor's water and parameters.

Though the purpose is to know if others share the same experience. I don't have an old enough kyusu working on japanese green teas to have a statement to make. But I am working on it !

[Chasm]

I don't really have an explanation for the banko cup. It's part of a set, and I've never had anything similar happen with the pot. My experience has been that I like what brewing in banko-yaki does to Japanese greens more than any other material for the brewing vessel.

I'm sitting here with the banko cup I used and another from the set, and I can see that the luminescent glow of the interior of the cup that was in use has dulled. Between that and the buildup of bitterness, clearly I wasn't cleaning it sufficiently. I just poured water into both cups and will let it sit a bit; I'll report back on the results.

Edited to add: It's not the leaf that's the problem, by the way. The leaf is O-Cha's 2010 Sae Midori.

[Chasm]

Okay, so tasting the water after letting it sit in the two banko cups was interesting. In the unused one, I got the enhancement of sweetness and sensation of lightness I'm used to from banko-yaki. Not in the used and patina'd one.

Fascinating.

Edited to add: I de-patina's the one cup, then ran the water test again. I thought I tasted a difference, so I went away until I couldn't remember which cup was which. After that, I couldn't find a difference or be sure which was which.

[Stentor]

Very interesting, Chasm. Thanks for performing these tests!
Your findings would seem to concur with mine.

I'm surprised that you noticed a "problem" after only one week. I've been using my cleaned kyusus for weeks now and they are still fine. They still look clean as well.

Does this suggest that the theory of "seasoning" a pot is wrong then?? O.O

I don't know about that. I certainly can't speak on the subject of other teas and other clays. It seems to be an established practice and general consensus that seasoning a teapot improves the tea brewed in it if one sticks to one type of tea.
With sencha and reduction fired tokoname clay however, I have not found "seasoning" to be beneficial. In fact, as I've said, I've found the opposite to be the case.

One might try how it works out if you really stick to one specific tea and only brew this tea in this teapot. However, I would assume that the result would not be much different. After all, the chemical composition of one sencha vs. the next should not vary too much and therefore the patina that is left should be composed of the same residue.



By the way, I had neglected to mention what kind of water I use. It was all Brita-filtered water, even the boiling water I used to rinse the kyusu after use.
(Hard and unfiltered) Tap water was only used for the very quick rinses to get the leaf particles out.

[rdl]

Does this suggest that the theory of "seasoning" a pot is wrong then?? O.O

With sencha and reduction fired tokoname clay however, I have not found "seasoning" to be beneficial. In fact, as I've said, I've found the opposite to be the case.

i fully agree with you, stentor. it's a bit like feeling wet rubbed sencha on your fingers; it isn't a clean residue that would season but rather like a fine paste, which i feel over time turns bad.
for others who feel differently i wonder what the results of stentor's testing would be. i'd be interested to hear to see if a greater range of tests gives any firm conclusions.

[Tead Off]

By the way, I had neglected to mention what kind of water I use. It was all Brita-filtered water, even the boiling water I used to rinse the kyusu after use.
(Hard and unfiltered) Tap water was only used for the very quick rinses to get the leaf particles out.

Recently, I did a ph test on my tap water. It measured about 7. I always run it through a Brita as it is a hard water with chlorine added and not really drinkable. I then tested the ph and the Brita lowered it to 5.8. This is too low for good tasting tea, so I switched to a mineral water bought locally with a ph of about 7.2. The difference in taste was very noticeable, the higher ph sweetening the tea especially Japanese greens.