Green tea with Kyusu is not working for me

[Tead Off]

But, what is more interesting to me is even with the information that is out there regarding clay and its effect on tea, there are those who completely disregard it, dismiss it, in favor of that which is only pretty or cheaper.

What is even more interesting to me is that I haven't found so far any convincing information about clay effect on matcha although tea ceremony is an ancient and very documented tradition.

This is probably because matcha isn't steeped; it's whisked and consumed immediately. So there isn't the concern with seasoning that you find in vessels that are used for steeping tea leaves. My guess is that a chawan whose composition noticeably affects the taste of matcha is by definition a "bad" chawan.

Since this post was made, I have seen Tokoname, Bizen, & Shigaraki chawan, all unglazed. With the focus on Matcha, I bet there is an effect on the taste, a smoothing one. It makes sense. But, I'm not sure if Olivierco believes clay has an effect on steeped teas.

[olivierco]

I'm not sure if Olivierco believes clay has an effect on steeped teas.

I don't believe in magical clay. I do however believe than clay can have an effect on water, so it would be better to find the right water than to modify the taste of a just decent one, as long as you brew a very good tea.

Banko purple clay can withstand very high temperature up to 1200-1300 degree Celsius. Due to the high-temperature baking process, clay becomes more porous and no taste of soil remained when brewing the tea. Moreover the surface area will drastically increase and this will expedite the interaction between water and minerals in clay.

[Chip]

Truly very interesting perspectives. I try not to think of these things too much or my head starts to hurt.

[JBaymore]

Most all true "stoneware" clays fire in the 1200-1300C range. That is the "normal" maturing range for pretty much all stoneware clays. Most all of the high-fire claywork that you see coming out of Japan will have been fired somewhere in this broad end-point temperature range.

It was when the sueki type primitive anagama was introduced into Japan in the late Kofun Jidai from Silla Dynasty Korea that the Japanese potters were finally able to hit the "magic" 1200 C + range..... at which flyash started to melt into shizenyu (natural ash glaze). Observation of this melting ash on the sholders of Sueki pieces over time, when combined with the knowledge of applied sansai glazing that came into Japan from seeing the sancai lead glazed wares out of Tang China, eventually resulted in the developemnt of the Sanage wares in the early Heian Jidai. These were the first deliberatley applied high-temperture ash based glazes in Japanese pottery.

So 1200-1300 C is common, not all that "special".

FYI......... In firing clay, potters actually deal with what is more correctly called "heat work"..... a combination of temperature increase over time. Within certain limits, you can get the same amount of vitrification of the clay body and melting of the glazes by firing to a slightly lower temperature over a longer peiod of time as you can by firing to a higher temperature in a shorter period of time.

If the body is significantly iron bearing, then the effect of reduction conditions in the kiln at the correct time will increase the amount of vitrification that is occuring in the clay body due to the refractory Fe2O3 being reduced to FeO. Reduction at the wrong time or in the wrong amount can lead to body defects like bloating.

Unlike Fe2O3, FeO is a strong and active flux on the SiO2 (silica) in the clay and glazes. This has the effect of causing more melting in the clay structure, which usually "tightens" the body. FeO fluxed glass is very brittle and weak. A body with too much of this development in the glassy phase can be weaker and more fragile than it can/should be.

You can think of the crystalline clay materials getting glued together by the melting silica glass sort of like fiberglass cloth (the crystalline stuff) getting saturated with epoxy resin (the melting silica).

best,

.............john

PS: Sorry about contributing to your headache, Chip.

[Maitre_Tea]

Is there anything else "magical" about stuff that gets fired at the +1200 Fahrenheit range? This kind of firing temperatures are also important in Yixng (another subject that can cause even greater headaches), so it would be interesting to see why 1200+ is such a "magical" temperature

[Intuit]

Well, yeah. We haven't talked about the organic fraction of clay and it's effect on clay working, firing mechanics and finished clay body characteristics.

Primers:
http://en.wikipedia.org/wiki/Clay
http://en.wikipedia.org/wiki/Kaolin
http://en.wikipedia.org/wiki/Yixing_clay

Six main schools of pottery production/kiln styles in Japan, differentiated by the clay mineralogy and pottery uses:
Japanese Pottery Information Center
http://www.e-yakimono.net/guide/
http://www.e-yakimono.net/guide/html/clays.html
http://www.e-yakimono.net/guide/html/keshiki.html (glazing techniques)

From the e-yakimono website main page on Japanese pottery:
"Each ceramic style has its own special qualities and characteristic appearances, although there is some overlap. This is a function of not only styles, but also the chemical composition of the clay of the region.

Minerals like iron and magnesium fuse with the clay to provide different colors and surface textures, and combine with other factors like the type of wood used to fire a kiln to provide a unique style. Some of these styles are more porous, others are smoother, lending themselves to glazing. Even from within the same region, mountain clay and rice-field clay give rise to different qualities"
...
"Some artists fire pieces for only a few days, and some fire pieces for as long as several weeks. The interaction of the ash from the wood used as fuel and the clay gives rise to the various characteristic appearances. Most of these will change color to some degree as they are used, as water and other elements impart subtle chemical reactions."

A little history on changes in Tokonameware with clay source, mountain erosional deposits versus rice field clay that is rich in iron and organics deposited by rivers under highly reducing conditions.
http://www.japan-net.ne.jp/~tokoname/history2.htm
http://www.kougei.or.jp/english/crafts/0407/f0407.html

Pottery produced in China and Japan has as much art as science in it's manufacture. In Japan, in particular, artisan pottery production is actively supported by the population as an important ethnic/cultural aesthetic

http://www.kougei.or.jp/english/pottery.html

[JBaymore]

Pottery produced in China and Japan has as much art as science in it's manufacture. In Japan, in particular, artisan pottery production is actively supported by the population as an important ethnic/cultural aesthetic

Absolutely! When I am in Japan working it is always a pleasure.... because being a potter there is a very well respected endeavor amongst most of the general population. It is a good feeling to be "appreciated" .

There is no question that each different clay body pretty much has it's own set of characteristics. The question unforunately remains about HOW these characteristics actually affect either the water's chemistry or the tea's chemistry to impact percieved taste.

best,

..............john

[silverneedles]

while i understand part of the teaware fascination (some are pretty), most of it seems aberrant to me as chasing all kinds of pots made of materials that change the taste of the tea - so then you're not tasting the tea itself... but then people also want natural organic "best quality" leaf to put into pots that interact with and affect the flavor of the liquor...

[JBaymore]

Friend of mine...... Louis Katz....... college lecture on firing of clay:

http://www.delmar.edu/sat/lecture2_2009.html

best,

.............john

[Tead Off]

while i understand part of the teaware fascination (some are pretty), most of it seems aberrant to me as chasing all kinds of pots made of materials that change the taste of the tea - so then you're not tasting the tea itself... but then people also want natural organic "best quality" leaf to put into pots that interact with and affect the flavor of the liquor...

I think with a high fired clay pot (porcelains included), you are not tasting the clay. What else can you be tasting beside the tea? The combination of good water, good clay, and, good tea, is ideal, no? All these tools bring out the true flavor of the tea. Not all tools will bring it out in the same fashion. Brewing tea is an alchemy. If you just want tea, you can eat the tea leaves. Tasting the tea itself when brewed, doesn't exist. You need a vehicle.

[silverneedles]

if i want a salad i eat leaves, we're talking about drinking tea so water and vessel is involved...
a proper vehicle is one which allows the true flavor of the tea to come thru, inert in interaction with tea particles, function of which is to hold water and affect temperature--> which will help express the tea... not properties of clay/iron content/etc which enhance or mellow nuances.
i agree there are many variables in producing an infusion, but the goal should be to simplify not introduce more into the equation.

[David R.]

It is said that clay doesn't affect "tea particules" but the water in itself. Wishing an inert vehicle is choosing porcelain over green/purple/red clays. Is it what you are implying ?

[Tead Off]

if i want a salad i eat leaves, we're talking about drinking tea so water and vessel is involved...
a proper vehicle is one which allows the true flavor of the tea to come thru, inert in interaction with tea particles, function of which is to hold water and affect temperature--> which will help express the tea... not properties of clay/iron content/etc which enhance or mellow nuances.
i agree there are many variables in producing an infusion, but the goal should be to simplify not introduce more into the equation.

Yes, simplicity, but, not indifference, eh? Everything affects everything. This is my point. Using different water will affect the flavor of tea. It's still water, but, there are better waters with better flavor. No falling asleep for you. Sorry.

[JBaymore]

Wishing an inert vehicle is choosing porcelain over green/purple/red clays. Is it what you are implying ?

Actually the closest thing to completly "inert" would not be porcelain or any clay based product with a glaze on it. All ceramic glazes are "softer" than a pure silica glass due to the relatively high level of fluxing additions necessary to lower the melting temperature to a range that allows them to melt before the underlying clay body.

If somone wants a vessel that is as inert as possible, they'll want labrotory quality silica glass or possibly borosilicate glass. Drink you tea out of a nice lab beaker!

best,

.............john

PS: And in the end,.... isn't it about enjoying the way the tea tastes...... no matter HOW you GOT that taste?

[Chip]

PS: And in the end,.... isn't it about enjoying the way the tea tastes...... no matter HOW you GOT that taste?

+1

Whatever brings the most pleasure in the process and enjoyment.

Like how you brew, brew how you like.