> Hi Bill,
>
> Based on your cogent, intelligent, and thoughtful
> prose above, I look forward to more about clay.
> Be as specific as you feel you can be without
> causing our eyes to lose focus. Thanks.
>
> Michael

Thanks for your encouragement Michael. Here we go...

How To Select Quality Zisha Teapots continued:

After a teapot meets ergonomic needs, and our aesthetic standards, the
most important factor is the quality of the clay.

I will assume readers know what is zisha (purple clay). Basic
information on zisha teapots can be read at this article: "Introduction
to Zisha Teapots" at http://www.chinaflairtea.com/introteapots.html.

The best teapots are made from pure zisha clays, that are highly
porous, and fired at approximate temperatures of 1,200°C.

How do we look for such teapots?
Many people like to test the tone/ring that is made from tapping the
teapot. A popular method is to use the lid to gently tap the side of
the teapot. (I will mention more about tapping a teapot later). The
conventional idea is that the high-pitched rings are produced from
clays that are dense. Since high porosity is desired in zisha clay, we
may frown on high-pitched rings, which mimic the sound of striking hard
metal.

The most common types of zisha clay that produce these sounds are
vibrant red. These clays have very high iron content that produce red
colored teapots which are popular in the Chinese market. When extra
iron is added to the clay, the teapot will not only become very red, it
will also become very dense and produce the metallic ringing.

On the other hand, a low dull pitch does not indicate highly porous
clay. If the sound is a low, dull thud, it often indicates a teapot
that was made at temperatures too low. When teapots are fired at low
temperatures, they will emit the odor and taste of clay. Just rinsing
the teapot with boiling water will release the pungent odor of dirt.
Using such teapots to make tea will produce bitter, clay-tasting brews
with scattered and course textures.

There are no styles of tea that can benefit or endure the effects of
low temperature clays. Ugly black spots and stains will also develop
throughout the teapot after some use. The more you try to nurture and
develop the teapot's patina, the worse it gets.

Clays suffering from insufficient temperatures are worse than dense
clays. The high-pitched teapots mentioned earlier may not be ideal,
but they do maximize aroma. For example, Taiwanese teapots, which are
not made of zisha clay, are not porous. They are very dense and make
very high-pitched rings. There is absolutely no problem using these
teapots to make high mountain Taiwanese oolongs to enjoy their light,
fresh character. High-pitched and dense zisha teapots are the same.
They work well with light Taiwan and Tiegaunyin oolongs. However,
avoid heavy roasted oolong teas or traditional Chao Zhou gungfu brewing
techniques with dense teapots. The density of the clay will overly
concentrate the astringency and bitterness of even the most well
roasted oolongs.

So far:
Tap a teapot with the lid and listen to the sound.
Low dull pitch = bad
Very high pitch = good for light oolongs only (no medium/heavy roasted
oolongs)
Simple right? Well...not really.

We still haven't considered the thickness of a teapot or its shape.
Square shaped, hexagonal shaped, rosettes, etc., do not ring when they
are struck. Thick-walled teapots don't ring the same as thin-walled
teapots. Cylindrical shapes don't sound the same as round teapots.
This means really good zisha clays can ring low and dull if they are
made very thick, or if they have shapes with many corners and
edges-good zisha teapots can be mistaken for bad clay.

OK, so we can't trust the sound test. Now what? Well, now I gotta
go take a break.

Before I go I would like to mention the etiquette of sound testing
teapots. Please ask the owner if you may tap the teapot before doing
so. The owner may prefer to demonstrate the sound for you. Never use
the thin flange under the lid to strike the teapot, because it is the
most fragile section of the entire teapot. Rather, use the knob on top
of the lid to gently tap the side of the teapot. Better yet, only drag
the knob along the side of the teapot and listen to the vibration.
Please avoid partially lifting and dropping the lid back onto the body
to test the vibration, as the lid can be damaged, and the sound will
not be accurate anyway.

A little knowledge is a dangerous thing. Tapping is a very common test
and every week people tap my teapots in ways that make my heart jump to
my throat. Even tea aficionados frequently commit the acts above. A
teapot collector struck my antique teapot that is over 100 years old
with the thin flange of the lid. I had a heart attack.

I haven't fully explained how to look for quality, but I hope that I
have so far provided some interesting and helpful information. I can
share more about clay if anyone is interested in reading such long
explanations. This is really a very advanced topic and there's just
so much to the art of tea.

Bill Lee
www.chinaflairtea.com