About the clay in Yixing today

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Chi-Lin Lu
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Sun Jan 07, 2018 7:14 am

Shane wrote:
Sat Jan 06, 2018 8:41 pm
If there is no smell, should there still be a concern?
Smell should be only one of the indication. Color and texture should also be concerned.
Atlas
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Sun Jan 07, 2018 11:45 am

Chi-Lin Lu wrote:
Sun Jan 07, 2018 7:13 am
Atlas wrote:
Sun Jan 07, 2018 12:37 am
Thanks Dr Lu!

I imagine it wouldn't be worth it for cheap pots, but at $11 it seems that something like THIS might be a good idea if someone has any concerns.
Wow, this looks good. How about the sensitivity of it ? Because the metal-ion dissolved should be very little, if the sensitivity is not high enough, may not be examined.
The vendor suggests a strong colour indicates concentrations >= 5PPM.

I'd have to have a look around, but you may well be right about that being too high a threshold (or higher than the EPA threshold for drinking water, at least) although I believe you could account for this somewhat by, say, filling a pot with boiling distilled water, lidding the pot, and leaving it for a day. I'm not comfortable enough with chemistry to suggest how much more might be extracted from the pot walls during that period compared with a dozen short steeps.

I suppose you could fill the pot, let it rest for whatever period, then boil it down in a glass vessel to ~1ml for testing - you could increase the "effective sensitivity" of the test by a factor of ~x times for an x ml pot.
Last edited by Atlas on Tue Jan 09, 2018 12:45 am, edited 1 time in total.
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Chi-Lin Lu
Posts: 18
Joined: Mon Dec 11, 2017 6:06 pm
Location: Taiwan

Sun Jan 07, 2018 9:00 pm

Atlas wrote:
Sun Jan 07, 2018 11:45 am
The vendor suggests a strong colour indicates concentrations >= 5PPM.

I'd have to have a look around, but you may well be right about that being too high a standard (or higher than the EPA standards for drinking water, at least) although I believe you could account for this somewhat by, say, filling a pot with boiling distilled water, lidding the pot, and leaving it for a day. I'm not comfortable enough with chemistry to suggest how much more might be extracted from the pot walls during that period compared with a dozen short steeps.

I suppose you could fill the pot, let it rest for whatever period, then boil it down in a glass vessel to ~1ml for testing - you could increase the "effective sensitivity" of the test by a factor of ~x times for an x ml pot.
Yes, it sounds reasonable and feasible. This could be an option for the people who worry about the oxides in pot.
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tealifehk
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Sun Jan 07, 2018 9:37 pm

Iron tetsubin only seem to give off 1-2 ppm of iron after boiling water in them, so I wonder if a clay pot would exude enough heavy metal ions for the test to work...even with the overnight method!
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Brent D
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Sun Jan 07, 2018 10:38 pm

Great read Dr. Lu!
Wonderful to have your knowledge here:)
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Demea
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Joined: Mon Dec 11, 2017 1:26 pm

Fri Jan 19, 2018 2:39 pm

Rather discouraging perspective on the modern clay situation:

https://www.bitterleafteas.com/blog/dig ... ng-part-ii
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