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Reading Shine Magical's experience w/ the clay pot & porcelain pot, I am surprised. My clay pots do not produce a wider array of flavors than porcelain. (I know that all clay is not the same.)
As Bok noted, a metallic taste seems awful. If that taste is due to pesticides or some other toxin, where does the bad stuff go that we used to taste but don't when we find a way to get rid of its taste?
Is there a chance that what one person experiences as an awful metallic taste, is what some others may experience as minerals? (I used to like only the smallest hint of minerals. More than that hint made a cup undrinkable. So, I wonder if some people have zero tolerance for tasting minerals in their drink.)

Another guess I have is that I used the pot so much that it eroded some of the clay inside and a result some of the interior was reacting with the brews... the inside turned rather blue and shiny after a while that I had thought was patina since the flavor did improve and become brighter but after another while it turned more orange-y and I started to occasionally taste more metallic flavors I started to get more suspicious.

Sorry to derail the gaoshan thread with clay pot mysteries.

Shine Magical wrote: ↑

Mon Aug 26, 2019 1:08 pm

Another guess I have is that I used the pot so much that it eroded some of the clay inside and a result some of the interior was reacting with the brews... the inside turned rather blue and shiny after a while that I had thought was patina since the flavor did improve and become brighter but after another while it turned more orange-y and I started to occasionally taste more metallic flavors I started to get more suspicious.

Sorry to derail the gaoshan thread with clay pot mysteries.

Curious, can you share a picture of this pot? Are you tasting metallic notes in any other beverages or foods? Maybe it is what Ethan mentioned, high mineral count. I know you buy high quality oolong so I doubt it’s bad tea

Sure, though it’s hard to get a good pic of the inside of a teapot

Ethan Kurland wrote: ↑

Mon Aug 26, 2019 10:34 am

Reading Shine Magical's experience w/ the clay pot & porcelain pot, I am surprised. My clay pots do not produce a wider array of flavors than porcelain. (I know that all clay is not the same.)

Really? I find this to be the case from time to time... the clay shifts the flavor in a certain direction which just changes the taste of the overall brew vs what you might find in porcelain.
I find it especially noticeable in puer.

I usually turn to clay to mute harshness. It curbs the taste of char for roasted oolong & tones down bitterness of Pu-erh. If a flavor is too strong without clay but toned down with it, other flavors can be tasted better (of course), but the clay may also take away from floral & aromatic effects. Overall, for me porcelain produces a more flavorful drink.

I use a pot from Taiwan that is porous inside for roasted oolong; porcelain for other teas that I drink regularly. (I don't drink Pu-erh at home more than a few times a year. For pu, I use Yixing.)

Shine Magical wrote: ↑

Mon Aug 26, 2019 2:14 pm

Sure, though it’s hard to get a good pic of the inside of a teapot

Interesting iridescence inside your pot. What kind of clay is it, made by? Looks like Hokujo stoneware.
Are you getting metallic taste with any other unglazed teapots?

Victoria wrote: ↑

Mon Aug 26, 2019 5:26 pm

Shine Magical wrote: ↑

Mon Aug 26, 2019 2:14 pm

Sure, though it’s hard to get a good pic of the inside of a teapot

Interesting iridescence inside your pot. What kind of clay is it, made by? Looks like Hokujo stoneware.
Are you getting metallic taste with any other unglazed teapots?

It is Taiwanese clay from Miaoli, fires in a wood kiln over a couple of weeks. This treatment should in all experience completely seal the surface of the clay, due to continuous expanding/shrinking and the formation of a sort of ash deposit glaze.

I remember that particular firing which was even longer than what they usually did. Some very unique pieces were in that kiln, among them the one above

Have you tried resetting it?

No, the handle broken and so I decided to give the pot to a friend that likes to do kintsugi.
What's there at the bottom of the pot seems permanent and wouldn't come out with boiling water imo.

Shine Magical wrote: ↑

Mon Aug 26, 2019 1:08 pm

Another guess I have is that I used the pot so much that it eroded some of the clay inside and a result some of the interior was reacting with the brews... the inside turned rather blue and shiny after a while that I had thought was patina since the flavor did improve and become brighter but after another while it turned more orange-y and I started to occasionally taste more metallic flavors I started to get more suspicious.

Sorry to derail the gaoshan thread with clay pot mysteries.

Shine Magical wrote: ↑

Mon Aug 26, 2019 2:14 pm

Sure, though it’s hard to get a good pic of the inside of a teapot

nah, i don't think you eroded the surface. pretty sure it's thin-film interference. the color is a function of film thickness and will change as the film builds. it will also present as a rainbow across uneven areas. not sure what the film is, probably just tea lipids.

the off tastes can probably be remedied with a reset.

Shine Magical wrote: ↑

Fri Aug 30, 2019 7:55 am

No, the handle broken and so I decided to give the pot to a friend that likes to do kintsugi.
What's there at the bottom of the pot seems permanent and wouldn't come out with boiling water imo.

'imo'? as in you haven't tried it?
when you get the pot back, try mechanically removing it -- cover your finger with paper towel (or cotton) and scrub the inside with baking soda paste (very mild abrasive made from baking soda and a little water). maybe the pot will perform like it used to, and the off tastes will go away. dunno.

Great find @pedant. Now I know why oil film and soap bubbles have iridescent rainbows. What you propose makes a lot of sense.

Shine Magical wrote: ↑

Mon Aug 26, 2019 2:14 pm

Sure, though it’s hard to get a good pic of the inside of a teapot

This below is a pot made by myself with the same clay, different firing session:

and it wasn't all shiny/rainbowy like that initially, right? it became like that with use?

pedant wrote: ↑

Sat Aug 31, 2019 3:32 am

and it wasn't all shiny/rainbowy like that initially, right? it became like that with use?

No it was like that from the start, some wood fired pieces turn out like this. Outside has some of it as well.

oh. maybe i misread what @Shine Magical wrote. nevermind then