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Modern Purple Clay Additives
Posted: Sat Apr 14, 2018 7:21 am
by tealifehk
I've noticed some modern purple (zini) pots have an odd odor from an additive. I've noticed this at several price points. The pots look unnaturally purple compared to old zini. Anyone know what the factories are adding to clay to make it go purple?
Re: Modern Purple Clay Additives
Posted: Sat Jun 23, 2018 1:55 pm
by burritofingers
Do you still notice the smell after using / seasoning the pot, or is it just the smell of the dust? Thinking that the older pots have had more time to be seasoned, so they may ha e their own smell by now, whereas the new pots still just smell like clay.
Re: Modern Purple Clay Additives
Posted: Sun Jun 24, 2018 10:05 am
by tealifehk
burritofingers wrote: ↑Sat Jun 23, 2018 1:55 pm
Do you still notice the smell after using / seasoning the pot, or is it just the smell of the dust? Thinking that the older pots have had more time to be seasoned, so they may ha e their own smell by now, whereas the new pots still just smell like clay.
It's an entirely different smell, and it doesn't go away after several uses. I'm too scared to drink from these pots!
Re: Modern Purple Clay Additives
Posted: Sun Jun 24, 2018 11:57 pm
by njm
I know that ochre is a traditional iron-containing colorant used for darkening clays, which also happens to be somewhat foul smelling. But I would expect that smell to dissipate. How would you describe the scent, out of curiosity?
Re: Modern Purple Clay Additives
Posted: Mon Jun 25, 2018 1:04 am
by Bok
One issue might be soil pollution in China. I know a farm operation which wanted to go organic, but proved almost impossible due to to the soil pollution. It would take them over 10 years to (maybe) get it clean enough. They resorted to aquaponics instead to solve the problem.
Re: Modern Purple Clay Additives
Posted: Mon Jun 25, 2018 9:18 pm
by tealifehk
njm wrote: ↑Sun Jun 24, 2018 11:57 pm
I know that ochre is a traditional iron-containing colorant used for darkening clays, which also happens to be somewhat foul smelling. But I would expect that smell to dissipate. How would you describe the scent, out of curiosity?
I didn't know purple ochre existed! I can't describe the smell and the pots look so artificially purple compared to old purple clay that I don't want to use them! I'll have to get a picture of the two next to each other. I can't describe the odor as it's like nothing else, but it's definitely not a natural clay odor.
Re: Modern Purple Clay Additives
Posted: Mon Jun 25, 2018 9:19 pm
by tealifehk
Bok wrote: ↑Mon Jun 25, 2018 1:04 am
One issue might be soil pollution in China. I know a farm operation which wanted to go organic, but proved almost impossible due to to the soil pollution. It would take them over 10 years to (maybe) get it clean enough. They resorted to aquaponics instead to solve the problem.
While that is an issue, it isn't the issue in this case. There isn't much good purple clay around, so they have to 'make' it.
Re: Modern Purple Clay Additives
Posted: Mon Jun 25, 2018 9:53 pm
by njm
I didn't know purple ochre existed!
It's actually yellow until it's fired in a kiln. At a high temperature in a reduction atmosphere, it converts to dark iron oxide and can impart a purplish hue to the clay body, somewhat similar in principle to natural zini I might imagine. Still and again, I wouldn't expect the scent to persist past the firing. Were these pots slip cast by chance?
Re: Modern Purple Clay Additives
Posted: Mon Jun 25, 2018 11:03 pm
by tealifehk
njm wrote: ↑Mon Jun 25, 2018 9:53 pm
I didn't know purple ochre existed!
It's actually yellow until it's fired in a kiln. At a high temperature in a reduction atmosphere, it converts to dark iron oxide and can impart a purplish hue to the clay body, somewhat similar in principle to natural zini I might imagine. Still and again, I wouldn't expect the scent to persist past the firing. Were these pots slip cast by chance?
No, handmade. Whatever it is, I don't think it's ochre.
Re: Modern Purple Clay Additives
Posted: Tue Jun 26, 2018 12:26 am
by Stephen
I've only had 1 teapot whose smell didn't resolve with a soak/simmer in hot water and soak/simmer in tea water. It was a modern dark zi ni with a notable chemical smell. Thankfully a return was easy enough. Do you have a picture of the teapot(s)?
Re: Modern Purple Clay Additives
Posted: Tue Jun 26, 2018 8:11 am
by tealifehk
Stephen wrote: ↑Tue Jun 26, 2018 12:26 am
I've only had 1 teapot whose smell didn't resolve with a soak/simmer in hot water and soak/simmer in tea water. It was a modern dark zi ni with a notable chemical smell. Thankfully a return was easy enough. Do you have a picture of the teapot(s)?
I'll take some: I've got three with the odor, and they all have the same odor!