Yixing advice

[steanze]

So, I've recently done some TC reading on niangaotu (NGT) and it seems that its main disadvantage is that it significantly lacks porosity, because of the way the clay was processed and its resulting density. I assume that this is what you mean by saying that "it's not very yixing-like" or like porcelain.

Yes

But then in what sense is it better than many later hongnis?

It does not impart a metallic taste (not all later hongnis do), it forms a nice patina.

I'v also read that it usually seasons very well (what does that mean?), is this what makes good in your view?

That it forms a nice shiny patina.

Finally, holding other things equal, to which tea would you pair it?

Gaoshan oolong if the walls are thin, if the walls are thick then aged sheng that was stored with not too much humidity, or dry stored aged oolongs

[ShuShu]

I'v also read that it usually seasons very well (what does that mean?), is this what makes good in your view?

That it forms a nice shiny patina.

Thank you very much for clarifying this steanze!
I have one more question, if I may .
In that TC discussion, Kyarazen writes that:

I wouldnt think that nian gao is "non-porous", it doesnt act like glass, its just that yixing clay has multiple porosity. The primary porosity comes from the particle nature, aluminium oxide particles etc have their own porosities. Secondary porosity comes from how the clay is processed, hammered, compacted etc. nian gao loses its primary porosity as much of the particles have been ground down, but the fact that it seasons very well, it excels in the secondary porosity

Not sure I understand that last part in bold - whatever makes it develop a nice patina (or the fact that it seasons very well) is also what makes it more porous ? in what way?
Would be glad if you could shed some light on this

The discussion on TC is at https://www.teachat.com/viewtopic.php?t=20125&start=15

[steanze]

In that TC discussion, Kyarazen writes that:

I wouldnt think that nian gao is "non-porous", it doesnt act like glass, its just that yixing clay has multiple porosity. The primary porosity comes from the particle nature, aluminium oxide particles etc have their own porosities. Secondary porosity comes from how the clay is processed, hammered, compacted etc. nian gao loses its primary porosity as much of the particles have been ground down, but the fact that it seasons very well, it excels in the secondary porosity

Not sure I understand that last part in bold - whatever makes it develop a nice patina (or the fact that it seasons very well) is also what makes it more porous ? in what way?
Would be glad if you could shed some light on this

In geology, primary porosity is porosity due to how sediments deposited to form sandstone. Secondary porosity derives from subsequent processes like erosion. You can read a bit more about it here: https://www.spec2000.net/12-phibasics.htm
I am not sure whether the terms "primary" and "secondary" in the passage you are quoting are being used with their common geological meaning, although we could consider processing as an "erosion-like" mechanism (let's keep in mind that it also involves weathering/exposure to elements). My understanding would be that because of secondary (erosion) processes, niangaotu loses its original (primary) porosity. But you are right that it seems like the passage is suggesting that secondary porosity is increased. In principle, there might be mechanisms during processing that could increase secondary porosity, but if that were the case I would expect to observe a stronger effect on the brew. You might want to ask KZ for more clarification

[ShuShu]

In geology, primary porosity is porosity due to how sediments deposited to form sandstone. Secondary porosity derives from subsequent processes like erosion. You can read a bit more about it here: https://www.spec2000.net/12-phibasics.htm
I am not sure whether the terms "primary" and "secondary" in the passage you are quoting are being used with their common geological meaning, although we could consider processing as an "erosion-like" mechanism (let's keep in mind that it also involves weathering/exposure to elements). My understanding would be that because of secondary (erosion) processes, niangaotu loses its original (primary) porosity. But you are right that it seems like the passage is suggesting that secondary porosity is increased. In principle, there might be mechanisms during processing that could increase secondary porosity, but if that were the case I would expect to observe a stronger effect on the brew. You might want to ask KZ for more clarification

Unfortunately, I failed to reach KZ, but I think that one of his posts (cited below) explains what he means.
As you say and as he writes, primary porosity refers to the porosity of the clay particles themselves while secondary porosity refers to the space between the particles, which is "determined by the maker’s clay pounding and processing". The second porosity allows pots to develop a patina, which is generated due to "the repeated expansion and contraction of the pot surface" when it is in use. As there is more space between particles so the pot will better/quicker develop a patina. Therefore, I guess his assumption here is that the fact that NGT quickly develops a nice patina means that there is considerable space between particles and therefore pots made of NGT are indeed porous in important respects though the particles themselves are very fine and have very little (primary) porosity...



https://www.kyarazen.com/patina-develop ... ing-pots/#

[tealifehk]

In geology, primary porosity is porosity due to how sediments deposited to form sandstone. Secondary porosity derives from subsequent processes like erosion. You can read a bit more about it here: https://www.spec2000.net/12-phibasics.htm
I am not sure whether the terms "primary" and "secondary" in the passage you are quoting are being used with their common geological meaning, although we could consider processing as an "erosion-like" mechanism (let's keep in mind that it also involves weathering/exposure to elements). My understanding would be that because of secondary (erosion) processes, niangaotu loses its original (primary) porosity. But you are right that it seems like the passage is suggesting that secondary porosity is increased. In principle, there might be mechanisms during processing that could increase secondary porosity, but if that were the case I would expect to observe a stronger effect on the brew. You might want to ask KZ for more clarification

Unfortunately, I failed to reach KZ, but I think that one of his posts (cited below) explains what he means.
As you say and as he writes, primary porosity refers to the porosity of the clay particles themselves while secondary porosity refers to the space between the particles, which is "determined by the maker’s clay pounding and processing". The second porosity allows pots to develop a patina, which is generated due to "the repeated expansion and contraction of the pot surface" when it is in use. As there is more space between particles so the pot will better/quicker develop a patina. Therefore, I guess his assumption here is that the fact that NGT quickly develops a nice patina means that there is considerable space between particles and therefore pots made of NGT are indeed porous in important respects though the particles themselves are very fine and have very little (primary) porosity...



https://www.kyarazen.com/patina-develop ... ing-pots/#

That's what I thought he meant! Thanks for confirming that.

[steanze]

Unfortunately, I failed to reach KZ, but I think that one of his posts (cited below) explains what he means.
As you say and as he writes, primary porosity refers to the porosity of the clay particles themselves while secondary porosity refers to the space between the particles, which is "determined by the maker’s clay pounding and processing". The second porosity allows pots to develop a patina, which is generated due to "the repeated expansion and contraction of the pot surface" when it is in use. As there is more space between particles so the pot will better/quicker develop a patina. Therefore, I guess his assumption here is that the fact that NGT quickly develops a nice patina means that there is considerable space between particles and therefore pots made of NGT are indeed porous in important respects though the particles themselves are very fine and have very little (primary) porosity...



https://www.kyarazen.com/patina-develop ... ing-pots/#

Yes, that is an interesting hypothesis. Let's remember though that I have not yet seen conclusive evidence in its support. In particular, the hypothesis does not account (to my limited knowledge) for why secondary porosity would not interact with the taste and texture of tea as primary porosity does. I suppose one could attempt an explanation based on different size scales of the pores, but for the time being a bit more work might be needed before this hypothesis accounts for all the available evidence.

[jessepat84]

I’ve had a question in mind about more modern F1 (White Label onwards) and F2 pots.

We know that pots from the 90s onwards are more likely to contain a certain amount of artificially added oxides, like Fe oxide in Hongni and Mg oxide in Zini. From what I know, for F1/F2 there was a legal cap to how much could be used (I’ve seen a value of 0.5% being mentioned, although I don’t know if this is % of the overall weight or something else). On the other hand, clay used in the 80s and earlier was less likely to be adulterated.

I have some F1 pots from the 70s and 80s, and also some from the early 90s. Aside from differences in appearance, I haven’t noticed anything negative as such when using the newer ones (people often recommend checking for a rough feeling in the back of the throat, chemical scents etc, but I’ve never encountered these types of problems with Factory pots). I’ve also done some metal tests for water that was sitting inside the pots and didn’t see anything that would set apart the 90s pots from the older ones. However, this was a home test kit, so nothing very accurate or with a high level of sensitivity.

Purely from a safety perspective, how concerned should one be about using Factory pots that are past-80s (or late 80s/early 90s, such as White Label)? Additives aren’t a new topic as such and I know people often seek out older clay, but I don’t think I’ve seen this type of discussion with reference to newer F1/F2 in particular. Thanks for any insights!

[Bok]

There is this guy in China on Fb who is testing all sorts of Yixing with scientific methods. All in all it tells you what is in the clay, yet it does not tell anything about long term exposure when using these pots. If there negative side effects they are probably only apparent in the long term.

Dr Lu has a few post 80s sets which includes that green and blue clay that was developed then, he doesn’t dare to use it and just leaves it as a collection item...

[jessepat84]

There is this guy in China on Fb who is testing all sorts of Yixing with scientific methods. All in all it tells you what is in the clay, yet it does not tell anything about long term exposure when using these pots. If there negative side effects they are probably only apparent in the long term.

Dr Lu has a few post 80s sets which includes that green and blue clay that was developed then, he doesn’t dare to use it and just leaves it as a collection item...

Ah yes, I saw that post here too (about those tests...). The green / blue ones are probably worth extra concern. I don’t have any of those, just Zini and Hongni, but still wonder about any long-term issues.

[Stephen]

Purely from a safety perspective, how concerned should one be about using Factory pots that are past-80s (or late 80s/early 90s, such as White Label)? Additives aren’t a new topic as such and I know people often seek out older clay, but I don’t think I’ve seen this type of discussion with reference to newer F1/F2 in particular. Thanks for any insights!

I can't speak to factory pots, but in terms of safety I think the concern is with materials that may leach. After a teapot goes through firing an additive in the clay may (or may not) be essentially stable. If I remember right there was some insightful discussion of this by JBaymore on teachat way back when.

[jessepat84]

I can't speak to factory pots, but in terms of safety I think the concern is with materials that may leach. After a teapot goes through firing an additive in the clay may (or may not) be essentially stable. If I remember right there was some insightful discussion of this by JBaymore on teachat way back when.

Might be this thread here: https://www.teachat.com/viewtopic.php?f=87&t=20451

[Stephen]

Might be this thread here: https://www.teachat.com/viewtopic.php?f=87&t=20451

Yes! I think that's it. I think there's also a similar thread about glazes and overglazes, but that's not as applicable here.

[Tetsubin]

Hi,

I have a zini pot that mutes a bit to much for my taste. it is very new though, will this muting change over time with use or will it always steal flavor?

[steanze]

Hi,

I have a zini pot that mutes a bit to much for my taste. it is very new though, will this muting change over time with use or will it always steal flavor?

It could mute a bit less with use. How long have you been using it? Do you have a picture? What tea do you use it for?

[Tetsubin]

Hi,

I have a zini pot that mutes a bit to much for my taste. it is very new though, will this muting change over time with use or will it always steal flavor?

It could mute a bit less with use. How long have you been using it? Do you have a picture? What tea do you use it for?

I got it last week and I really like everything else with it. Its just that i have been using a modern Zhuni quite heavily for about 8 months and that pot really accentuates the teas. I drink semi aged raw puerh out of these. The new one is a modern one out of Dicaoqing clay.