A contemporary and F1 hongni ware. Collection of the author.

Editorial Conversation: Chapter 8, Section 5: Hongni Ore and Clay

Jason M Cohen
Jason M Cohen

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A full transcript is included on the episode page and below:

[00:00:06] Jason Cohen: Hello everyone, I'm Jason Cohen, the author of An Introduction to the Art and Science of Chinese Tea Ceremony. Today we're discussing Book Two, Hongni Ore and Clay. Here to talk about this chapter is our editorial team, Patrick Penny, Zongjun Li, and Emily Huang.

[00:00:21] Zongjun Li: Hello, hello.

[00:00:22] Jason Cohen: Hello, everyone.

Some background to my first question.

The editorial team was surprised by the phrase, "Hongni (红泥) is weathered by Ni (泥)". We've discussed the process of physical and chemical weathering in previous chapters. What was it about this statement that surprised you?

[00:00:38] Pat Penny: As we read through what Baini (白泥), Jiani (甲泥), Nenni (嫩泥), all these were, I think mentally, I had kind of blocked them off as unique rock structures, as unique ore and didn't really think about their degradation over time or how they might morph into other materials.

And then I think particularly maybe for Baini (白泥) to Hongni (红泥), I had mentally seen Hongni (红泥) as just these blocks of ore within the clay and within the different stratas. But maybe it's because of the coloration, I never really imagined… because seeing the fire color of Baini (白泥), right? It is white.

There might have been something mentally there where I just could not imagine how something that is fired to be white could also be fired to be red, even though obviously iron content plays a huge role in that. But yeah, I think just that piece, the weathering was something that didn't come to mind when I had actually thought about Hongni (红泥) ore.

[00:01:27] Jason Cohen: And this isn't a fast process. This is happening on a, on a geological time scale. Zongjun, do you want to describe a little bit about this process where Baini (白泥) turns into Hongni (红泥)? This isn't something that you wake up one morning and look at your strata and say, “wow, we've, we got it!” Right? This is something that's happening on the order of thousands of years.

[00:01:47] Zongjun Li: Yeah, just, spray some magic water and some scoby and we'll ferment into a Hongni (红泥) eventually. No, that's not, (laughs) not how it happened. It's mostly a cross effect of oxidation and also rainwater, weathering the Baini (白泥) structure. That's why oftentimes you would observe Hongni (红泥) being adjacent layer to some Baini (白泥) or yellow stone structure.

[00:02:11] Pat Penny: And through the chapter I was reading that Hongni (红泥) occurs underneath the yellow stone layer. Zongjun, as you were talking about rain weathering, Jason, is that kind of a factor where as weathering is occurring, there's materials that are able to make it through that yellow stone layer, some that are not, and is that a factor in the formation of Hongni (红泥) ore?

[00:02:29] Jason Cohen: Yes, that's exactly correct. So if you think about yellow stone layer, it's a catalytic sandstone and the material that's going to filter through the yellow stone layer bed is going to be selective. It’s permeable, but it is not inert. It's going to catch certain compounds. It's going to filter certain compounds. So you're going to get a migration predominantly of iron compounds and other silicates through the yellow stone layer, deposited into the Baini (白泥), some of which it catches and holds, forming the Hongni (红泥) ore. And so you'll see that there's still Baini (白泥) strata scattered throughout Yixing.

And so what you'll see is, is that not all Baini (白泥) under yellow stone layer turns into Hongni (红泥). It's only some of it that happened to have the right precipitate, that happened to have the right chemical weathering, and the materials for chemical weathering to be transported via physical weathering in order for that transformation to take place.

My next question, all red colored Zisha (紫砂) clay from the Ming and Qing dynasty are blends of Zhuni (朱泥) and Hongni (红泥). Do you have a personal process in differentiating the dominant clay in the blend?

[00:03:31] Zongjun Li: A lot of contemporary scholars now they start to clarify what exactly Hongni (红泥) is. In the past, Hongni (红泥) is really like umbrella, confusing, overarching term that refers to anything that looks red after fire and what we know nowadays is a lot of the ores like Zini (紫泥) or Hongni (红泥) or Zhuni (朱泥) when they are fired in certain temperatures, they could look red or orange red.

So before the, the contemporary era, when you are talking about Hongni (红泥), you are really talking about a mixture of a lot of stuff that needs to have a clarification on the contemporary notion.

[00:04:09] Jason Cohen: Well, we talk about that in the chapter on Pin Pei (拼配), on the historical art of blending and that most of the historical wares were made for some types of blended ores. They didn't have the same focus on purity or pure ores that we do today. And so when we look at red clay, I think what you're saying is that it's very difficult to look at a historical ware and say, “ah, of course, this is a 30 percent Zhuni (朱泥) and 60 percent Hongni (红泥) and 10% Shihuangni (石黄泥) grains.”

[00:04:33] Pat Penny: You're not able to do that, Jason? You can't just do that?

[00:04:37] Jason Cohen: Off the cuff? Well, you know, my process for determining the composition of an antique ware is you just smash it. Take one look at it, you smash it, and you examine the shards.

[00:04:46] Pat Penny: Send it in for, you know, analytical testing. Yeah, that's the best way to do it.

[00:04:50] Jason Cohen: No, so obviously, right, we need some kind of non destructive intuition in order to be able to do this. So the question is, in a complex matrix, do you have a process for doing this? Do you think that this is valuable, or do you believe that actual knowledge like that is impossible without some type of analytical work, preferably non destructive analytical work?

[00:05:41] Pat Penny: Well, I, I prefer to cultivate my destructive intuition, but using my non destructive intuition, I think when I'm looking at Zhuni (朱泥) versus Hongni (红泥), or trying to determine, right, therefore I think texture plays a big role in it for me. So from what I've seen and what I own, at least, of Hongni (红泥) pots, Hongni (红泥) often ends up being much smoother than a lot of Zhuni (朱泥), both contemporary and historical Zhuni (朱泥), which obviously is containing some Hongni (红泥) tends to have some pretty distinct textures, wrinkling texture, pear skin texture, sometimes bumpy texture that can be seen to a degree in Hongni (红泥), but I think it's always emphasized more in Zhuni (朱泥). And so that's one place that I'll look.

I think color is a dangerous road to go down, but at least from the experiences that I've had in the teapots I've handled, I do have somewhat of a mental model of the color range of Zhuni (朱泥) versus Hongni (红泥) and there's a lot of overlap. So it's probably not the most useful tool.

But then from there, I think brewing. So I do think that I have an understanding of some slight differences in effect between Zhuni (朱泥) and Hongni (红泥). If you give me modern of one and antique of the other, could get a little muddled. But at least contemporary for both, I could probably tell you from brewing it and the effect it has on the tea what I think it would be. But you don't always get that chance, right, when you're trying to buy a ware. Getting to really brew with it.

So I think texture is probably going to be my big one. Definitely curious what everyone else's tools are to try and determine between the two.

[00:06:30] Zongjun Li: Yeah, I think those are pretty good matrix to make decisions.

One thing that I would also notice is the shining sparkles on the surface, which are usually the mica, Hongni (红泥) has usually far less mica than Zhuni (朱泥) or blends with other types of clay. So if I see a Hongni (红泥) or a red teapot with a significant less mica, but has a very good texture and the color, I would say it's probably more leaning more on the pure Hongni (红泥) side of the matrix.

[00:06:59] Jason Cohen: The primary indicator in my mind is usually the texture, the formation of pear skin or various waves, bumps, lumps that is usually indicative of a higher content Zhuni (朱泥) ware in my mind. That's not perfect. It's possible to make a very shiny, smooth Zhuni (朱泥), but that tends to be much more modern contemporary than the traditional texture you expect from a Zhuni (朱泥) ware.

Is there an advantage to blended Zhuni (朱泥) and Hongni (红泥)? Why don't we see many blended Zhuni (朱泥) and Hongni (红泥) wares today?

[00:07:27] Pat Penny: From being a consumer, what I see is Zhuni (朱泥) generally seems like it's selling for more money. So if I was going to be a producer and I had both ores, I'd probably try and maximize the value that I can get out of both of them. Sell my Zhuni (朱泥) for as much as possible, sell my Hongni (红泥) for as much as possible instead of blending and potentially seeing my Zhuni (朱泥) price dip a little bit because it's blended with Hongni (红泥) or vice versa. So that, that's probably one reason why.

I think from a performance standpoint, we do have a lot of good antique pots that show that blended Zhuni (朱泥) with some Hongni (红泥) performs well. So I wouldn't be surprised if you still have some contemporary artists who are playing around with that blend.

[00:08:03] Zongjun Li: I've never personally used a ware that has a blend with Hongni (红泥) and Zhuni (朱泥). So I can't really make a judgment on the performance. That would be an interesting experiment to try. Maybe for our next commission, we can try to replicate a traditional recipe of a clay blend and test the effect.

[00:08:21] Jason Cohen: Oh, that would be fun. We go 30/70, and then we go 50/50, and then 70/30. That could be very, very interesting and look at the three different time points of the approximate historical ratios.

[00:08:33] Zongjun Li: Yeah.

[00:08:34] Pat Penny: Zongjun, how much money you trying to spend this year on Yixings, man, just keep coming up with these ideas.

[00:08:40] Emily Huang: That sounds like a lot of money because following up to Jason's question about why they would start the blend in the first place and why we don't have a lot of blends nowadays. One big part of it, I think, would be the ore is rare. It's very hard to find Zhuni (朱泥). So I think one of the reasons they started blending was also because if you make a part with one hundred percent that ore, it would be very pricey. And blending it just let you pace yourself throughout your supply. And then now again, same reason, it’s more difficult, rare to mine, all that.

And the technique itself of blending is very difficult. So, it requires a lot of art and experience to master.

[00:09:21] Jason Cohen: Rarity was certainly a factor during the F1 period. They had begun to ration the clay because of different shortages, and it actually spurred some innovation in creating substitute clays.

[00:09:32] Emily Huang: Correct me if I'm wrong, that the discovery of Hongni (红泥) was also because they had a shortage. They started to realize that they are experiencing a shortage in Sydney.

[00:09:42] Jason Cohen: I wouldn't say that discovery was driven by that. The separation between Zhuni (朱泥) and Hongni (红泥) happened later, and so there wasn't really an idea of that, but the mining regions continuously expanded throughout the Ming until the mining was banned at the end of the F1 period in 1992 or so.

[00:09:58] Emily Huang: I see.

[00:09:59] Pat Penny: My mind goes down a slightly different route. We're talking about the blends of Zhuni (朱泥) and Hongni (红泥) and Jason, you go on to write in this chapter why they're, from a geological standpoint, categorically separate ores, I'm really interested since these are coming from different mines or different strata within different mines. How do you think people decided to start blending them when they're coming from pretty different sources to begin with? This wasn't a paragenesis or something, right, where they just saw it together and decided to use it together.

[00:10:28] Jason Cohen: That's totally correct. They came from different mines. My most likely explanation, which I do believe to be correct, is that they ran firing tests. So they looked at the colors that they fired, and the Zhuni (朱泥) would frequently break.

And so, by blending two red firing ores they were able to get a more consistent reduced breakage rate and actually produced wares that were usable. I think it was a very utilitarian explanation that they needed to come up with blends that didn't crack in the Dragon Kiln or crack in first use.

[00:10:57] Zongjun Li: Yeah, so not only just blends with Hongni (红泥) and Zhuni (朱泥), later on, you will see blends with all the other red color materials too, like Shihong (石红) and some gradient Shihuang (石黄). And even blending those with Zini (紫泥) to sometimes increase the saturation of the color.

[00:11:12] Jason Cohen: And another point that goes back to the high breakage rate is we know, even in antique wares, they would take previously fired Zhuni (朱泥) and re mill it. And use the cooked clay (Pat interjects: the grains) in order to stabilize the wares for next firing.

[00:11:27] Zongjun Li: Yeah, they called grog?

[00:11:29] Jason Cohen: Grog.

[00:11:30] Zongjun Li: Yeah.

[00:11:30] Jason Cohen: And the Chinese word cooked clay. Shou cha?

[00:11:32] Zongjun Li: Shou Sha (熟砂). Cooked grain.

[00:11:34] Jason Cohen: As we've been discussing, I wanna talk a little bit about the confusion in naming. So Hongni (红泥) at various times referred to all red color Zisha (紫砂) clay, referred to a blend of Zhuni (朱泥) and Hongni (红泥), or Hongni (红泥) and Zini (紫泥), and its subcategories also bear confusing names: Hong Qingshuini (红清水泥), Nian Gao Tu (年糕土).

Is there a reason why Hongni (红泥) in particular has such a confusing naming scheme?

[00:11:55] Emily Huang: So confusing. Even for a native Chinese speaker, it was hard to follow at first the different types of Hongni (红泥), where they were categorized, that they used to mistakenly be one, and then they were actually different ores. I think it has a lot to do with the color that after they fired and probably the content of iron inside. So before actually having more knowledge of the different gradients and the different chemical compositions in these ores it would probably just be commonly called Hongni (红泥) because of the relatively more red color that it is, but then after more knowledge, understanding of the geography, the chemical compositions, et cetera then people get to know a little bit more.

[00:12:45] Zongjun Li: Yeah, I would agree on the point that the iron oxidate being such a ubiquitous content in a lot of clay type that a lot of these clay ores, whether or not it's Duanni (段泥), Zini (紫泥), Hongni (红泥) or Zhuni (朱泥), after they get fired in some temperature range, they all appear red.

It's like when we are drinking tea, we talk about oolong (乌龙) cha, but oolong (乌龙) is such a wide oxidation range from ten percent all the way to ninety percent that a lot of these tea can be called oolong (乌龙), but there's a very distinct differentiation between like Taiwanese gaoshan oolong (高山乌龙) versus a yancha (岩茶) from Wuyi.

[00:13:21] Pat Penny: In the beginning of this book and in our previous book, we talk about how different centers of knowledge may come up with different terminology for these items. And so it's likely that the miners had their own name for these ores. The craftsmen bought it, purchased it and kind of had their own terminology for certain ores.

And then probably the collectors, users, right? The intelligentsia literati also probably then categorized further and further and further. And I think because the red color as Zongjun and Emily definitely hit upon just appears so much, there probably was so many names that involve red that it kind of makes sense that there would become an umbrella category using that name, even if it wasn't correct to a specific ore classification.

[00:14:02] Zongjun Li: Totally agree. There's definitely a knowledge discrepancy between the miner and the ceramic artists and also the collectors because there's also a color changing process between the ore and after the ore gets fired or gets processed. So frequently people will call something Hongni (红泥) because it appears red as an ore, but after it gets fired, voila, it turns into a darker color or even sometimes a paler color.

So depending on who you ask really, you frequently end up getting different names for same type of ore or clay.

[00:14:38] Jason Cohen: So Hongni (红泥) is more confusing. It is particularly confusing, I should say, because the name refers to the color after it's fired, whereas most of the other ores refer to the name before it's fired.

[00:14:45] Emily Huang: Just in case some of our listeners don't know, Hong is red in Chinese and Zhu is also another color of red in Chinese. So when we say Hongni (红泥) and Zhuni (朱泥) that is why it's even more confusing. Not to mention there is Xiaohongni (小红泥) and Da Hong Pao (大红袍), which if you just read it, it could be super confusing.

[00:15:03] Jason Cohen: Speaking of, most Hongni (红泥) wares are simply labeled as Hongni (红泥) when you go to a merchant to purchase a teapot or they're given very aggrandizing names such as the Da Hongni (大红泥), Da Hong Pao (大红袍). Why are the subcategories and variations of Hongni (红泥) so much less known than Zini (紫泥)? Why don't we see more distinction within these sub variations, particularly at the merchant level when going to purchase Hongni (红泥) wares?

[00:15:27] Pat Penny: Is it possible the merchants don't know from what ore that their pots were fired from?

[00:15:33] Emily Huang: Maybe they know and they just say it's part of Zini (紫泥) because Zini (紫泥) has already a good consumer base – shopper base and a good awareness level to it.

[00:15:42] Jason Cohen: Do you mean Zhuni (朱泥)? I think it'd be a little difficult to pass off Hongni (红泥) wares as a Zini (紫泥). Zhuni (朱泥) is plausible.

[00:15:49] Emily Huang: Mmmm, mmm (agrees). And maybe also the same rationale behind the blends.

[00:15:53] Jason Cohen: Zongjun, you don't agree? You think that the merchants do label that you could go and buy a specific Hongni (红泥) ware? Or do you think that there's not enough percolation and consumer knowledge to bother making the differentiations beyond aggrandizing names?

[00:16:07] Zongjun Li: I think it's a mixture of the latter and also just generally less consumer recognition on Hongni (红泥).

And I would really raise my eyebrow when I walk into a shop and see a Hongni (红泥) teapot marked as Da Hong Pao (大红袍) on the shelf, with a very high price tag. It's usually quite suspicious. Being a super rare clay to begin with, it's like, calling your best teapot in your tea shop traditional ancient Tian Qing Ni (天青泥).

I think that consumers are not willing probably to pay a much higher price for Hongni (红泥) to begin with. And with all of these notions, it's harder to educate the market to pay a higher price.

[00:16:47] Jason Cohen: This chapter mentions the color changing effect, where a Yixing teapot changes color when heated with boiling water. Have you personally experienced a color changing teapot? And should such a color changing effect be considered desirable?

[00:17:01] Zongjun Li: Zhu se bian se (朱色变色).

[00:17:02] Pat Penny: I've seen videos of the color changing effect. I have not experienced using a pot myself that had that.

[00:17:09] Emily Huang: Yeah, me neither.

[00:17:10] Zongjun Li: I have seen wares that change color after usage, but on the scene…I don't think I've seen that before. Have you Jason?

[00:17:18] Jason Cohen: I think I accidentally purchased a ware that exhibit a very minor amount of color changing effect. It's a ROC Tiaosha (调砂) Zini (紫泥) but when pouring boiling water over it, it brightens and turns a brighter shade of red, which I was quite surprised because it was not mentioned in the negotiation on that teapot.

[00:17:36] Pat Penny: Maybe they never tried brewing tea with it.

[00:17:38] Jason Cohen: Yeah, it's possible.

[00:17:40] Zongjun Li: Is it a bug or a feature? Maybe I should not tell.

[00:17:43] Jason Cohen: It's a good question. Is it a bug or a feature? In a contemporary pot, I would be very concerned. In a contemporary teapot, I would think that this has been doped or dosed with some artificial colorant that changes color.

And we've seen that in Yixing, we've seen those little statues or cha chongs that change color very vibrantly. So it wasn't mentioned. The teapot dates to its claim. It is ROC. But it's the only one I've ever used and I have no idea whether or not it represents any type of improvement in the utility of the teapot or its interaction with tea.

[00:18:16] Pat Penny: Good party trick, though.

[00:18:17] Zongjun Li: Yeah, it's certainly a fancy and beautiful. That's why it got recorded in Yang Xian Sha Hu Tu Kao (阳羡砂壶图考).

[00:18:24] Jason Cohen: Okay, so let's mark that as one of the many experiments. We all need to buy an antique color change teapot and see if it performs well.

[00:18:31] Pat Penny: As long as you'll find them for us, we'll, we'll buy them.

[00:18:33] Jason Cohen: As long as I don't have to pay for all of them. 

[00:18:37] Jason Cohen: My last question. Hongni (红泥) forms a few interesting distinct subtypes, such as Hong Qingshuini (红清水泥), a blend of Hongni (红泥) and Qing Shui Ni (清水泥) Zini (紫泥), which was popular in Taiwan during the F1 period and Shihuangni (石黄泥), a natural mix of Hongni (红泥) integrated sandstone. What is special or unique about these materials?

[00:18:57] Pat Penny: At least what I understand from the chapter is that some of these were at least at some point, natural blends that were occurring near each other and most likely were just kind of mined together and process together. So you kind of got a unique and specific blend, but I think over time that changed.

So I think one of the original points, at least for some of those named blends, something that was unique was that they were kind of naturally occurring together. Nian Gao Tu (年糕土) is the only one that I've actually seen and actually had opportunities to purchase and was happy I did not. So I haven't seen Shihuangni (石黄泥) in real life.

I have seen Shihuang (石黄) when we went to Yixing. But the Nian Gao Tu (年糕土) I know at least from what I've seen is a really dense clay. And I think the versions that I saw were the post 1982 and Jason, I had sent you a link saying, “Hey, you know, what, how does this look?” And you're like, “don't buy, do not buy.”

[00:19:42] Jason Cohen: (laughs) That sounds, that sounds right.

[00:19:45] Zongjun Li: Although it's from a legendary place and era, it's one of the first experiment of adding artificial colorants and oxidates into the clay. The effect on the tea, I think it's debatable. But certainly not of a natural blend.

[00:20:00] Jason Cohen: I have also never seen Shihuangni (石黄泥). And I don't know if I would immediately recognize it if presented with something that's obviously Hongni (红泥) with the integrated, degraded, yellow stone layer sandstone. Without having seen it before, I don't really know how unique or different or differentiated it is from other Hongnis (红泥). That’s one that we should track down.

[00:20:22] Pat Penny: We'll get a couple of coasters made out of it before we get a few teapots.

[00:20:25] Jason Cohen: So we can play, feel, and understand the clay before determining if it's worthwhile to put into a teapot form.

[00:20:32] Jason Cohen: Well, thank you, everyone. That is all the time that we have for today. Thank you for joining us in this edition of Tea Technique Editorial Conversations. Please join us again for our next conversation, Zhuni (朱泥) Ore and Clay.


Jason M Cohen

Master of Ceremonies at Tea Technique. Founder & CEO of Simulacra Synthetic Data Studio. Previously: Founder of Analytical Flavor Systems & Founder of the Tea Institute at Penn State (defunct).