Yixing Clay: Hongni

 

Where does it come from and what is it? Hongni is one of the most enigmatic clays in Yixing. While we discussed the category of hongni or “red clay” briefly in our previous posts, hongni, one of the fundamental categories of Yixing clay, deserves its own article.

What is Hongni?

Put simply, hongni “red clay,” is any Yixing clay that turns red after firing in the kiln. This broad category of hongni is believed to make up roughly 8% of all zisha.

Within this broad category of hongni are what we will term “zisha hongni” (“sandy” red clay) and zhuni.

Zhuni vs Zisha Hongni

	Shrink rate	Clay Body Texture
Zhuni	17% - 25%	Denser, smaller pores, greater thermal conductivity.
Zisha Hongni	10% - 13% (similar to zini)	Sandier, larger pores, more breathable, better at retaining heat.

 

This article discusses zisha hongni. Check out our earlier article here to learn more about zhuni clay.

Huanglong Mountain Hongni Varieties

When we talk about hongni teapots, we are usually talking about zisha hongni (hereafter “hongni”). At present, all original ore (unmixed) hongni is mined from Huanglong Mountain. This group can be further subdivided into varieties, some of which are very rare and may even be no longer available.

1. Huanglongshan Hongni 黄龙山红泥
Huanglongshan Hongni, Xiao Hongni, Lao Hongni, or simply Hongni. When discussing original ore hongni today, chances are that this is the clay being discussed. This hongni is further divided according to natural weathering into:

A) Old Hongni, lao hongni 老红泥, which is found as outer layers of ore. Its long period of natural weathering gives this ore its name.
B) Young Hongni, xiao hongni 小红泥 is found in deeper layers unexposed to natural weathering. The hongni currently mined from Huanglong Mountain is Young Hongni.

Raw Ore: light yellow, with mica, sandy
Firing temperature: 1140-1170C
Firing shrink rate: around 12%
Fired Clay: red with yellow tone, turns darker red if fired at a higher temperature.

2. HuangLongShan Da Hongni 黄龙山大红泥
Also known as “Dahongpao,” this type of hongni is extremely rare, perhaps no longer available. Please see our earlier article on the different kinds of dahongpao for more information.
 
Raw Ore: red
Firing temperature: 1120-1150C
Firing shrink rate: around 12%
Fired clay: Dark Red

 

3. HongPiLong 红皮龙
Like all original ore hongni, HongPiLong is also mined from HuangLong Mountain. The clay is noted for its special texture after firing.

Raw ore: brownish red, sandy, rusty red, with green spots
Firing temperature: 1140-1200C
Firing shrink rate: around 13%
Fired clay: dark red, pear texture

4. Jiangpohongni 降坡红泥
A clay first discovered in the 1990s. Jiangponi is a natural combination of hongni, zini and duanni. The variety containing a greater percentage of hongni is called “Jiangpohongni” “red jiangponi,” is classified as a type of hongni and behaves similarly to other clays in this category. Please see our previous article on jiangponi to learn more.

Raw ore: Red, brown, grey, sandy.
Firing temperature: 1150-1200C
Firing shrink rate: around 12%
Fired clay: Red-brown color with flecks of pale yellow.

 

Mixed Hongni and Factory 1.

One myth we often see regarding hongni, is that hongni must be a mixed clay and that there are no original ore hongni teapots. This is not true, as the hongni unearthed from HuangLongShan is a quality material that has been and continues to be used without adding other clay to make teapots. This myth has its origins in the Factory 1 production period of the 1970s-80s.

Prior to hongni being mined from HuangLongShan, quality hongni was mined from ZhaoZhuang. ZhaoZhuang Hongni is very close in character and quality to the HuangLongShan Hongni used today. ZhaoZhuang Hongni 赵庄红泥 was widely used until the 1970s to make Yixing Teapots in the famous state-owned Factory 1.

During the 1970s, Zhaozhuang hongni had been mined to the point of exhaustion and alternative hongni began to be used. The replacement hongni used by Factory 1 since then,  ChuanBu Hongni 川埠红泥 and Fudong Hongni 洑东红泥, were far from the quality of ZhaoZhuang Hongni. These were sometimes mixed with other clays. From the 1980s onwards, the factory began to add iron oxide to enhance the color of Fudong Hongni. The practice of adding iron oxide continues to this day in the production of lower quality teapots. Baiyan Hongni 白砚红泥, ZiHongNi 紫红泥, and ShiHuang 石黄 and ShiHong 石红 – varieties not mined from either Zhaozhuang or HuangLongShan – are also sometimes added to other clays to make a lower firing temperature possible, and to enhance the color and richness of the mixed clay.

 Brewing Tea with Hongni

Hongni is closer in character to zini than to zhuni, however it is less porous than zini. Hongni teapots will mute some of the flavour of a tea, rounding off some notes, but in general, will have less of an impact on the flavour than zini teapots do. We find ourselves using our xiao hongni teapots for young sheng pu'er and lightly roasted and oxidized rolled oolong. As always, we recommend trying your hongni teapot with different teas to see which combination you prefer.

 

References

宜兴紫砂矿料 by 朱泽伟  等 Yixing Zisha Mineral Material by Zhu Zewei et al.

阳羡茗砂土 by 刘玉林 等 YangXian MingShaTu by Liu Yulin et al.