Sesame Duan is a distinctive type of clay within the Duan clay family. It's named Sesame Duan because, after firing, numerous white, red, and black particles naturally and densely cover its surface, resembling sesame seeds.

The black or reddish particles are very prominent. Commonly, Sesame Duan has black particles spread all over the Teapot, yet the layers of particles are relatively clear, like colored dots on a sheer fabric.

Image: ChaWoo Network

▲Sesame Duan Clay Teapot

The original Sesame Duan clay is primarily sourced from Huanglong Mountain. It's a coexisting ore of Duan clay and Purple clay. The ore displays a gray-green color with dark red blood-like spots (as shown in the following image), which result from iron oxidation. Its cross-section is coarse but not rough, and the texture is porous, disintegrating into granules when exposed to water.

▲Original Sesame Duan Ore

Sesame Duan has a high quartz content, a large amount of sand, and coarse particles, making it less adhesive and less plastic. It is prone to cracking during firing, leading to a low production rate. Precise temperature control is required during firing to prevent discoloration. Compared to ordinary Duan clay, the firing temperature for Sesame Duan is relatively higher, ranging from 1150°C to 1200°C, with the ideal temperature being between 1190°C and 1200°C. Higher temperatures can cause the black particles to separate and create defects.

At 1150°C, the appearance is reddish-yellow, and the sound is slightly muffled;

At 1170°C, the appearance is yellow-brown with barely visible sesame-like speckles, and the sound remains slightly muffled;

At 1190°C, the appearance turns yellow with a reddish hue, and the sesame-like speckles become more apparent, which is the result of iron undergoing high-temperature firing (as shown in the following image).

At 1210°C, the temperature is too high, resulting in a dull color and an increased likelihood of defects.

Characteristics of Sesame Duan:

Due to the larger particles in original Sesame Duan, it has a strong sandy feel and a high porosity, allowing for smooth airflow and good breathability. It also has a higher iron content than regular Duan clay, causing the particles to turn dark red after long-term brewing. This effect is particularly noticeable when using Pu'er or black Tea for brewing.

The storage of original Sesame Duan is very scarce, as it is the result of Duan clay and Purple clay coexisting under specific environmental conditions, leading to a limited natural yield.

▲Artificially Blended Sesame Duan Teapot Lid

Most Sesame Duan available on the market today is artificially blended. By mixing Duan clay and Purple clay in a certain ratio, an artificial Sesame Duan is created. The artificial blend appears dull in color, has coarser particles, and a stronger sense of impurity. After brewing, it tends to “discolor,” giving off a dull and unsatisfying look, lacking the luster and feel of the original material. Its texture, water color, and the effects of brewing cannot compare to the original material.