Many purple clay enthusiasts have a good understanding of the subject, but they may not know much about the firing process. Today, we will discuss two key issues related to firing purple clay Teapots.

Kiln Temperature

Enthusiasts who favor Duan clay teapots often ask about the issue of “black spitting.” In previous articles, we mentioned that this problem occurs when the Teapot is fired at an insufficient temperature, which is a kiln temperature issue.

Does this mean that the higher the firing temperature, the better? Actually, this is not the case.

Different types of purple clay have their own optimal firing temperatures, and once these are reached, the desired result is achieved. The same type of clay can produce different effects under different temperatures.

Zini (Red Clay) has a higher degree of crystallization compared to Zini (Purple Clay), and Duan clay has the lowest. This is one reason why Duan clay has good breathability.

If the temperature is too low, we call it underfired, resulting in a pale and unclean color tone, and Duan clay will absorb black pigments, causing “black spitting.” If the temperature is too high, we call it overfired, leading to a rough surface, small cracking, and even deformities or blistering.

A dense body reduces breathability and water absorption. Therefore, higher temperatures are not always better; rather, achieving the required temperature to meet the desired effect is what matters. However, during the first firing, the teapot is usually underfired, and only in the second firing does it reach the required temperature. This is what we commonly refer to as firing a Purple Clay Teapot twice, with a low-temperature firing followed by a high-temperature firing.

In practice, the first firing is done at a low temperature. Afterward, the teapot is removed and its mouth and lid are adjusted to ensure a flat and tight fit, a process known as “finishing the mouth.”

The second firing is done at a high temperature to achieve the crystallization temperature of the clay. At this point, the teapot is generally considered complete. Sometimes, after the second firing, if the color of the clay is not ideal, the teapot goes through a third firing.

The more times a teapot is fired, the higher the degree of crystallization, but there is also a higher risk of damage. Additionally, teapots after the first firing must not be exposed to water, otherwise, problems will occur during the second firing, potentially ruining the teapot. High-temperature firing and multiple firings are essentially firing techniques aimed at producing the best possible object.

Regardless of the temperature or number of firings, as long as the final product is as close to perfect as possible, then the technique is a good one, worthy of pursuit. Enthusiasts should understand this and avoid biases against high-temperature firing or multiple firings. They should have a correct understanding and perspective on these techniques.