The Yixing clay gaiwan in traditional Chinese style is made of the famous Chinese purple clay, called Zi Sha Hu in China. This type of clay is the most famous in China, and its accessories have been used in the tea ceremony for a very long time. They are so named because of a small town located in Jiangsu Province, where a specific iron ore compound causes the unique coloring of these accessories. They were fired without glaze and used to prepare specific types of tea. Because of the porous nature of clay, the Gaiwan would have to be gradually tempered by using it to steep a type of tea. This seasoning was part of the reason for using Yixing accessories.
Gaiwan and other Yixing accessories
Gaiwan Yixing are intended to be used with black (red) and Oolong teas, as well as aged Puer tea. They can also be used for green or white tea, but the water must be allowed to cool to about 85°C before pouring it into the vessel. Yixing Gaiwans absorb a small amount of tea into them during brewing. After prolonged use, the Gaiwan will develop a layer that retains the flavor and color of the tea. For this reason, soap should not be used to clean the Gaiwan Yixing.
Instead, they should be rinsed with fresh water and left to air dry. A knowledgeable tea connoisseur uses only one type of tea in a particular teapot so as not to corrupt the absorbed flavor.