The Tsubame city (燕市） in Niigata Prefecture (新潟県） produces traditional hand-craft called Tsuiki-Doki. Tsuiki-doki means the “hammered” copper ware in English.
The tsuiki-doki includes not only tea equipment but also sake equipment, flower vase and many other accessories. The artist beats the plate and forms it into the desired shape of particular equipment. Normally, the copper plate is laminated with tin. At the moment, the brands that HOJO is introducing are using liner made of 99.99% tin. In fact, they were not using 99.99% tin in the old days. Once upon a time people concerned about the lead in tin and this has affected the Tsuiki-doki industry. Since then, most of manufacturers had stopped using ordinary tin and swtiched to 99.99% tin. The color of the surface of copper ware is created by the fire. Depending on the oxygen level during firing process, it creates different colors. The copper teapot comes with filter that enables efficient filtration of most type of tea leaves.
With this copper teapot, the internal tin liner which made of 99.99% of tin significantly improves the intensity of flavor and the depth of after taste. It gives a very clean taste with smooth and “silky” mouthfeel. After you have drunk the tea, it does not leave your mouth feeling dry or astringent; instead it gives a lingering after taste that is complex and evolving. Thsi materrial does not enhance the body. It keeps body moderate that makes the taste of tea gentle. This teapot is suitable for most types of tea, unless you are a person who may not like to enjoy strong after taste.
The tin liner may get dark spot in a long run. However the performance of tin does not really change or decrease even if the tin is oxidized. Most importantly, after using the tsuiki-doki teapot, we have to leave the lid off and let the teapot dried completely. When the teapot is used for a long time, some layer of scale might be formed on the surface of tin and this will protect the teapot from the rust. It is very important to stick to one type of water for both brewing and washing. I have experienced that the teapot that is used by my friend for a few months, when I used it with my own water, it never perform as how it is supposed to be!