Does Material of Teapot Affect the Taste?

Yakishime pot can brew better tasting tea

Yakishime is a type of ceramic. It is baked in a high temperature without any glaze. Tokoname and Banko wares are best example of this product. I have written “Tokoname teapot can brew more delicious tea than teapots made of other materials” in a past entry. Lately, I found an interesting site that explains about the theory. It’s the site of FOOD ANALYSIS TECHNOLOGY CENTER (http://www.mac.or.jp/mail/100401/02.shtml) and they mention three causes. I’ll introduce the summary in the next paragraph.

Temprature, Iron and Texture

When comparing the four materials; yakishime, porcelain, glass and aluminum, yakishime has the most modest thermal conductivity. When brewing, it keeps the water warm to encourage extracting substances more.  
The clay often used on Tokoname or Banko ware is rich in iron. The iron adsorbs the bitter substance, catechin. It is considered that polyphenols like catechin has a functional group and they are easy to compound with the teapot’s surface with iron.
In the physical aspect, unglazed clay has some texture comparing with the smooth surface of glass and aluminum. The clay has a greater physical absorption of the bitter taste.

Still Wondering

So, the article says that yakishime pots encourages extracting more substances and adsorb bitter taste. That is the reason that it can brew good tasting tea. However, I find some contradictions between this theory and the data from my previous post. I still don’t understand all functions completely. I just wanted to introduce one of opinions regarding teapots’ material that I found. Anyway, both the theory and the data saying that yakishime teapots has advantage. Actually many people experienced it in the survey. This time, I’ll test it myself how effective it is.

The conditions:
Fine Sencha: 2g
Water: 27ml 70C
Time: 1min
Vessel: Left; Yakishime, Right; Porcelain

Potential of Yakishime and Porcelain

I was absolutely appalled by the result. The difference was obvious. The tea brewed in yakishime had a rounded fullfilling flavor with rich umami. The tea with porcelain was washy. I could not find the rich umami that I found in yakishime. The bitter taste exceeded the umami. The result might differ depending on the conditions, but I found that the difference in this test is almost like I was trying the teas from two different grades.　I knew it as a knowledge that yakishime can brew better tasting tea. Also, I’ve been actually using both yakishime and porcelain pots at home so I’ve been vaguely conscious of it. However, I’ve never compered them in the same condition at the same time. I was not aware it has such difference. I can definitely recommend yakishime pots for people who enjoy premium green tea. A yakishime pot can make your tea one rank better.