In the atelier where sumi ink sticks are made, there's a soot-covered rice cooker. It's a somewhat peculiar sight, but this is an indispensable tool for making sumi ink.
Sumi ink is made from soot, Nikawa glue, and fragrances. After mixing soot and Nikawa, a black lump called "raw sumi ink" is produced. To keep this raw sumi ink warm, a rice cooker comes into play.
After mixing the soot and Nikawa, sumi ink undergoes important processes: kneading, molding, and drying. Kneading isn't just about mixing; it's also about removing air bubbles. Since Nikawa, essentially gelatin, solidifies when cooled, any unused raw ink is stored in the rice cooker.
