Granular carbon (Ryujotan)

Granular activated carbon (ryujotan) is a carbon material that plays an important role in the sake-making process. It is used mainly to purify brewing water and water used for diluting sake, to decolorize sake, to adjust flavor and aroma, to prevent discoloration, and to prevent hiochi (spoilage caused by hiochi bacteria). This carbon falls under the broad category of carbon materials of all kinds, and plant-derived carbon is the most common type used in sake production. Granular carbon is distinguished from powdered carbon by its form. Compared with powder, it is easier to handle and more reusable, which allows the intended purpose to be achieved efficiently. Granular carbon also comes in types such as steam-activated carbon and zinc chloride-activated carbon, each used according to its particular characteristics. This makes it possible to produce higher-quality sake.