Iromodori (color reversion after carbon filtration)

Iromodori (色戻り) refers to the phenomenon in which sake that has undergone activated carbon filtration darkens in color again at a later stage. It is caused by iron contained in the activated carbon or filtration aids used during filtering, or in the material of the storage container, dissolving into the sake. As a result, the sake can become darker in color than it was before filtration. Iromodori can affect not only appearance but also flavor, so it requires attention during the brewing process.