Himatsu doban (water droplet entrainment during steaming)

Himatsu doban (飛沫同伴, "droplet entrainment") is a phenomenon that occurs during the steaming process in sake production. It refers to water droplets produced by the boiling water in the steaming kettle being carried along with the steam and scattered into the koshiki (the steaming vessel), where they mix with the raw materials. It occurs especially easily when too much water is filled into the wagama (traditional kettle), and so requires careful handling. When it occurs, excess moisture can adhere to raw materials such as rice and barley, which can upset the balance of the brewing. For this reason, managing the proper amount of water and the steaming process is important in sake brewing.