Boiling or steaming rice wrapped in bamboo leaves, sheaths or tree leaves is common throughout eastern Asia. In Kagoshima Prefecture, akumaki is a traditional local confectionery served during the Boys’ Festival in May. Akumaki is made by wrapping glutinous rice in a bamboo sheath, then simmering it for several hours in lye, the clear upper portion of water in which plant ash has been dissolved. When cooked, akumaki turns a golden brown color with a soft, sticky texture, and is usually cut with a string, rather than a knife.
The glutinous rice of cooked akumaki has no flavor itself, and so is typically enjoyed with a sprinkling of sugar blended with kinako (roasted soybean flour) or drizzled with brown sugar syrup. Despite its high water content, akumaki can be kept for many days, thanks to the alkalinity of the lye and bamboo’s antibacterial properties.