Tororo konbu is kelp that has been soaked in vinegar for a day before being shaved into fine flakes and dried. Adding soy sauce and boiling water to the flakes produces a tasty soup. It is commonly added to vinegared salads, known as sunomono, put in clear soup and is a popular flavouring in o-nigiri rice balls. With zero calories, it is an ideal seasoning for those trying to eat healthily. Tororo konbu can be stored for a long period of time without spoiling.