Freshness of Niboshi

Niboshi which are not fresh or those which have been grilled can give rise to bad smells and tastes when incorporated into dashi, so it is best to store them in the refrigerator and use them up as quickly as possible. While using the freshest possible niboshi is always best, there are alternatives for not-so-fresh niboshi. If the niboshi oxidise and turn yellow, the taste becomes bitter, so it is best to roast them in a pan until golden brown.