Put the kombu and ● water in a pot, and heat on medium for about 5 to 6 minutes (depending on the season), then let sit. This is to get the water to close to a temperature of 60°C.
Heat the pot, remove the kombu when it floats to the top, then boil.
Add the ◎ water, simmer, turn off heat, then add the bonito flakes, and let sit until they settle to the bottom of the pot.
Strain the dashi, transfer to a sterilized container, then store in the refrigerator. Use up as soon as possible.
Story Behind this Recipe
This is our family's method of making bonito and kombu dashi stock.
When preserving for a long time, freeze it in an ice cube tray. The bonito flakes may settle to the bottom, so strain them when transferring for stock. Depending on who you hear it from, some say that the best temperature for making kombu dashi is 60°C. So, I trusted and followed this advice for Step 1.