Dashi

How to tell it is going right

• It is clear enough to read the bottom of the pan through it. Cloudiness means it boiled, or the kombu stayed in past the first small bubbles, and neither can be strained out afterwards.
• Pale gold rather than brown, nearer the colour of weak tea. A brown dashi has been cooked too hard or too long and will taste of the pan rather than of the sea.
• The kombu came out before the water reached a simmer, and it is supple rather than slimy. A slippery surface on the sheet means alginates have started to leach, and the broth will feel viscous on the tongue.
• Strained without pressing. Squeezing the flakes or the kelp forces out bitterness and fine particles, and the difference is obvious in the finished bowl.
• Tasted alone it is savoury and faintly sweet with no fishiness and no bitter edge. Fishy means the katsuobushi steeped rather than settling; bitter means heat.

Where it goes wrong Heat, or time, or both. Kombu boiled gives up alginates and turns the broth slippery and faintly bitter; katsuobushi left to steep turns it sour and fishy. Almost every dashi failure is an excess of one of the two things the cook controls, and neither is recoverable once it has happened.