Ichiban Dashi (First Brew Dashi Stock)

Ingredients

• 1 liter cold filtered water
• 15g dried kombu (kelp), approximately one 10cm x 15cm piece
• 20g katsuobushi (dried bonito flakes)

Instructions

1. Wipe the kombu piece gently with a dry cloth to remove any surface dust, but do not rinse it — the white powder on its surface is glutamic acid, a key source of umami flavor.
2. Place the kombu in a medium saucepan with 1 liter of cold filtered water. Let it soak for at least 10 minutes at room temperature to begin releasing its flavor.
3. Place the saucepan over medium-low heat and slowly bring the water to just below a simmer, approximately 60–70°C (140–158°F). This should take about 10 minutes. Watch carefully — do not let it fully boil with the kombu still in it.
4. Just before the water reaches a full boil, you will see small bubbles beginning to form around the kombu and it will start to rise. Remove the kombu from the pot and discard it or reserve it for niban dashi.
5. Bring the kombu-infused water to a full boil over medium heat, then immediately add all 20g of katsuobushi flakes at once, gently pushing them down into the water with a spoon.
6. Turn off the heat immediately after adding the katsuobushi. Do not stir. Allow the flakes to steep undisturbed for exactly 3 minutes — they will slowly sink to the bottom as they absorb water.
7. Set a fine-mesh strainer lined with a piece of cheesecloth or a paper towel over a large bowl or container. Gently pour the dashi through the strainer, allowing it to drip through naturally. Do not press or squeeze the katsuobushi, as this will make the dashi bitter and cloudy.
8. Discard the spent katsuobushi. The finished ichiban dashi should be a clear, pale amber color with a clean, subtly smoky aroma. Use immediately or let cool and refrigerate in an airtight container for up to 3 days, or freeze for up to 1 month.