Dashi

Name: Dashi
Prep time: 10 min
Cook time: 35 min
Total time: 45 min
Cuisine: Japan
Ingredients: 1 l (4¼ cups) cold water, soft or filtered if your tap water is hard; 10 g (a 10 × 10 cm piece) kombu (dried kelp), do not wash off the white powder; 20 g (about 2 loosely packed cups) katsuobushi (bonito flakes)

Japan's ten-minute stock of kelp and smoked bonito

Makes: about 900 ml (3¾ cups)
Hands-on: 10 min
Total: 45 min
Level: Easy

Dashi is the base of miso soup, noodle broths and many Japanese sauces. It takes two ingredients and about ten minutes of actual cooking, and once you have it in the fridge, much of Japanese home cooking opens up.

Ingredients

1 lcold water (4¼ cups)soft or filtered if your tap water is hard
10 gkombu (dried kelp) (a 10 × 10 cm piece)do not wash off the white powder
20 gkatsuobushi (bonito flakes) (about 2 loosely packed cups)

Diet: Pescatarian, Gluten-free, Dairy-free
Allergens: fish
Origin: Japan

Method

Wipe the kombu lightly with a damp cloth to remove grit. Put it in a pan with the cold water and leave to soak for 30 minutes (or up to overnight in the fridge). 30 min
Heat over medium-low until small bubbles form on the bottom of the pan and the water reaches about 60–70°C (140–160°F), 8–10 minutes.
Remove the kombu just before the water boils. If you leave it in at a boil, the dashi turns slimy and bitter.
Bring the water to a boil, then turn off the heat and scatter in the bonito flakes.
Leave for 2–3 minutes, until the flakes sink. 3 min
Strain through a sieve lined with a paper towel or muslin. Let it drip; do not squeeze, or the dashi becomes cloudy and fishy.

Why it works

Kombu is rich in glutamate and bonito in inosinate; together they create a savory intensity much greater than either alone, a synergy that multiplies umami, the savory taste. Kombu gives up its glutamate readily in hot water below the boil, while boiling pulls out kombu's slippery alginates and a marine bitterness, so you take it out first. Bonito needs only a brief steep in very hot water; longer extraction draws out sour, fishy notes.

Common mistakes

Boiling the kombu: the dashi turns slimy and harsh.
Squeezing the bonito flakes: cloudy, fishy stock.

Variations

Vegan kombu-shiitake dashi: Soak 10 g kombu and 4 dried shiitake in 1 l cold water in the fridge overnight, then strain. No heating needed.
Second dashi (niban): Simmer the used kombu and flakes in 500 ml water for 10 minutes and strain; use for simmered vegetables and stews.

Make ahead and storage

Keeps 3 days in the fridge; freezes for 1 month, though the aroma fades.

Notes

Instant dashi granules are a fair shortcut: 1 tsp per 500 ml water. Most contain MSG and some contain lactose or wheat, so check the label.