How to Make Kombu Dashi (Japanese Kelp Stock)

Kombu dashi is one of the most fundamental soup stocks in Japanese cooking — and it happens to be naturally vegan. Made with just water and kombu (dried kelp), this clear broth is full of gentle umami and forms the base of many Japanese dishes like miso soup, noodle broths, simmered vegetables, and even sauces. Another plant-based favorite is shiitake dashi, made from dried mushrooms and known for its deep, earthy umami. Both are excellent bases for soups, hot pots, and everyday Japanese cooking.

It’s incredibly simple to make, yet it brings a beautiful depth of flavor to any dish. I love how just two ingredients can feel so calming and grounding — and it’s a staple in my kitchen when I want something light, clean, and nourishing.

🧾 Ingredients

• 1 piece dried kombu (about 10 cm / 4 inches long)
• 500 ml water

👩‍🍳 Instructions

1. Wipe the kombu (optional)
   Gently wipe the kombu with a dry or lightly damp cloth to remove excess white powder (don’t rinse it — the white powder is umami!).
2. Soak the kombu
   Place kombu in a bowl or pot with 500 ml cold water. Let it soak for at least 30 minutes, or up to 2–3 hours. For deeper flavor, soak overnight in the fridge.
3. Heat gently
   Place the soaked kombu and water on the stove over medium-low heat. Slowly bring it almost to a boil — but do not let it boil.
4. Remove kombu
   Once tiny bubbles appear (just before boiling), remove the kombu. Your kombu dashi is ready to use!

💡 Tips

• Don’t boil kombu — boiling can release bitterness.
• You can reuse the kombu once to make a second, lighter dashi (called niban dashi), or slice it for simmered dishes.
• Kombu dashi can be stored in the fridge for up to 3 days, or frozen in small portions.

Kombu Dashi (Japanese Kelp Stock)

Kombu dashi is a simple, plant-based Japanese stock made by soaking dried kelp in water. Full of clean umami flavor, it’s the perfect base for miso soup, noodle broth, or simmered dishes.

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Prep Time 5 minutes mins

Cook Time 3 hours hrs

Course soup base, stock

Cuisine Japanese

Ingredients

  

• 1 piece dried kombu (about 10 cm / 4 inches long)
• 500 ml water

Instructions

 

• Gently wipe the kombu with a dry or lightly damp cloth to remove excess white powder (don’t rinse it — the powder is full of umami!).
• Place the kombu in a pot or bowl with 500 ml of cold water. Let it soak for at least 30 minutes, or up to 2–3 hours. For a deeper flavor, soak overnight in the fridge.
• Transfer the kombu and water to a saucepan. Slowly heat over medium-low heat.
• Just before the water starts to boil (you’ll see small bubbles), remove the kombu. Do not boil it — this helps avoid bitterness.
• Use immediately as your soup base, or let it cool and store in the fridge for up to 3 days.

Notes

Notes:

• You can reuse the kombu once to make a second, lighter dashi (called niban dashi).
• Kombu dashi freezes well in small portions (ice cube trays or jars).
• Great as a base for miso soup, noodle soup, or simmered vegetables.

Keyword Japanese stock, kombu dashi