Awase Dashi (Japanese Soup Stock with Kombu & Bonito Flakes)

Awase dashi made easy–learn 3 foolproof methods and the why behind each step. Get richer, more flavorful Japanese soup stock every time.

I used to rely only on dashi packs (Kayanoya is/was my favorite!) because I thought making dashi from scratch was too much work. But once I tried it, I realized it’s super easy, especially if you start soaking the ingredients in the morning. You’ll have homemade dashi by dinner in just a few steps!

Awase dashi is my go-to for all kinds of Japanese dishes like miso soup with tofu, oden, and simmered dishes. I hope this recipe, and the little cooking science sprinkled in, helps you feel confident making it at home. 🙂

💡Curious about dashi? Check out my complete Dashi Guide to learn all about it!

Why You'll Love This Recipe

• Stress-free and sustainable: I’ll walk you through three different ways to make awase dashi, so you can choose the method that fits your lifestyle best, whether you’re in a rush or have time to slow down.
• Science-backed but doable: I dug into the best ways to bring out maximum umami (hello, cooking science nerds! 🙋‍♀️), then simplified the technique so you can do it easily at home with no fancy tools needed.
• Super flexible: I’ll show you how to adjust the ratio of ingredients to water so you can make dashi that’s just right for how you plan to use it, whether it's for miso soup, mentsuyu, or anything in between.
• Adjusted for readers outside Japan: I made a few tweaks to help this recipe work well even if you don’t have the “ideal” dashi-making setup, like super high-quality kombu, fancy bonito flakes, or soft water. So even if you’re outside Japan, you can still make delicious dashi at home 🙂

What are Awase, Ichiban, and Niban Dashi?

Awase dashi is a classic Japanese soup stock made by combining two ingredients: kombu (dried kelp) and katsuobushi (bonito flakes). It has a balanced flavor with deep umami and works well in all kinds of dishes.

There are two types of dashi: ichiban dashi and niban dashi.

• Ichiban dashi is the first brew, made with fresh ingredients. It has a clean, delicate flavor and is perfect for dishes that highlight the taste of dashi, like suimono (clear soup) or chawanmushi (savory egg custard).
• Niban dashi is the second brew, made by reusing the same kombu and katsuobushi from ichiban dashi. It’s not as refined, but still has good umami and is great for everyday dishes like miso soup or nimono (simmered dishes).

In home cooking, most people just make ichiban dashi and use it for everything. Some also mix ichiban and niban dashi to stretch the batch and reduce waste.

Notes on Ingredients

See the recipe card for the full ingredients list.

Kombu (Dried Kelp)

There are four main types of kombu used for dashi in Japan: Rishiri, Ma, Rausu, and Hidaka.

For awase dashi, since it’s combined with bonito flakes, you want kombu that has presence but isn’t overpowering. Ma kombu or Rishiri kombu are ideal, but they're hard to find and usually expensive outside Japan.

If you're in the States, look for kombu that:

1. Comes in large sheets (not pre-cut strips)
2. Feels thick and firm

I tested with WEL-PAC Dashi Kombu, and it worked well.

👉 Quick tip: The white powder on the surface isn’t mold, it’s natural glutamate (aka umami)! So don’t rinse your kombu. You’d be washing the flavor away.

👉 Why not just use MSG?
Kombu has natural umami, plus minerals and other nutrients. MSG mimics umami but doesn’t offer the same health benefits.

Katsuobushi (Dried Bonito Flakes)

There are different types depending on flake thickness:

• Usu-kezuri (薄削り) – thin shaved
• Chiai-nuki (血合抜き) – bloodline removed
• Atsu-kezuri (厚削り) – thick shaved

The most versatile and easy-to-find type is usu-kezuri (thin shaved). It releases umami quickly and preserves the aroma well.

Try to avoid the super fine “topping” flakes, they’re too powdery. I recommend something like Kaneso Hanakatsuo or other standard bonito flakes.

Water

Water quality affects dashi more than you might think. Soft water is better because it draws out more umami.

Hard water (which has more calcium and magnesium) makes it harder to extract flavor and can cause cloudiness or bitterness.

Since most tap water in the U.S. is hard, I recommend using a water filter like Brita to soften it. It’s cheaper and more eco-friendly than buying bottled soft water every time.

💡You can find these ingredients at Japanese or Asian grocery stores, or online at Amazon or Weee!

Substitutions and Variations

• Kombu: If you can’t find kombu or need to avoid it, try other types of dashi that don’t use it, like katsuo dashi, iriko dashi, or shiitake dashi. Or, if you want to experiment, you can swap kombu for other umami-rich ingredients that are high in glutamic acid or guanylic acid, like dried shiitake mushrooms, vegetables, or even MSG powder, if you’re open to it.
• Katsuobushi (Bonito Flakes): You can replace katsuobushi with other fish-based umami sources like dried anchovies (iriko or niboshi). To use niboshi, soak about 10g of dried anchovies with kombu, heat gently, remove the kombu as instructed in the recipe, and simmer the anchovies for about 5 minutes.
• Shortcut Options: If you forgot to soak the ingredients or need dashi fast, dashi powder is a handy backup. To mimic awase dashi, mix kombu dashi powder and katsuo dashi powder in a 1:2 ratio, or use a dashi pack like Kayanoya Dashi.

💡Think About What You’re Cooking: The key to a flavorful dish is combining an amino acid (like glutamate) with a nucleic acid (like guanylate or inosinic acid). So if you’re swapping ingredients, try to add back the missing umami component somewhere else in the dish.

For example:

• If you can’t use kombu, make bonito dashi (rich in inosinate) and cook with tomatoes or onions (which are high in glutamate).
• If you can’t use bonito flakes, make kombu dashi (rich in glutamate) and use dried shiitake or dried tomatoes (which contain nucleic acids).

👉 If you're curious, here's a list of umami-rich ingredients by their umami compound.

Why Mix Both Kombu and Katsuobushi?

There are three main types of umami compounds:

• Glutamic acid (an amino acid)
• Inosinic acid and guanylic acid (nucleic acids)

Research shows that when you combine an amino acid and a nucleic acid, the umami taste becomes much stronger. This effect is called umami synergy.

Kombu is rich in glutamic acid, and bonito flakes (katsuobushi) are high in inosinic acid. That’s why awase dashi, which uses both, tastes richer and more savory than dashi made from just one ingredient.

Studies also suggest that the umami is strongest when glutamate and inosinic acid are present in a 1:1 ratio. This combination can make the umami taste 7 to 8 times stronger than either one on its own.

To get close to this balance:

• Kombu contains about 1,200–3,400 mg of glutamate per 100g
• Bonito flakes contain about 470–800 mg of inosinic acid per 100g

So, using 10g of kombu and 20g of bonito flakes is a great starting point. It gets you close to that ideal 1:1 ratio for maximum umami.

How to Adjust Dashi Based on How You'll Use It

You can adjust the amount of kombu and bonito flakes depending on how you plan to use the dashi.

Total Ingredient-to-Water Ratio (by weight)

For example, if you're using 1 liter of water, a 3% ratio means using a total of 30 grams of kombu and bonito flakes combined.

Kombu to Katsuobushi Ratio

By adjusting both the total concentration and the ratio of ingredients, you can make delicious dashi that fits your dish and works well even outside of Japan.

How to Make Awase Dashi

You can make awase dashi in three different ways depending on your schedule and how hands-on you want to be.

Option 1: Cold Brew (Overnight Method)

Best when you want to prep ahead without cooking.

1. Add kombu and bonito flakes to a container with water.
2. Let it sit in the fridge for 8 to 12 hours.
3. Strain out the kombu and flakes.

Option 2: Cold Brew Kombu + Hot Steep

A middle-ground method that boosts flavor with a little heat.

1. Add kombu and water to a container and cold brew in the fridge for 8 to 12 hours.
2. Remove the kombu and pour the liquid into a pot.
3. Turn on the heat to medium. Once you see small bubbles rising, turn off the heat.
4. Add bonito flakes and let steep for 1 minute.
5. Strain through a paper towel or fine strainer. Don’t squeeze the flakes.

Option 3: Quick Steep (Stovetop Method)

The fastest method, perfect when you need dashi right away.

Step 1: Lightly wipe the surface of the kombu.

Step 2: Add kombu and water to a pot. Let it soak for 30 minutes to 90 minutes.

Step 3: Heat over medium-low until small bubbles appear around the edges of kombu (don’t boil).

Step 4: Remove the kombu and increase the heat slightly. Once you see small bubbles rising, turn off the heat.

Step 5: Add bonito flakes and let steep for 1 minute.

Step 6: Strain through a paper towel over a fine strainer. Don’t squeeze the flakes.

Reusing Dashi Ingredients

Don’t throw away your used kombu or bonito flakes, even if you’ve already made niban dashi! You can still turn them into tasty, no-waste side dishes and seasonings. Here are a few easy ideas:

• Furikake: Chop the ingredients into small pieces, dry-sauté in a pan, and season with soy sauce and mirin. Sprinkle over rice or veggies for an umami boost.
• Tsukudani: Slice into thin strips and simmer with soy sauce, mirin, and sake until soft and flavorful. It stores well and goes perfectly with rice.
• Onigiri Filling: Use tsukudani as a savory filling or mix-in for rice balls.
• Dashi Ponzu: Soak chopped kombu or bonito flakes in ponzu sauce. The added umami is great with grilled dishes like salmon.
• Dashi Soy Sauce (Dashi Shoyu): Soak the used ingredients in soy sauce to create a versatile, umami-rich seasoning for stir-fries, tofu, or fried rice.

How to Use Awase Dashi

Awase dashi has the best of both worlds: deep, long-lasting umami from kombu and bold, aromatic flavor from bonito flakes. That perfect balance makes it super versatile for all kinds of dishes, not just Japanese ones.

Some of the most popular ways to use it include:

• Miso soup: A comforting classic. 
• Oden: A cozy simmered dish perfect for cold days.
• Dashimaki tamago: Japanese rolled omelet that’s fluffy, savory, and perfect for bento. 

You can also use awase dashi as a base for:

• Simmered dishes (nimono)
• Chawanmushi (savory egg custard)
• Udon and soba soups
• Japanese curry (yes, it adds extra depth!)

Once you have awase dashi in your fridge, you'll find it’s easy to whip up delicious meals any day of the week.

Storage Instructions

• Dashi: Store in an airtight container for up to 3 days in the fridge or 2 weeks in the freezer (ice cubes work great for small portions).
• Used dashi ingredients (kombu and bonito flakes): Pat dry and store in an airtight container for up to 1 week in the fridge or 1 month in the freezer.

FAQs

Explore Other Types of Dashi

Awase dashi is just one of several delicious types of dashi, and each one has its own unique flavor and use.

If you’re wondering what makes each type different or how to choose the right one for your cooking, check out my Ultimate Guide to Dashi. It covers everything from the basics to ingredient tips, and it’ll help you find the best dashi for your kitchen.

Ready to try more? Here are other dashi recipes you might like:

• 🌱 Vegan Dashi
• 🍄 Shiitake Dashi
• 🌿 Kombu Dashi
• 🐟 Bonito Dashi (Katsuo Dashi)
• 🐟 Iriko Dashi (Dried Anchovy)
• 🥣 Awase Dashi (You’re here!)