Recipe Highlights

Dashi is the soup stock at the heart of Japanese cooking, and it’s what gives Japanese dishes their distinctive depth of flavor. I usually reach for my homemade Kombu Dashi (昆布だし) when making soups, simmered dishes, and hot pots.

When I’m meal prepping, I’ll start a batch of cold-brew kombu dashi the night before. On busy weeknights, a quick stovetop simmer makes dashi ready in minutes.

Here’s why I keep coming back to this recipe:

• The easiest dashi to make from scratch, with just two ingredients
• Naturally vegan—no animal products
• Make it two ways: a hands-off cold brew method or a quick stovetop simmer

To learn more about Japanese soup stocks, read my in-depth guide: What is Dashi and How to Make It. Looking for other plant-based dashi recipes? Try my Vegan Dashi and Shiitake Dashi recipes next.

Ingredients for Kombu Dashi

Find the printable recipe with measurements below.

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How to Make Kombu Dashi

1. Prep the kombu. Wipe the kombu with a tightly wrung-out damp cloth, leaving any white powder intact. Cut slits in the kombu to help release more flavor.
2. Method one: Cold-brew Kombu Dashi (Mizudashi). Add the kombu and water to a large jar or pitcher. Steep covered at room temperature for 2 to 3 hours in summer, 4 to 5 hours in winter, or overnight in the refrigerator. Remove the kombu before using.
3. Method two: Stovetop Kombu Dashi (Nidashi). Add the kombu and water to a pot and steep for at least 30 minutes. Heat over medium-low, skimming any scum with a fine-mesh skimmer, until barely simmering, about 10 minutes. Remove the kombu just before it simmers and turn off the heat.
4. Use or store. Use the dashi right away, or refrigerate it in an airtight container for later.

Variations

Here are a few easy ways to make this recipe your own.

• Add dried mushrooms. Add a few dried shiitake mushrooms to the bottle or pot for a fuller, earthier flavor. Known as Vegan Dashi or shojin dashi, this stock is a staple of shojin ryori, the traditional vegetarian cuisine of Japanese Buddhist temples.

• Stronger stock. Double the amount of kombu for noodle soups and hot pots, where a more prominent dashi flavor is required.

• Experiment with kombu.  Different varieties of kombu bring subtle differences in flavor and aroma to the broth. Use my kombu guide to learn about each type and find your favorite.

How to Use Kombu Dashi

Once your stock is ready, try these recipes:

• Vegan Miso Soup – A simple miso soup with silken tofu and wakame seaweed, ready in 20 minutes.
• Kenchinjiru – A warming vegetable soup with plenty of vegetables and tofu, rooted in Zen Buddhist temple cuisine.
• Yaki Onigiri Chazuke – A crunchy grilled rice ball in a comforting kombu dashi broth.
• Dashimaki Tamago – A silky, savory rolled omelette made with kombu dashi whisked into beaten eggs.

Storage and Reheating Tips

To store: Transfer the cooled dashi to an airtight container or bottle. Refrigerate for up to 4 to 5 days, or freeze for up to 2 weeks. Use it sooner for the best flavor.

To reheat: Warm gently in a saucepan over medium-low heat until just steaming. Avoid boiling, which dulls the flavor.

FAQ

I’d love to hear how yours turned out! 💛 Please leave a star rating and comment below to share your experience. Your feedback not only supports Just One Cookbook but also helps other home cooks discover recipes they can trust.

Editor’s Note: This post was originally published on February 12, 2013, updated with new images in April 2019, and republished with more helpful content on June 3, 2026.