Wondering what to do with leftover kombu from your Japanese recipes? Make delicious simmered Kombu Tsukudani cooked in a sweet and savory sauce. My tender seasoned kelp recipe is an easy and tasty side dish for your plain steamed rice or onigiri!
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Once you start making Japanese dishes, you will realize you are left with a lot of used kombu from making homemade dashi (Japanese soup stock), mentsuyu (noodle soup base), or ponzu sauce. You may wonder what to do with the spent kombu.
Don’t throw those leftover kombu pieces away! You can repurpose them into a delicious simmered kombu dish called Kombu Tsukudani. Follow my recipe and tips below to make this easy and tasty side dish.
Table of Contents
What is Tsukudani?
Tsukudani (佃煮) is a preparation where an ingredient is simmered for a long time in a sweet and savory sauce (typically made from soy sauce, sugar, and mirin). It usually has an intensely sweet and savory flavor, which helps preserve the ingredients.
Because of the strong flavor, tsukudani has been served as a side dish to accompany plain steamed rice since the Edo period (1600s–1800s). We call it gohan no okazu (ご飯のおかず), or rice side dish, as it’s eaten with steamed rice as a flavoring agent.
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What is Kombu Tsukudani?
Kombu tsukudani (昆布の佃煮) is one of the most common types and it’s an excellent way to use up all your spent kombu. Other typical ingredients to make into tsukudani are seafood/fish (like baby sardines), shellfish, meat, seaweed, and vegetables.
Kombu tsukudani keeps for up to 2 weeks in the fridge, so it’s a great dish to make ahead and keep on hand. Tsukudani is always served and eaten chilled from the refrigerator and is not cooked again prior to eating.
Why You’ll Love This Recipe
- Repurpose spent kombu – Save those leftover kombu pieces in the freezer until you have time or enough kombu to make this dish.
- Great meal prep dish – It’s one of Japan’s delicious plant-based dishes that you can add to your meal prep recipe collection.
- Flavor booster for your bowl of rice or rice ball – Tsukudani adds a wonderful savory boost to your steamed rice or onigiri. For a spicy kick, try adding chopped dried red chili pepper!
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Ingredients for Kombu Tsukudani
- spent kombu (kelp) – leftover from another use; I used hidaka kombu that‘s tender and easy to cook
- toasted sesame seeds
- dried red chili pepper (赤唐辛子) – If you like it spicy, you can add two pieces, but one is good for our family
- water
- mirin
- sake
- rice vinegar (unseasoned)
- soy sauce
- sugar – you can add more for a sweeter taste
- katsuobushi (dried bonito flakes) – optional; skip for vegan/vegetarian
The Best Kombu for Tsukudani
For the best texture, hidaka kombu (日高昆布) is the most suitable choice for tsukudani. It gets tender a lot faster than other types. Ma kombu and rishiri kombu are thick and hard to cook.
Do you know which type of kombu are you using? If not, check out my kombu post where I discuss the different types.
If you use different types of kombu in your cooking like I do, I recommend freezing the spent kombu separately based on variety. Then you can cook it according to kombu type for a consistent result.
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How To Make Kombu Tsukudani
- Cut the kombu into thin strips.
- Cut the chili pepper into thin rounds.
- Simmer the kombu strips in a medium saucepan with the water, sake, and mirin. Then, add the rice vinegar, Japanese soy sauce, sugar, and optional katsuobushi. Add the red chili pepper.
- Bring the liquid to a boil over medium heat, then reduce the heat to low.
- Simmer until most of the liquid evaporates, about 20–25 minutes. If the kombu is still not tender, add water and continue to cook. Taste and adjust the seasoning to your liking.
- Sprinkle with sesame seeds.
You can store the leftovers in a jar or other airtight container in the fridge for up to 2 weeks. Serve it chilled.
3 Tips for Tender Kombu Tsukudani
Here are my tips for making delicious, tender kombu tsukudani:
1. Choose the right type of kombu.
If you plan to make kombu tsukudani, pick a tender variety of kombu like hidaka kombu. But sometimes you just have to use whatever kombu you have. In that case, try my next tip #2.
2. Add rice vinegar while simmering.
In Japan, kombu is often cooked with a little bit of rice vinegar, which tenderizes the kombu. Don’t add too much though. You don’t want the tsukudani to taste vinegary.
3. Refill the water and cook until tender.
If the kombu hasn’t turned tender after simmering for 20–25 minutes, add some water and continue to simmer until it gets to the right texture.
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Kombu Tsukudani (Simmered Kombu)
Ingredients
- 2 oz used kombu (kelp) (you can use up to 4 oz (113 g); I used spent Hidaka kombu that‘s tender and easy to cook; Ma kombu and Rishiri kombu are thick and hard to cook; read about the different types of kombu)
- ½ tsp sesame seeds
For the Seasonings
- 1 dried red chili pepper
- 1 cup water
- 1 Tbsp mirin
- 1 Tbsp sake
- 1 tsp rice vinegar (unseasoned)
- 2 Tbsp soy sauce (or more, if needed)
- 2 tsp sugar (or add more for a sweeter taste)
- ½ tsp katsuobushi (dried bonito flakes) (optional; skip for vegan/vegetarian)
Instructions
- Gather all the ingredients.
- Cut 2 oz used kombu (kelp) into thin strips.
- Remove the seeds from 1 dried red chili pepper and cut it into thin rounds.
- Transfer the sliced kombu to a medium saucepan. Add 1 cup water, 1 Tbsp sake, and 1 Tbsp mirin.
- Add 1 tsp rice vinegar (unseasoned), 2 Tbsp soy sauce, 2 tsp sugar, and ½ tsp katsuobushi (dried bonito flakes).
- Add the red chili pepper. Bring the liquid to a boil over medium heat.
- Once boiling, reduce the heat to low and simmer until the liquid is almost evaporated, about 20–25 minutes. If the kombu is still not tender, add water and continue to cook. Check the taste and add more sugar and/or soy sauce, to your liking.
- Sprinkle ½ tsp sesame seeds on top. It‘s ready to serve.
To Store
- Keep the Tsukudani in the refrigerator and consume within 2 weeks.
Easy and tasty to make. I added on garlic and substitute dry chilli with real chili instead, tasted good as well.
Hi Neko! Thank you for trying Nami’s recipe and sharing your experience with us!
We are glad to hear you enjoyed it!
I made this to avoid food waste after making the vegetarian ramen from this blog (it was a big hit with my friends! Highly recommend) and it has been in the fridge for a little while because I was uncertain about it. I tried a piece by itself and it was a bit “sea” at first but then I couldn’t stop eating it. It’s really delicious with steamed rice! These are my first two recipes from this blog and I will definitely be back. Thank you!
Hi, Angela! Aww. We’re so glad you enjoyed Nami’s recipes!
We currently have over 1,000 recipes. We hope you will continue to enjoy her recipes.
Happy cooking!🤗
I always make this after I use the kombu to make vegan dashi for my ramen. Great way to use the kombu!
Hi Qchan! Thank you so much for trying Nami’s recipes and for your kind feedback.
We are glad to hear about your happy cooking!🥰
Is there a non-alcoholic substitute for mirin and sake?
Hi Jess, Thank you so much for trying Nami’s recipe!
Mirin is also available without alcohol. You may also use sugar and water instead of Mirin.
In place of sake, you may try Dashi or Broth.
For more details, please visit the following links.🙂
https://www.justonecookbook.com/mirin/
https://www.justonecookbook.com/sake/
We hope this helps!
Wait….over 2 cups of liquid (I had to double the recipe for a bigger batch today) are supposed evaporate over low heat in 25 minutes? Please help me with this, because it took me over one hour last time I tried at the usual size recipe with 1 cup of water (yes, the konbu got softer than I’d’ve liked), and at 15 minutes in today, I still have half a pot of liquid and kombu.
Surely I’m not the only one for whom none of these numbers are adding up?
Hello Dei! Thank you for trying out Nami’s recipe!
When doubling the recipe, it’s best to reduce the amount of water for this recipe since it’s mainly used to cook the Kombu to the right texture along with the condiments.
How much Kombu did you use? This recipe is suitable for up to 4 oz of Kombu. If cooking more, make sure to use a larger pot to evenly cook and evaporate the moisture from the Kombu.
As for the cooking time, it may vary depending on the type of pan and heat distribution. So adjustments may be necessary. We hope this information is helpful to you!
This is actually a very common but understandable mistake people also make when cooking rice for example. When cooking 2 versus 1 cups of rice they also double the amount of water, which wouldn’t work for the same reason. Since in the set cooking time, only a given amount of water will evaporate.
Yes, totally agree. I actually did a 6x version of the recipe and there is no way I should have added so much water. There should be a note to only add enough water to cover the kombu (or something like that).
Yes, totally agree. I actually did a 6x version of the recipe and there is no way I should have added so much water. There should be a note to only add enough water to cover the kombu (or something like that).
The best way to use kombu from dashi stock. Delicious!
Hi Julia! Aww. We are so happy to hear you enjoyed the dish!💞
Thank you so much for reading Nami’s post and trying her recipe. Happy Cooking!
This is a great way to use up leftover kombuwhen making dashi stock, taste great, thankyou. x
Hi Rob, Thank you so much for trying Nami’s recipe and for your kind feedback!
We are so happy to hear you enjoyed the homemade Kombu Tsukudani.
Happy Cooking!
Hi! I have a question regarding the kombu. I had a failed dashi attempt (accidentally left the kombu in overnight) and even though I’m restarting the dashi for another dish, I was wondering if the oversoaked kombu would be okay to use in this? I absolutely love this dish (from Mitsuwa onigiri!) and would love to make as much as possible with the “old” used kombu and the new one. Thanks!
Hi Jen! Thank you for reading Nami’s post and trying her recipe!
Yes. You can use the Kombu for this recipe.
We hope this helps!😉
after finding this recipe i’ve made it countless times and i absolutely adore it. Thank you for brining it into my life!
Hi, alex! Aww. Thank you very much for trying Nami’s recipe and for your kind feedback!
We are so happy to hear you enjoyed Kombu Tsukudani!
QUESTION: If I used the kombu for making dashi, then froze it, how would I reheat it for this recipe? Would I need to simmer as long? Thank you!!
Hi Amber! Thank you very much for trying Nami’s recipe!
If the Kombu is ready to use (It has been cut into small pieces before freezing it.), you can follow the recipe without defrosting. At Step 7, when it reaches the boiling point, the Kombu is defrosted already. If it is hard to cut, you can defrost it overnight in the refrigerator or until it gets soft enough to cut.
We hope this helps!
Wow. This came out AMAZING. I used the kombu left over from my dashi, as you suggested. I’m vegan, so I left out the katsuobushi, and I didn’t have any sake so I left that out as well. My tamari has reduced sodium; I’m happy with the salt level that it produced in this dish. My kombu tsukudani is intensely flavorful with a nice soft texture. I’m so happy to know how to make this dish that I’ve enjoyed many times but didn’t even know the name of before I found your website.
Hi Beth! We couldn’t be happier to hear how much joy and excitement Nami’s recipe has brought to you!
Thank you very much for trying the recipe and for your kind feedback!🥰
Hi! Is this fresh katsuobushi or also leftover from making dashi?
Hi Brice,
This recipe is using dried bonito flakes Katsuobushi, and it is not leftover from making dashi.
We hope this helps!
Sound yummy can’t wait to try!
Hi Candy!
Thank you! Let us know how it goes.😉