Wondering what to do with leftover kombu from making Japanese soup stock (dashi)? 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!
Once you start making Japanese dishes, you will realize you are left with used kombu from making homemade dashi (Japanese soup stock), Mentsuyu (noodle soup base) or Ponzu Sauce. Don’t throw these leftover kombu pieces away! We’ll make them into delicious Simmered Kombu called Kombu Tsukudani.
What’s Kombu Tsukudani?
Tsukudani (佃煮) is seafood/fish, shellfish, meat, seaweed, or vegetable that has been simmered in sweet and savory sauce (typically with soy sauce, sugar, mirin) for a long time. 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 the Gohan no Okazu (ご飯のおかず), or rice side dish, as it’s eaten with steamed rice as a flavoring agent.
Tsukudani is always served and eaten chilled from the refrigerator and will not be cooked again prior to eating.
Kombu Tsukudani (昆布の佃煮) is one of the most common tsukudani, and I think it’s the best way to use up all your used kombu.
Did You Know Kombu has Varieties?
Do you know which type of kombu are you using? If you are new to Kombu, check out my Kombu post which I discuss different types of kombu.
For the best texture of Kombu Tsukudani, I think Hidaka Kombu (日高昆布) is the most suitable choice. It achieves tenderness a lot faster than the other types of kombu.
If you are like me who use different types of kombu in your cooking, I highly recommend freezing the used kombu separately based on the variety. Then you can cook the same type of kombu at the same time for a consistent result.
3 Tips on Tenderizing Kombu
Before you start cooking, it’s good to know that some kombu can be hard to eat as it takes a long time to get tender. Here are my tips for making delicious, tender Kombu Tsukudani.
1. Choose the right type of kombu
If you plan to make kombu Tsukudani, it might be a good idea to pick the tender variety of kombu such as Hidaka Kombu. But sometimes you just have to use whatever kombu you have. Then 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 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.
Final Thoughts…
- Freeze Used Kombu: We don’t have to make Kombu Tsukudani right after you have used kombu. Freeze those used kombu pieces in a glass container and put away in the freezer until you have time or you have enough kombu to make Tsukudani.
- Great Meal Prep Dish: Tsukudani is a wonderful side dish to add to your meal prep dish collection. It lasts for 2 weeks in the fridge and it’s perfect to go with simple steamed rice!
- Add Some Kick: I recommend adding some chopped dried red chili pepper (赤唐辛子) to this dish. If you like it spicy, you can add two pieces, but one is good for our family, just enough to add some kick.
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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.
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.😉
Is there a good substitute for katsuobushi in this? I would like to make a vegetarian version.
Thank you!
Hi Leona!
You may skip the Katsuobushi or use Shiitake mushroom instead.
We hope this helps!
Thank you! How would one use shiitake mushrooms in this?
Hi Leona!
It is our pleasure!
You can thinly slice the Shiitake mushrooms and add them at Step 4.
If you are using the dried Shiitake mushrooms, let them soak in the water and make Shiitake dashi stock, then use the dashi instead of the water for this recipe. You may also add the soaked Shiitake mushrooms at Step 4 as well.
We hope this helps!🙂
I have a question about the KOMBU TSUKUDANI recipe. When you say”Add the red chili pepper and bring the mixture to a boil.” Do you mean that the kombu can boil? I thought that kombu may not boil, or is this incorrect? Thanks!
Hi Sien!
If you are making Dashi from Kombu and extracting the Umami from it, yes, you can not boil the Kombu in the water.
In this recipe, we cook with a Sauce and adding flavor to the used Kombu, so it is OK to bring the sauce to a boiling point and reduce the heat to simmer.
We hope this helps!
What non-alcoholic alternatives would you recommend for sake and mirin?
Hi Fairuz!
The non-alcohol mirin is available. As for Sake, you may replace the amount with water or broth.
You can learn more about substitutes in these posts.
https://www.justonecookbook.com/mirin/
https://www.justonecookbook.com/sake/
We hope this helps!☺️
Had a rather funny experience with this one. I cannot find katsuobushi anywhere nearby, so I was forced to attempt this recipe without any (I’d had my kombu frozen for about a month, so I needed to use it). The result was alright (although my partner disliked it), but I found myself thinking it could really use some fish. Whoops!
Ah well, hopefully by the time I’ve amassed another round of kombu I’ll have all the proper ingredients. In the meantime I’ll just have to find the right stuff to eat it with I suppose.
Hi DC,
Thank you very much for trying this recipe!
If you can’t find or use Katuobushi, we recommend substituting it with the Shiitake mushroom. It will add more flavor to this dish. We hope this helps!
Hello,
I used to get riceballs from my high school friend w/ this kombu inside and loved it! I was able to purchase it by the packets already cooked. Do you know where I can purchase it already prepared (on line maybe)?
Hi Jahnna!
You can purchase these types of kombu in refrigerated sections of Japanese/Asian grocery stores. You can also purchase Shio Kombu on Amazon (https://amzn.to/3dF4iIF).
We hope this helps!