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.
I had no idea type of kombu I had until I checked the packaging and it is the type you recipe recommended. I had just made the spinach with kombu and I immediately tried this recipe. I am so impressed. Such flavoring with so little effort. The chili definitely gave it a strong kick. The family loves it!!
Hi Maggie! Aww I’m glad to hear that you and your family enjoyed this simple dish! Thank you for your kind feedback. xo
I feel so fortunate to have found this website, Japanese food has always been intimidating to me but your recipes and explanations of ingredients are so helpful! I just made this recipe for the first time, but didn’t have sake or bonito flakes. I tried it anyway since I had a bunch of Kombu and it was SO delicious! My family loved it, now everyone would like us to always have a container of it in the fridge for snacking. Thank you! If you ever release a cookbook I’ll be in line to get it!
Hi Nathalie! Thank you for your kind feedback. I’m so happy to hear you enjoyed this recipe and my recipes. It meant so much to me that you enjoy cooking Japanese food at home! 🙂
And thank you for your interest in my cookbook. Maybe one day… we’ll see. 🙂
Thank you so much for your beautiful recipe. I will certainly make it for my family. When you say ‘used kombu’ – do you mean if you use kombu to make soup or dashi? Kombu is boiled and then taken out? — does the nutrition of the kombu remain in the soup and still remain in the kombu pieces as well? If I want to add the goodness and ‘umami’ of kombu to cooking oil – can I just leave the kombu in the oil? – how long should I leave it for? Have you tried doing this? – would it work you think? Sorry I have so many questions. I am very interested in food and it’s health value as well.
Hi Virginia! Yes, that’s correct. The kombu that you take out from making dashi. I think the nutrition and fibers remain in the kombu, but it’s more like for enjoying the texture and not wasting the edible food. Adding to the oil… Not sure if that would work, especially with the used kombu. Not much flavor left. 🙂
Hi – I cannot figure out what type of kombu this is (and whether it would be suitable for Kombu Tsukudani): Wel-Pac Dashi Kombu Dried Seaweed. Can you please let me know?
Hi JP! This one is to make dashi (especially package said dashi kombu) and it’s a bit lower quality (especially if they don’t want to say which t type of kombu)… so it’s possible that the kombu stays too tough even after cooking for a long time. Hidaka Kombu gets tender nicely.
https://www.justonecookbook.com/kombu/
This was lovely! I always wondered if I could reuse or somehow eat kombu after making broth from it and this was the perfect sidedish. Thank you for sharing the recipe!
Hi Heeyoung! Thank you so much for trying this recipe. I’m so glad you could reuse your kombu and liked this dish. Thanks fo your kind comment! xo
Hey Nami,
I found it hard to cut the kombu in even stripes because of it’ sliminess.
And I can’t figure out which kind of kombu. It only says dashi kombu, dried kombu. I ordered from Amazon, wel-pac is the name of the company. Think i’m gonna use tip 2.
First I waa freezing it until I got time in my cooking plan. Thanks for this too.
Have a nice day when you read this
Hi Anna! Kombu has different varieties (https://www.justonecookbook.com/kombu/) and some type of kombu can remain tough even after simmering. The great kombu for simmering is Hidaka Kombu – they are tender and so easy to eat. Kombu packages/brands (such as Wel-pac) don’t show which type of kombu…and they tend to be not higher quality. When it says “Dashi Kombu”, the name is too general and it’s mostly lower grade. I get kombu that is a bit more expensive than those brands from the Japanese market here, and they are decent (but not as great as ones we can buy in Japan). So if possible, get ones that specify what type of kombu. Hope this helps!
This is a great recipe but I have a question! I tried making this with 16oz of kombu instead of 2oz since I use it very often because I love it so much… I multiplied the ingredients by 4 instead of 8 because I thought it’d be too salty (except the katsuoboshi, I left that alone)… it still came out very salty! Should I have stuck to the original measurements?
Hi Alex! It’s Tsukudani so it is supposed to be salty per se: 1) to keep the food for a longer time (preserved food) and 2) to eat small amount with steamed rice – it’s like a condiment. However, I’m not sure how salty yours was… the kombu takes a long time to get tender, so it cooks for a long time. If you feel it was too salty, reduce the amount of soy sauce. But it’s not something we eat it by itself too. 🙂
Oh! Sorry, maybe I wasn’t clear enough, my bad.
I actually am of Japanese heritage, my father is Polish-American but my mother is a mix of several European heritages and Japanese. However I did not grow up eating much Japanese food because of limited access and my mother did not know how to cook it. We did however eat a lot of short grain rice.
I started teaching myself how to cook Japanese food about 13 years ago as a late teenager. I am aware this is salty and eaten with rice. What I meant was I tried making a large batch and messed up somewhere because it was unbearably salty!
Thank you for the response, I hope you have a great day 🙂
Hi Alex! Wow, you’ve been cooking Japanese food for a long time! That’s wonderful!!! It’s possible that the liquid evaporated faster and saltier. Add water to dilute when you need to cook for a longer time will help. Also adjust soy sauce (gradually add). Since you have more kombu to cook, that might be helpful. 🙂
It has been a long time but I still consider myself a student! I continue to learn all the time. Your blog is especially great, you have so many neat and unique recipes.
Thanks for the tips!! I’ll try that next time. 🌸
Thank you so much for your kind words, Alex! Happy cooking!
Thank you for sharing. This is easy and delicious. I’ve learned so much from your recipes. 🙏
Hi Ursula! Thank you so much! I’m glad you enjoy my recipes. 🙂
[…] bring it to a boil. Once boiling, remove the kombu from the liquid (You can make Kombu Tsukudani with the used kombu). If you are not vegan/vegetarian, you can add a little bit of katsuobushi to […]
[…] extract umami from kombu as much as possible. Right before boiling, discard the kombu (you can make Simmered Kombu or Homemade Furikake (Rice Seasoning)). If you leave it inside, it gets slimy and leaves a bitter […]
awesome. i recognize this as one of the things i had but did not know what it was in japan! thank you again. i am learning and loving your site so much!
Aww thank you so much Grace! Hope you enjoy making all the Japanese dishes back home that you enjoyed in Japan!
[…] Dashi and utilize the used kombu and katsuobushi to make Homemade Furikake (rice seasoning) and Kombu Tsukudani (simmered kombu) after collecting enough used kombu and katsuobushi. This way, there will be no […]
[…] not throw away the leftover kombu as it is can be repurposed into Kombu Tsukudani (Simmered Kombu) or Homemade Furikake (rice […]
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I would love to see you publish a hard cover cook book. Problem with kindle is you have to print out the recipe if you don’t have a tablet. If I am camping off grid and want to cook something without WIFI I can’t see the book.
I do enjoy your recipes and am learning the terminology, because your posts are thorough and easy to follow.
Hi Mary! Thank you so much for your interest in my hardcover cookbook. 🙂 Maybe one day with the right publisher and timing, I’ll be able to write a cookbook. Right now, my time is dedicated to sharing free recipes on my website and YouTube channel so people in the world will get to cook Japanese food at home. This takes up so much of my time (besides raising 2 kids). If you enjoy my recipe, please use a print out button in the recipe card to collect in your binder. Hopefully, I can write a book after my kids go off to college!