Onsen Tamago, or “hot spring eggs“ in Japanese, are slowly poached in the shell in volcanic hot spring water. This creates the most luxurious, silky egg whites and custard-like yolks. Learn how to make this delicious, easy recipe at home with my foolproof method.
![A white bowl containing Onsen Tamago (Japanese Hot Spring Egg) drizzled with dashi-based broth and garnished with sliced green onion.](https://www.justonecookbook.com/wp-content/uploads/2024/04/Onsen-Tamago-7660-II.jpg)
Japan is world famous for its 30,000+ natural hot springs or onsen. Visitors can take a natural hot spring bath at one of Japan‘s 3,000 onsen resorts for a most relaxing and therapeutic experience. The warm hospitality and cuisine of the ryokan or traditional inns at these resorts is truly unforgettable as well.
When I stay at a ryokan, one of their breakfast dishes that I eagerly anticipate is onsen tamago (温泉卵, “hot spring egg”). Why? Because this Japanese-style poached egg has the silkiest and creamiest texture. It‘s so comforting and satisfying to eat with hot steamed rice in the morning!
Back in the U.S., I find myself craving onsen tamago. Luckily, it’s easy to make this luxurious egg dish in your own kitchen. Whether you’re an onsen-tamago lover or first-time eater, let me show you my foolproof method today so you can make it at home anytime!
Table of Contents
What’s Onsen Tamago?
In Japanese, onsen means “hot spring” and tamago means “egg.” Onsen tamago (温泉卵), also known as ontama (温玉), is an egg that’s slow-poached in the shell using volcanic hot springs water.
![Onsen Tamago in a flower-shaped bowl.](https://www.justonecookbook.com/wp-content/uploads/2020/05/Onsen-Tamago-2952-I.jpg)
What’s so special about these eggs? They are perfectly poached inside their shell, and the white is silky, creamy, and softer than the half-cooked yolk. This is the opposite of a typical poached egg cooked in simmering water, with a firm white and soft yolk.
The Chemistry Behind Onsen Tamago
We can achieve this special texture because the egg yolk and white solidify at different temperatures. The yolk solidifies at 158°F (70°C) and the white solidifies at 176°F (80°C).
To achieve perfect onsen tamago with creamy and silky whites and soft-cooked yolks, we must cook eggs in hot water at a constant temperature of 149–154°F (65–68°C) for 30 minutes or 154–158°F (68–70°C) for 20 minutes. This mimics the temperature of Japan’s volcanic hot spring waters.
Disclaimer: Many people in the world, including the Japanese, consume uncooked eggs in their cuisine. However, according to the FDA, eggs should be cooked to 165°F (74°C) in order to be considered safe. Please know that the perfect temperature for cooking onsen tamago is below the guideline. There is a risk of salmonella by consuming undercooked eggs.
![A white bowl containing Onsen Tamago (Japanese Hot Spring Egg) drizzled with dashi-based broth and garnished with sliced green onion.](https://www.justonecookbook.com/wp-content/uploads/2024/04/Onsen-Tamago-7699-III.jpg)
Why This Recipe Works for Everyone
As we don’t have a steady supply of hot spring water at a constant temperature, here’s a method that works for typical home kitchens. This technique does not require special equipment like a microwave, thermometer, or sous vide machine (immersion circulator). It also does not use ice cubes for cooling the cooked eggs; this simplifies things, as some of you don’t keep ice cubes handy.
Here’s what you’ll need:
- A stove, a heavy-bottomed small pot, and a ladle (I use a fine-mesh skimmer). Why a heavy-bottomed pot? It retains heat better.
- Boiling water and tap water to create an ideal starting temperature for the cooking water.
- 4 refrigerated large eggs. Cold eggs offset the higher starting temperature of the cooking water. Some recipes require eggs at room temperature, but our readers’ kitchens have different temperatures depending on where they live, and I wanted to avoid the extra uncertainty.
If you follow my recipe precisely, you will achieve perfect onsen tamago as the final result. If you change the recipe, it will affect the water temperature and you may not achieve a perfect outcome.
🙋🏻♀️ Also, keep in mind that you can customize the firmness of the yolk by increasing or decreasing the cooking time.
![Onsen Tamago in a flower-shaped bowl.](https://www.justonecookbook.com/wp-content/uploads/2020/05/Onsen-Tamago-2968-IV.jpg)
![Onsen Tamago over steamed rice.](https://www.justonecookbook.com/wp-content/uploads/2020/05/Onsen-Tamago-3007-III.jpg)
How to Make Onsen Tamago
Here are the simple instructions on how to make perfect onsen tamago without a thermometer or immersion circulator.
- Prepare the cooking water: Boil 4¼ cups (1000 ml or 1 L) of water in a small heavy-bottomed pot. Once boiling, remove it from the stove. Add ¾ cup (200 ml) of cold tap water to the boiled water.
- My hot water temperature at this stage was 180°F (82°C).
- Cook the eggs: Gently submerge 4 refrigerated large eggs, one at a time, in the hot water. Cover the pot, set a timer, and poach for 17 minutes for a runnier yolk and 20 minutes for a creamier yolk.
- My hot water temperature gradually declined to 154–158°F (68–70°C).
- Remove from the water: Open the lid, remove the eggs from the hot water, and set aside for 5 minutes. The residual heat will continue to cook the eggs.
- The water temperature was 154°F (68°C) when I opened the lid after 20 minutes.
- Ready to serve: Serve warm or at room temperature with a drizzle of the dashi soy sauce or add one to curry rice, noodle soup, a hambagu meal, a rice bowl, or a plate of cold noodles.
What if I don’t have a heavy-bottomed pot?
A lightweight or thin-bottomed pot is usually made with materials that may heat up and cool down more quickly than heavy-bottomed pots. Therefore, try using less water, about 100–150 ml instead 200 ml. If you try this method, keep us posted in the comments below.
Can I use medium eggs?
Since they are smaller, they will cook faster. Please shorten the cooking time. FYI, a large egg without the shell is 50 grams.
How to Serve Onsen Tamago
Onsen tamago with a dashi-based soy sauce (だし醤油) is a typical choice of egg to serve for Japanese breakfast.
You can also serve onsen tamago in various dishes. I adjust the onsen tamago’s cooking time to cook the egg yolk more or less depending on how I use it. For example, I prefer a runny yolk on Japanese curry and a firmer yolk on hambagu.
![Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion, onsen tamago (poached egg), and fish cake slices.](https://www.justonecookbook.com/wp-content/uploads/2024/03/Kake-Udon-7569-I-2.jpg)
![White ceramic bowls containing Cabbage and Onsen Tamago Miso Soup topped with green onions and shichimi togarashi.](https://www.justonecookbook.com/wp-content/uploads/2024/03/Cabbage-and-Onsen-Tamago-Miso-Soup-7514-I-2.jpg)
Here are some of my suggestions:
- Put it over fried rice: Kimchi Fried Rice, Garlic Fried Rice
- Top your Japanese curry rice: Japanese Dry Curry, Keema Curry, Chicken Curry, Vegetarian Curry, Beef Curry
- Add it to a rice bowl: Gyudon, Yakiniku Don, Tamago Kake Gohan
- Put it in noodle soup: Kake Udon, Cold Tanuki Udon, Vegetarian Udon, Soba Noodle Soup, Miso Ramen, Vegetarian Ramen, Shoyu Ramen, Mazesoba (brothless ramen)
- Top a main dish: Hambagu (Japanese hamburger steak), Nikomi Hambagu (stewed hamburger steak), Loco Moco, spaghetti carbonara (my favorite), Avocado Toast
- Put it in your soup and hot pot: Classic Miso Soup, Cabbage and Onsen Tamago Miso Soup, Cold Miso Soup (Hiyajiru), Zosui (Japanese rice soup), Nabeyaki Udon, Miso Nikomi Udon
![A white bowl containing Onsen Tamago (Japanese Hot Spring Egg) drizzled with dashi-based broth and garnished with sliced green onion.](https://www.justonecookbook.com/wp-content/uploads/2024/04/Onsen-Tamago-7681-I-1.jpg)
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![Onsen Tamago in a flower-shaped bowl.](https://www.justonecookbook.com/wp-content/uploads/2020/05/Onsen-Tamago-2952-I-500x500.jpg)
Onsen Tamago (Japanese Hot Spring Egg)
Video
Ingredients
- 4¼ cups water (1 L)
- 4 large eggs (50 g each w/o shell) (refrigerated)
- ¾ cup tap water (200 ml; colder than room temperature)
For the Sauce
- ¼ cup dashi (Japanese soup stock) (4 Tbsp; use standard Awase Dashi, dashi packet or powder, or Vegan Dashi)
- ½ Tbsp mirin
- 1½ Tbsp soy sauce
- 2 Tbsp katsuobushi (dried bonito flakes) (skip for vegetarian)
For the Garnish
- green onion/scallion
Instructions
- Before You Start: You will need a small heavy-bottomed saucepan (I use a 2-QT saucepan) in which you can completely submerge the eggs in the water. Please use exactly 4 refrigerated large eggs for this recipe to achieve the correct water temperature for poaching. Now, gather all the ingredients.
To Poach the Eggs
- To the saucepan, add 4¼ cups water (1 L). Cover with a tight-fitting lid and bring it to a boil.
- Once boiling, remove the pot from the heat. Remove 4 large eggs (50 g each w/o shell) from the refrigerator.
- To the pot of just-boiled water, add ¾ cup tap water (200 ml) that‘s colder than room temperature. Into this hot water (now at roughly 180°F or 82°C), gently submerge the cold eggs, one at a time, using a fine-mesh skimmer.
- Immediately cover with a lid and set the timer for 17–20 minutes. Poach 17 minutes for runnier yolks and 20 minutes for creamier yolks. If you follow my method precisely, the water temperature will be 154°F (68°C) when you open the lid after 20 minutes. Note: If you prefer a firmer yolk, you can experiment with a longer poaching time.
To Make the Sauce
- Meanwhile, make the sauce. Combine ¼ cup dashi (Japanese soup stock), ½ Tbsp mirin, 1½ Tbsp soy sauce, and 2 Tbsp katsuobushi (dried bonito flakes) in a small saucepan and bring it to a boil.
- Once boiling, turn off the heat.
- Strain through a sieve and set the sauce aside.
To Finish the Onsen Tamago
- After 17–20 minutes, gently take the eggs out of the water, one at a time. Set them aside for 5 minutes. The residual heat will continue to cook the eggs.
- Meanwhile, cut the green onion/scallion into thin slices and set aside.
To Serve
- Enjoy the Onsen Tamago either warm or at room temperature. Crack the egg into a small bowl, pour the dashi-based sauce into the bowl, and garnish with the sliced green onion as a part of a Japanese breakfast. Try the egg on top of steamed rice with a splash of soy sauce. It’s also delicious in a rice bowl, on top of Japanese curry rice, in hot noodle soup, or on a plate of cold udon or ramen noodles. See below for serving ideas.
To Serve Onsen Tamago in Other Dishes
- Top a rice dish: Onsen Tamago is a protein-rich topping for fried rice like Kimchi Fried Rice and Garlic Fried Rice. Try adding one to finish a Japanese curry rice plate like Japanese Dry Curry, Keema Curry, Chicken Curry, Vegetarian Curry, and Beef Curry.
- Add it to a rice bowl: It‘s a silky and rich topping for Gyudon (simmered beef bowl) and Yakiniku Don (grilled beef bowl). It also works beautifully in a poached-egg version of Tamago Kake Gohan.
- Put it in noodle soup: Up the protein and add one to your Kake Udon (classic udon noodle soup), Vegetarian Udon, Cold Tanuki Udon, and classic Soba Noodle Soup. It‘s also great in Shio Ramen, Miso Ramen, Vegetarian Ramen, Shoyu Ramen, and Mazesoba (Japanese brothless ramen).
- Top a main dish: Add one to your Hambagu (Japanese hamburger steak), Nikomi Hambagu (stewed hamburger steak), Loco Moco, and spaghetti carbonara (my favorite). It also works well on Avocado Toast.
- Put it in your soup and hot pot: Bulk up your Japanese soups by adding one to classic Miso Soup, Cabbage and Onsen Tamago Miso Soup, Cold Miso Soup (Hiyajiru), and Zosui (Japanese rice soup). It‘s delicious in Nabeyaki Udon, Miso Nikomi Udon, and Hot Pot for One, too.
To Store
- You can keep the uncracked Onsen Tamago for 1–2 days in the refrigerator. To reheat, remove it from the refrigerator and bring it to room temperature. To warm it up further, place it in a bowl of 160ºF (70ºC) water for 10 minutes. Do not reheat higher than that; otherwise, the heat will cook the egg. Keep any leftover sauce in the refrigerator for 4–5 days.
For those of you who live at a high altitude (my home ~6,200ft), I tended to get the best results with 21 minutes![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Hi O. Cornali, Thank you so much for trying Nami’s recipe and sharing your experience with us.
This helps other readers who live at high altitudes. Thank you very much!
Worked very well, great that you don’t need a thermometer with this technique. We made the Onsen Eggs as a topping for our homemade Abura Soba![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Hi Kurara! Thank you so much for trying Nami’s recipe and for your kind feedback!
We are glad to hear this method worked well for you!
I tried this recipe a few weeks ago and I did something wrong as my eggs were overcooked. Still tasty and they worked in the recipe I was making them for. I think either my tap water wasn’t cold enough or I took the eggs out of the fridge too soon.
I will be retrying the recipe again today as I have a craving for an egg over rice. I will be using a thermometer to make sure that the water temp is in the range listed.
I will update after I give it my second try. I hope it works, as I love onsen eggs!
Hi Victoria! Thank you so much for trying Nami’s recipe and sharing your experience with us.
We are sorry to hear that your first attempt did not go well. Hopefully, with a thermometer, it will be more accurate and work better for you.
Thank you for experimenting with Nami’s recipe!
It could also be an issue of a difference in altitude, in case you want to check that. Someone else said that for them, at a high altitude, 21 mins works the best.
Hi,
Would it be possible to have the quantities for one or two eggs only? I live alone, so I can’t eat four eggs in only one or two days…
Thanks a lot for your help.
Hello, Lilpea. Thank you so much for taking the time to read Nami’s post and try her recipe.
We only experimented with four eggs, but if you have a thermometer, try reducing the temperature of boiling water to 65~68C (149~154F). If you can maintain the temperature it should work with one or two eggs. We hope this helps!
I’m not sure what I did wrong with this recipe. I followed it very closely and watched the video as well and my eggs came out with a half clear egg white. I did use 4 eggs, although there are two in the photo. All I can think is maybe my tap water is too cold or I took the pan off the heat too quickly after it came to a boil or something. Any ideas what might have happened?
Hi, Teresa! Thank you for attempting Nami’s recipe!
We’re sorry to hear this recipe did not work out for you. It could be the altitude difference.
The boiling point temperature is lower at higher altitudes. It could also be the different temperatures of the tap water.
We hope that increasing the water temperature slightly next time will yield a better result.
Thank you for your reply. We are not at high altitude, but I wonder if it might be the tap water being too cold in winter. My basement is not heated, it only gets passive heating from the furnace being down there and it stays in the mid 50s F in the colder months in winter.
Did you ever test the temperature of the tap water used in the recipe? I’m just curious how my water compares. I will give it another try and let my tap water sit out for a little while first.
Hi Teresa! We didn’t check the tap water temperature, but the temperature after adding the tap water will be around 65~68C (149~154F).
We hope this helps!
I think you might want to check your 1 person serving adjustment to the recipe because I did as you said exactly. My egg wasn’t cooked 🙁
Hi Bec! Thank you for trying Nami’s recipe!
We’re sorry to hear you had trouble cooking the egg.
As Nami mentioned in this post, the cooking time is for 4 large eggs, and cooking only one egg may not work.
We hope this helps.
I followed the recipe exactly and it came out perfectly! Amazing how you guys figured out the logistics of the eggs, water, time and temp. This is definitely a super tasty way to make and eat eggs! Thank you!![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Hi Jjanon! Aww. We are so happy to hear this recipe worked out well for you!
Thank you very much for trying Nami’s recipe and for your kind feedback!🥰
Followed this recipe to a T and these came out perfectly! Will be making on the reg now.![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Hi Paige, We are so happy to hear Nami’s recipe worked very well for you!
Thank you very much for trying her recipe and for your kind feedback.😊
Wow!! These eggs have a wild texture I’ve never seen before. They were delicious on a beef bowl I made from your website. Much better texture than a typical soft boiled egg. Joe
Hi Joe! We are glad to hear you enjoyed Onsen Tamago! 😊
Thank you very much for trying Nami’s recipe and for your feedback!
Omg I’ve never made this before and this recipe was perfect and I can’t believe how yummy the eggs were with the sauce 😩 I’m so going to make it again!!![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Hi Francesca! We are glad to hear you enjoyed Onsen Tamago!
Thank you very much for trying Nami’s recipe!
It really works, I didn’t believe it 😯. I accurately followed the recipe (1000 ml boiling water, 200 ml cold water etc.) but took only two eggs as I am single and they were really BIG with 65 grams with shell.
Made Onsen Benedict with it and it was sooooo good. Thank you for this ingenious recipe, will do it again soon.
Greetings from Switzerland
Brigitta
Hi Brigitta! We are so happy to hear this recipe worked very well for you!
Thank you very much for trying Nami’s recipe and for your kind feedback!☺️
17-mins on the stove cooked the eggs too much, I ended up with a hard boiled egg!![1 star](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
You weren’t supposed to leave them on the stove but let them heat slowly from the remaining heat in the water.
Thank you, Celeste!🙂
this is called not reading and following the instructions![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
Dear Nami, thanks so much for this recipe! how long and at which temperature should i cook the large eggs in a sous-vide to get the same consistency?
Hi Lena! Thank you very much for trying Nami’s recipe!
We have not tested this recipe with sous-vide before and are not sure of the actual temperature. However, the targeted temperature is 65~68C (149~154F) after you place the eggs in the pot. You can try that temperature for 17 minutes and see how it goes?
We hope this works!
THanks so much 🙂 i will do so and let you know about the result. regards from Switzerland!
Hi Lena! Yes, please! We would like to know how it goes!
Thank you for trying.😊
Hi Naomi! This is maybe 2 years too late, but I tested it out at 75C (~167F) for 13 minutes in a circulator, and it came out perfectly!
Hello, Danny. Aww. Awesome! Thank you for sharing the results with us! 🤩
Have been enjoying your recipes immensely.![5 stars](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4MCIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDgwIDE2Ij48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSIjZWJlYmViIi8+PC9zdmc+)
I am a Canadian born and raised in Japan and am at present still resident in the Tokyo area. Due to the fact that my Mother is a Canadian, I wasn’t given much instruction in Japanese cooking methods. What I learned was from friends and asking heaps of questions, so JOC site has very helpful in creating my confidence in the Japanese cooking methods. Many thanks for your thoughtful posts and recipes.
One question I have for you. When you speak of large eggs, you state that they should be 50g without the shell. How on earth are you supposed to know how much they weight when you are making things like onsen tamago or ramen tamago when these are dishes we cook with shell on.
In Japan there isn’t a standardized measurement for eggs like we get in the States or Canada, therefore your eggs come in various sizes in one case….
Hi Elizabeth, Thank you very much for your kind feedback!
Nami and JOC team are pleased to hear our posts and recipes help create your Japanese cooking confidence.😊
The standardized measurements for eggs are different in different countries, and our recipe shows both the egg’s US size and weight. Japan also uses the standardized measurement for eggs, and you should see a little colorful letter M, MS, L, LL in the egg cartons. The eggshell is usually 10% of the egg weight. So if you are in Japan, a Medium size 58g~64g “M” egg will be a good size for the recipe called for 50g egg without a shell.
We hope this helps!
I’m looking forward to trying this. One thing, I live at altitude (2500 meters) and water boils at around 91C. Should I put less cold water in or increase the amount of time the eggs sit in the water? A regular soft-boiled egg takes 3 1/2 minutes at this altitude.
Hi Mark, Thank you for trying this recipe! The reason to add the cold water to the boiling water is to lower the temperature so that Onsen Tamago will cook at 65~68C after you place the eggs in the pot. We don’t have experience cooking at an altitude of 2500 meters and unsure how the outcome will be. Maybe add less water?? In your case, we recommend using a thermometer to test it once. We hope this helps! Let us know how it goes!
Thanks. That makes sense.
Doing it now! I’M EXCITEEEEEEEEEEEEEEEEEEEEEEEEEEEEEDDDDDDDDDD!!! Will use homemade ponzu sauce since it’s on hand
Hi Meg, We hope it turned well and you enjoyed it! Thank you for trying this recipe!