onsen tamago

March 31, 2008 at 7:18 am 24 comments

onsen tamago

I don’t know when the obsession started, but I began dreaming about hot spring eggs (onsen tamago) a week or so ago. I blame Amy and all her wonderfully documented meals in Japan. Even more so when I discovered that it was so simple to make yourself at home. Short of a hot spring in your backyard, an onsen tamago is only ever a few short steps away (as long as you’re making rice in a rice cooker in the first place, that is).

Backtracking a bit – some of you might be wondering “What the heck is onsen tamago anyway?” The short answer is that it’s a gorgeous egg dish that’s commonly served as a breakfast item at hot springs hotels in Japan. The reason being that the temperatures of the hot springs (ie below boiling point) are perfect for poaching these eggs so lightly that they just become ethreally silky and just slide lusciously down your throat. It also works so that the yolks are set on the outside, but the whites are only loosely set and creamy. Essentially, the eggs are ‘poached’ inside the shells; when they’re ready, you crack it open into a bowl filled with a mixture of dashi, mirin and soy sauce, sprinkle over some spring onions, and slurp it all down. It’s fascinating that such a simple dish can be so satisfying (though those of you who feel squeamish at the thought of semi-raw eggs should turn away, now!).

So how do you make it? First thing would be to get the ‘broth’ ready for your egg. All I did was use a teaspoon of dashi powder dissolved in about 4 tablespoons of water, a teaspoon of mirin and a teaspoon of soy sauce. Mix together and leave to chill in the fridge until needed.

Clearly, it’s important to make sure you get the freshest eggs you can, and make sure they’re at room temperature (run under warm water if you take them straight out of the fridge and want to use immediately). Then, all you need is a rice cooker that’s just finished cooking some rice, and some kitchen paper. Because I was steaming rice for dinner anyway, this all worked out fine.

onsen tamago

Once the rice has finished cooking, the rice cooker will automatically switch to the handy ‘keep warm’ function – which coincidentally maintains the perfect temperature for making onsen tamago. All you need to do then is wrap the egg in a layer of kitchen paper (this is just to make sure the eggs aren’t heated directly) and set it gently on top of the cooked rice. Cover, and leave to ‘cook’ for one hour. When time’s up, gently crack your egg open and let it slide into the dashi/soy sauce/mirin mixture you’ve made in advance. Sprinkle over some chopped spring onions, and, if you’re feeling particularly decadent, a few bonito flakes. Slurp it all down in one go a la prairie oysters, or eat the egg white and yolk separately in spoonfuls. The egg whites take on a super silken tofu-like texture, which is extremely yummy and even better when eaten with the broth.

onsen tamago

Too bad I didn’t get to experience the entire egg yolk, considering I dropped it after taking the first photo on the left! I managed to salvage half. The things I do for this blog…

The much harder way to make onsen tamago is to keep a pot of warm water going at the constant temperature of 65C for 20-30 minutes while you cook the eggs, but that requires way too much patience and a thermometer (both of which I do not have). Another way, I’ve heard, was to fill a thermos full of hot water and keep the egg in it overnight, so you can have it the next morning! Not so sure about that one though, it seems like leaving a semi-warm egg overnight and then eating it seems like you’re just asking for food poisoning.

Entry filed under: eggs, homemade, hot spring eggs, japanese, london, onsen tamago, recipe.

smooth (tofu) operator jerez, part 1

24 Comments Add your own

  • 1. mr. eric  |  March 31, 2008 at 1:04 pm

    Haha, you should’ve said “a dash of dashi powder” lol! I’m good aren’t I? (But I guess a teaspoon is not really a dash… whatever, I’m sticking to what I said!)

  • 2. bal  |  March 31, 2008 at 1:10 pm

    Nice to meet you.
    I had a look at blog.
    Please link to this site.

  • 3. Su-Lin  |  March 31, 2008 at 8:47 pm

    Oh genius! I never would have thought to use my rice cooker – definitely going to have to try this one. I’ve also been thinking of onsen tamago for a while – and I also blame Blue Lotus!

  • 4. Charmaine  |  April 1, 2008 at 5:31 am

    Eric – You’ve caught the pun bug! I am shocked!

    Su-Lin – I had to resist the urge to make it again today, having had eggs for breakfast! Try it out :D

  • 5. Eric  |  April 1, 2008 at 1:58 pm

    lol, I was always pun-tastic!

  • 6. Amy  |  April 8, 2008 at 8:55 am

    Hey thanks for the link! Your egg looks way better than mine do– I really haven’t gotten the hang of onsen tamago yet, and I never know what I’m going to get when I crack one open.

    For that reason I offer this tip: crack the finished egg into an empty bowl rather than one filled with the sauce. If the egg does turn out you can then pour on the sauce, but if you’re as unlucky as I am and you wind up with a still-raw egg or a hard-boiled one, you’ll be able to use it for something else.

    The rice cooker method is a really popular one here in Japan but I’ve resisted because I think rice tastes best really fresh and don’t like letting it sit around too long after cooking. Plus I’m never organized enough to have rice ready one whole hour before a meal! I guess I’ll have to give it a try though…

  • 7. Charmaine  |  April 8, 2008 at 10:16 am

    Hi Amy! Are you kidding? The one I saw on your blog looked so inviting I just had to make it (even though it was only one of many delicous looking dishes in the photo)! I have to admit I never considered taking that precaution of pouring in the sauce after the egg… which makes a ton of sense. I guess I was lucky that my egg turned out alright the first time :D

    I agree with the fresh rice thing… alas, the things we have to do for a good onsen tamago!

  • 8. kevlars  |  April 13, 2008 at 12:19 pm

    This looks excellent!

    Back home the local coffee-shops do a soft-boiled egg breakfast too. Methodology’s v. simple – two room-temperature eggs in a bowl, cover in boiling water for 3-4 minutes. Crack into a flat dish, add dark soya sauce + white pepper to taste. You should have a whole yolk, set but still very runny on the inside, and a soft cloud of white about it. Some people mash the eggs up, I usually try to pop the entire yolks whole – which is why I truly feel your pain that the yolk fell on the table.

    Can’t compare it to the onsen tamago ’cause… I’ve never had one. :/

  • 9. Charmaine  |  April 15, 2008 at 12:12 am

    Kevlars – Woah, how could I have missed that! They do it in HK? The only ‘raw’ egg dish I’ve ever heard of was the one where it’s a raw egg in a sugared water drink? I think I may have to try this water in a bowl method and see how it turns out.

  • 10. ifoods chef  |  April 17, 2008 at 3:29 pm

    i loved your recipe on onsen tamago it really is so well made with lots of thought and very interesting as well! I just started a video recipe site that shows you step by step how to make stuff, http://www.ifoods.tv and i also started out as a blogger so it’s great seeing other bloggers doing well, keep up the good work”

  • 11. madeleine  |  June 19, 2008 at 6:17 pm

    i love your onsen tamago somuch and will give it a try definitely!. my hometown malaysia use to have this ‘half boiled eggs with soysauce and some pepper as breakfast with coffee and toast bread. just like Kevlars says, place the eggs in a container with boiling water for few minutes and its done! perfect match with coffee and toast bread!
    this are few links that give you an image of malaysian style of breakfast which is half boiled eggs+toast bread+ coffee.
    and there’r also kinda half boil egg maker. could ‘t discribe it so the only thing that i can do is to send you the link of ebay
    enjoy and thanks for your recipe of onsen tamago!

  • 12. Towards the perfect soft boiled egg » blog.khymos.org  |  April 13, 2009 at 1:09 am

    […] at home is accurate temperature control (just as with sous vide in general). One tip I found was to place the egg on top of rice that has just cooked in a rice cooker. Leave the eggs to “cook” for about one hour while the “keep […]

  • […] but wouldn’t that take away money from Akihabara? Probably, but since my friend mentions Onsen Tamago.. I wonder..since I love eggs.. will I be able to get this elsewhere? Probbaly not.. onsen gun ho.. […]

  • 14. meemalee  |  April 22, 2009 at 5:13 pm

    Well, your technique worked for me – thanks :)

    I’ve always toyed with the idea of getting an egg coddler – meant to give a similar result, I think …

  • 15. Rhiannon  |  May 2, 2009 at 4:23 am

    Someone give the poor clueless American a hint, what the heck are coddled eggs? How do you make them?

    I love eggs in any way (I’ve ignored that stupid “eggs are bad for you” think for ages, butter is also NOT bad for you. Think about it, it melts at room temp. Margarine on the other hand? Does not melt at body temperature, so……what exactly is it doing in your body? solidifying most likely. Hydrogenated veggie oil is bad for you)

    My current egg obsession is miso marinated boiled eggs. Boil your eggs, peel them, mix a few tablespoons of miso with some maple syrup or honey (I know, sounds funky, but is so good!) put a glob of marinade on saran wrap, drop the peeled egg on it, wrap it up good an tight so that there is marinade all around the egg. Put in the fridge for a couple days, then pull out and gently wipe of marinade. Slice up egg (you will find the marinade makes it a lovely golden colour all throughout) and serve over rice or in soup or a a bento or whatever.

  • […] a situation that is similar to Rai. So I was so happy to see her! I had my first experience of the Onsen Tamago. Wished that the Onsen Tamago came like this, but as Meek said – only one place in her […]

  • 17. Eddy  |  January 10, 2010 at 11:17 am

    1 hr inside the rice cooker was simply too long for me; It turned out ‘Hard Boiled’ for me

  • […] עדיין נוזלי. ביצים כאלה מכינים ביפן, והן נקראות אונסן טמגו (onsen tamago), כלומר 'ביצי מעיינות חמים'. יפן שוכנת על הר-געש […]

  • 19. Leisurely food: the 60 minute boiled egg  |  January 22, 2012 at 7:48 pm

    […] an egg-white with ‘a super silken and tofu-like texture’ – so elegantly described in this post about onsen tamago (Japanese hot spring eggs) – the eggs were carefully pushed aside, with […]

  • […] home is accurate temperature control (just as with sous vide in general). One tip I found was to place the egg on top of rice that has just cooked in a rice cooker. Leave the eggs to “cook” for about one hour while the “keep warm” […]

  • 21. BobbyWong  |  May 15, 2013 at 5:54 pm

    Here’s an idea – make some minimal amout of rice as “sacraficial rice” for the eggs to sit on.

  • 22. Pablito Rojo  |  August 4, 2013 at 10:11 pm

    This worked great: I got an electric kettle w digital temp control (mostly for coffee & tea). When set to 140F/60C, it actually bounces between 60-63 for 1hr, then shuts itself off. 1-4 eggs, set & forget. Perfectissimo!

  • 23. In praise of the egg cooker - FlyerTalk Forums  |  December 11, 2013 at 12:30 pm

    […] has just made rice is one of the simplest ways to make Japanese style soft "boiled" eggs https://tastytreats.wordpress.com/200…/onsen-tamago/ My rice cooker even has egg indentations in the little steamer – so when I want standard boiled […]

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A freelance journalist and full-time gourmand, eating her way mostly through London and Hong Kong.

Current location: London


Charmaine currently digs: the smell of coffee; adding ponzu to everything; bill granger; still eating natto with every meal; caressing her Nikon FM2n.



March 2008

my flickr photos

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