Onsen Tamago (Hot Spring Egg 温泉卵)

I was first introduced to Onsen Tamago when I was living in Japan. They are quite different a bit like a soft poached egg. The whites are very soft / runny whilst the yolk is firm with almost a custard texture.
In Japanese “Onsen” means “Hot Spring” and “Tamago” means “Egg”. In Japan the eggs were traditionally cooked in hot springs around 70C for 30 minutes. Then they would crack them open into a small bowl and add dashi (Japanese stock), soy sauce with a few chopped spring onions. I will introduce you how to make Onsen Tamago / Hot Spring Egg at home with just a few simple steps.

What is the history of Onsen Tamago?

It is said to have originated in Onsen Towns in Beppu, Oita prefecture. It is said that the first Onsen Tamago was made over 300 years ago when a traveler left his eggs in a hot spring by accident and found them cooked when he returned.

How long you can keep the eggs?

First you need to make sure your eggs are fresh. With fresh eggs you can keep them with shell in the refrigerator for 2 to 3 days. But if your shell has been cracked, once you cook it you should just eat it immediately or it will go off.

How to eat Onsen Tamago?

The most simple way to eat the Hot Spring Egg is to add dashi (Japanese stock), soy sauce and some green onion. You can add it into Cesar salad, it is also good with rice and noodles, you can just eat with rice and add a little soy sauce or as pictured add some Japanese natto, kimchi and seaweed or a beef rice bowl. If you like Japanese Udon then you should try to add an Onsen Tamago in as it makes the texture better.
You could even just enjoy it on a slice of toast like you would a poached egg.

Onsen Tamago (温泉卵)

This is how to cook perfect Onsen Tamago at home. It can be relatively easy once you get the hang of it. When you have mastered my method, you can enjoy it at home with lots of different dishes.
Servings 4 servings
Prep Time 5 minutes
Cook Time 20 minutes
Total Time 25 minutes


  • 4 Eggs ( around 58g~63g room temperature)
  • 1 litre Water to boil
  • 200 ml Tap Water
  • 1 bowl Ice

Easy Sauce for one egg

  • 1 tbsp Concentrated Fish Soup Stock
  • 1 tbsp Water


  • Boil 1 Litre of water, once it has boiled take it off the heat and add the 200ml water (it will become around 65°- 68°). Using a large spoon add the eggs into the water, put on the lid. Leave it for 14 minutes (Depending on different conditions the time can vary 12 to 15 minutes).
    Add the eggs into the 65° water
  • Add the eggs into the hot water
  • Ready a bowl with cold water and ice in, after 14 minutes add the eggs into the bowl and leave it for 5-10 minutes, until the eggs have completely cooled down.
    add the eggs into the cold water
  • While the eggs are cooling down, make the sauce, mix fish soup stock and water, then crack the egg in to a bowl and enjoy 😀
    onsen egg


  • The 1 Litre of water is only for 4 eggs. If you use more eggs you will require more water. The temperature will change though.
  • Tip: Gently shake the egg 3 times before cracking it open, this will stop the egg from sticking to the shell.
  • Course: Breakfast, Side Dish, Snack
    Cuisine: Japanese
    Keyword: egg

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