Onsen Tamago : The Easy Japanese-style Soft Boiled Egg Recipe

If you have a chance to go on a hot spring trip in Japan, you may see hen’s shell eggs placed under the hot spring water in the Onsen (Japanese hot spring) resort you visit. Those eggs are usually put into a mesh basket and cooked through by the use of the middle to high temperature of the natural hot spring.

When you keep the hen’s shell eggs submerging in the hot water between 65 to 68℃ for 30 minutes or so, they become soft boiled eggs whose white is softer than their egg yolk. Specifically, the egg white is softly set, while the egg yolk has a custardy texture. This is because the solidifying temperature of egg yolk (about 70℃) is lower than that of egg white (about 80℃).

The Easy Onsen Tamago Recipe

Using these properties, you can easily make the soft boiled eggs, or “Onsen Tamago (温泉卵 : Japanese hot spring egg)” at home. Today, I actually made an Onsen Tamago egg according to a popular easy-to-make Onsen Tamago recipe posted on Cookpad.com. For those who are interested in the Japanese-style soft boiled egg, this time I want to share the instructions with images.

The Ingredients and The Advance Preparation 

All you need to prepare for this Onsen Tamago recipe are as follows,

  1. Large hen’s shell egg : 1 – 4 eggs
  2. Water : 1000 cc
  3. Additional cold water : 400 cc
  4. Kikkoman’s Hon Tsuyu soup base (Amazon.com) : 1 teaspoon
  5. Shiro Dashi soup base : 1 teaspoon
  6. Mirin sweet cooking rice wine : 1 teaspoon
  7. Water for sauce : 3 tablespoons

In addition, prepare the sauce for the Onsen Tamago egg in advance : just mix No.4 to No.7 ingredients in a small bowl.

The Instructions 

1 Put 1000 cc water in a pot and bring it to the boil
2 Once the water has boiled, turn off the heat. Then, add 400 cc cold water
3 Put a hen’s shell egg in the water gently with a ladle
4 Then, cover up the pot with a lid and let it sit for 25 minutes or so

About 25 minutes later, take the boied egg out from the pot. Then, transfer it into cold water in a bowl and let it cool down for a while


6 Break the shell egg and put its inside in the prepared sauce. Enjoy Onsen Tamago!

(Reference page of this article : Wikipedia 温泉卵 )


Hi, I'm Tomo, a Japanese blogger living in Niigata Prefecture, Japan. I want to introduce things about Japan on this blog, especially unique Japanese products, cooking recipes, cultures and trivia.

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