Japanese Food Report Logo (Wide)
Onsen Tamago, or poaching eggs in their shells

Onsen Tamago, or poaching eggs in their shells

Learn about onsen tamago, a Japanese egg poaching technique used in ramen and other dishes. Discover the history behind onsen tamago, how to replicate it at home, and some delicious serving ideas. Find out more at Japanese Food Report.

Onsen tamago is a technique for poaching an egg inside its shell. While we add onsen tamago to certain styles of ramen here at Ganso, Japanese owe this cooking method not to noodles, but to the country's bountiful natural hot springs. Hot springs or "onsen," dot volcanic Japan from tip to tip (dipping into a steaming onsen one of the great pleasures of visiting Japan), and a custom for cooking eggs at these springs evolved over the years -- toss them into the hot water, wait a bit, and the egg magically poaches. The secret is the onsen's water temperature, which causes the egg's yolk and albumen congeal into a nice sphere on the outside, and beautifully creamy and tasty on the inside. It's a great way to cook eggs if you're a stone's throw (or make that, an egg's throw) from an onsen. But supposing you're not, how do you replicate this at home?

Onsen Tamago Recipe


  • 4 eggs


  1. Prepare the Water: Fill a large pot with water and bring it to a boil.
  2. Cook the Eggs: Once the water is boiling, turn off the heat and gently add the eggs. Leave them in the hot water for about 30 minutes.
  3. Temperature Control for Perfection: For a perfectly spherical poached egg, maintain the water temperature at exactly 145°F (65°C) during the cooking process.
  4. Serve: Remove the eggs from the water, crack them open, and enjoy your onsen tamago.

Serving Suggestions:

  • With Daikon and Shoyu: Serve the onsen tamago with grated daikon radish and a splash of shoyu (Japanese soy sauce).
  • Over Rice: Create an indentation in a mound of steaming rice, place the onsen tamago in it, add a few drops of shoyu, mix, and enjoy.
  • Frisee Salad Topper: Place the onsen tamago on top of a fresh frisee salad.
  • In Hot Broth: Float the onsen tamago with soba or udon noodles in a hot broth.
  • Natto Mix: Combine the onsen tamago with natto (fermented soybeans) and shoyu.
  • With Yama Imo: Mix the onsen tamago with grated yama imo (mountain yam) and shoyu.
  • Steak Topping: Use the onsen tamago as a rich, creamy "sauce" for a beautifully grilled ribeye steak.

Techniques and Their Purposes:

  • Soaking Eggs in Hot Water: This method mimics traditional Japanese onsen (hot springs) cooking, resulting in a delicately poached egg with a soft, custard-like yolk and smooth white.
  • Maintaining Water Temperature: Keeping the water at a constant temperature ensures the egg cooks evenly without hardening, preserving the unique texture characteristic of onsen tamago.
  • Versatile Serving Options: Onsen tamago's mild flavor and creamy texture make it a versatile component that enhances a variety of dishes, from simple rice bowls to elaborate salads and main courses.