Thunder Bread Recipe - A Geothermal Bake Off in Iceland (2024)

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (1)

There’s a rye bread that’s been baked underground in geothermal springs in Iceland for generations. The Icelandic bread is dark, dense, deliciously sweet and it’s called Hverabrauð, Thunder Bread or Icelandic rye bread. Read on to find out about our day in Iceland and for the thunder bread recipe which I recommend you have a go at making at home (you don’t actually need a thermal lake in your garden to do this).

I went on a whirlwind, 24-hour visit, to Iceland to discover how Thunder Bread is made and to catch a behind-the-scenes glimpse of the Celebrity Cruises and Waitrose ‘Taste of Travel’ food and travel series. The series is filmed with the lovely Rosie’s Deli Cafe owner and presenter Rosie Lovell.

A day in Iceland and a Thunder Bread recipe


Thunder Bread Recipe - A Geothermal Bake Off in Iceland (2)

On the road in Iceland

This post may contain compensated links. Find more info in my disclaimer.

On the Road in Iceland

We set out from Reykjavik at early doors, driving through some stunning Icelandic scenery on our journey. We had a very quick stop at Þingvellir (pronounced Thingvellir) National Park, home to the world’s oldest parliament, where we were able to check out the amazing views.

We walked through one of the fault lines where the earth’s tectonic plates of the Mid-Atlantic Ridge have shifted. It was good to see the Icelandic scenery in the summer. The last time I stood here during our Golden Circle Tour and looked at this viewit was early February with a very wintery looking scene and a vicious wind.

Get a taste for Iceland in an Icelandic Food Tour – check rates and availability

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (3)

Þingvellir (Thingvellir) National Park

Laugarvatn Fontana

We arrived at Laugarvatn Fontanaand met Sigurdur Hilmarsson (Siggi), manager and chef. Siggi would be teaching Rosie how to make Icelandic Thunder Bread from a recipe handed down by his grandmother.

Laugarvatn Fontana is a geothermal spa with pools, saunas and a restaurant with a strong Icelandic design vibe. It sits on the edge of Lake Laugarvatn which laps onto a black volcanic shoreline and has three geothermal springs. The springs provide energy for the entire village and the spring at Fontana is used for cooking the Thunder Bread.

Read more: Tips for Visiting Reykjavik | | Touring Iceland’s Golden Circle

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (4)

Laugarvatn Lake, Iceland

What is Thunder Bread

Thunder Bread is just a nickname, it’s actually called Hverabrauð (hot-spring bread), or rugbrauð and is a type of rye bread. It’s steam-cooked underground in a geothermal spring. Every Icelandic family’s recipe for Thunder Bread is slightly different with ‘more of this’ and ‘less of that’. Of course, each family thinks theirs is the best.

Thunder Bread is a year-round essential food in Iceland, eaten with smoked trout, salmon, herring or just plain butter.

It is also served at Thorrablot, the Viking festival honouring Thor, the god of thunder. As Siggi says ‘It’s pure Iceland’.

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (5)

Rosie and Siggi making thunder bread

Recipe for Thunder Bread

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (6)

Yield: 1 loaf

Icelandic Bread - Thunder Bread recipe

Prep Time: 15 minutes

Cook Time: 5 hours

Total Time: 5 hours 15 minutes

A recipe for Icelandic Thunder Bread also known as Rye Bread


  • 320g rye flour
  • 85g all purpose flour
  • 200g sugar
  • 8g baking power
  • 1g salt
  • 500ml milk


    Mix together all the dry ingredients in a medium bowl. Add the milk and mix together. The dough will be very wet.

    Grease a metal pot (with a lid) so the bread won’t stick when it’s cooked.

    If, like me, you don't have a geothermal spring in your garden(!) Siggi suggests you bake in the oven at 120 degrees Celsius (with the lid on) for five and a half hours, or until bread is cooked in the middle.

    Alternatively you could simmer in a slow cooker or crock pot around 4 hours. The bread will steam if cooking this way and you'll need to add water to the crock pot and check regularly to ensure it doesn't boil dry.

    Split the dough into two and place intwo medium ceramic bowls or tin cans, ramekins could also be used. Whichever you use, tent with aluminum foil to steam the bread.


To convert to cups measurement use this converter.

Nutrition Information



Serving Size


Amount Per ServingCalories 246Total Fat 2gSaturated Fat 1gTrans Fat 0gUnsaturated Fat 1gCholesterol 4mgSodium 64mgCarbohydrates 53gFiber 4gSugar 23gProtein 6g

Nutritional information is estimated.

If rye flour isn’t available in your local supermarket you can buy it here.

Burying the Thunder Bread

We went outside to the lakeside to watch Siggi bury the bread in the geothermal spring. We could see steaming bubbles exploding in the black volcanic sand by the water’s edge and smell the faint, eggy smell of sulphur in the air.

First, Siggi dug up the previous day’s thunder bread and cooled off the hot pot in the lake. Next, he buried the freshly made pots of thunder dough in the geothermal spring.

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (9)

Burying Thunder Bread

The thunder bread is taken out of its pot and neatly sliced ready to eat…

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (10)

Thunder bread with Rosie and Siggi

What does Thunder Bread Taste Like?

The Thunder Bread was delicious! It was very dense and almost cake-like. I ate it, still warm, without any topping – it was moist and had a faint caramel-like taste. Really yummy. If I had a thermal spring in our garden at home I’d be baking it regularly!

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (11)

Icelandic Thunder bread

Why is Hverabrauð called Thunder Bread?

Apparently if you eat too much Hverabrauð you’ll experience a ‘gas situation’! Since we were getting on a flight that afternoon I only had two slices so can’t confirm whether this is farty fact or farty fiction.

Filming with Rosie

It was fascinating to be part of a film shoot and see the painstaking procedure that goes into making just a short 2-3 minute film. The crew, Rosie and Siggi patiently filmed over and over until the producer was happy with the footage and sound.

I can’t even imagine the amount of work that goes into editing everything to produce the final film. The crew have worked on a number of ‘A Taste of Travel’ videos with the Celebrity Cruises and Waitrose partnership. ‘How to make ‘Manti’ in Istanbul and what goes into producing the best gelato in Florence.

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (12)

Filming in Iceland

Rosie Lovell

We had a chance to have a quick chat with Rosie Lovell, cookery writer, cafe/deli owner and presenter before filming started. After leaving university, Rosie went to Glastonbury, came home and straight away opened Rosie’s Deli Café in Brixton – she’s never looked back. She recently opened a second Deli Cafe in Peckham – ‘I’ll only in open in places I love, she says – I’m too emotional!’ She’s very hands-on and splits her time between the two cafes cooking up breakfasts, brunches, sandwiches and cakes.

Rosie’s written two cookery books which, she says, charter her age. Her first book, Spooning with Rosie, has simple, student, comfort food. The second, Supper with Rosie, is a bit more grown up. When asked about herfood/travel wishlist there was barely a hesitation. ‘Tokyo because it’s so immersive and different; overwhelming, exciting and fundamentally foreign.’

So where does Rosie head when she’s going out for a meal? Now that we have a son it’s more neighbourhood – easy, seasonal, accessible and appealing. All I want is ‘a really flipping nice supper!’ I couldn’t agree more.

Have you come across any unusual foods on your travels – tell all, what and where in the comments below. Let me know if you bake this thunder bread recipe and what you think of the result.

Many thanks to Celebrity Cruises for inviting me along to this big Icelandic bake off!

Pin it for later!

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (13)

Some of the posts on this site contain affiliate links. If you buy an item after clicking on one I receive a small (tiny!) commission (at no extra cost to you). If you choose to buy anything it’s very much appreciated, thank you.

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (14)

Suzanne Jones

Suzanne Jones is a full-time travel blogger and writer at The Travelbunny website which she started in 2011. A serial traveller, she enjoys culinary encounters and the outdoors. When she’s not indulging her wanderlust or writing about her adventures you’ll most likely find Suzanne, camera in hand, enjoying coastal walks on England’s South Coast.

Suzanne also runs Hello Sussex a website which showcases the best of East & West Sussex. Read more about Suzanne here…

Thunder Bread Recipe - A Geothermal Bake Off in Iceland (2024)
Top Articles
Latest Posts
Article information

Author: Prof. An Powlowski

Last Updated:

Views: 5848

Rating: 4.3 / 5 (44 voted)

Reviews: 91% of readers found this page helpful

Author information

Name: Prof. An Powlowski

Birthday: 1992-09-29

Address: Apt. 994 8891 Orval Hill, Brittnyburgh, AZ 41023-0398

Phone: +26417467956738

Job: District Marketing Strategist

Hobby: Embroidery, Bodybuilding, Motor sports, Amateur radio, Wood carving, Whittling, Air sports

Introduction: My name is Prof. An Powlowski, I am a charming, helpful, attractive, good, graceful, thoughtful, vast person who loves writing and wants to share my knowledge and understanding with you.