Making Thunder Bread in Iceland

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

On the road in Iceland

On the road in Iceland

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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 view it 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

Þingvellir (Thingvellir) National Park

Þingvellir (Thingvellir) National Park

Laugarvatn Fontana

We arrived at Laugarvatn Fontana and 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 | What to Eat & Drink in Iceland | Touring Iceland’s Golden Circle

Laugarvatn Lake, Iceland

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’ and, 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. As Siggi says ‘It’s pure Iceland’.

making the thunder bread recipe

Rosie and Siggi making thunder bread

Recipe for Thunder Bread 

Icelandic Thunder bread

Icelandic Thunder Bread Recipe (Rye Bread)

A recipe for Icelandic Thunder Bread also known as Rye Bread
5 from 4 votes
Prep Time 15 mins
Cook Time 5 hrs
Total Time 5 hrs 15 mins
Course Bread
Cuisine Icelandic
Servings 1 loaf
Calories 120 kcal


  • 320 grams rye flour
  • 85 grams all purpose flour
  • 200 grams sugar
  • 8 grams baking powder
  • 1 gram salt
  • 500 ml 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. You could also cook in a slow cooker.
    To convert to cups measurement use this converter.
Keyword Icelandic bread, rye bread,, Thunder Bread

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.

Burying Thunder Bread

Burying Thunder Bread

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

Thunder bread with Rosie and Siggi

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! 

Icelandic Thunder bread

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 going into the spring

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 her food/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!

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Sliced Thunder Bread on wooden board with knife

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