Sustainable Icelandic sea salt is now a Michelin chef favourite – discover its remote origins

At the Saltverk production facility in Reykjanes, doors, walls, and the weathered and worn woodwork are covered in cakes of salt crystals. Even the hot, sticky air is saturated with sea salt. You can literally taste it as you breathe. Salt gets in everywhere.

“As you can see, this is a very harsh environment for any material. Everything deteriorates rapidly within this atmosphere,” says Saltverk founder Björn Steinar Jónsson. In 2011, he became a pioneer when he began making sea salt using the geothermal energy of an abandoned hot spring in Iceland’s rugged and remote Westfjords.

Carefully, we step out on wooden boards and look down from above into the open tanks where scalding hot sea water evaporates at temperatures of at least 70 degrees. A fall here would mean being boiled alive.

Related: Say cheese: How this Norwegian breakfast staple is melting fine foodies’ hearts

But Icelanders are no strangers to danger. The whole country sits on ferocious geothermal forces that shake the earth regularly, shape the landscape, and create havoc when pressure builds and volcanoes erupt. In the Westfjords, evidence of nature’s brutality is everywhere: cliffs cut by volcanic activity, black sand beaches, and a barren, majestic landscape criss-crossed by deep fjords. These mighty underground powers are a great natural resource. Today, geothermal energy provides 90 per cent of Iceland with emission-free central heating. The public swimming pools are geothermally heated and bananas are grown year-round in geothermally heated greenhouses.

However, it was only 12 years ago that geothermal energy began being used as a sustainable way of harvesting salt from the sea. In the mid-2000s, Jónsson was a young engineering student living in Copenhagen. Working a student job as an untrained chef, he experienced first-hand the revolution that took place within the Copenhagen food scene where coffee roasters, bakeries, and restaurants were breathing new life into well-known ingredients.

“It really inspired me to see if I could do something similar with an Icelandic ingredient. Problem was I didn’t know which one,” says Jónsson. He discovered that Reykjanes in the Westfjords used to have a production of sea salt back when Iceland was under the rule of Danish King Christian VII in the late 1700s. Inspired by this story, Jónsson travelled to the original source to try his hand at salt-making. Using a home-made cast-iron salt pan placed directly on the near-boiling source, it took him a whole week to boil down 100 litres of seawater into roughly 200 grams of sea salt. After drying it, he went straight to Gunnar Karl Gíslason, then head chef at the Michelin-starred Dill, who, much to Jónsson’s surprise, was intrigued by the quality. “That was a very pivotal moment,” says Jónsson. “The idea that you have a sustainable product that you can har vest with your own hands, that really resonated with me.”

Today, we take salt for granted. However, throughout history, salt has been one of the most important trade commodities, vital for the preservation of fish and meat. When Danish monks discovered hyper-saline groundwater on the island of Læsø in the 1100s, it laid the foundation for one of the first great industrial adventures of the Nordics. For the next 500 years, the small island of Læsø supplied the Danish kingdom with tonnes of the white gold, harvested by reducing sea water in woodfired salt pans.

In Iceland, however, there are virtually no trees and no wood to fire the pans. Instead, the king’s men used a hot spring to boil down the sea water to get the salt so vital for salted cod – stockfish – a prized product that was shipped to France, Spain and Portugal and traded for more salt from southern Europe’s salt marshes. Export continued, but at some point, the geothermal sea salt production was abandoned and forgotten.

It was not revived until 2011, when Jónsson went almost straight from doing what he calls “useless reports” for a large IT company to extracting salt from sea water. Since the king’s men in the 1700s, no one had thought about using the geothermal energy for making sea salt on a commercial scale. Jónsson was convinced that he was on to something. With the help of an innovation fund and his own savings, he took over an abandoned salmon farm and started cooking.

Related: Icelandic Lava Bread: The beautiful tradition of baking bread in the ground

How does making sea salt work exactly? Well, the sea water in the Westfjords is around three per cent salt, and crystals start to form when it reaches a salt content of around 28 per cent, explains Jónsson. To get to that point, the sea water is ‘pre-cooked’ in the former salmon tanks, heated by circulating hot spring water and transferred from one tank to the other as the salt content rises. When the salt content reaches around 20 per cent, the water is pumped to the ‘salt pans’ – each the size of a king-size bed – and also geothermically heated. From these pans, the salt is manually harvested with a specially designed shovel once it has separated and has fallen to the bottom.

For every 1,000 litres of seawater that is pumped in from the depths of the fjord, Saltverk can extract around 28 kilos of salt. However, only half of that is the desirable sodium chloride. The rest is magnesium chloride, which is undesirable and must be separated. Luckily, the sodium chloride separates first, forming on the surface and then falling to the bottom of the pan, explains Jónsson. The magnesium chloride is not wasted, though. The by-product is used by Jonsson’s wife, Iris Laxdal, who is behind the natural skincare brand Angan, to make salt scrubs, bath salts, and other natural skincare products with wild Icelandic botanicals.

A trained architect, Laxdal did her master thesis on how to make full-circle use of both the salt production and the geothermal powers involved. “I’d never imagined that I would become a skincare entrepreneur,” she admits. “But while doing the research and analysing the different components of the salt, I found out that magnesium and other trace minerals like calcium and potassium actually have relaxing and anti-inflammatory properties.”

Cooking a batch of salt takes around four to five days and all steps in the process – from heating the sea water to drying the salt – are driven by geothermal energy. Once the salt is har vested, it is drained and dried in storage until the moisture is at 2-3 per cent, making it easy to crush.

That was not the case at first. “It was far from perfect to begin with,” Jónsson admits. Yet, he aimed high and went straight to Noma. “They said ‘no’ maybe the first five times I came knocking,” he says. The salt crystals were too hard and not easily crushed between the fingers, the chefs said. Now, however, Noma and many other renowned restaurants prefer his sea salt, which has the added benefit of carrying virtually no carbon footprint.

Related: A spoonful of Lurpak is just as enjoyable as a good piece of chocolate”: Meet Denmark’s professional butter tasters

The cold, wind-swept peninsula of Reykjanes sits a four-hour drive from Reykjavik and 90 minutes from the nearest grocery store. It used to house a boarding school, but now only a handful of people live here including Saltverk’s 10 employees, who produce 500-1,000 kilos of salt per day. One of them is Petar Štakić, the operations manager. Štakić says making salt is a physically demanding job, but the hardest part is not the heat, humidity, or the physical strain. It’s the darkness, he says, and the isolation.

“We try to make it very clear to people beforehand, but still, we’ve had some people throwing in the towel after just a few weeks,” says Štakić, who used to work as a raspberry farmer in Serbia. However, after a few terrible harvests and price slashings, he gave up agriculture and went on to Iceland to make salt. He and his wife have worked here for six years and welcomed twin boys to their family in 2023.

A new generation of salt makers is probably not the worst idea; Jónsson’s sustainable salt is in high demand. Currently, he is planning a new facility at Reykjanes where he can ramp up production and introduce more visitors to the pristine sea salt and the rugged beauty of the Westfjords.

Until then, Jónsson leaves his salt in the creative hands of some of the world’s finest chefs.