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Most chocolate starts to melt at 30 degrees. Photograph: PA

We have been indulging in it in various forms for at least 3,000 years, arguing over its influence on everything from our sexual appetites to our waistlines.

But now scientists for the world's largest chocolatier believe they have stumbled on the holy grail of chocolate: a recipe that is both melt-resistant and low-calorie.

Vulcano is the internal code name for the new product by the Swiss chocolate manufacturer Barry Callebaut. Developed in a laboratory under top-secret conditions by an international team of food engineers, it not only has 90% fewer calories than the average chocolate product, it is also heat-resistant to temperatures of up to 55C (131F). Most chocolate starts to melt at 30 degrees.

The company aims to target calorie-conscious European and US markets as well as emerging markets in Asia and Africa where local temperatures have hindered the spread of chocolate.

"It's called Vulcano because it can be eaten when it's hot, and its airy and full of bubbles, like volcanic rock," said Gaby Tschofen, a spokeswoman for Barry Callebaut, which annually makes 1.1m tonnes of cocoa and chocolate-based products for customers around the world, including Cadburys and Nestlé.

The product, like so many good inventions, resulted from a mistake, this time by technicians in the company's lab who were working on another invention. "Suddenly we realised we'd produced a very special chocolate, of a crispy, light consistency, like an airy foam, and we thought let's see if we can develop this further," food engineer Simone Cantz told Swiss television.

Under current plans it could be in a shop near you within two years, meaning an end to finding a melted chocolatey mess in your pocket on a hot day or worrying about your waistline.

While chocolatiers have been trying to produce a lower-calorie chocolate for years, the obstacle has often been how to keep the rich and lingering taste and ensuring it is still a pleasure to eat.

The US manufacturer Hershey began experimenting with a melt-proof chocolate during the second world war. But the result was a very hard bar that was never produced commercially.

Tschofen said she could not give away Vulcano's recipe, but she had tried it. "It's nice and chocolatey, with a strong aroma, and crispy rather than creamy.

"It does melt in the mouth, but it is the enzymes in saliva rather than the heat of the tongue that causes it to dissolve."