All it took was a little butter and sunflower oil and, in less than 10 minutes, the world's most expensive burger, grown from muscle stem cells in a lab, was ready to eat.

"I was expecting the texture to be more soft," said Hanni Rützler of the Future Food Studio, who researches food trends and was the first to get a taste of the synthetic beef hamburger at a lavish event in London on Monday that bore more resemblance to a TV set than a scientific press conference.

The lack of fat was noticeable, she added, which meant a lack of juiciness in the centre of the burger. If she had closed her eyes, however, she would have thought the cultured beef was definitely meat rather than a vegetable-based substitute.

The burger was grown by Dr Mark Post of Maastricht University. Photograph: David Perry/EPA

The fibres had been grown in the lab and bound together, coloured with beetroot juice and shot through with saffron to complete the burger that, from a distance at least, looked perfectly ordinary. The chef tasked with cooking it was Richard McGeown of Couch's Great House Restaurant in Polperro, Cornwall, who said it was slightly more pale than the beefburgers he was accustomed to but that it cooked like any other burger, was suitably aromatic and looked inviting.

American food writer and author of the book Taste of Tomorrow, Josh Schonwald, was next up to take a piece of the precious burger. He said he had never been pleased by meat substitutes but, after chewing a bit, gave it full marks for its "mouth feel", saying it was just like meat and that the bite felt like a conventional hamburger.

But he also noted, several times, the absence of fat or seasoning. "I can't remember the last time I ate a burger without ketchup," he said, when trying to explain whether or not it compared well to a real hamburger. Later in the tasting he described the texture as "like an animal protein cake".

Dr Post shows the hamburger to the world's press. Photograph: David Parry/EPA

Mark Post, the scientist behind the burger, which took three months to make, said the ambition was to improve the efficiency of the cell-growing process and also to improve flavour by adding fat cells. He wants to create thicker "cuts" of meat such as steaks, though his would require more tissue engineering expertise, namely the ability to grow channels - a bit like blood vessels - that can feed the centre of the growing steak with nutrients and water. Similar technology had already been shown to work for medical applications, said Post.

The €250,000 cost of making the burger was paid by Google co-founder Sergey Brin, who said he got into the idea for animal welfare reasons. In a film to mark the taste test of the burger, he said that people had an erroneous image of modern meat production, imagining "pristine farms" with just a few animals in them. "When you see how these cows are treated, it's certainly something I'm not comfortable with."

The hamburger was made from 20,000 muscle fibres grown from stem cells. Photograph: David Parry/EPA

Dr Post's team at Maastricht University used the money to grow 20,000 muscle fibres from cow stem cells over the course of three months. These fibres were extracted from individual culture wells and then painstakingly pressed together to form the hamburger that was eaten on Monday. The objective is to create meat that is biologically identical to beef but grown in a lab rather than in a field as part of a cow.