AS FREEBIES go, it was a disappointment. Of the hundred-odd representatives of the world’s media who crammed into a television studio in London on August 5th, none got so much as a bite of the food on offer. What they did get, though, was a taste of what may prove to be the future of eating. The meal they gathered to witness other people digest consisted of the world’s first hamburger made of meat grown from scratch in a laboratory.

What the 140-gram patty lacked in heft it made up for in price. At more than €250,000 ($330,000), a tab partly picked up by Google’s co-founder, Sergey Brin, it must rank among the most expensive dishes in history. After sizzling in a pan for a few minutes under the watchful eye of a chef, the burger was served to two preselected tasters—a nutrition scientist and a food writer. Their verdict, “like meat” but “not that juicy”, did not perturb Mark Post of Maastricht University, who grew the beef. In fact, Dr Post, who also savoured some of his creation (and is pictured holding it), had every reason to call it “a good start”.

Besides powdered egg and breadcrumbs (for binding) and beetroot juice and saffron (to enhance colour), the patty was composed entirely of cultured muscle cells. To make it, Dr Post began with stem cells taken from two live cows (a Blanc Bleu Belge and a Blonde d’Aquitaine). He multiplied these cells a trillionfold and then merged them into myotubes (in essence, artificial muscle fibres), each less than 3mm long. This done, he wrapped the myotubes around hubs of agarose, a gel-like polymer extracted from seaweed, and fed them a diet of amino acids, sugars and fats (all derived from plants) to make them big and strong.

Muscle cells’ natural tendency to contract and relax meant that the myotubes bulked themselves up into rings of muscle tissue through continual movement. When each ring had grown sufficiently (this took three months, which is, as Dr Post points out, “faster than a cow”), he cut it free to create a strand. He used 20,000 of these strands to make the historic burger.

The result was a far cry from a Porterhouse or a fillet steak. Cultivating something like that would mean growing the cells into big three-dimensional structures—which would in turn entail delivering nutrients deep inside the tissue. To do so would require blood vessels or some artificial equivalent. A real steak would also contain fat cells, the absence of which explained the lack of juiciness. Such cells are harder to culture than muscle. Dr Post and his team are working on both these points.

Carnivores should cheer. The world’s appetite for meat is forecast to rise by 70% by 2050. Nearly a third of the world’s ice-free land is already used to raise livestock or grow fodder for these animals. Without a radical technological shift the new demand will be hard to satisfy. Vegetarians, too, have reason to egg Dr Post on. A single sample of stem cells could, he reckons, yield 20,000 tonnes of “cultured beef”. This is enough to make 175m quarter-pounders, a number that would require 440,000 cattle to be slaughtered.

In addition, animal husbandry is responsible for 18% of the world’s greenhouse-gas emissions, since cattle produce prodigious quantities of methane—a gas whose warming potential is 20 times that of carbon dioxide’s over the course of a century. Growing meat in factories would help reduce these emissions. And if home-based meat kits eventually became available, it would give a whole new meaning to the phrase “hand-reared”.