Celebrity chef Heston Blumenthal is famous for his scientific approach to cooking.

But the beefburger he could be serving up in eight months' time will surpass even his most outlandish efforts.
The "test-tube burger" will be the first beef patty ever created in the laboratory.

Its price tag - 250,000 euros (£207,535) - reflects just how exclusive this culinary experience will be.

The burger's true "chef" is Dutch stem cell scientist Dr Mark Post, from the University of Maastricht.

After experiments which progressed from mouse meat to pork, he is now ready to produce an artificial burger that looks, feels and tastes like the real thing.

Sandwiched between two buns, it will make a grand public entrance in October.

The current plan is for Blumenthal to cook it for a mystery guest, to be chosen by the research project's anonymous funder.

The minced meat will have been grown from bovine muscle and fat stem cells cultured in Dr Post's laboratory.

Speaking at the annual meeting of the American Association for the Advancement of Science (AAAS) in Vancouver, Canada, Dr Post said: "In October we're going to provide a proof-of-concept showing that with in-vitro methods, out of stem cells we can make a product that looks like and feels and hopefully tastes like meat.

"That first hamburger is going to cost 250,000 euros."

Right now Dr Post is still working with unappetising half-millimetre thick strips of lab-grown meat that are pinky-yellow in colour.

But he is confident that over the course of this year he will produce a burger virtually indistinguishable from one bought in the high street.

The research has a serious aim - to address the problem of unsustainable livestock farming.

"These animals are very inefficient in the way they convert vegetable matter to animal protein," he said. "Cows and pigs have an efficiency rate of about 15%, which is pretty inefficient. Chickens are more efficient and fish even more.

"Meat demand is going to double in the next 40 years. Right now we are using 70% of all our agricultural capacity to grow meat through livestock.

"You can easily calculate that we need alternatives. If you don't do anything meat will become a luxury food and be very, very expensive.

"If we can raise the efficiency from 15% to 50% it would be a tremendous leap forward."

In time, he expected the cost of test-tube meat to be brought down to affordable levels. It may then present consumers with the same kind of choice they currently have between buying battery farm or free range eggs.

Test-tube meat would greatly reduce the number of cattle taken to slaughter, with each animal theoretically capable of producing 100 million burgers.

It would not even be necessary to kill them to extract their stem cells, and the conditions they lived in could be much improved, said Dr Post.

He added: "I have spoken to the chairperson of the Dutch Society of Vegetarians who said probably half their members will start to eat meat if you can guarantee that it costs much less animal lives."

Another reason for making test tube meat is environmental. Livestock produce more greenhouse gas emissions than transport vehicles - 39% of all methane, 5% of carbon dioxide and 40% of nitrous oxide.

The process of making test tube meat involves first obtaining the stem cells and allowing them to proliferate around 30-fold. Every muscle cell is accompanied by four or five stem cells.

The stem cells are grown in a culture medium containing all the nutrients and vitamin "food" they need.

To construct three dimensional tissue, the cells are mixed with a collagen gel in a culture dish containing velcro "anchor points".

Between the anchor points, they self-organise into fully-fledged chunks of muscle. An important step is to make them contract using electrical stimulation. This has exactly the same effect as body-building exercise, generating more muscle protein.

Finally the beef strips are harvested, minced up, and moulded into a patty. To make the burger more realistic, the muscle meat is mixed with fat grown the same way from a different kind of stem cell. Three thousand pieces of muscle are combined with around 200 pieces of fat.

Dr Post believes it will be a relatively simple matter to scale up the operation, since most of the technical obstacles have already been overcome.

He said: "I'd estimate that we could see mass production in another 10 to 20 years."

A big advantage of test-tube meat is that it can be customised for health, for instance by boosting levels of polyunsaturated fats, he added.

Moving on to manufacturing steaks presented much greater technical challenges, said Dr Post. Some kind of blood vessel system, or an artificial version of one, is needed to carry nutrients and oxygen to the centre of the tissue.

Making chicken or fish from stem cells might be easier, but less necessary because of their more efficient vegetable to meat protein conversion rate, he said.

Dr Post refuses to reveal the identity of the private individual financing the research, who wants to remain anonymous.

But he said he was a well known figure with "deep pockets".