You lucky cow!

Massaged to ensure tenderness, and fed a diet of beer and grain to maximise taste, Japan's best known beef export is among the most expensive and tastiest in the world.

Wagyu is the best-tasting beef in the world," proclaims Leon Aart. His statement should not come as a surprise as Aart sells around 90% of the Wagyu consumed in Britain through Discerning Food, the company he owns with his wife Sarah.

Wagyu beef, is of course, the food that has gourmets and farmers alike drooling in appreciation. The Japanese breed, originally from Kobe, is massaged and fed on grain rather than grass, is given beer to drink and produces meat that is mouth-wateringly tender with extraordinary marbling. The fat melts at room temperature so "if you rub it between your hands, it will melt like a little bit of butter," says Aart, lovingly.

Two years ago, Aart bought 30kg of the meat and struggled to sell it. Now he sells around 3,500kg a month trying to satisfy demand from both the London restaurant trade (he supplies all three Nobu restaurants plus Zuma and Hakkasan) and his mail-order business.

Aart is not surprised at how popular the meat has become: "I always believed in it. The flavour is absolutely amazing. When I first tasted it 10 years ago I was blown away. I'd never experienced anything like it."

And Aart's testimonial is not just the marketing-speak of a businessman. Chefs and food-critics agree. One newspaper critic described the texture as "not dissimilar to that of foie gras: when you bite, the centre melts to a succulent paté".

The flavour comes from genetics, says Aart. The Wagyu breed has blood lines hundreds of years long, the result of isolated Japanese communities whose cows bred only within a limited pool. But a pedigree likes this comes at a price, and the cost per kilo (around £85) is almost as famous as the meat's legendary flavour.

The massive price is partly determined, says Aart, by the degree of marbling. Marbling is rated on a scale of 1-12. Meat with a score of 1 has no marbling and 12 is a very specialist product that is more fat than meat. Meat rated 10, 11 and 12 isn't available outside of Japan. "Good Aberdeen Angus beef is about a three, and Wagyu is usually a six," says Aart, who adds that the rich, soft meat means that cuts usually used for braising are suitable for eating as steaks. "Because of the genetics you can use the blade or the flank, they're great steak cuts," he says.

As the word spreads, Aart's business is growing. He buys the meat from Britain's only Wagyu farmer, David Wynne Finch, whose farm lies in north Wales, but because only 20 animals a year are slaughtered there, he also imports, mainly from Australia.

"They are really happy animals," he says of the beer-swilling bulls. "The meat's popularity will only grow." And with Britain's ever-growing interest in rare-breeds and specialist meat, he is probably right.