Beef encounter: Meet the master taster who can tell a cow's age, gender and breed from one mouthful of meat

Take nine sirloin steaks, varying in gender, maturation, breed and feed. Add to this the time of year it died and whether it was stressed prior to slaughter. Reckon you could tell the difference? You might be surprised.

I was. Like most carnivorous consumers, I'm happy to think about animals on farms and the meat I buy but I tend to do so separately. Research shows most of us are largely ignorant, not to mention uncomfortable, about the link between the two. And yet the difference these factors make to the eating experience is astonishingly marked – and, says Laurent Vernet, hugely underestimated, even by top chefs.

Vernet is to beef what Jilly Goolden is to wine. With no carnivorous equivalent to the Master of Wine, he is self-taught. Nonetheless, his renowned perfect palate for tasting meat – which enables him to tell sex, age and breed (among other things) from a single bite of steak – was long ago snapped up by Bristol University to assist them with studies on taste and flavour of meat, and more recently by Scotch Beef.

Self-important he is not, however. Whilst others brand his skill unique, he isn't so sure. "There's almost no science involved. I've met farmers and butchers who can immediately identify the same things I can, but they do it informally," he tells me as we sit in London's Landmark Hotel waiting for executive chef Gary Klaner to rustle up the first few cuts. "In any case, I want people to understand the differences in beef so they can find their favourites. You wouldn't pick up any old red wine without thinking about your preferences. Why shouldn't the same go for beef, which after all, tends to be the most expensive food in your shopping trolley?"

Keen to set the record straight on one of the greatest myths about beef, Vernet has organised for our first three steaks to have differing levels of maturation. Beef, like any food, has fashions. The current hit, especially in London butchers, is 46-day maturation. A mere nine days is, in some circles, now considered so bland that you might as well chuck it in the kids' packed lunch. Vernet disagrees and he's right that while its taste lingers for a shorter time than its two longer-matured equivalents, it is juicier and melts in the mouth. "Beware of the butcher that says all his beef is matured for x number of days," cautions Vernet. "The reality is they should get to know the individual carcasses, checking them every day, recognising every animal is different in terms of its premium state."

The second steak, matured for 21 days, definitely has stronger tastes – hints of mushroom and a discreet malt finish. Vernet says he'd have it with some Chanterelles. Meanwhile, the super-strength 46-day steak is just that – firm and bitter, even like liver. "I'm getting cold sweat flavour and a sour milk aftertaste," says Vernet. He's right, yet it tastes good – although I agree it's not superior to either of the others. "Ultimately, it comes down to individual preference," he says. "Provided it's good-quality well-reared beef, you can't (as some butchers and chefs do) say one type is categorically better than another."

Preference itself is a loaded concept in the world of beef. Indeed, in Vernet's first desk job, where he was tasked with selling the abattoir's meat to different countries, he soon learned that while the Italians, for example, favour very light flavours in their beef, people across the French border in Bordeaux – so not very far away – accept nothing less than, as Vernet puts it, "in your face flavours".

Scotland is another good example. "Traditionally, those on the Scottish west coast eat stronger beef. Game is plentiful there and in days gone by, eating beef or lamb just didn't happen unless they were a casualty, which usually meant the animal was older and therefore tasted stronger. Meanwhile, the grazing on the east coast means it's possible to rear more animals, which is why they have a preference for milder flavours."

In his next job, for the Meat Commission of Northern Ireland, Vernet travelled the world exploring the potential for beef sales (which, after BSE, never took off). "It was here that I learned about the Americas," he says. "North America, for instance, tends to favour juiciness, sweetness and the taste of fat, which comes from being used to animals fed on grain, usually natural grain like maize. England is similarly conservative on the whole. New Zealand, for example, loves to include the flavour of apple in their meat artificially but that wouldn't go down well here."

At Bristol University, Vernet started discovering subtle effects on beef like, for instance, the fact that "stressed" meat (an animal suffering any sort of pain or discomfort prior to being put down) has an excessively sweet flavour and squeaks against your teeth like polystyrene.

Vernet declares it's time to talk sex over our next three steaks. The first has a slight metallic taste, which I learn is due to female hormones, while saltiness in the second steak points to the animal being a bull. Both have a distinct sourness (in a good way), which is typical, apparently, of younger animals, especially in the spring when they are full of hormones.

The third is quite different. Not only are the fibres a brighter red, but there's a milky flavour. And when you chew, the texture is almost like the soft back of leather. Vernet is keen to know if I like it. Yes, it's delicious. He smiles, telling me the differences in colour, texture and taste are due to it being a cow bred to have babies and therefore very active. "And critically, while the other two animals were no more than 24 months old, this was over seven years old." Just because an animal is older, it doesn't automatically mean it will be like eating old boots. "Some butchers boast that their beef is no older than x months old – often 26 or 36. But you need to know more about the context. What's the breed, for example? Pure breeds taste better younger, for example, while with cross breeds, it doesn't matter so much."

What you're looking for in a good steak is three to four chews per mouthful, he says. "You chew beef at the back of your mouth and if it's too tough, you get beyond about four chews and automatically bring it forward. That's when you know you have a problem. But that's not necessarily anything to do with age."

Our final three steaks are different breeds – Aberdeen Angus (nice marbled meat, full of sweet dairy flavours), Limousine (cattle that originally came from France and give a more delicate meat due to thinner muscle fibres) and Charolais (also originally from France and whose muscles deliver strong toffee flavours and a tobacco aftertaste).

"A lot of people won't touch the last two because they say they're reared away from their natural habitat. A worthy complaint if it were true, because it does affect taste, but they've been in this country for over 100 years, for goodness sake," says Vernet. "They've got long hair because they've adapted to the weather. In fact, I would never ask a butcher for a particular breed. When I see restaurants specialising in one breed, I think why? Variety is the spice of life and much of what we eat is cross-bred."

He believes that feed is more significant to the taste of the meat than breed. "When I worked in the abattoir and the occasional animal escaped into the garlic field, you certainly knew about it once it had been slaughtered. The smell!" However, the idea that animals should only be fed grass is another current trend that Vernet disagrees with. "They need other things in winter and turnips or barley – two examples – develop sweetness and a nice marbling, which ultimately give more juiciness."

In fact, Vernet has no time for fear of fat, pointing out that if all traces of marbling and fat are stripped from a piece of lamb and a piece of beef, it is almost impossible to tell them apart. He admits to being miffed by what he calls "the rush for fillet" in preference to sirloin or rump. "Sure, it's lean and tender – it's a part of the body cows don't use – but there's very little flavour."

Perhaps the biggest irony about Britain's relationship with beef, Vernet says, is that while supermarkets ("even the most unexpected ones", although he won't say which) are now more inclined to inform customers about the origins and circumstances of the beef they sell, many catering colleges aren't even teaching chefs about beef. "They say it's too expensive, so they focus on chicken instead."

The perfect steak: Vernet's tips

Use the right pan: For juicy cuts, use a griddle. For dryer steaks, use a flat pan. If you place a juicy steak on a flat pan, the liquid will boil and ruin taste and texture. If you put a dry steak on a griddle, you'll make it even dryer. If you're not sure which category your steak fits into, ask your butcher. Alternatively, go by the rule that the more marbling, the more juice.

Get your temperatures right: Your pan needs to be very hot. Top chefs think nothing of heating the pan five to ten minutes before putting the steak anywhere near it. The steak itself should ideally be room temperature. If it's too chilled, the meat fibres will contract together and produce a massive release of juice, potentially drying out your steak.

Cooking your meat: Steaks can be trimmed of fat before or after cooking. The latter option adds a little more flavour. Lightly coat the steak with oil before placing on your pan/griddle and allow the meat to cook until the desired amount of browning occurs. Go by the rule of two-and-a-half minutes each side for rare; 3-4 minutes each side for medium rare; 4 for medium; 5 for medium well; and 6 for well done. If using a griddle, rotate the steak 45 degrees while cooking for a criss-cross effect.

Bone or no bone? Some butchers say steaks best retain their flavour when cooked on the bone, but there's no evidence or logic to suggest this is true. Since butchers have to pay to dispose of bones, they may have an ulterior motive. That said, bones are always good for stock or soup.