Going behind the trend of long ageing in the world of high-end beef

YOU HAVE TO be a certain type of person to look at a piece of uncooked, long-aged beef and see any kind of beauty. The type of person who knows that, hidden behind the darkened flesh, yellowing fat and creeping mould, lies something that has the potential to be truly spectacular. Or, if you're of a totally different mind, something that's gone beyond the point of being plain old beef and drifted into an altogether different place – and not necessarily a place you or your palate want to go.

Either way, there's a lot of old beef about; meat aged for several months (as opposed to weeks, if that) is a familiar fixture in butchers, on restaurant menus and on the Instagram feed of carnivorous foodies with a sort of looming, go-on-I-dare-you-to-cook-me presence.

And it's not just long-aged beef; it's long-lived beef, too. If you haven't heard about – let alone tasted – the steak from a 12-year-old Galician ex-dairy cow at hotter-than-the-sun Kitty Fisher's in Shepherd Market, which planet have you been on, and why weren't you checking your Twitter feed?

Those who can't get enough of this kind of meat will tell you one taste will change your life; that ageing – specifically dry-ageing – beef for long periods of time extracts flavours from the meat that you never knew existed, notes of strong cheese, nuts and what you'll often hear referred to as 'funkiness'. They'll say similar things about the flavour and texture of beef from older cattle. Others will tell you it's social-media fodder or marketing bluff that's more a bigger-is-better arms-race than a genuine pursuit for better-tasting meat. However you look at it, when it comes to beef, age matters. But why?

Age ain't nothing but a number

"All meat needs to be aged to some extent," explains Richard H Turner, a man who – as executive chef of Hawksmoor, one half of butcher Turner & George and part of the team responsible for bringing US food festival Meatopia to London – is one of London's most influential evangelists for good beef. "You can't eat meat that's freshly killed unless you've got teeth like a tiger's," he says.

Once a cow has been slaughtered, decomposition begins and enzymes, microbes and other chemical processes start to act on the tissue, making it tender enough to eat and altering the flavour.

Much of the beef we eat in the UK is 'wet-aged'; packaged in vacuum-sealed bags for a few days or more with no contact with the air, only blood. In dry-ageing – until a few decades ago the dominant form – the meat is hung in a cold room for an extended period of time, which changes the flavour and texture dramatically.

How long, exactly, depends on a complicated combination of factors, including the individual animal it the meat came from (the breed, what it was fed, how old it was), the precise piece of meat you're ageing, and personal preference. The former two are all about the quality of the beef and the skill of the butcher, while the latter is up for serious debate among steak-lovers.

"There's a trend for long-hanging of meat all over the world right now," says Turner, "but I don't really believe in it. I think meat probably shows best at about five weeks – which is still quite a long time – so between five and six weeks is ideal. If it's really good meat, and it's reared ethically and properly on grass, it doesn't need the ageing – the sweetness and funkiness cover up sins."

Gavin Lucas, who as Burgerac is one of London's best-known burger bloggers, agrees. "The thing about beef and age is that it's a complex balancing act: different parts of a carcass will age at different rates and the exterior will take on age more than the interior.

"A lovingly aged steak can be delicious – but I personally want to taste beefiness more than I want to taste aged fat."

So what changes once you get past the 35-day mark? Nathan Mills, of south-east London's the Butchery, conducted a test with a group of chefs, food bloggers and friends – blind-tasting beef dry-aged for different times in search of the sweet spot.

"Everyone really enjoyed the 28-day aged beef, but we were all looking for more beefiness and tenderness," he says. "Once we got to 100 days, we found that the muscle structure of the meat had broken down so much it was almost like a pâté."

By 100 days the muscle had broken down so much it was more like paté

The winner was the 55-day-aged steak: "The meat's tasty, the fat's tasty and it's really tender."

As Mills points out, though, all animals aren't created equal, and the results of dry-ageing can vary from cow to cow, but the potential to stretch the ageing process to deliver what he calls "that beef wow factor" is clear, even if it isn't for everyone.

"Some people don't agree with beef that's been aged for, say, 65 days, because they don't like either the texture or the flavour – and that's just one of those things. If we can give people as much information as possible and say 'this is what it's going to eat like', they can make an informed decision."

But for those who do like to push the boundaries there are plenty of options, and one London chef currently using very long-aged beef (and one of Mills's customers, as it happens) is Michael Hazelwood of Soho restaurant Antidote. Hazelwood has put a 90-day sirloin on the menu – caramelised in the pan, then roasted on a rack in the oven for a few minutes. He's even served 90-day-aged tenderloin as a tartare, dressed in its own rendered fat: "It went down well. A few people said it was a bit strong, but no one said they didn't like it."

Time waits for no cow

Whatever end-point you're after – whether you're looking for fresh, unfettered beefiness or complex, funky flavours – what's clear is that you're only going to get there with a pretty special animal, and sometimes that means it's old. But how old is 'old'?

Most commercial cattle are slaughtered by 18 months old, and measures left in place after the BSE crisis in the 1990s mean there are complications (and costs) associated with slaughtering cattle more than 30 months old. That, and the fact that keeping a cow for ten years instead of two requires care, money, space and patience on the part of the farmer.

"We generally only slaughter older cattle [between three and six years]," says Jon Wilkins of the Butcher's at pub and restaurant the Pointer in Brill, Buckinghamshire. Unusually, the Pointer has its own herd of English longhorn cattle and in-house butchery.

"We believe the older animals have a more rounded marbling and in turn impart a better flavour. You can't hide behind a steak so it has to have the best flavour possible."

Slow-cooked beef at Meatopia

The Pointer's longhorns are grass-fed, so "they need the time to mature naturally", and the the owners remain committed to this, rather than unnatural, energy-rich feeds like corn. "Part of the reason for selecting longhorn was their timid and relaxed nature," Wilkins says. "Grass-feeding allows us to keep that theme through their entire life – not stressing the animals, which has a greater impact on the finished beef."

As the Butchery's Nathan Mills says, however, feed and lifestyle (not to mention breed) have a big impact on the ease of ageing the meat. A ten-year-old ex-dairy cow, raised on a heavily supplemented grass diet, will typically have a very different fat content compared with a cow fed exclusively on grass.

The latter's is, he explains, "like the kind of fat you find in Iberico pork, which melts on your tongue. You find that in grass-fed, aged, old beef – it starts to melt very quickly and ageing that is a lot harder than ageing meat from a dairy cow of the same age."

Those who love eating meat from older cattle, however, will tell you the farmer's hard work and the careful balancing act performed by the butcher is worth every bit of effort and money, though you might not necessarily expect the results to end up in a bun.

It's the best beef I've had, with a flavour almost like parmesan

"I just wanted to source the best beef I could find for my burger, with the deepest flavour," says Adam Rawson, head chef of Peruvian-inspired Marylebone restaurant Pachamama.

His menu includes a burger made with beef from Galician cows aged anything up to 17 years, though currently he's using beef from eight-year-old Basque ex-dairy cows. The older beef, he tells me, "unfortunately doesn't shine through as much in mince," so he's adding it to the menu on its own. "It's the best beef I've ever had, with an aged, almost parmesan-like flavour."

Flavours with that degree of intensity won't be for everyone, but if you're a carnivore looking for something truly different – and, let's face it, an experience that plays well in a food scene where social media matters – the extreme ends of the age spectrum offer some serious clout.

When I sit down with Hawksmoor's Turner, he's freshly returned from a research trip to Northern Spain, where he ate meat from both older cattle (they call it buey, or ox) and beef aged for as long as eight months. In the hands of José Gordón of La Bodega El Capricho, near León – "a master and a fanatic," says Turner – it was "delicious", though he admits he's not sure whether this kind of meat even qualifies as steak at all.

"It's from the same animal and it's fantastic, but it's so far removed from what we're used to that a lot of people wouldn't recognise it."

Either way, you can expect to see more of it appearing on menus and butchers' blocks in London. Whether you think that's a good thing is – as with anything we eat and drink – a matter of taste. But if it's one you've acquired, there's never been a better time to be a steak-loving Londoner. ■