It could be a cocktail found in any refined bar with its elegant crystal tumbler, heap of misty ice, twist of orange and cherry garnish. Except that it's jet black, the liquid inside like molten licorice. The drink looks inviting yet repellent - a challenge. The taste holds smoky notes softened by a flowery sweetness, a hint of spice and something dry, clean and textured. The cocktail, served in London's Bull in a China Shop, is the classic Old Fashioned with a very dark twist - made of Japanese whisky, home-made chamomile syrup and Angostura bitters, its colour and texture comes from the addition of powdered charcoal.

It's not the first time those in the culinary world have experimented with things burned. Ferran Adrià of El Bulli played with charcoal oil, while Andoni Luis Aduriz of Mugaritz, also in Spain, cooked grilled toast of bone marrow with herbs and horseradish ash. René Redzepi of Copenhagen's Noma served up leek ash, Simon Rogan of Britain's L'Enclume blitzed whole burned onions, and Yoshihiro Narisawa of Creations de Narisawa in Tokyo coated beef in "sumi", a Japanese charcoal made from charred vegetables.

In Hong Kong, too, Michelin-starred restaurants have used charcoal, including at Shang Palace, which has offered bamboo charcoal noodles prepared with a variety of dishes.

Charred ingredients have also made it to the apothecary stocks of trend-setting bartenders around the world. Alex Kratena at London's Artesian bar added vegetable ash to his existentially fraught Dream Within A Dream cocktail, while The Carbon Bar in Toronto serves the lethal-sounding Black Mamba Margarita with charcoal-infused Avion tequila, St Germain elderflower liqueur, Bowmore single-malt Scotch, lime and a sea salt rim.

So what's driving this obsession with the darker side of culinary experimentation?

Certainly there's the drama of the colour and the textural effect.

"Activated charcoal doesn't have much taste, but it gives a gorgeous black colour. It also adds texture, with a mouth-feel that's somewhere between grainy and powdery," says Simon Chan, part-owner of Bull in a China Shop.

"The fact that it has no flavour is exactly why we used it for our Charcoal Old Fashioned - we found that many twists on the classic recipe don't end up tasting like an Old Fashioned. But with ours, the charcoal makes the cocktail look radically different, but it tastes authentic."

The cosy bar and restaurant located in London's hipster neighbourhood of Shoreditch also serves up a panko-crusted chicken burger with a charcoal bun and mango chilli relish.

Charcoal can also be used in sweets. ATUM Dessert in Causeway Bay has a platter of bamboo charcoal ice cream, chocolate ice marshmallow, chocolate caviar and raspberry sorbet on its menu. The charcoal powder is mixed into chocolate, giving the ice cream a very dark brown, almost black appearance.

The charcoal and strawberry ice cream served at London's OXO Restaurant & Brasserie last summer, however, was grey. The creation was part of a limited-edition superfood ice cream trio, with the other flavours being Baobab, Chia Seed and Cranberry, and Bee Pollen and Raspberry Ripple. "We mixed charcoal powder with fresh strawberries and a hint of rosewater to give the ice cream a subtle, summery flavour to create a boundary-pushing ice cream with added benefits," says Penny Wabbit, the restaurant's head pastry chef.

"We wondered how a grey-coloured ice cream would be received, but our customers are an adventurous bunch and loved trying something rather different."

The fact that charcoal is included in a "superfood" dish points to another reason why chefs and mixologists are integrating it into their recipes. Charcoal is used to treat extreme cases of poisoning by certain chemicals present within the gastrointestinal tract. It is also gaining popularity today as a health supplement. Goop, actress Gwyneth Paltrow's lifestyle website, named charcoal lemonade as one of the best juice cleanses in 2014, and over the past 12 months, sales of activated charcoal capsules have soared at health food outlets.

Activated charcoal is not to be confused with regular charcoal - grinding up leftover lumps of charcoal after a barbecue will not do - nor is it the same as eating the charred layer on overcooked toast. Activated charcoal is produced by heating a high-carbon substance to high temperatures, and then oxidising it. The particles that remain are almost pure carbon, and the resulting structure has an enormous surface area, giving it the ability to absorb various chemicals to its surface.

Activated charcoal, which is not absorbed in the gut, has been touted, therefore, as a detoxifier with the ability to remove toxins from the body. These claims are, however, contentious.

"There is insufficient evidence to support the use of activated charcoal to help the body 'detox', lower cholesterol, decrease flatulence and remedy hangovers, which some claim," says Hong Kong-based registered dietitian Sally Poon Shi-po.

So the Charcoal Old Fashioned may not be the imbiber's holy grail - a drink that leaves you magically hangover free - but it's a dramatic elixir for those on a quest for something new and adventurous.

 

BODY AND CHARCOAL

Charcoal has been used for centuries in Chinese and other Asian traditional medicines. It is ingested for stomach pain, and is used externally in moxibustion therapy, which involves the burning of the herb mugwort (artemisia argyi), sometimes in the form of charcoal sticks or cones.

Chef Yoshihiro Narisawa of his eponymous Tokyo-based restaurant has previously stated that his sumi beef - which is covered in a layer of charcoal made from vegetables - has detoxifying properties.

"The char has cleansing power. You can't eat too much, it's not good for your stomach and intestines if you have too much, but a small amount can cleanse your system. Some tribes will eat raw soil for the same reason."

Activated charcoal is also now being used as a natural "detoxifier" that removes impurities from the body, although there is little evidence to support such claims. Natural health enthusiasts say one tablespoon of activated charcoal powder a day with plenty of water is about the right dosage. Too much and some believe the charcoal will also strip out health-giving vitamins and minerals from the body.

Activated charcoal, and charcoal sticks for water purification, can be found at health food shops. Bamboo charcoal is the most readily available, but there is also powder from coconut husks and other woods.