SHOVING a carafe into the soda stream, I jump back as brown, fizzy, sticky liquid spurts over the brim and on to my hands, forming a puddle on the worktop.
The surface is already a mess. Vials of fragrant essential oils are scattered around carelessly, while a white mound of pure caffeine sits ominously atop of a set of digital scales. I lick my finger. It tastes like Coke.
This week, the American historian Mark Pendergrast published a formula for the world's most prolific soft drink - and this is not just any recipe. This is the original "secret formula", as used by pharmacist John Pemberton when he first mixed the drink in 1886, in Columbus, Georgia.
Now, more than a century later, there are only two places in the world where you cannot buy Coca-Cola: North Korea, and Cuba. Despite this, and with the help of Pemberton's formula, I am attempting to recreate it from scratch.
At first glance, the formula appears simple. Printed in the third edition of Pendergrast's book For God, Country and Coca-Cola: The Definitive History of the Great American Soft Drink and the Company That Makes It, it is a brief list, with no instructions.
The handwritten notes are from the pen of Frank Robinson, Pemberton's commercial partner and the man whose handwriting forms the company's distinctive italic logo. Passed down through the Robinson family, copies of the notes were eventually given to Pendergrast by Laura Robinson-Vanwagner - the great grand-daughter of the original Robinson.
This isn't the first time that Coca-Cola's coveted secret formula has been revealed, nor the first time someone has tried to recreate it. Pendergrast himself found and published what he believed to be a version of the original formula in 1993. In 2011, presenters of the US public radio show This American Life revealed that they had found a version of the recipe in the pages of a 1979 edition of the Atlanta Journal-Constitution newspaper (the Coca-Cola Company is headquartered in Atlanta). They cooked up a batch, which was meant to taste pretty accurate.
"I think it's quite possible to make it," says Pendergrast. "There are a lot of generic colas that taste very close. But to get it exactly right I think would be very difficult even if you have the formula, as the formula isn't very precise."
Surprisingly, Pendergrast himself has never tried to do this himself. "I wouldn't know where to get hold of all the stuff!" he tells me. "But I encourage you if you can to find some whole coca leaf, so you get the actual cocaine content in it. Which is illegal, though I do have some friends who brought some back from Peru for me, but I haven't tried it yet … The interesting thing about this formula is that something is obviously the matter with it because it has got nutmeg on twice, as fluid extract and nutmeg oil, which doesn't make any sense."
I'm not absolutely sure that the incorporation of illegal drugs in the recipe is a brilliant idea, but the nutmeg thing seems a more practical concern. I ask which one I should leave out. "I have no idea!" exclaims Pendergrast. "Don't ask me, I'm just a historian."
Indeed, as Pendergrast suggests, acquiring the necessary ingredients is far more of a challenge than expected. My local grocery store does not stock neroli oil. Caffeine is not visible in the aisles at Sainsbury's and, despite a cursory wander through my local market for a Peruvian vegetable stall, coca leaves are nowhere to be seen. The ingredients required for the Coca-Cola flavour itself is a mix of seven essential oils. After hours of hunting, I have only vanilla.
Eventually, I track down a specialist online food supplier, Sous Chef, where I get my citric acid, lemon oil, cinnamon oil and caramel-based colouring. As I sit on the train back from its North London warehouse, I stare enviously at the woman opposite me drinking happily from a red-and-white can.
Food-grade essential oils, it transpires, are not only very difficult to get hold of at short notice, but also quite poisonous if used incorrectly. Likewise pure caffeine, not to mention the coca leaves, which I can tell you now did not form part of The Independent's reicpe. As the day ticked on, it was becoming clear that I was not going to be able to manage alone.
In a last-ditch attempt for assistance, I cold-call Bompas and Parr, the food art studio best known for making architecture out of jelly. Apparently, making Coca-Cola from scratch isn't such a big deal after all; they invite me in to use their kitchen, which, I am assured, is stocked with all the essential oils I could possibly need.
Helping me in the kitchen is Bombas's "chief jellymonger" Olivia Bennett, who is reassuringly unphased by the task. Compared to the studio's usual creations - caves made out of sugar, a chocolate-based climbing wall and exploding wedding cakes - my project did start to seem rather pedestrian. As if to prove this point, while I start fumbling with the SodaStream, Olivia and a colleague begin discussing the possibility of making the bubbles go down, rather than up. "We could make backwards cola," she suggests.
Leaving that particular idea for another day, I start preparing the flavouring formula while Olivia measures out the sugar. Even after scaling down the recipe to produce 1.5 litres of the concentrated syrup, there is still one kilogram of sugar to go in. Luckily, being a studio that predominantly makes jelly - a sign on the industrial-sized fridge is marked "Jelly Only" - there is a vat of about 30 times this amount hiding helpfully beneath the table.
I place a drop of each of the oils into a small amount of 63 per cent over-proof rum, which can act as the alcohol base, then add the lime juice, caffeine and citric acid. We boil the sugar water and brown caramel colouring until it is a thick syrup, then stir in the potent, aromatic flavouring. It smells like a mixture of perfume and Coke, probably because I have been a bit overzealous with the vanilla and neroli oil, a flavour used in a lot of cosmetics.
As for the caffeine, the amount suggested is several times more than you could possibly want to consume and this is a recipe that is also meant to contain cocaine. We decide that the prudent thing to do is reduce the amount by half in order to avoid a potentially fatal overdose.
Finally, we add one part syrup to five parts water before putting it through the SodaStream to carbonate it. The gas steams out of the carafe like smoke. Like an alchemist who has created black gold, I pour the fizzy black liquid into my glass. It looks like Coke. It smells like Coke. It tastes … not quite like Coke. It's sweeter and there's a slight medicinal scent to it, although it's certainly not bad. Colleagues in the office agree. Still, having spent an exhausting day trying to concoct it, the sugar hit was much appreciated. But I suppose it's true what they say: you can't beat the real thing. Still, if you can get the requisite kit, it can be pretty entertaining to try.
The original formula (caution: includes liquid cocaine)
For 36 gallons:
216 pounds of sugar
18 gallons of water
29oz lime juice
29oz citric acid
3 quarts colouring
15 quarts (ﬂuid extract) coca
For the flavouring:
1½ quarts of alcohol
12oz [ﬂuid extract] nutmegs
19oz ext vanilla
13 d [illegible-"drops?"] oil lemon
10 d oil cinnamon
12 d oil nutmeg
15 d oil coriander
12 d oil neroli
Home brew from a cocktail maestro
In my eyes Coca-Cola is the most iconic soft drink. No matter where you are in the world, the brand is famous. Whether it's the classic glass bottle or red and white logo, everyone knows it and they know what to expect the moment they take a sip. In my 30 years of working in the bar and alcohol industry, Coca-Cola has never gone out of fashion, which I think is because it's so versatile.
Of course, Coke is a great mixer with alcohol, a vital component for a Jack Daniel's and Coke, or a classic cocktail such as a Long Island Ice Tea, which I would use it for to give it a hint of vanilla and coffee-like aftertaste.
My home-made cola is pretty simple. Allow all the ingredients to infuse in the hot water for 30 minutes and stir periodically to dissolve the sugar, then fine strain. Cool the mixture in a fridge, then pour it into a carbonating system - such as a Soda Stream - give two blasts of carbon dioxide, and voila!
Salvatore Calabrese's bar, Salvatore, is at the Playboy Club in Mayfair, central London
500ml hot water
10ml lemon Juice
Zest of 2 oranges
Zest of 2 limes
Zest of 1 lemon
1 vanilla pod
2 dry bay leaves
10 coffee beans
1/2 cinnamon stick
A piece of a liquorice
1 tsp caramel syrup
1 tsp malt extract
3 tablespoon caster sugar
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