The only official written copy is supposedly held in a US bank vault and only two company employees alive at any one time are said to know the whole formula that gives the fizzy drink its distinctive flavour.
But now, 125 years of near-total secrecy look to be over, as a website claims to have uncovered a list showing the ingredients and quantities used to make the drink.
The list, it claims, was actually published without fanfare in a 1979 local newspaper article in Coca-Cola’s US hometown of Atlanta, Georgia – but no one appeared to realise its significance.
The website, Thisamericanlife.org, said the 32-year-old article – buried on Page 28 of the Atlanta Journal-Constitution – shows a photograph of a recipe purported to be an exact replica of Coca-Cola creator John Pemberton’s.
The recipe had apparently been written by a friend of pharmacist Mr Pemberton’s then passed down through the generations. A can of Coca-Cola currently simply refers to its specialist ingredients as “Natural flavourings including caffeine” alongside carbonated water, sugar, phosphoric acid and colour (Caramel E150d).
Thisamericanlife.org consulted historian Mark Pendergrast, who has written a history of the drink and believes the recipe could be, as Coca-Cola’s famous slogan goes, the real thing.
He said: “I think that it certainly is a version of the formula.”
Should he be right, it would unlock the key to one of the world’s most recognisable brands which is sold in more than 200 countries. In 2010 Coca-Cola had become the first brand to top £1-billion in annual UK grocery sales.
So it is perhaps no wonder that the firm has been eager to keep its recipe from competitors.
Asa Candler, one of the first presidents of the company, was so worried that the “Holy of Holies” would fall into the wrong hands he made sure it was never written down.
He removed all the labels from the containers of the ingredients so they were identified only by the sight, smell and where they were put on the shelf.
A crucial part of the formula was also given the name “7X” to add to the mystique.
Mr Candler even used to go through company mail himself and remove invoices for ingredients so no one in the accounts department could sell the recipe to a rival.
“The company has always said, and as far as I know it’s true, that at any given time only two people know how to mix the 7X flavouring ingredient,” said Mr Pendergrast.
“Those two people never travel on the same plane in case it crashes; it’s this carefully passed on secret ritual and the formula is kept in a bank vault.”
In more recent times Coca-Cola has defended a string of legal challenges to force it to reveal its formula.
In 1977 it pulled out of India rather than divulge it to the government.
The closest the company itself has come to divulging its recipe was the admission that it originally included cocaine, although the narcotic was removed in the early 1900s.
It is not clear whether, cocaine aside, the discovered recipe would be the same as that used today, or whether the company has made any changes to the formula since then.
With thanks to Daily Mail