The makers of Jack Daniel's, America's favourite whiskey, have admitted for the first time that a Tennessee slave was behind its fabled recipe.
For 150 years, credit for teaching the young Jack Daniel how to distil had gone to the Rev Dan Call, a Lutheran preacher in Lynchburg.
But the company has now said that it was not Call but his slave, a man called Nearis Green, who in fact provided the expertise.
As a boy Jasper Newton "Jack" Daniel, was sent to work for Call, who as well as being a minister ran a general store and distillery.
In the mid-19th century distilleries were owned by white businessmen but much of the work involved in making the whiskey was done by slaves.
Many slaves relied on techniques brought from Africa and became experts, often making it clandestinely themselves.
George Washington had half a dozen slaves working under Scottish foremen at his distillery in Virginia.
In 1805, Andrew Jackson, the future president, offered a bounty for a slave who had run away, describing him as a "good distiller".
The key role of Nearis Green in advising Jack Daniel had been suspected before but, like that of many slaves, his contribution to the development of US whiskey was never recorded.
One history of Jack Daniel's written in 1967 did suggest that Call had instructed the slave to show Daniel how to distil. The minister was said to have remarked: "Uncle Nearis is the best whiskey maker that I know of".
In 1866, a year after slavery officially ended, Daniel founded his own distillery and employed two of Green's sons.
Jack Daniel died from blood poisoning in 1911 and the company never officially acknowledged the role Green had played.
As it did so now, it denied there had been any attempt to hide the work of a slave in creating a whiskey that now sells more than 10 million cases a year.
Phil Epps, the global brand director for Jack Daniel's, told the New York Times there had been "no conscious decision" to whitewash Green from history.
Research associated with the brand's 150th anniversary had shown there was substance to the claim. Epps said: "As we dug into it we realised it was something that we could be proud of."
Nelson Eddy, Jack Daniel's in-house historian, said it had "taken something like the anniversary for us to start to talk about ourselves".
On tours of the Jack Daniel's distillery in Lynchburg, Tennessee, it is being left up to individual guides to decide if they want to inform visitors about Green's role.
It has not yet been decided if information about him will be added to exhibits in the visitor centre.
There have only ever been seven Master Distillers overseeing the making of the whiskey, the first one being Jack Daniel himself.