Thanks to Robert Louis Stevenson, who wrote a poem about it, and Bruce Williams, who started brewing it commercially 15 years ago, heather ale is now firmly associated with Scotland.

But in fact the Irish have just as great a claim to be the home of heather ale, with good evidence that it was brewed in Ireland and exactly the same folk myths found in Ireland about “the most delicious drink the world has ever known” and the father and son who died to keep its recipe a secret that are also found in Scotland – though with one fascinating difference in the protagonists.

In almost all the Scottish versions of the legend of heather ale, including Robert Louis Stevenson’s 19th century poem on the story, the people who know the secret of brewing heather ale were the Picts, the mysterious people, perhaps Celtic, perhaps not, speakers of an unidentified language, who inhabited the northern and north-eastern parts of Caledonia from pre-Roman times until their lands were conquered from the west by the kingdom of the Scots under Kenneth mac Alpin around 843AD.

In the usual telling of the story, a father and son are captured by the Scots after a tremendous battle when all the rest of the Picts have been killed. The king of the Scots tells the Pictish pair they can go free, if they tell him the secret of brewing the heather ale. The father says he will tell, but they will have to kill his son first, as the son will otherwise kill the father for revealing the great secret of heather ale to another race. The son is then killed by the Scots: but the father just laughs at them, saying they have done what he wanted. His son might have revealed the secret to save his life, but he, the father, never will. The recipe thus dies with the last of the Picts.

The Irish versions, of which around 200 have been collected, are almost identical, except that the race with the secret of brewing heather ale is almost always not the Picts, but the Vikings. The Irish knew who the Picts were, since several Pictish tribes lived in Antrim and Armagh in Ulster. The Irish called them, and their Scottish brothers and sisters, Cruíthin, the Irish or Q-Celtic version of the British or P-Celtic name for the Picts, Priten. (Which is, incidentally, probably the source of the name Britain). So why did the Vikings become the heroes of the legend of heather ale in Ireland, when it was the Picts in Scotland?

The answer may be that there was no tradition of the Irish Picts being wiped out, while there was a strong folk recollection in Ireland of a massive defeat for the Vikings. Many of the Irish tales about heather ale feature the last big clash involving the Irish and the Vikings, the battle of Clontarf, just outside Dublin, in AD 1014. The battle is traditionally presented as a victory for the Irish under their High King, Brian Boru, over the Viking invaders of Ireland. In fact both sides were a mixture of Irish and Viking warriors, with Brian’s army containing his own Viking allies from places such as Limerick as well as Irish warriors from Munster and elsewhere, while his opponents, who were fighting to resist the High King’s domination rather than trying to impose their own, were an alliance of Dublin Vikings and Irishmen from Leinster. But as far as folk memory is concerned, the Gael defeated the Gaul, or foreigner.

In all the tales in Irish the heather ale is called bheóir Lochlannach, Lochlann being the Irish for Viking, and the phrase is always translated as “Viking beer”. But there is another mystery here. The Irish words for ale, or beer, were cuirm or lionn. The word beóir must come from the Old Norse word bjórr. But bjórr and its Old English equivalent, beór, are what linguists call “false friends”. They almost certainly don’t mean “beer” in the modern sense of a fermented malt liquor, but a strong, sweet, honey or honey-and-fruit drink: 10th century Anglo-Saxon glossaries gave beór as the equivalent of “ydromellum”, hydromel, or mead, while cervisia, beer in Latin, was translated as eala, “ale”. It seems quite likely, therefore, that bheóir Lochlannach was a heather-flavoured mead or something similar, perhaps even a heather-flavoured cider, rather than a heather-flavoured beer.

One of the fullest accounts of the story of “heath ale”, (“heath” being another name for ling heather) appeared in the Ulster Journal of Archaeology in 1859. It was written by John Locke, who said he was told the tale by a peasant living in Cork in 1847 who claimed to be nearly 100 years old, and who said he got the story from his grandfather, which would take us to at least the late 1600s. Locke recounted the story of an elderly Danish Viking captured with, this time, two sons after the battle of Clontarf, who conned the Irish into killing his sons and was then killed himself for refusing to divulge the secret of bheóir Lochlannach.

Locke’s peasant informant told him that the flavouring for bheóír Lochlannach was wood avens or Herb Bennet (Geum urbanum), called minarthagh in Irish. The type of heather used for bheóír Lochlannach, he said was ling (Calluna vulgaris), which is actually known in some parts of Ireland as Viking heather, fraoch Lochlannach. (Fraoch is pronounced “free”, as in Yeats’s poem “The Lake Island of Inishfree” – “I must away and go now/and go to Inishfree”. Inishfree is Inis Fraoch, Heather Island in Irish. Now tell me – d’ye get this sort of literary trivia in any other beer blog? I think not …)

Bheóír Lochlannach, Locke said, was made from a wort derived from steeping ling in water. Some Irish versions of the legends say tormentil, or bloodroot, Potentilla tormentilla, also went into bheóír Lochlannach. Tormentil, a small plant with yellow flowers, a member of the rose family, has bitter-tasting roots which will cause vomiting if taken to excess but which, at the same time, smell pleasantly of roses

The heather ale story excites folklorists because of its underlying theme, captive fools captors into killing his companion to preserve secret. This is the same as the theme found in one of the Norse Eddas and the Germanic Niebelungenlied, and turned into the opera Das Rheingold by the 19th century composer Richard Wagner; except that the secret Attila, the king of the Huns, wanted to get from Gunnar the Niebelung was the whereabouts of the Rhine gold, rather than the recipe for a decent beer. Which tale came first, the story of the Rheingold or the story of the heather ale?

A tradition of brewing with heather seems to have lived on in Ireland after the Vikings vanished. The Victorian journalist John Bickerdyke, in Curiosities of Ale and Beer, written in 1889, said that “as later as the commencement of this century”, that is, around 1801, “an ale flavoured with heather … was brewed in many parts of Ireland. The practice, it is believed, is now almost if not quite extinct.” The method, Bickerdyke said, was to let the wort drain through heather blossoms placed at the bottom of tubs, so that during its passage the wort gains “a peculiar and agreeable flavour”.

An earlier writer, Samuel Morewood in 1838 said that “a few years ago” men digging a watercourse in County Limerick found a mill and “a portion of brewing materials. together with some cakes of bread and heather, concealed in the position where they were left by the Danes.” Morewood said that “it was also stated that a book or manuscript containing the receipt for the making of heather-beer had been found at the same time, but that it was clandestinely taken away.” This manuscript, if it ever existed, has not been seen since. It seems unlikely that it was as old as the Danes, though, and it must be more probable that this was a modern, albeit illicit brewer whose kit was uncovered.

England had a faint tradition of heather ale brewing, though the legend of the lost recipe is almost completely unknown. John Bickerdyke in Curiosities … quoted a manuscript owned by the Duke of Northumberland at Hexham that described a large trough cut from solid rock at Rudchester, or Vindovala (which he erroneously calls Kutchester) on Hadrian’s Wall, a mile west of Heddon. The local Northumbrian peasants, the manuscript said, had a tradition “that the Romans made a beverage somewhat like beer, of the bells of heather, and that this trough was used in the process of making it.”

Since Bickerdyke’s time, findings at a Roman fort near the wall, Vindolanda, have shown that the Romans did indeed brew ale at this northern extremity of their empire. However, the trough, hewn out of grey sandstone and ten feet long, which was still at Rudchester farm in 1974, has been identified by archaeologists as a sacrificial bath from one of the many temples that once stood around the fort, not a stone mash tun.

In Yorkshire, according to Bickerdyke, home brewers in his time made a beer called “gale beer” flavoured with “the blossoms of a species of heather found growing on the moors in that part of the country.” But the main flavouring ingredient in gale ale must have been sweet gale or bog myrtle, Myrica gale. The antiquarian Robert Plot said in 1686 that about Shenstone in Staffordshire “they frequently used Erica vulgaris [that is, Calluna vulgaris], heath or ling instead of hopps to preserve their beer, which gave it no ill taste.” I have also seen hints, but nothing definite, that heather ale was brewed in Devon. At any rate, with the greatest respect to the Williams Brothers’ Fraoch Heather Ale, which is certainly in my list of top 50 beers, heather ale – entirely Scots it ain’t.