Karen Gregory, a tourist from Oklahoma, visited Dublin this week, inhaled an aroma of malted barley at Teeling Whiskey Distillery, and picked a side in a centuries-old contest. “Definitely Irish. It’s lighter and brighter. Scotch is too heavy.”

The crowd of visitors merrily sipping neat whiskeys, whiskey cocktails and whiskey-infused coffees suggested more converts to the Irish side of a rivalry that has pitted two venerable traditions in a battle for market domination.

Ireland’s distilleries prevailed in the 19th century, accounting for more than 60 per cent of sales in the US, before disaster struck. The Irish ignored new technologies, curbed exports during US prohibition in the 1920s, and got caught in a trade war with the UK. Scotland seized its chance and ramped up global exports, establishing scotch as a synonym for all types of whiskey.

“We fell from 60 per cent to 2 per cent in the US, that’s some trick,” says John Teeling, a doyen of Irish whiskey producers. Then he smiled: “But I think we’ll overtake the Scots by the end of the decade. There’ll be a huge party when that happens.”

After decades of quiet woe, Irish whiskey is roaring back. From just four operational distilleries in 2010, there are now 42 on the island of Ireland. Annual global sales have surged from 5 million cases (60 million bottles) in 2010 to 14m cases (168 million bottles) last year, fuelled by new offerings and younger drinkers.

Growth in the US has been especially strong, rising 16 per cent last year to a record $1.3 billion (€1.25 billion), according to the Distilled Spirits Council. If the trend continues, Irish whiskey sales in the US — currently 5.9 million cases — will overtake scotch, which has plateaued at about 8 million cases, by 2030.

It’s a bigger game now — the worldwide whiskey market has hovered at $80 billion over the past decade but is projected to jump to more than $100 billion by 2024, according to the consumer data company Statista. Japanese brands, too, have exploded in popularity, earning $340 million in sales last year.

Last month, the Irish Government launched a €750,000 “spirit of Ireland” campaign to promote Irish products in US bars and liquor stores. For Ireland’s distillers, overtaking scotch in the US would be a psychological boost and rectify a century-old fiasco in the world’s biggest market.

It would also underscore an ambition to challenge Scotch’s enduring dominance elsewhere, including Britain. “The UK used to be a graveyard for Irish whiskey,” says John Teeling. “Not any more.”

Celebrities have launched their own Irish whiskey brands, with the stars of the US sitcom It’s Always Sunny in Philadelphia this week debuting a 15-year-old single malt to celebrate the show’s 15th season. The former mixed martial arts fighter Conor McGregor launched a brand in 2018.

Popular culture flagged Irish whiskey’s revival a decade ago when the Jameson brand appeared in songs by Rihanna and Lady Gaga and in the TV shows Mad Men and South Park.

Exports to Russia, the second biggest market, have halted, and the UK’s dispute with the EU over Northern Ireland could cause disruption, but the future is bright, says Lavelle. “It’s a renaissance.”

Ireland claims — as do other countries — to be the home of whiskey. There is a reference to the drink in the Red Book of Ossory, a medieval manuscript produced in Co Kilkenny in the 14th century.

At one point, Ireland had more than 1,000 distilleries. By the 19th century a cluster of producers in Dublin’s Liberties district supplied much of the world.  However, they shunned innovation — such as a new type of pot still — and shrivelled during US prohibition, and Ireland’s trade war with Britain in the 1930s. Scottish whisky — which omits the “e” — filled the gap with peatier, darker offerings. Ireland’s traditionally smoother fare acquired a reputation for blandness.

By the 1980s, Ireland had only two distilleries producing a tiny fraction of Scotland’s output. The turnaround began after the French drinks giant Pernod Ricard bought Irish Distillers, giving multinational heft to its Jameson brand, and the Teeling family opened a new distillery, emboldening other newcomers.