THOUSANDS OF pubs across Ireland got an unexpected phone call over St Patrick’s weekend, a polite voice asking one simple question: how much is a pint of Guinness?

On the other end of the line was ‘Rachel’, a Northern Irish-sounding AI chatbot tasked with ringing bars across the country to gather prices for the ‘Guinndex’, a new attempt to track the cost of a pint nationwide.

The project is the brainchild of Matt Cortland, an American AI engineer with strong Irish ties, who said he built the system after noticing a glaring gap in the data.

Cortland told The Journal that he had been trawling through Central Statistics Office figures when he realised pint price tracking had stopped more than a decade ago.

Amid a number of recent Diageo price hikes, and some slightly egregious tourist-focused pricing in some pubs (Cortland paid €7.80 for a pint in Dublin earlier this month), he said it prompted him to dig further.

Over the course of the weekend, Rachel called more than 3,000 pubs across all 32 counties.

The AI chatbot’s job was straightforward: ask the price of a pint of Guinness, say thanks, and hang up.

Out of more than 2,000 answered calls, over 1,000 pubs gave a price, forming the backbone of what is now the most comprehensive pint price index in Ireland.

What did it find?

The national average came in at €5.95.

Laois was the cheapest county on average at just €5.38. Dublin, unsurprisingly, was the most expensive at around €6.75.

There were even a handful of pubs, including a select few in Dublin, where a pint could still be bought for €5 or less.

“I was floored,” Cortland said.

Change for a fiver after buying a pint? I didn’t think that was even a thing anymore.

Cortland attributed much of the success to the ‘personality’ of the AI caller, Rachel.

He explained that he had tested several AI-generated voices before settling on a Northern Irish accent, which he felt sounded the most natural for the task.

“I tried an American voice, that was a no. I tried an Irish voice as well and it just felt a bit off. This one just worked,” he said.

The name itself came from reality TV. Cortland said he had recently watched the latest season of The Traitors on BBC, and took inspiration from Rachel, one of the winners (who is from Newry).

“Rachel was just so convincing. She played an absolute blinder. That’s what I wanted, someone warm, someone you’d believe,” Cortland added.

A graphic from the Guinndex. Guinndex.ie Guinndex.ie

Cortland is a fan of Guinness himself, though he doesn’t attribute this to his Irish partner, rather his years spent in Ireland. He previously lived in Dublin after receiving a US-Ireland Alliance scholarship, and studied at TUD.

He’s since worked across the startup sector and now runs his own consultancy, Prime Directive AI, based in London.

How did the chatbot calls work?

The process of building the voice agent involved repeated testing with Claude (an AI language model designed to understand and generate text in a conversational way), with small batches of calls used to refine how Rachel spoke and responded before scaling up to thousands of pubs.

Only a handful of those who answered the calls appeared to realise they were speaking to an AI. 

“You’re ringing a pub, there’s noise, people are busy, maybe there’s a match on. It’s just a quick question. People don’t really stop to think about it,” Cortland said.

The calls themselves threw up plenty of memorable exchanges.

At one pub in the Midlands, a bartender laughed and offered to buy Rachel a drink if she couldn’t afford one.

In another pub in Northern Ireland, another joked the price was “25 pound” before dropping it to a fiver.

During a later call, Rachel was subjected to a full interrogation about where she was calling from and who she was, while in another pub, a man who didn’t even work behind the bar went off to check the price anyway.

Others were less forthcoming. At two separate bars in the South, she was told she’d have to come in to find out, while another publican bluntly told her to “fuck off”.

The use of an AI voice to contact businesses without explicitly stating did raise some questions around transparency, though Cortland said he was conscious of the line between acceptable use and nuisance.

“There’s a difference between calling a person on their phone and calling a business that has a public number,” Cortland said.

“I didn’t call individuals, that would be wrong.”

He added that he aimed to keep interactions brief and non-intrusive.

“I’ve been a pub owner. I know what it’s like on the other end. The goal was to keep it as light-touch as possible,” Cortland said.

Matt Cortland.

Regulatory guidance generally advises transparency when AI is used in phone calls, particularly as efforts continue to combat scam calls.

The idea behind the Guinndex, Cortland explained, was to help direct customers towards pubs offering good value.

“It’s good to channel business to places that are charging reasonable prices,”he said.

While the site highlights top-rated pubs and the range of prices available, he said he deliberately avoided naming and shaming lower-rated venues.

“That’s not helpful, the aim is to do no harm.”

The Guinndex is now open to the public, with users invited to submit prices themselves to keep the data up to date.

“The whole point is for this to be a living index, not a one-off snapshot,” Cortland said.

“Rachel got us started, but keeping it accurate means hearing from actual people in actual pubs.”