By A frustration over the price of a pint has turned into an unlikely nationwide experiment in transparency, as one AI startup founder built a crowdsourced database tracking the cost of Guinness across Ireland—exposing sharp regional differences and, in at least one case, prompting a pub to lower its prices.
Matt Cortland, 37, was visiting Dublin when he paid €7.80 for a pint of Guinness and suspected something was off. With Ireland’s government no longer tracking beer prices—a practice it ended more than a decade ago—Cortland decided to find out for himself what a pint should actually cost.
What followed was an unusually modern solution to an old problem. Cortland built an AI voice agent named Rachel, powered by the ElevenLabs voice generation platform and designed with a convincing Northern Irish accent. Over St. Patrick’s Day weekend, the system placed more than 3,000 calls to pubs across all 32 counties of Ireland, asking a simple question: how much for a pint of Guinness?
The response rate was striking. Of roughly 3,000 calls, more than 2,000 pubs answered, and over 1,000 provided a confirmed price. Cortland then turned to Anthropic’s Claude AI model to process the transcripts and compile the results into a live database—the Guinndex—which maps Guinness prices nationwide. The data currently places the all-Ireland average at between €6.01 and €6.02 per pint.
“This means my pint in Dublin was absolutely overpriced, and now I had the cold, hard data to back it up,” Cortland reflected on the project.
The voice behind the operation was itself a nod to popular culture. Rachel was designed as an homage to Rachel Duffy, winner of the UK version of The Traitors, though Cortland made clear it was only inspired by her voice, not a direct replica. In practice, the illusion appears to have worked. Many pub staff reportedly did not realize they were speaking with an AI, and some even offered discounts, assuming they were dealing with a regular customer.
The project has already produced tangible results. In one instance, a pub owner lowered the price of a pint by €0.40 after seeing their listing on the Guinndex and later updated the entry personally. Others have used the database to avoid higher prices in well-known areas, with one user reporting they skipped an expensive pint in Temple Bar after checking the map and walking a short distance to a cheaper alternative.
For Cortland, the project is less about Guinness specifically and more about what the technology makes possible. “I was like, ‘Well can I just call every pub in Ireland and conversationally ask them with AI?’ I pulled the thread, and I just kept pulling the thread, and here we are,” he told Fortune.
He now sees broader applications for the same approach, envisioning tools that allow consumers to track and compare prices across a range of everyday goods—effectively outsourcing price discovery to autonomous systems.
The Guinndex continues to grow, now incorporating data from more than 6,000 pubs and revealing what Cortland describes as “huge price swings” depending on location. Not every establishment has adjusted in response, but the visibility alone has begun to reshape how customers think about value in Ireland’s pub scene.
