A man used AI to call 3,000 Irish bartenders to track the cost of Guinness. Now pubs are lowering their prices to compete
The "Guinndex": How One Man Used AI to Call 3,000 Pubs and Map the Price of a Pint
For many in Ireland, the cost of a pint of Guinness is more than just a transaction—it’s a social barometer. So, when 37-year-old tech entrepreneur Matt Cortland was charged €7.80 ($8.93) for a single stout in Dublin, he didn’t just grumble; he built an AI to investigate.
The result is the "Guinndex," a living consumer price index powered by artificial intelligence that is bringing unprecedented transparency to the Irish pub scene—and even forcing some owners to lower their prices.
Meet "Rachel": The AI with a Northern Irish Accent
Cortland, the founder of an AI startup, discovered that Ireland’s Central Statistics Office stopped tracking the price of the nation's favorite beer in 2011. To fill the data gap, he created Rachel, an AI voice agent developed via the platform Eleven Labs.
To ensure the AI felt authentic to local bartenders, Cortland gave Rachel a Northern Irish accent (an homage to The Traitors winner Rachel Duffy). Rachel then systematically called over 3,000 pubs across the island of Ireland to ask one simple question: "How much for a pint of Guinness?"
Surprising Findings from the Front Lines
The data, processed using Anthropic’s Claude AI, revealed a startling lack of consistency in the market. While Cortland paid nearly €8, the "Guinndex" found:
- Average Price: Approximately €6.01.
- Most Common Price: €5.50.
- The Ceiling: The most expensive pint recorded hit a staggering €11.00.
Perhaps more interesting than the numbers was the human reaction. Transcripts showed that most bartenders had no idea they were speaking to a machine. One bartender in Enniskillen jokingly offered a "wee drink" for a fiver, while another in Kilkenny offered a free pint to the AI if she was short on cash.
The "Amazon Effect" for Pubs
The goal of the Guinndex is transparency, and it’s already impacting the real world. Cortland reports that at least one pub owner, after seeing how his prices compared to neighbors just 100 yards away, lowered his price by €0.40 and manually updated the Guinndex entry to stay competitive.
"If you’re charging €11 for a pint of Guinness, that’s fair enough," Cortland told Fortune. "But people should know that information."
Beyond the Bar: The Future of AI Tracking
While tech giants like Google and OpenAI focus on using AI to solve global crises or cure diseases, Cortland’s project highlights the power of "small" AI. By automating the tedious task of 3,000 phone calls, he has empowered consumers in a way manual data collection never could.
Cortland doesn't plan to stop at stout. He is eyeing future "indexes" for high-stakes markets, such as prescription drug pricing in the U.S. or the famously fluctuating cost of a New York City pizza slice.
For now, Irish drinkers have a new tool in their pocket to ensure their next round doesn't come with a side of "tourist tax."