The tasters were sent to dozens of different pubs around the world where they ranked their pints taking into consideration the ambience of the pub, the appearance of the Guinness, the flavour of the beer, and its aftertaste. In the end, the perception of Guinness in Ireland had an average score of 74/100 while the score in other countries averaged 57/100.
This wasn’t a test purely on its taste, as indirect factors like pub ambience were counted, but while the study may not have concluded the question, there are theories as to why Guinness tastes different in Ireland:
One widely accepted reason is that there’s a long time during the export process for Guinness to lose its edge. Especially when shipping to North America, the beer simply won’t be as fresh as it would be had it been drunk in Europe.
Another reason may be the oversight that Guinness upholds over pubs in Ireland. Every pub in the country which serves the beer is consistently checked by representatives from the brewery to ensure their kegs are stored properly, their bartenders are pouring well, and that taps are working right. Guinness incentivises the best-performing pubs, which leads to them trying their hardest to make the best pint possible.
Ultimately, though, the difference may well be all in your head. Pete Brown, a beer expert, told The Daily Mail that “Drinking Guinness in Ireland is always going to be more enjoyable than in London or Paris, or anywhere else. People will go to Dublin with the intention of ordering a pint of the black stuff, so you’re already gearing yourself up for that satisfaction before it’s passed your lips.”