Scientific Evidence: Guinness Tastes Better in Ireland

(Image credit: Guinness)

Untold millions of pints of Guinness Draught will be consumed around the world today (March 17), but none of those will taste as good as those downed in Ireland. That Guinness tastes better in its home country is a long-held claim (and tourism slogan), but now there is science or close enough to it to support the legend.

The findings, which were published in the March 6 issue of the Journal of Food Science, come from the substantial efforts of a four-man team of international scientists. First, the crew received formal instruction at the Guinness brewery in Dublin on how to craft Guinness' "Perfect Pint." They then set out, testing Guinness at random bars in random countries for the next year, totaling 103 tastings in 14 countries (42 tastings in Ireland; 61 outside of Ireland).

The testing protocols were rigorous. Upon stepping into a pub, the tester would record the pub conditions and ambience and take the establishment's temperature using a digital thermometer. They would then note the pubtender's experience, whether he or she was of Irish origin and whether he or she had ever received formal instruction on how to craft a "Perfect Pint" of Guinness.

A stopwatch was used to time the length of the pour, and the tester noted the number of pours and whether the tap pulling order met the Guinness guidelines, as well as whether a shamrock design was drawn in the foam. After the beer had sat for two to three minutes, the beer's core temperature and head height were measured.

Once the tester had sipped the beer to the top of the Guinness logo, he recorded three sensory measurements on a scale of 0 to 100: mouth feel (creaminess), flavor (soft or bitter), and aftertaste (short to long). These measurements were combined to produce a "Guinness overall enjoyment score," or GOES.

After analyzing the data and adjusting for researcher, pub ambience, Guinness appearance and the three sensory measures, the team found statistically significant evidence that Guinness tastes better and is more enjoyable in Ireland (with a GOES of 74.1) than outside (a GOES of 57.1). This lends some support to the claim that the beer does not travel well, and that pourers outside of Ireland do not give it the proper respect when filling a pint.

The reasons, the scientists write, could be many. The overall atmosphere of pubs in Ireland was rated higher, which the data showed had some effect on overall enjoyment. There's also what they call the "line" theory: The regularity at which pints of Guinness are pulled in pubs in Ireland ensures that customers are receiving fresh beer straight from the barrel, rather than stuff that's been sitting in the connecting tubing.

Finally, they note that Guinness is served in 100 countries and brewed in 50, often using local ingredients, including the water. Therefore, one could argue that Guinness brewed outside Dublin can never taste the same as the home brew.

The samplers confess that none of the four is a professional tester. They were, however, able to exclude potential outside influences, such as the presence of women (possibly leading to an overestimation of enjoyment). Before each testing session, the researchers noted the number of women in the bar but, in examining their data, they did not find an association of female presence and tasting scores. "Hence, women did not have a confounding effect on the outcomes, nor did their beauty inflict any unplanned blinding of the testers, who were all dedicated to the measurements," the group wrote.

In the end, the scientists point to evidence that no matter where you consume your pint o' Guinness, it's only as good as the company you keep.

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Bjorn Carey is the science information officer at Stanford University. He has written and edited for various news outlets, including Live Science's Life's Little Mysteries, and Popular Science. When it comes to reporting on and explaining wacky science and weird news, Bjorn is your guy. He currently lives in the San Francisco Bay Area with his beautiful son and wife.