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Tuesday, August 31, 2010

More than one too many, I think

Yes, this is a post about beer. Or is it?

Under the "Brew Blog" category, the Houston Press Eating Our Words blog published a chart describing that a Bud Light has as high an alcohol content as a Guiness. I found the data visualization shoddy, and sought to do a better job of it. Following the links described to, I found no direct path to the data used to create the chart. However, the author had kindly provided a second link to a more "scientific study" at

On this chart, open (unfilled) circles are the light beers, and nonalcoholic brews are triangles. Dark circles are the rest. What I immediately noticed is that the data from the two sources cited did not match. Bud Light has a markedly lower alcohol and calorie content than Guiness. Good data visualization enables humans to detect such patterns easily, and a careless job of it can obscure them. Of course, if one cherry picks the sources, then one can report all sorts of patterns, but may have little bearing on reality.

Or perhaps the author has had a little too much to drink while interpreting quantitative data. :)

While we are on the topic, note that calorie and alcohol content pretty much track linearly, although the definition of light beer significantly overlaps with regular brews. On average, regular beers are about 50% more calories, and 30% more alcohol, but in some outliers, the lightest regular brews are as light as the lightest beer, and a German light beer is as potent as a regular brew (up there with Guiness in calorie content, and exceeding it in alcohol).


  1. Thanks for this follow-up! Much more enlightening. =)

  2. I always appreciate the "homework" you do on a topic. Excellent analysis.

  3. There are a several types of Guinness. The Ratebeer numbers are for the lowest strength version which is called Guinness Draught or just Guinness and is available here on draught and in "widget" cans and bottles. The numbers from refer to Guinness Extra Stout which comes in an ordinary brown bottle with a paper label and is infused with CO2 rather than a Nitrogen/CO2 mix. Other versions, alas not sold here, can be as strong as 8% ABV.