Math in the News
Beer Gauge Helps You Get a Full Pint
September 4, 2009
Physicist Chris Holloway, who knows science and mathematics, also knows his p's and q's. When the top half-inch of a pint-sized glass of, say, beer is unfilled, you're holding only 85% of what you're entitled to, he told Carl Bialik, who writes the "Numbers Guy" blog for the Wall Street Journal.
That's because people tend to focus on the height of the liquid in a container rather than its width when taking the measure of liquids, Holloway said, and the top of a standard pint glass is nearly twice as wide as the bottom. So a little bit missing at the top adds up to a significant amount of liquid.
To remedy this inequity, Holloway, who prides himself on his frugality, has come up with the Beer Gauge, a card that fits a standard U.S. pint glass. Its lines indicate the height at which you attain a full pint of beer.
When bartenders fail to hit the mark, Holloway has a habit of telling them that the 15-20% of the beer missing from his glass is their tip. "They are more willing to fill the glass at that point," he said. "They know me now, and I have to admit, when I order a beer, it's filled to the top."
In Europe, Holloway noted, where glasses have 0.3-liter and 0.5-liter etchings, "they fill the liquid to the 0.3-liter or 0.5-liter marks and the head can then fill the remaining volume in the glass. Thus, you get the amount of beer liquid you paid for."
The state of Oregon, it appears, is joining this bandwagon. It's considering a measure allowing establishments that have glasses that hold at least a pint to display pint-certifying stickers.
We'll drink to that—and to Holloway!
Source: Wall Street Journal, Aug. 24, 2009.