STRANGE BUT TRUE- Beer pour: How to reduce your 'fobbing'


Q. Beer drinkers of the world, are you guilty of "fobbing" your brew? –C. Conklin

A. You may already know better than to "create excessive foam when pouring," says Mark Denny in Froth! The Science of Beer. Because surface scratches can act as bubble nucleation sites when the pressure is released, one strategy for reducing the amount of fobbing is to fill the container with water, then pour it out and pour in the beer.

The water closes up some of the sites. A considerable lore has arisen on the correct pour: Tip a clean, air-dried glass (few nucleation sites) to an angle of 45 degrees and pour the beer slowly (to avoid mechanical agitation and allow time for the head to form). Gradually, raise the glass upright as it fills, then finish with a flourish by increasing the distance from bottle to glass to generate more froth, so that it projects above the glass, with a little spilling over the edge.

Not only is a good head with uniform, small bubbles visually appealing with a creamier look, but it also "presents the beerophile with his favorite tipple in two forms: foam and liquid. He will knowingly sip the foam and then the beer, sensing the different hoppiness of the two."

Q. It's surprisingly easy for your body to fool your brain, generating illusions aplenty. What's one you can pull on yourself using only a bag of potato chips and a pair of earplugs? –F. Lay

A. Charles Spence of Oxford found that the perceived crispness of chips depends on how they sound when you bite them, says Graham Lawton in New Scientist magazine. Damp down the sound of the crunching (or muffle the higher frequencies) and people report "the chips feel stale." So put on some earplugs as you munch and experience this for yourself. 

Another example of "cross-modal interaction"– where what you feel is affected by what you hear– is to wear the earplugs while writing on a blackboard with squeaky chalk. The board will feel smoother when you can't hear the chalk. The same rule applies to sparkling water and electric toothbrushes: Place a microphone in front of a glass of the water, pump up the volume and the water will feel fizzier to your tongue. Similarly, electric toothbrushes can be made to feel smoother by damping down their high-frequency sounds (Journal of Dental Research).

Q. What's a dramatic airlines tale illustrating the cautionary generality, "Quantities without proper units are meaningless numbers"? –F. Laker

A. Air Canada Flight 143 was bound for Montreal and Edmonton on July 23, 1983, just after Canada had switched to the metric system, says Jearl Walker in The Flying Circus of Physics. The flight crew knew they needed to begin the trip with 11,300 kilograms of fuel, but when they asked the ground crew for the amount already on board, their response was based on pre-metric habits, confusing the conversion factor from liters to kilograms with that from liters to pounds. This meant Flight 143 left Montreal with only 45 percent of the fuel necessary for the trip.

On route to Edmonton, at an altitude of 7.9 kilometers (26,000 feet), the plane ran out of fuel and began to fall, but the pilot managed to put it into a long downward glide toward an old nonworking airport nearby. Unfortunately, the runway there had been converted to a track for race cars with a steel barrier constructed across it. Fortunately, though, as the airplane hit the runway, the front landing gear collapsed and the airplane skidded to a stop just short of the steel barrier, with the stunned race drivers and fans looking on. All on board the airplane emerged safely.


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