I had a Beck’s this evening with dinner.
The special Beck’s glass, like the Samuel Admas Perfect Pint Glass, has a small segment at the bottom that forces the dissolved CO2 to form bubbles, and yields a [near] constant head on the beer.
For those of you that saw the Mythbusters episode dealing with Mentos and Diet Coke, you’ll recall an extensive discussion on nucleation. According to the wikipedia article, “nucleation is the onset of a phase transition in a small region. The phase transition can be the formation of a bubble or of a crystal from a liquid.” Indeed, the SAPPG terms its laser-etched ring at the bottom a ‘nucleation site’. None of the other beer-specific glasses I have seen explicitly use this term.
Certainly, though, watching the bubbles constantly streaming upwards, at differing rates depending on local eddy conditions, is entertaining in itself. But the fact that it helps beers that otherwise appear quite flat to maintain their fizzy head.
I don’t know if it always makes a difference on taste, but it certainly does for Beck’s and Sam Adams.