"Is the beer pouring foamy," I asked the bartender. "No,' she replied. "That's the way we pour our beer here."
The refreshing 'bite' a drinker gets from a beer is caused not only by the tactile sensation of the bubbles, but by an acidic reaction (in fact, the primary sensation).
When pressure is reduced by opening a bottle of beer or releasing it from the tap, some of the carbon dioxide is released from the solution in the form of bubbles. After a sip, enzymes in the mouth convert the remaining free carbon dioxide into carbonic acid. The acid then activates sensory nerve endings, which signal the mild irritation that we refer to as ‘bite.’
— Monell Chemical Senses Center (Philadelphia, PA)
There are beers (such as German-style wheat beers, or hefeweizens) which are meant to be served with spumous heads. This beer was not. With her incorrect technique, the bartender had altered the taste of the beer from what its brewer had intended. In other words: although pretty, flat. It would take several minutes for the head to subside enough for the beer to be drunk. Still, not all bad, that!
As seen, heard, and drunk at a pub (to remain unnamed), in the Washington, D.C., metropolitan area.
3 December 2013.