Bubbles, foam and gush
A ting of metal against glass. The lights are dimmed. Voices turn to a murmur. All eyes are set on the bottle of champagne and its cork as it is gradually eased out. Then a pop, and your host is nervously juggling with glasses and a challenging flow of bubbles. These are bubbles we expect. However, sometimes bubbles emerge in an uncontrollable gush. Take a can of beer; one that has been waiting patiently in the fridge. It hasn't been shaken. It hasn't fallen. The can itself is pristine. You slip a finger under the tab and pull. You expect some foam but not the untamed rush of bubbles that spills over your hands and onto the ground. When it finally ends and you peer into the can, there's little left to drink. Gushing such as this is a defect which occurs in carbonate beverages. At the beginning of the 20th century, scientists speculated that something biological was probably the culprit, but they were unable to put their finger on it. Today, researchers postulate that gushing is most likely caused by hydrophobins. Hydrophobins are proteins synthesized by fungi that have infected the grain used in the production of beer. In particular, class II hydrophobin 5 from Fusarium culmorum.
