Magnets keep shaken beer from volcanic gushing

Eric Hopton for – Your Universe Online
There are people who believe that human civilization reached its highest point with the discovery of the magical process that creates beer. Part of the mysterious alchemy of this wonderful liquid lies in the surging foam that, in the best real and living ales, ends up forming the “head”. But getting the right balance between too flat and too fizzy is a tough challenge for commercial brewers.
No true beer lover likes a flat head, except, in my experience, those who dwell in certain parts of southern England where flat beer is the norm. Poor souls, they just don’t know any better. Still, too much gas in the beer can be just as bad – especially in bottled beer when “popping the top” can lead to what the brewers call “gushing”. This is that dreaded moment when the top flies off and the amber nectar bursts out in a flood of tiny bubbles, like lava from an Icelandic volcano, wasting precious liquid and soaking anything in its path.
According to a piece in The Atlantic, science might have found an answer to over-excited beer in bottles. The secret is magnets. Magnetized beer creates less foam, according to a group of Belgian food scientists who have just published the results of their research in the Journal of Basic Biology.
Belgium is one of the world’s premier beer nations so it is no surprise that such dedication to the perfecting the brewing process took place there. The study paper, entitled “Identification and characterization of gushing-active hydrophobins from Fusarium graminearum and related species”, tried to establish why, on occasion, an unshaken bottle of beer will suddenly overflow uncontrollably when opened.
The tests discovered that the main cause of gushing is a protein known as hydrophobin. The hydrophobins are derived from the Fusarium graminearum fungus that infects malt. During the brewing process, these hydrophobins attract carbon-dioxide molecules in the beer and carry them to the surface. When this gets out of hand, instead of a smooth pour, the foam bursts out.
One way of controlling the hydrophobins is to add extra hops into the brew. Hops are traditionally used to impart a bitter taste, but they are also an anti-foaming agent. They slow down the process of proteins binding with carbon dioxide. But even this cannot totally prevent surging.
Belgian food scientists had previously observed that magnetic fields can emulsify mayonnaise by dispersing particles. They decided to emulate this effect in the brewing of beer at the Belgian Orval Brewery. After the hops were added to the brew, the beer was passed through a glass tube surrounded by a magnet.
The magnetic field had the effect of breaking the hops apart and spreading them more thoroughly through the beer and increasing their effective surface area. This increased area allowed the anti-foaming hops to bind with more hydrophobins.
The resulting “magnetized beer” did in fact produce less foam and the Belgian team is now experimenting with different combinations of hops and magnetism.
If they get it right, beer lovers all over the world will be happy, with less “lost” beer and better control over the bitterness of their favorite drink as the brewers will be able to reduce the amount of hops in their products.