The Smelly Side of Beer

Beer has been know to have the skunk-beer smell and taste to come out when it is exposed to light. Until around 2001, it was not know why this happened. Malcolm D.E. Forbes of the University of North Carolina and Denis De Keukeleire of Ghent University did a study to figure out why this happens. They tested this by exposing the beer to laser light. By using computer models they discover how the light sensitive compound in the hops, know as isohumulones, broke down. These compounds would then bond with sulfur. The research concluded that the isohumulones would absorb light in a 5 carbon ring in its structure. The isohumulones would transfer energy to a carbon chain that would break off the ring. It is because of the skunking in beer that most beers are in either green or brown class bottles. However, Miller Genuine Draft is severed in clear glass bottles because they use genetically altered hops that do not produce the skunk smelling molecule. Modelo, the maker of Corona, suggest putting a lime in the beer to mask the smell and favor.

I never know that beer could smell so bad. It is really interesting to hear about all the different thinks that can happen with just a few compounds. Just leaving a beer in the sun will make it go back. I'll be sure now not to leave any of my beers out during the day. I do not think drinking skunk flavor would be pleasant. I head that limes were added to Corona's to keep flies out of then. This was because Corona become popular from Americans visiting Mexico and would add the limes to keep the flies out.

Jessica Gorman. Science News. Washington: Oct 27, 2001. Vol. 160, Iss. 17; pg. 262, 1 pgs