The perfect beer foam

BREWERS know the importance of bitter compounds in hops, and these include iso-alpha acids, according to Cornell’s Karl J. Siebert, a professor of food science and technology at the New York State Agricultural Experiment Station in Geneva, New York.  He says that dissolved gases in beer which contain carbon dioxide and sometimes nitrogen, as well as acidity, ions ethanol, viscosity, etc, play a role in foam. But what gives beer the perform foam is the lipid transfer protein no. 1 or LTP1.

“To some beer aficionados, the sign of a good head – the proper consistency, colour, height, duration – is to draw a face with your finger in the foam, before taking the first sip,” he says. “If the face is still there, when the glass is drained and the liquid is gone – that’s seriously good foam.”

Beer foam is important as it adds to the sensory experience, says Mr Siebert who was at one time a research chemist at Stroh Brewery Co. in Detroit. His report, “Recent Discoveries in Beer Foam” where he talks about LPT1 and more, will be featured in an upcoming issue of Journal of the American Society of Brewing Chemists. - H. Roger Segelken