This is from Cornell University:
It’s an unlikely beer-drinking toast: “Here’s to L-T-P-One!”
Yet, the secret to optimal foam in the head of a freshly poured brew, according to Cornell food science research, is just the right amount and kind of barley lipid transfer protein No. 1, aka LTP1.
Bitter compounds found in hops, like iso-alpha acids, are important to brewers, says Cornell’s Karl J. Siebert, principal investigator and author of “Recent Discoveries in Beer Foam,” set for publication in next issue of the Journal of the American Society of Brewing Chemists.
“Dissolved gases in the beer – carbon dioxide and, in some instances, nitrogen – play a role. So do acidity, some ions, ethanol levels, viscosity and numerous other factors that have been tried by brewers and scientifically tested,” says Siebert, professor of food science and technology at the New York State Agricultural Experiment Station in Geneva, N.Y. “But LTP1 is the key to perfect beer foam.”
Fascinating as foam is to chemists, it’s of vital importance for the sensory experience of beer appreciation, insists Siebert, formerly a longtime research chemist in the industry, including at the former Stroh Brewery Co. in Detroit.
“To some beer aficionados, the sign of a good head – the proper consistency, color, height, duration – is to draw a face with your finger in the foam, before taking the first sip,” the food scientist notes. “If the face is still there, when the glass is drained and the liquid is gone – that’s seriously good foam.”