The perfect pour—not quite rocket science, but close.     Photo: Jonathan Austin Daniels / Thinkstock

The Perfect Beer Foam

Just in time for American Craft Beer Week

Many beer aficionados consider the perfect pour to be a science. Selecting the proper glass, tilting it at the perfect angle, determining how quickly to allow the brew to flow from the bottle—to us, the process sounds like a fun experiment with the lure of delicious beer at the end.

But this is no faux science, at least not if the Journal of the American Society of Brewing Chemists has anything to say about it. In the journal's upcoming issue, Cornell food scientists report that they've unlocked a chemical clue to pouring the perfect head—just in time for the end of American Craft Beer Week.

The study, "Recent Discoveries in Beer Foam," confirms that a number of chemical factors—including dissolved gases, acidity, ions, ethanol levels, and viscosity—affect a beer's head in addition to the barman's skill. Lead author Karl J. Siebert says the presence of LTP1, a kind of barley lipid transfer protein, proved most crucial to perfect beer foam. Beers with optimal levels of LPT1 will produce the best foam.

"Alright, buddy," you may say. "I left my chemistry kit at home. How can a beer plebe such as myself determine my foam's quality?"

"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," Siebert says. "If the face is still there when the glass is drained and the liquid is gone—that's some seriously good foam."

If you're looking to test Siebert's technique yourself, get out to a bar or liquor store to celebrate American Craft Beer Week. At Outside, we're considering picking up Anchor Brewing Company's California Lager—the business announced today that some proceeds from the beer will now support the National Parks Conservation Association and the California State Parks Foundation and that they'll start shipping the beer in cans for greater outdoor versatility.