Might sound silly but make sure your glass is clean.
http://www.ibabuzz.com/bottomsup/2008/10/28/beer-101-first-be-sure-the-glass-is-clean/
“Finally, in a well-made beer, you have a proper head of foam. It’s an integral part of enjoying a glass of beer.’’
But, Lewis said, the foam often doesn’t last long. And that’s a not-so-subtle clue that you’ve poured your beer into a dirty glass.
Foam is quite stable. If it disappears rapidly, there’s something on the glass that is reacting with foam and killing it, Lewis said.
If you’re in a pub and that happens, you should suggest they take that glass out and smash it, he said. “Make sure your glass is clean, so at least the beer has a chance,’’ Lewis said.
“Foam on beer is a bubble of gas that has escaped; it’s an emulsion of a gassy liquid. Impurities, (grease residues, soap traces, other invisible compounds) on the glass will de-stabilize the foam.
First, run an empty dishwasher with soap through its cycles. Then take all the beer glasses, put them in the dishwasher and wash them twice with soap.
After that, never in the rest of your days, put your beer glasses in the same load with other dishes. And don’t use your beer glasses for anything except beer.
Here are a few more tips, from Professor Lewis and other experts:
Let glasses air dry; if droplets remain or if spots show, it usually means the glass still isn’t clean. Wash it again.
Wash beer glasses in very hot water with a detergent, not soap.
In Belgium, bartenders immerse each beer glass quickly in cold, running water before pouring beer into the glass.
