A team of German scientists have developed a genetically modified beer that will always have a foaming head.

Ulf Stahl of the Technical University of Berlin said brewers were "unofficially" already showing interest in the work.

The development uses genetically modified barley, and stems from the fact that grease from crisps or lipstick can destroy the surface tension that makes the bubbles.

"The basis of foaming beer is the LPT1 gene [in barley]," Dr Stahl told New Scientist magazine. The gene produces a protein that dissolves in fats but not water.

On being poured it attaches itself to the bubbles of carbon dioxide and floats to the top of the glass but greasesucks up any spare protein, making the bubbles collapse.

The German team added the LPT1 gene to brewer's yeast, so that there will always be plenty of foam produced to give the beer a good head.