The regular way of creating foam on beer is by shaking the fluid, as happens when beer gets poured. This gets air into the fluid and creates carbon dioxide bubbles. After this, it takes a few moments for the gas bubbles to rise to the surface of the fluid. When the gas bubbles have collected near the surface, the fluid starts to seep down between the bubbles. This creates foam on the beer, with thin separation layers between the gas bubbles.

The rising of the gas and the seeping down of the beer happens due to the force of gravity. Therefore, no foam is formed on beer in space!