For some a good head of froth at the top of a glass of beer can leave them feeling a little short changed, but new research suggests they might be better off not asking for a top up.
It seems that having some foam in your glass can help to stop you from spilling it as you walk back to your table.
A team of physicists have discovered that a head of tiny bubbles can help to dampen the movement of liquid as it sloshes around in a container.
Having a descent head on your beer could help prevent you from spilling it. Researchers have found bubbles on top of a liquid can help to dampen a sloshing motion in a container (pictured)
They found that the bubbles create tiny capillary effects close to the walls of a glass or container which help to reduce the slowing action.
WHY YOU SHOULD HAVE A HEAD ON YOUR BEER
Aside from helping to prevent sloshing your precious beer all over the floor, having a good head on your drink can bring other benefits.
The foam in beer is largely caused by protein found in barley and other grains known as Lipid Transfer Protein 1.
This is hydrophobic meaning it repels water, so it forms around bubbles of carbon dioxide that rises to the surface and help to maintain the head.
These tiny bubbles then release aromatic molecules from the beer into the air, and your nose as you lift to drink, helping to enhance the flavour.
The texture of the foam can also alter how a beer tastes, delivering a silky or soft sensation.
'We saw something that we couldn't believe,' said Dr François Gallaire, a physicist at the École Polytechnique Fédérale de Lausanne in Switzerland who helped lead the research.
Previous theories of fluid motion have suggested that as a liquid sloshes backwards and forth in a container, it loses energy and the waves gradually get smaller.
This means, however, that while the waves shrink, they never totally vanish. In the real world, though, sloshing can come to a halt relatively quickly.
The researchers, whose study is published in the journal Physics of Fluids, reveal new evidence that explains how this happens.
They used soapy liquids to create bubbles, which induce tiny pressure gradients near to the walls of the container.
This occurs due to capillary action, which uses the surface tension of water to adhere to the side of the container, which dampens the waves far faster than normal.
While some drinkers do not like a head on their lager or beer (pictured), it can actually help them keep more of their drink in their glass as the capillary action of the bubbles in the foam against the side of the glass can transfer energy out of the moving liquid
Pierre-Thomas Brun, a mathematician at the Massachusetts Institute of Technology who also took part in the research, said: 'Those capillary forces are small, but they're very important as soon as the sizes or motions get small.'
The findings may explain why it is so much easier to spill non-frothy drinks such as cider compared to beer.
While a foamy head can mean the beer also has further to travel before spilling over the glass, having a good top of bubbles could also stop it from sloshing around as much.
The foamy head of most beers (pictured) occurs due to gas becoming trapped inside tiny bubbles of hydrophobic proteins that are released during the brewing process
Asking bar staff to top up the glass could then mean that drinkers risk losing more of their beer as they move back to their table.
The researchers say their results could also be used to prevent sloshing of other liquids in contianers, such as fuel in a rocket tank or oil in a cargo ship.
In these cases sloshing can destabilise the vehicle and risk an accident.