Pouring Draught Beer: Technique and Common Faults

Even a well balanced dispense system can produce a poor result if the beer is poured incorrectly. Pouring technique is a skill that affects head retention, carbonation, aroma and overall presentation, and most common faults can be traced to a specific step in the process.

Glass preparation

Before beer is poured, the glass itself matters. A glass that has residue from detergent, oil or previous drinks will disrupt the beer's natural carbonation, often causing excessive foaming or, conversely, a flat appearance with poor head retention. Glasses used for draught beer are generally rinsed in cold water immediately before pouring, rather than used straight from a rack, since this removes dust and any remaining residue and also tempers the glass slightly.

Shape also plays a role. Taller, narrower glasses tend to support a longer lasting head and show off carbonation as rising bubbles, while wider glasses encourage faster release of aroma but can lose head more quickly. Neither shape is universally correct, since the right glass depends on the style of beer being served.

The pour itself

A standard pouring technique involves tilting the glass at an angle, usually around forty five degrees, and starting the pour down the side of the glass rather than directly into the base. As the glass fills, it is gradually straightened, so that the final portion of the pour goes more directly into the beer itself, building a controlled head rather than an uncontrolled rush of foam.

Pouring too fast, with the tap fully open and the glass held upright from the start, tends to agitate the beer and release carbon dioxide too quickly, resulting in a large head with very little beer underneath it. Pouring too slowly or too gently can have the opposite effect, leaving the beer under carbonated in appearance and reducing the aroma that a proper head helps release.

Reading the head

The head on a glass of draught beer is not simply foam to be tolerated, it serves a functional purpose. It traps aroma compounds and releases them gradually, and it also acts as a visual indicator of carbonation and pour quality. A head that collapses almost immediately often points to a dirty glass or a beer that has lost carbonation, while a head that never fully forms can indicate a line or gas pressure issue further back in the system.

Common faults and their usual causes

Several recurring problems are reported across different venues and systems, and most trace back to a small number of root causes.

Excessive foam from the first pour of the day, which often points to beer that has warmed slightly in the line overnight.
Flat looking beer despite a correctly carbonated keg, which is frequently linked to dirty glassware or a pour that is too gentle.
Inconsistent pours between taps on the same system, which usually suggests uneven line lengths or pressure settings that have not been adjusted to match.
A sudden change in pour quality partway through a keg, which can indicate the keg is nearing empty and drawing in gas unevenly.

Why technique and system both matter

Pouring technique cannot fully compensate for a poorly balanced dispense system, and a perfectly balanced system can still be let down by careless pouring. The two work together, and most noticeable problems in a glass of draught beer can be explained by looking at both the physical setup behind the tap and the way the beer was actually poured into the glass.