2-Furaldehyde is often used as an analytical indicator of beer flavour deterioration. Although 2-furaldehyde itself has a flavour threshold far above levels generally present in beer, it can be used as a good marker of heat damage of beer. A reversed-phase liquid chromatographic assay, using ultraviolet-visible detection, was applied to investigate the behaviour of 2-furaldehyde throughout the brewing process and during extended storage of beer. The impact of storage temperature, sulphur dioxide and oxygen content on the level of 2-furaldehyde was studied. It was found that the concentration of 2-furaldehyde markedly increases during wort boiling and is rapidly reduced by yeast during the first hours of fermentation, emphasising the yeast reducing capacity as a determinant factor for the 2-furaldehyde content found in the final beer. The results obtained suggest that sulphur dioxide and oxygen content play a key role on the 2-furaldehyde content in packaged beer. 2-Furaldehyde increase during ageing is oxygen dependent and sulphur dioxide retards its development by possibly protecting beer against the occurrence of oxidative reactions.