Abstract: A process is disclosed for producing substantially pure liquid carbon dioxide, and subsequently re-evaporating the substantially pure liquid carbon dioxide to produce substantially pure gaseous carbon dioxide from impure carbon dioxide gas which is produced during the fermentation step of a brewing process or has been used as an overgas in a brewing plant, the substantially pure gaseous carbon dioxide being for use in carbonating the brewed product or as an overgas in the brewing plant. The process comprises the steps of:(a) removing impure carbon dioxide gas from the brewing plant;(b) pressurizing the impure carbon dioxide gas.The present invention also provides an apparatus for carrying out the process.