When beer is bottled, its residual oxygen content must be kept as low as possible. To this end, breweries employ two different methods, either alone or in combination. Bottles are flushed with CO2 and filled with beer via a long-tube filler. In this case, the filler tube is inserted into the bottle and the bottle is flushed with carbon dioxide before actually being filled with beer. This method consumes a relatively large amount of CO2. Bottles are evacuated and then flushed with CO2. This method greatly reduces carbon dioxide consumption because most of the oxygen is already extracted.