Draught Beer Quality Manual

Please find the follow link to Draught Beer Quality Manual produced by the brewers association found at this link


Saved in PDF should the external link change DBQM

The follow text is excerpted from the manual on the importance of a pure gas source.  This excerpt is talking about using CO2 only to push beer up and out to the tap.   In this scenario the CO2 is not an ingredient but it will still dissolve into your beer (temp and pressure dependent).  To me this highlights the importance of pure CO2.  Even when the CO2 is just pushing purity it is important.

page 14……..
“Draught systems depend on gas pressure to push beer from the keg to the faucet. To achieve this, kegs should be pressurized with carbon dioxide, or a car-bon dioxide and nitrogen mix. Gas used for draught dispense should be “beverage grade.” Gas selection and purity affect the freshness and quality of the beer served through the draught system. Remember: The gas you use fills the keg as the beer drains. Thus, off-flavors or impurities in the gas quickly migrate to the beer to spoil its freshness and flavor. “
page 14……..
“All gas used for beer dispense should meet the specifications of the International Society of Beverage Technologists or the Compressed Gas Association…”
“Retailers may purchase beverage grade gas in cylinders that will be delivered by the gas vendor and swapped out when empty. Such cylinders are filled,maintained, and inspected by the vendor…. A gas filter may be installed to help reduce the likelihood that any contaminants in the gas reach the beer…”
page 29…..
Carbon Dioxide Gas (CO2)
“CO2 is the primary gas used to dispense draught beer. CO2 in the headspace of the keg or tank serves to maintain proper carbonation within the beer, and also provides pressure to help move the beer from the cooler through the beer lines to the faucet. CO2 used for beverage dispense must be of sufficient purity and free of off aromas or organic or other contaminants.”
page 32….
Gas Filters
“Beverage grade CO2comes from many commercial and industrial operations and is supplied for many uses besides beverages. (e.g., fire extinguishers, welding, food processing, etc.) CO2 bottles can be contaminated by poor handling and storage. They can be contaminated by beer or soft drinks if a check valve malfunctions and the beer or soft drink flows back into an empty CO2 bottle. A gas filter helps safeguard beer by removing unwanted impurities or contaminants from the gas. Filters must be replaced periodically per the manufacturer’s instructions.”