The Facts About Draught Beer Carbonation

1 Are you using 60%CO2/40%N2 to dispense your beer ? Chances are some if not all of your beers are slowly going flat and potentially falling out of the brewer s desired Carbonation range. Recently, the Brewer Association Technical Committee endorsed a beer industry-wide guideline that changes the default dispense gas blend from 60% CO2 to 70% CO2 for any systems that need CO2-rich blends (see back of page for criteria). Extensive market research indicates that when used as the sole gas blend, 70% CO2 keeps more beers within their respective Carbonation a near-constant effort to maintain high-quality Draught beer at retail, brewers have long battled gas systems which compromise the Carbonation levels of their beers.

2 Long-draw systems in need of high pressure gas too often employ beer -flattening blends of 25% or 30% CO2 (which are only intended for dispensing nitrogenated beers), or even flavor-ruining air compressors to drive the beer the extra distance. The com-mon alternative has long been a more CO2-rich blend of 60% CO2/40% N2, most often produced by a gas blender on-site, or supplied as blended bottled gas. This has in recent years become the default blend for long-draw systems. The fact is, however, that on the average system, even this blend can cause a beer s Carbonation levels to drop below desired levels; hence the move to 70% CO2. Keeping Your beer Properly CarbonatedThe key to maintaining a keg s Carbonation relies on fine-tun-ing 4 elements: 1.

3 The CO2 percentage2. Applied pressure3. Keg temperature4. A particular beer s Carbonation levelWhen all the elements are in balance, the beer will stay prop-erly carbonated. The problem is that the average Draught system is pouring beers with differing levels of Carbonation ; with the three other elements remaining constant, this causes many beers to become solution lies in making adjustments to either of the two elements we can readily adjust: CO2 percentage, and applied pressure. Let s look at these Percentage AdjustmentThe adjustment of CO2 percentages for different beers has historically been difficult if not impossible. Gas blending pan-els usually have only one CO2-rich blend available, with dual blend panels typically accommodating nitrogenated beers with the second blend.

4 Gas blending panels are now available which offer three blends: the nitro beer blend and two differ-ent CO2-rich blends for regularly carbonated beers. As it turns out, most regularly carbonated beers can be divided into two general groups of Carbonation levels. These new panels allow the installer to customize a gas blend for each of these two ranges by following the chart below:The Facts AboutDraught beer CarbonationPhoto by Michael Lichter v/v MediumPressureStorage Temp. 35-37 Storage Temp. 38-40 16-20 psi75% - 80%80% - 85%20-25 psi65%70% v/v MediumPressureStorage Temp. 35-37 Storage Temp. 38-40 16-20 psi80% - 85%85% - 90%20-25 psi70%75%Brewers For more information on Draught system cleaning or other components of a Draught beer system, visit the Brewers Association s Draught beer Quality Manual at: Pressure AdjustmentInstallers may choose to use a single gas blend for regularly carbonated beers and adjust the applied pressures on indi-vidual kegs to maintain proper Carbonation .

5 This is a helpful option in existing systems with a single CO2-rich gas blend or when a multi-blend gas blender is not available for use. When regularly carbonated beers are divided into two differ-ent groups, depending on their Carbonation level, appropriate pressures for individual beers can be determined from the chart below:*Add 1 psi for every 2,000 ft. of elevation to account for differ-ences in atmospheric systems have all lines restricted equally, so applying differ-ent pressures to different beers will result in certain beers flowing faster or slower than others in the same system. These flow rate variances are normally not an issue, still allowing for nearly optimal flow rates of 2 ounces per second as long as the pres-sure variance between different beers is kept at or below Use of Gas BlendsIt is important to remember several things About the proper use of the CO2-rich blends discussed here: Other than CO2, the balance of the gas blend should always be Nitrogen, and should never be compressed air.

6 Only higher %CO2 gas blends should be used for dis-pensing regularly carbonated beers. Nitrogenated beers need a richer Nitrogen blend of 25% CO2/75% Nitrogen. Gas blends are meant to be used in long draw systems where : The length of run is long enough (usually 30-35 feet or longer) that the desired flow rate is unattainable at ideal pressure of straight CO2 The cooling system of the Draught lines cannot guar-antee consistent temperature from the keg cooler to the Draught lines Gas blends are not meant to be used in conjunction with pneumatic beer pumps, which use straight CO2 for applied keg at 60% v/v4027-333825-3129-353725-3028-343523-2 826-32psi at 70% v/v4021-2624-293820-2523-283719-2422-273 518-2220-25psi at 80% v/v4017-2119-243815-2018-223715-1917-213 514-1816-20psi at 65% v/v4024-3027-333822-2826-313722-2725-303 520-2523-28psi at 75% v/v4019-2422-263817-2220-253717-2120-243 516-2018-22psi at 85% v/v4015-1917-223814-1816-203713-1716-193 512-1614-18