Cicerone Certified Beer Server Practice Exam

What should never be used instead of CO2 or a CO2-nitrogen mix in a draft dispensing system?

1. Propane gas

2. Compressed air

3. Natural gas

4. Helium

The correct answer is: Compressed air

In a draft dispensing system, the choice of gas used to propel the beer is crucial for maintaining the quality and integrity of the beer. Compressed air is not suitable for this purpose due to its composition and how it interacts with beer. Using compressed air introduces oxygen into the system, which can lead to oxidation of the beer. Oxidation can cause off-flavors, diminishing the freshness and quality of the beer. Unlike CO2 or a CO2-nitrogen mix, which are inert and do not react chemically with the beer, compressed air contains a significant amount of oxygen that can spoil the beer during dispensing. In contrast, CO2 is the standard gas used because it is soluble in beer, which helps maintain proper carbonation levels while ensuring that the beer tastes as intended. A CO2-nitrogen mix is also common, especially for beers such as stouts, as nitrogen helps create a smooth and creamy mouthfeel without excessive carbonation. Using any other gas, such as propane or natural gas, would be completely inappropriate and potentially dangerous, but in this context, compressed air stands out due to its detrimental effects on beer quality. Helium is also unsuitable, as it does not have the properties necessary for beer dispensing, but the primary concern here