Which gas mixture is NOT commonly used in draught beer systems?

In draught beer systems, the gas used to pressurize and dispense beer plays a critical role in maintaining the quality and characteristics of the beer being served. Using a mixture of gases helps to maintain carbonation levels while also ensuring the beer is dispensed at the right pressure.

Air is not commonly used in draught systems because it contains a mix of gases, including nitrogen and oxygen, which can have detrimental effects on the beer. The introduction of oxygen can lead to oxidation, negatively affecting the flavor and freshness of the beer. Therefore, using air compromises the integrity of the beer served.

In contrast, gas mixtures like 70% nitrogen and 30% CO2, as well as 75% CO2 and 25% nitrogen, are used to achieve different carbonation levels and mouthfeel. Carbon dioxide is essential in providing the necessary pressure and preserving the beer’s carbonation, while nitrogen can create a smoother texture and creamier head, often used in specific styles like stouts or nitro beers.

100% CO2, while less common for all beer styles, is still employed in certain draught systems for specific serving situations where higher carbonation is desirable. Each of these gas mixtures serves a specific function that enhances the quality of the draught beer