How must draft beer be served?

Draft beer must be served using CO2 or a CO2-nitrogen mix because this method helps maintain the beer's carbonation and freshness. CO2 is the primary gas used in the dispensing process as it is highly soluble in beer, allowing for effective carbonation while also helping to prevent oxidation and spoilage. A CO2-nitrogen mix is often used for certain styles of beer, such as stouts, which benefit from the creamy mouthfeel that nitrogen provides.

Using compressed air is not suitable for dispensing beer because it contains moisture and may lead to contamination or off-flavors. Serving beer at room temperature is generally not ideal, as many beers, particularly lagers and wheat beers, are best enjoyed when chilled. Additionally, shaking the keg is detrimental because it can cause excessive foaming and disrupt the beer's natural carbonation, leading to a poor serving experience. Therefore, the correct method for serving draft beer is through CO2 or a CO2-nitrogen mix, ensuring the beer is served properly, maintaining its quality and taste.