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

In draft dispense systems, using compressed air instead of CO2 or a CO2-nitrogen mix is highly discouraged. This is because compressed air contains water vapor, which can lead to spoilage or damage to the beer due to oxidation and contamination. Additionally, compressed air can introduce unwanted flavors and aromas into the beer, adversely affecting the quality and taste.

CO2 is essential for maintaining proper pressure in the keg and ensuring a consistent flow of beer without introducing oxygen. A CO2-nitrogen mix helps in serving beers that are more nitrogenated, such as stouts, creating a creamy texture and fine bubbles. The unique properties of both gases help maintain beer quality and carbonation, which are crucial for serving beer in optimal condition.

Using nitrogen alone is not suitable for standard carbonated beers, but it does have its applications when mixed with CO2. Helium is not typically used in draft systems as it does not dissolve in liquid effectively and does not contribute to carbonation or pressure maintenance. Therefore, choosing anything other than CO2 or a CO2-nitrogen mix compromises the integrity of the draft system and the quality of the beer being served.