When fresh and properly dispensed, draft beer tastes the way the brewer intended—clean, flavorful, and enjoyable. Draft beer is susceptible to damage from a host of factors, such as age, heat, and air. But the number one factor affecting the quality of draft beer flavor and aroma is poor hygiene. Improper cleaning of beer system lines and components from the coupler in the cooler to the faucet at the bar can lead to significant changes in beer flavor, all of them unwelcome. Over time, poor beer line hygiene will inevitably result in loss of sales due to customer dissatisfaction, and to replacing beer lines at great expense. Staying ahead of these potentially costly outcomes is key to serving great-tasting draft beer.

This chart lists the most common off flavors that occur due to post-brewery unhygienic conditions and the mishandling of draft products. Beer-spoiling bacteria will ruin a beer’s flavor and aroma, and will inevitably lead to lost repeat business and potential sales. While these microorganisms are not health risks, they will cause bacterial infections in draft systems that are often difficult, if not impossible, to completely remove. By establishing a strict draft beer cleaning program, the occurrence of these off flavors can be prevented.

All content has been adapted from the Brewer’s Association Draft Beer quality manual.