Cicerone Certified Beer Server Practice Exam

The flavor pair of buttery and oily is most likely to develop if draft lines are not cleaned regularly due to the buildup of bacteria and yeast in the lines. When draft lines are not maintained, these unwanted microorganisms can produce off-flavors, including diacetyl, which gives a buttery flavor often associated with certain types of beer, particularly lagers. The oily sensation may arise from the residual oils from the brewing process or from the interaction of the beer with dirty lines, amplifying negative taste experiences.

Regular cleaning of draft lines helps to maintain beer quality and prevents such undesirable flavors from developing by removing bacteria, yeast, and other residues that can contribute to off-flavors. This helps ensure the beer maintains its intended characteristics, avoiding the introduction of flavors that could detract from the overall experience.

In contrast, the other flavor pairs listed, such as fruity and sour, sweet and tart, and malty and hoppy, are more associated with the natural characteristics of specific styles of beer rather than the effects of unclean draft lines.