Cicerone Certified Beer Server Practice Exam

If draft lines are not cleaned regularly, which of the following flavors is most likely to develop?

1. Musty

2. Vinegar

3. Oxidized

4. Bitterness

The correct answer is: Vinegar

When draft lines are not cleaned regularly, it creates an environment where bacteria and wild yeast can thrive. These microorganisms can produce byproducts that impart undesirable flavors to the beer. One common byproduct of this uncontrolled microbial activity is acetic acid, which is the primary component of vinegar. As these bacteria metabolize residual sugars and other components left in the lines, they can create a vinegary flavor that significantly degrades the quality of the beer being served. This is often recognizable as a sharp, sour taste that detracts from the intended flavors of the beer. In contrast, musty flavors might arise from mold or stale conditions but are less directly associated with the specific issue of draft line cleanliness. Oxidized flavors typically result from exposure to oxygen rather than from microbial activity in dirty lines, and bitterness is generally a characteristic of the hops in the beer or its aging process rather than a direct effect of line cleanliness. Therefore, a lack of regular cleaning is most closely linked to the development of vinegar-like flavors due to the proliferation of acetic acid-producing bacteria.