What beer attribute is fixed in bottled beer but can be affected in draft beer?

Carbonation is the correct attribute that is fixed in bottled beer but can be affected in draft beer. When beer is bottled, carbonation levels are typically established during the packaging process, where carbon dioxide is added, creating a consistent level of fizziness that remains stable throughout its shelf life.

In contrast, draft beer is served from kegs, where the carbonation can fluctuate due to various factors, such as the pressure used in the dispensing system and the temperatures at which the beer is kept. If the pressure is too low, the beer can become flat, whereas if it's too high, it may be overly carbonated, leading to excessive foaming when served. Additionally, draft lines can experience gas exchange, affecting the carbonation level over time.

The other attributes listed—alcohol content, flavor, and color—are generally established during the brewing process and remain relatively consistent in both bottled and draft formats, assuming they come from the same batch of beer. Thus, carbonation is the key attribute that can demonstrate variability in the draft format compared to the bottled format.