Study Guide
Read the full study guide: Complete Guide to Draft Beer Systems
Exam Focus
- Dirty draft lines can create buttery off-flavors.
- Dirty draft lines can create sour off-flavors.
- A suspected line problem should be escalated rather than served through.
What to know
Dirty draft lines may create buttery diacetyl, sour or vinegar-like acidity, musty character, or generally stale and unpleasant beer.
How it applies
Stop service on that line, tell a manager, and check cleaning records or draft service support rather than trying to mask the flavor.
- Dirty draft lines can create buttery off-flavors.
- Dirty draft lines can create sour off-flavors.
- A suspected line problem should be escalated rather than served through.
Why It Matters
- Dirty lines can add sour, buttery, or otherwise unclean flavor to every beer on the path.
- Recognizing a line-specific pattern prevents good kegs from being blamed or repeatedly replaced.
Practical Sensory Exercises
Dirty Draft Lines practice drill
Compare the same draft beer from the faucet and a known-clean package if available; record any sour, buttery, or dirty difference and check whether neighboring taps show a similar pattern.
Key Terms
- Diacetyl
- Butter or butterscotch-like flavor that can be associated with dirty draft systems or fermentation.
- Acetic
- Vinegar-like acidity that can indicate contamination.
- Draft contamination
- Microbial or residue problems in draft equipment that damage beer flavor.