Each bad flavor in draft beer has a cause. Figure out the flavor and you know where to look. One tip before you start: pour the same beer from a can or bottle if you have one. If the package tastes fine and the draft doesn't, the problem is in your system.
Vinegar
A sharp, vinegar taste is acetic acid. Acetobacter bacteria make it from the alcohol in beer. They live in dirty lines, faucets, and couplers. The fix is a full cleaning with caustic, with faucets and couplers taken apart. The first few pints after cleaning may still taste off until fresh beer pushes through.
Sour
Sour on a beer that shouldn't be sour, like a lager or pale ale, points to Lactobacillus or Pediococcus. The Brewers Association Draught Beer Quality Manual lists both as common in dirty lines. Same fix: clean the lines and stay on a 14-day schedule. See why lines need cleaning every two weeks.
Pouring a sour beer on purpose? Taste it against the can before you blame the lines.
Buttery or Butterscotch
That's diacetyl. Pediococcus in dirty lines makes it. It can also come from the brewery if the beer left too young. Check the can or bottle. If the package is clean and the draft is buttery, the lines need cleaning.
Musty or Barnyard
Musty, earthy, or barnyard flavors often come from wild yeast or mold. Faucets are a common source, especially when they don't get taken apart at cleanings. Pull the faucet and look. A black or brown film inside means it's been skipped.
Check the drip trays too. A tray full of old beer breeds mold and fruit flies right under the faucets. Empty and wash it every day.
Skunky
Skunky beer comes from light hitting the hop compounds. That happens to the keg in storage or shipping, before it reaches your lines. If a fresh keg tastes skunky from the first pour, the keg is the problem. Check where you store kegs and keep them out of direct light.
Medicinal, Plastic, or Band-Aid
This is usually chlorine. Chlorine sanitizer, or chlorinated tap water left in the lines, reacts with compounds in beer and makes chlorophenols. People can taste tiny amounts. The cause is a bad rinse after cleaning. Lines should be flushed well, and beer run through before anyone is served.
Stale or Cardboard
A papery, stale taste means oxygen got into the beer. Look for a worn coupler seal, a loose gas fitting, or a keg that's been on tap a long time. If it tastes stale from the first pull of a new keg, the keg itself may be old. Check the date.
Only One Tap Tastes Off
If one line tastes bad and the rest are fine, the problem is in that line, faucet, or coupler. Clean that line before you tap a new keg on it. A fresh keg on a dirty line goes bad too.
Keeps Coming Back?
If a flavor returns a few days after every cleaning, look at beer stone or worn tubing. See what beer stone is and when to replace draft lines.
Have a tap that doesn't taste right? Call (267) 282-1002 and we'll track it down.