7 Signs Your Draft Lines Need Cleaning

Most bars don't notice a dirty draft system until a customer complains. These are the earlier warning signs — catch them and you fix a maintenance issue; miss them and you're fixing a reputation problem.

1. Excessive foam or a "wild" pour

A pour that's mostly foam, or foam that won't settle, is often blamed on gas pressure alone — but biofilm and beer stone buildup inside the line change its interior diameter and roughen its surface, both of which agitate the beer as it travels.

2. Off-flavors: sour, musty, or "cardboard"

Bacteria and wild yeast living in an uncleaned line will flavor every keg that passes through it, no matter how fresh the beer was when it left the brewery. If a specific tap consistently tastes "off" regardless of which keg is behind it, the line is the problem, not the beer.

3. Cloudy or hazy pours (on beers that shouldn't be hazy)

Beer stone and protein buildup can cloud a pour that's supposed to be clear. If a customer asks why their lager looks hazy, that's a line-cleaning conversation, not a brewery quality issue.

4. Slow pour or low pressure

Mineral deposits narrow the interior of the line over time, restricting flow. If a tap that used to pour in a few seconds now takes noticeably longer, buildup is very likely the cause.

5. Visible gunk at the faucet

Pull a faucet apart and see a ring of grime, mold, or dried beer residue? That's not staying contained to the faucet — it's evidence of what's happening throughout the whole line.

6. Flat beer with no head retention

Oils and residue coating the inside of a dirty line and faucet break down carbonation and kill head retention, even on a beer that was properly carbonated at the keg.

7. Kegs kicking faster than they should

Excess foam and wasted pours from a dirty system mean more beer goes down the drain instead of into a glass — kegs that "should" last a week start kicking in four or five days instead.