The Beer Off-Flavor Series: Chlorophenol

By Drew Beechum

This is part 2 in The Beer Off-Flavor Series by Drew Beechum. Catch Drew at Homebrew Con 2019 where he’ll be presenting “Brewing Simple: Great Beer with Less Effort and More Fun.”

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Chlorophenol is a common off-flavor that I’ve tasted time and time again in homebrew from new brewers. Fortunately, it’s one of the easiest off-flavors to avoid once it’s understood!

With chlorophenol, prevention is the name of the game because once this compound hits your beer, there’s nothing else you can do but re-brew.

Key Indicators

The following characteristics are common when chlorophenol is detected in beer:

  • Plastic adhesive bandage (Band-Aid)
  • Mouthwash (Listerine)
  • Medicinal
  • Sweetness (think spicy cookies with an edge)

Causes & Prevention

Chlorine/Chloramine

Most municipal water systems add chlorine or chloramine (a stabilized chlorine solution that lasts longer in water). The chlorine reduces the likelihood of nasty contaminations of the water supply.

The tradeoff is water that’s not always ideal for making beer. Chlorine or chloramine in brewing water reacts with compounds in malt and yeast, resulting in the medicinal and plastic qualities that are a hallmark of chlorophenol.

Solution: If the issue derives from chlorine in your water source, the fix should is easy! Simply let your brewing water sit out overnight or bring it to a brief boil. This should drive off the chlorine. Chloramine, on the other hand, takes a bit more work. First, you can run your water through a charcoal filter or reverse osmosis system. Alternatively, a crushed Campden tablet (potassium metabisulfite) can simply be stirred into the brewing water and reduce the level in just minutes. Of course, you can also buy pre-filtered water, but know your source!

chlorophenol-water

Chlorophenol is typically a water-derived issue. Ensure the the quality of your water is up to par!

Water Hoses

Many a homebrewer has used a backyard garden hose to supply brewing water. You know, the old green one that hasn’t been coiled in years? Sending the water destined for your brew kettle through your garden hose can pick up vinyl and phenolic flavors, which are detectable in the  finished beer.

Solution: If you use the outdoor water faucet, opt for a white RV hose or other food-safe hose. You may have to get an adapter to fit your garden faucet.

Homebrew Con Seminars

Bacterial Contamination

Bacterial contaminants love to play merry hob and produce all sorts of off-flavors. Chlorophenol is one of them. Contamination from unwanted bacteria can be introduced at any point in the brewing/fermentation process after the boil.

Solution: If you suspect your chlorophenol issue is due to contamination, review your sanitation practices. Ensure all equipment is thoroughly cleaned of debris and then sanitized if it will come into contact with the beer any time after the boil. Also consider replacing plastic and rubber equipment that may harbor bacteria in scratches and cracks.

homebrew sanitization

Using no-rinse sanitizer in a spray bottle is an easy way to quickly and completely sanitize all homebrew equipment that comes into contact with the wort after the boil is completed.

Fixes

Prevention is the name of the game with chlorophenol: once this compound hits your beer, there’s nothing you can do to get rid of it.

Of course, you always have options to try to cover it up via blending, adjunct additions, or other flavor-infusion options.

Keep an eye out for the next installment, Beer Off-Flavor Series: Diacetyl, and be sure to check out the feature on acetaldehyde

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Drew Beechum lives in Los Angeles, Calif. When not busy playing with computers for pay, he plays with beer. Drew is a member of the Maltose Falcons, cohost of Experimental Brewing, and coauthor of Simple Brewing: Great Beer. Less Work. More Fun. 

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