How to Treat Brewing Water: Remove Chlorine and Chloramine

Chlorine and chloramine in tap water are the silent killers of homebrew flavor. These water treatment chemicals react with compounds in beer to create chlorophenols — medicinal, plastic-like off-flavors that ruin otherwise good beer.

The Problem with Treated Water

Municipal water supplies use chlorine or chloramine to kill bacteria. While safe for drinking, these compounds react with phenolic compounds in malt during brewing to form chlorophenols. Even tiny amounts create detectable off-flavors.

Chlorophenols produce a distinctive plastic, Band-Aid, or medicinal taste at incredibly low concentrations — parts per billion. Once formed, they cannot be removed. Prevention is the only approach.

Chlorine vs Chloramine

Free chlorine dissipates on its own. You can remove it by boiling water for 20 minutes or letting it sit uncovered overnight. Carbon filtration also works. However, many water utilities have switched to chloramine for its stability.

Chloramine is a bond between chlorine and ammonia that does not dissipate with boiling or sitting. It requires chemical treatment or specialized filtration. Check your local water report or call your utility to find out which form your water contains.

Treatment Methods

Campden tablets (potassium metabisulfite) are the fastest and cheapest solution. Half a tablet treats 10 gallons of water in under two minutes. It instantly neutralizes both chlorine and chloramine. Keep a bottle in your brewing supplies at all times.

Activated carbon filters remove both chlorine and chloramine, though chloramine requires longer contact time. Whole-house carbon filters or countertop units work well. Flow rate matters — slower is better for complete chloramine removal.

Reverse Osmosis Systems

RO systems remove virtually everything from water, including chlorine, chloramine, and all dissolved minerals. This gives you a blank slate for building any water profile from scratch using mineral additions.

Under-sink RO units cost $150-300 and produce enough water for homebrew use. The trade-off is waste water — most systems use 3-4 gallons of waste per gallon of pure water. Collection of RO water the day before brew day is standard practice.

The Verdict

The techniques and knowledge shared here build the foundation for consistent, rewarding results. Whether you are just starting out or refining your craft, focusing on fundamentals always pays dividends.

Start with what interests you most, practice deliberately, and do not be afraid to experiment. Every batch teaches you something new, and the journey of improvement is what makes this pursuit so engaging.