Dechlorinization Print
Learn - Tips & Tricks
Written by Mark Emiley   
Tuesday, 02 September 2008 08:56

The chlorine in your tap water that helps keep your water free of microbes is great for keeping your water clean, but not great for your beer.  Chlorine and chloramines can form chlorophenols which have unpleasant aromas.  They can create medical or plasticy notes in your beer.  Some are more sensitive to these aromas, but it is safe to say that we'd like to keep these to a minimum. 

There are a few easy ways around this.  First, you can carbon filter your water through something like a Brita filter.  This is very effective but is somewhat time consuming and you obviously need a filter setup.  Also, Brita filters unfortunately do not remove chloramines, which are becoming more and more common in water supplies.  You can also simply use drinking water purchased from your grocery store.  This is more expensive, but you don't have to worry about filtering.  You can also boil the water in advance which will drive off chlorine, but this is pretty time consuming (in heating and cooling) and takes energy.  Again, this won't drive off the more persistent chloramines.

The final technique is the one I highly recommend due to time, effectiveness, and cost.  By simply adding a campden tablet (potassium metabisulfite) to your brewing water, you will effectively remove chlorine AND chloramines.  It converts chlorine to chloride and the sulfite is converted to sulfate.  Chlorides and sulfates are a normal part of the brewing process and the amounts at which they are added to the beer are very low and well within brewing margins.  For chloramines, some ammonium ions are released into the water which is also okay because this is part of a brewer's mash.

One tablet will dechlorinate up to 20 gallons.  Don't worry if you are only doing 5-10 gallons, it won't be noticeable but if you want, you can break up the tablet in half.  Basically, just crush it up and add it in.  The reaction is very fast (done in minutes once dissolved) so you can crush, mix, and brew quickly.  Campden tablets are cheap (much cheaper than your other alternatives) and available at most brewing stores.