The water where I live and brew is lightly chlorinated by the water authority - free chlorine but no chloramine; you can just taste it occasionally in a glass of water or smell it in the steam from a hot shower. I have always removed the free chlorine prior to brewing by either gassing off my brewing water over 24 hours prior to brewing or boiling for 15 minutes. I have always done this as I have read in many places on the internet that chlorine in brew water (even if not able to be tasted directly) can potentially generate unwanted chlorophenols during the fermentation phase of the brew. Removing chlorine in this way therefore ensures the removal of one potential source of off flavours from the finished beer. But here is my question: if chlorophenols from chlorine in the brew water are only created in the fermentation phase through interaction of chlorine with yeast and fermentation byproducts and if boiling removes free chlorine in water, then would not the standard boil phase (60-90 minutes) in the brew process always remove free chlorine from wort prior to it getting into the fermenter? If so, how can chlorophenols be created from chlorine in the brewing water? They may obviously be generated from other interactions, but if there is no chlorine, which ones and how? I do not want to challenge any orthodoxy regarding chlorine and chlorophenols and, no matter what the answer to my question, I will still remove the chlorine from my brew water prior to use (it smells and tastes nicer), but have I missed something about chlorine, chlorophenols and boiling wort?