I have done many many brews with untreated local tap water, and I have only 3 times had an issue with chlorophenols. I now treat the tap water with 1 campden tablet/100l/20gl. But, revieing my records it looks like it was only pale ales that were affected.
This leads me to question do darker ales in some way buffer the chlorophenols?
Is there something in dark or aromatic malts that reduces chlorophenol generation?
Is it just when it happens they mask the flavour?
Or is this just random chance and it affects all ales the same but I just happen to have been affected on 3 pales?