The flow rate through the carbon filter was not indicated. For chlorine removal, we can generally get by with a flow rate of about 1 gallon per minute for the 10-inch filters. For chloramine removal, the flow rate has to be dropped even further to about 0.1 gallons per minute. If you were pushing water through the filter faster than this, it is likely that there was residual chlorine or chloramine in the brewing water that does create chlorophenols. Be aware that the taste threshold for chlorophenols is very low and it only takes a teeny bit of the chlorine or chloramine to ruin the beer.
Thanks for your input. much appreciated The flow rate Im using is much higher that 1 gal per min.. I was concerned with this, but after testing the water for chlorine, and not getting any readings,, I was convinced the filter was able to handle the high rate of flow and still be able to remove it significantly enough.. The water had no readings, and no smell or taste of chlorine.. and I have since found out that there is no chloramine in the cities water.. so at least that is good news.. Like I mentioned,, I have brewed with this same method time and time again, and have produced fantastic results.. not sure why now,, something has changed.. I will know if it was the filter after I ferment this one out,,, can only be the water in my opinion.. The yeast I have used like this at these temps over and over with fantastic results.. so im not convinced its a yeast-temp issue..as all the years ive been doing this, never had an issue with it before.. it taste clean, and after I lager it for 10 days at 2c it settles like a rock and is clear as can be,, has a nice dry clean lager finish,, some fantastic beer ... but if this brew dosent turn out.. then Im going to really have to look at it closer.. cheers john