How old is your beer? I'm not a new brewer but still getting different types under my belt. If you're getting that odd hard to describe sharp flavor at the beginning of the taste(rather than at the end, ie. you taste it first then it clears and you taste the beer) it's probably just "green beer." I didn't know that was a huge issue and am now waiting on my chocolate oatmeal stout
I've mostly brewed wheat beers and kolsch and never had to wait, or had been lazy and given the beer a few months before I even bottled/kegged it!! But now I'm going all out eager as hell and am learning you gotta wait.
Anyways, thought I'd throw that in. I have a whole house water filter as well as I get a lot of rust which affects the color of the beer(!!!) (even showers are reddish!) and that takes care of most of it, and I use a campden tablet as well(old habit, tho I'm sure it gets any remaining chlorine) before I boil as it gets rid of chlorine and chloramine.