Water from Pur filter (sink faucet filter)?

I'm not sure if this is best here, or in the Brew Science section; there seems to be more traffic here, but go ahead and move it if it's more appropriate over there.

I'm curious about the water profile that results from a typical sink faucet mounted filter (Pur/Britta), and how appropriate it is for brewing.

I have a Pur "mineralclear" filter setup, and only know that it makes my hard, chlorine-smelling city water taste a lot better and removes the chlorine taste/odor virtually completely.

It's a 3-stage filter; stage 1 traps sediment, stage 2 is an activated charcoal filter, and stage 3 adds back "natural minerals" (they also sell filters without stage 3, that just give you the plain charcoal filtered water).

How do such filters affect the mineral content of the water (or do they)? I like the taste of the mineral filter for drinking water, but I'm afraid it's giving me harder water than is ideal for brewing.

I'm a small-batch extract brewer looking to shift into PM or even AG to better make use of bulk ingredients, and water chemistry is one of the big "new" variables mashing seems to bring to the table.

I could always send "before filter" and "after filter" water samples away to be tested, but I'm not sure I'm $60 curious yet, especially if someone here can shed some light on how these types of filters effect the water.

IIRC, a carbon filter will not remove minerals from the water, but it will remove chlorine and VOC's. I am not familiar with the stage 3 thing you mentioned, but I doubt it would be beneficial to your beer. Not all water filters perform equally. I've had good results using a solid carbon block filter and nothing else. I often blend tap water and distilled water 50/50 when softer water is called for with some styles. Beyond that, I sometimes use calcium chloride or calcium sulfate when a recipe suggests it. I'm fortunate to have pretty good tap water where I live. I probably would not even need the carbon filter, but I figure it can do no harm.