does filtering water alter its chemistry profile?

of salts and other common ions or whatever?

I feel like I should know the answer to this, but I don't.

I currently DO NOT filter my tap water, we have very nice water and the beer is quite palatable.

But I have a filter housing on the way, for other reasons, and I'm wondering now... with the carbon filters and such people use for water treatment.

Do they affect your water chemistry for all-grain brewing? or can you go forward with the same chemistry assumptions?

I know they "remove chlorine taste and odor" and that is what is throwing me off...

Of course they can alter chemistry...that's the point in using them.

But the specific filter in question REALLY matters. Carbon is going to remove chlorines, odors, some minerals (mainly heavy metals)...and not much else.

But if you start adding any sort of RO membrane to the setup, and you'll be removing general and carbonate hardness, and alkalinity, which can greatly affect mash pH, among other things.

So, carbon filters are good for 'cleaning up' your tap water. RO/DI filters will strip you down to (ideally) pure water which needs to be reconstituted or it won't be healthy for the mash or the yeasties.

A carbon filter will remove a couple ppm of Calcium, Mg and HC03 but it's very slight and you might as well ignore it. This is based on a buddy of mine actually send pre and post filter samples to ward lab.

asking in regard to Carbon filters and mainly the things you see in the water adjustment spreadsheet:

Calcium Magnesium Sodium Chloride Sulfate Alkalinity