First, what processes are you referring to?
Second, if I use my tap water, dark beers come out fine but light beers don't taste right. What should I do if I don't modify the water profile - brew only stouts and porters?
Sounds like my city water in Kalamazoo. Tons of residual alkalinity. The dark grains get the pH closer to what is optimal for the mash/fermentation. For light beers, cut your water 50% with RO water and adjust down to 5.2-5.4 pH with lactic acid.
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