Water Chemistry is an important factor in building the flavor profile of beer. Depending on the type of beer you are brewing, you may want to accentuate the hops or bring out more character from your malt. When brewing historical, traditional or regional styles, matching the water profile of the commercial brewery will help you re-create the style.
Dwight Mulcahy has created a back-end tool to help calculate the mineral additions for custom water profiles from RO filtered water or your local water supply. Check with your water municipality to find the mineral content of your water. Running your brew water through a charcoal filter before adding the additions is highly recommended.
Basic Water Options