Where in the brewing process are water characteristics important and why?
Mashing: Establishing the proper mash pH is extremely important because alpha and beta amylase, which convert starches to sugar, work best in the range of 5.1 to 5.5 pH. Roasted malts are naturally acidic, and even small amounts in the grist can usually produce the proper pH even if mashed with distilled water. Pale malts are not acidic enough in this situation so adjustments must be made if the water is very soft, either through addition of brewing salts such as gypsum (calcium sulfate) which lowers pH, or conducting an acid rest where the malt sits for 30 minutes at about 95-110F. By the same token, dark malts do not work well with soft water; the pH becomes too low, the enzymes do not work correctly, and the pH must be raised with substances like chalk (calcium carbonate). Sparging: Sparge water should be at the proper pH as well. If the pH is too high tannins in the grain husks can leach out and cause astringency in the final flavor of the beer. The pH of the sparge water should be
