Water is by far the main ingredient in beer. It is therefore quite important to use water of good quality. Fortunately, my local water supply provides me with water that I can use straight from the tap without adding any PH-modifiers or decalcifiers — and they also don’t add any unwanted elements like chlorine which could negatively affect the flavour of the beer.
The water is a mix of 70% lake water, 20% aquifer and 10% spring water. It is relatively hard at 90.8 mg/l of calcium on average, but as the presence of calcium (Ca2+)-ions enhances the action of starch-splitting enzymes during the mashing phase, I see this as a plus. Magnesium and sodium, which can impart bitter, sour or salty flavours to the beer, are present at a very low level.
The name of this page, “dihydrogen monoxide”, is a joke I’ve occasionally played on people who demand their food be “chemical free”. Well — my beer isn’t. Dihydrogen monoxide is a chemical, and it contains more than 90% thereof…