Why Water Is So Important to Coffee

JP asked a great question on Twitter recently.  We were talking about a recent post of mine on making sure you use the right ratio of coffee to water.  JP followed it up with a question on water, specifically whether it makes a difference to use spring water versus tap water.My knee-jerk answer is to always advise applying the same standards to the water you use to make coffee as you would to your drinking water.  If you wouldn't drink the daily-recommended 2 liters of a particular source of water, then I wouldn't use that water in your coffee.  Coffee is 99% water.