Good water is critical to a great cup of coffee since it comprises mostly water. The flavor of coffee can easily be contaminated by other intruding influences. The best rule of thumb is “if the water you are going to use doesn’t taste right” don’t use it. It should have no discernible taste, or “character”, such as sharp or astringent qualities. Bad water makes bad coffee.
As a rule, bottled spring water is your best bet. Municipal water is usually not good enough for high quality coffee, unless you are using a good filtration system. Water that has been “softened” should also be avoided. It does not extract as well as non-softened water. Distilled water should not be used, because all of the mineral content has been removed. The minerals in water are essential to the extraction process. It is very important to note that if you’re using any type of container to store water in, it is very important to frequently, and thoroughly clean the container. The build-up of bacteria in water being used to brew coffee will have a dramatically negative effect on the coffee. This is one of the most commonly overlooked sources of trouble when brewing coffee.
The brewing temperature of the water used is very important. It should be between 195 F (91 C) and 205 F (96 C). The closer to 205 F (96 C) the better. Boiling water (212 F – 100 C) should never be used, as it will burn the coffee. Water that is less than 195 F (91 C) will not extract properly.
