Using hard water that's full of minerals won't bond well with the dissolved particulates from the coffee, leading to an under-extracted, weak coffee. Also, heavily filtered or distilled water can be destructive to your equipment. The lack of ions and mineral content will force the water to "leach minerals out of the metal components and degrade the machine's performance over time. You want water that is roughly in the middle of the spectrum, with a mineral balance of approximately 150 parts per million. Water from a Brita water pitcher or your refrigerator's filtered water will suffice.
anonymousMaking-Coffee July 25, 2018 at 9:44 pm10