Let’s just start off by saying, if you think that your tap water is doing your coffee justice… it’s not. Tap water (the stuff you get out of your kitchen sink) is called hard water. What is hard water? Hard water is water that has high mineral content, some of those minerals include: Iron (Fe), Calcium Acetate (Ca), Magnesium (Mg), Sodium (Na), Potassium (K), Carbon (CO3), Hydrogen Carbonate (HCO3), Sulfate (SO4), Chlorine (Cl).
Mineral content is okay for washing dishes, taking a shower and cleaning, but it is not recommended for coffee brewing (basically, don’t use it for coffee brewing – EVER). If you live in a place like Madison, WI with “very hard” water, it is recommended to use a water filtration system for the water you consume and brew coffee with. Also, stay away from distilled water, it lacks the mineral content level that is required to make your fair trade, organic coffee taste the way it should. Mineral content in small quantities is desirable in brewed coffee due to its positive effect on the body of the coffee (the feeling or consistency of the coffee in your mouth).
What other negative water qualities should you look out for?
- Water that has a strong odor (i.e. like chlorine or “off” smelling)
- Tastes “off” like chlorine or has a salty-slick mouth feel (barf)
- A buildup of mildew or calcium on your tap (those are signs that you are brewing with hard water)
So, take a look at your coffee and ask yourself… is your water doing your hand-picked, fairly traded, precision roasted organic coffee justice? Coffee is 98% water after all.
Lingle, T. R. (1996). The coffee brewing handbook: a systematic guide to coffee preparation (2nd ed.). Long Beach, CA: Specialty Coffee Association of America.