It's In the Water
By Mauro Cipolla

How important is water quality for home espresso extraction?

Let me start by making a bold statement: People do not have a clue about proper water quality for extraction! In most cases, water is either not filtered enough or filtered too much. Even worse, some people use distilled or purified water for home coffee extraction!

To optimize the flavor of specialty coffee, you must understand water quality. After all, water is more than 97 percent of the beverage. Water affects the taste and odor of the coffee we drink, yet we don't understand it. Why is water that should be treated not treated and water that should not be treated over-treated? Why do people buy filtering systems that do not meet their particular water needs?

In order to master this all too common problem, you must first realize that you are not just dealing with water--you are dealing with the water that comes out of your tap. No two water supplies are the same. Each comes into contact with different soils, municipal treatments and distribution channels. Furthermore, the condition, age and type of water conduit in your home will also alter the qualities and elements of your "very own water."

Next, you will need to take a water sample to a qualified company for testing. Water testing will tell you what is present in your water supply. Each water sample you have tested will have its own character due to turbidity, color, hardness, specific conductivity and percentage of total dissolved solids. You will want to eliminate certain chemicals through proper filtration to improve the aroma and taste of your coffee. You must also remember that not all chemicals should be removed from your water, since some of them are essential for the taste, color and aroma of brewed coffees.

For the best coffee extraction, your water should contain the following properties: total dissolved solids of more than 300 ppm (parts per million); a pH reading of more than nine; calcium and magnesium levels of more than 100 ppm; sodium and potassium levels of more than 50 ppm; and a total hardness of more than 150 ppm.

If the results of your water test indicate that you need to treat the water, make sure that the system you install is compatible with your needs and that you maintain it properly over the months or years of use. If you use water softener, please make sure that you do not soften the water too much--you may lose desirable coffee flavors and increase bitterness with water that is too soft.

The third step is to understand that certain coffee blends (due to their unique chemical and structural components) can mask the impurities and deficiencies of the water you use in the brewing process. So, as you test your water, keep in mind the flavor profiles of your favorite coffee blends, and marry the right water to the appropriate coffee.

Lastly, do not forget the water inside the boilers. Scaling, lime and related deposits inside a boiler can affect the taste of brewed coffee and damage the equipment. Proper maintenance, cleaning, and the use of a polyphosphate treatment on a regular basis will keep the water in your boiler from becoming tainted and your equipment functioning properly.

Learn how to look at your water to get some preliminary clues about its quality. How does the water look? Is it clear, or is it cloudy? Does it contain numerous large air bubbles? Does it settle and become clearer? How does it smell? How does it taste--hot vs. cold?

Learn to cup your water before you cup your coffees. Eventually, after practicing and fine-tuning your skills, you will enjoy your water supply and your coffees at their best.


Mauro Cipolla is the owner of Caffe D'arte, an award-winning, Seattle-based roaster with an international reputation. He can be reached at


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