By Carl Engelking
in Discover Magazine
Coffee, on its surface, is an incredibly simple beverage: just add hot water to ground up roasted beans. However — as in any great pursuit — achieving perfection remains elusive.
In the
quest for the flawless cup of coffee, aficionados have looked at everything
from roasting technique, to method of grinding, to the perfect ratio of water
to coffee (said to be 17.42 units of water
to 1 unit of coffee).
But
less often considered is the water itself. While we tend to view tap water as a
pure ingredient, it’s actually loaded with minerals that can influence coffee’s
flavor. And now chemists have pinned down how the chemicals in different types
of water interact with coffee beans to shape the taste of the brew that
results.
Science
to the Rescue
Coffee
is loaded with a tremendous amount of natural chemicals and over 1,000 aroma
compounds. Water, on the other hand, can be rich in minerals like calcium and
magnesium if it’s “hard,” or if it’s “soft,” rich in sodium — used by
water softeners to remove impurities.
For
this study, Christopher Hendon, a chemist from the University of Bath,
focused on the way different kinds of water affect the extraction of six
chemicals that contribute to the flavor of coffee. These flavors included
citric acid, lactic acid and eugenol — responsible for coffee’s “woodsy”
taste. He found that magnesium in hard water, for example, sticks to eugenol,
giving the resulting brew an even woodsier taste, Business Insider reports.
And bicarbonates in hard water will make the coffee bitterer. The findings were
published last month in the Journal of
Agricultural and Food Chemistry.
“Hard
water is generally considered to be bad for coffee, but we found it was the type
of hardness that mattered – while high bicarbonate levels are bad, high
magnesium ion levels increase the extraction of coffee into water and improve
the taste,” Hendon told Phys.org.
Selecting
the Right Coffee
Soft
water, unfortunately, lacks the sticky minerals of hard water, so it’s poorer
at extracting flavorful compounds. But if you live in a soft-water haven, don’t
dismay: a tactical selection of beans may help counter the problem.
Just
like one would pair wine with a certain type of food, the same is true for your
type of water and the coffee you brew. You can get a rough idea about the
hardness of your water by checking out the U.S. Geologic Survey
water map. Then, purchase beans that are best brewed with hard or
soft water, which a knowledgeable roaster should know.
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