Water from espresso machine or boiled separately?

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.

Postby mathof » Feb 13, 2018, 7:15 am

I brew coffee in my Chemex with water drawn from the hot tap on my espresso machine into a pouring kettle. This method seems to work fine, judging by taste and measured extraction levels. Nonetheless, I read from time to time that it is better to boil water on the stove top. Is this true? If so, why would that be?


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Postby another_jim » Feb 13, 2018, 11:40 am

The water in the boiler picks up metallic ions, same as the water in a storage heater. If you use the tap a lot, say a few times a day, so the water turns over quickly; this is not an issue; if you use it rarely, say a few times a week, it is best not to use it for drinking. The truth of it is either to use it all the time or not at all.
Jim Schulman


Postby mathof » Feb 13, 2018, 2:21 pm

Thank you for that explanation. In fact, I use about 1.5 to 2.0 litres of bottled water (Volvic) daily, which goes into the L1's 2.3 litre boiler. So, I guess that is enough churn to keep me safe. But if I go through a period of not turning the water over so frequently, I'll boil the water for brewing separately.