Recommended water composition for coffee brewing is approximately 30-50 parts per million calcium, 15-30 ppm magnesium, and 50-75 ppm bicarbonate, though these are not absolute targets and exist within a spectrum of acceptable ranges.

factualpending

Speaker

James Hoffmann

Evidence Quote

if I was talking about calcium I might say 30 to 50 parts calcium is good but if it was magnesium I might say more like 15 to 30 parts per million or milligrams per liter is good similarly with buffer I might say so between 50 75 maybe ppm

Source

The Best Water for Coffee - An IntroductionJames Hoffmann
Created: 8/13/2026, 9:49:47 AM

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