Coffee · Water
Water for coffee
Coffee is mostly water, and water is a recipe. Two numbers decide how it brews: hardness (magnesium and calcium, which grab flavour compounds out of the grounds) and buffer (bicarbonate, which soaks up acidity before you taste it). Set both and get a mixable recipe.
The chemistry is real: dissolved minerals control what extracts and how fast, and magnesium-rich water is among the strongest extractors. The units here are ppm as CaCO3, the convention water reports and the SCA standard use. This is taste tuning, not lab work.
Distilled water plus two pantry minerals. That is the whole trick.
Start from a preset
68 ppm
40 ppm
Your water on the map. The dashed box is the SCA acceptable range.
168 + 67 mgper litre
168 mg Epsom salt (MgSO4, from any pharmacy) and 67 mg baking soda into a litre of distilled water.
Too small to weigh? Make 100x concentrates: 16.8 g Epsom and 6.7 g soda, each in its own litre of distilled water, then dose 10 ml of each per litre of brew water.
68
ppm hardness