French Press Water Recipe
Good French press water should taste clean and give the coffee enough balance without muting its acidity. Hardness, alkalinity, and total dissolved solids describe different things; one TDS reading cannot tell you whether water will make good coffee.
Understand the three measurements
- Hardness: mainly calcium and magnesium, commonly reported as equivalent milligrams per liter of calcium carbonate.
- Alkalinity: the water's ability to neutralize acid, often associated with bicarbonate.
- TDS: an estimate of all dissolved material. It does not identify individual minerals.
High alkalinity can flatten acidity. Very low alkalinity can let a coffee taste sharply acidic. The best balance depends on your beans and preferences, so there is no single mineral number that guarantees sweetness.
A measured mixing approach
For a convenient option, use a coffee-water mineral product with the specified volume of distilled or reverse-osmosis water. Follow that product's directions exactly; packets intended for different volumes are not interchangeable.
For a DIY starting point, Barista Hustle's water recipes use separate 1,000 ppm hardness and buffer concentrates. Following its concentrate preparation, combine 70 g hardness concentrate, 40 g buffer concentrate, and 890 g deionized water. This gives approximately 70 ppm hardness and 40 ppm alkalinity as CaCO3 in one kilogram of brew water.
Use food-suitable ingredients in the exact chemical forms specified by the recipe. Do not add the same weight of dry salts directly to the final water. A pinch is not an accurate measure, and hydrated versus anhydrous salts give different concentrations.
Test against your usual water
Brew the same coffee at the same ratio and grind setting with both waters. Compare acidity, sweetness, and finish after cooling slightly. If one tastes better, repeat the comparison before changing the mineral recipe.
Water will not fix excessive sediment or every cause of French press bitterness. This is a manual-brewing recipe, not blanket approval for use in an espresso machine; machine water requirements must be checked separately.
