The coffee water

A cup of filter coffee is more than 98% water, so the water you use changes the taste as much as the grain. Dissolved minerals help to extract the flavors, but if there are too many they turn off the acidity and fill the coffee maker with lime.

The SCA, the association of specialty coffee, proposes these reference values:

• Total dissolved solids (TDS): ideal, 150 mg / L; acceptable, between 75 and 250.
• Calcium density: about 68 mg / L of calcium carbonate, between 17 and 85.
• Total alkalinity: around 40 mg / L, between 40 and 75.
• pH: 7.0, between 6.5 and 7.5.
• Sodium: about 10 mg / L.
• Chloro: nothing. Neither iron, manganese or copper.

In addition, the water must be transparent and not smell at all.

Each parameter has its role. Calcium and magnesium catch the flavors of coffee and take them to the cup. The alkalinity is a shock absorber: a little balanced, but much neutralizes the acidity and leaves the cup flat. The very soft or distilled water is bad and, in the machines, it can corrode the metal; the very hard leaves lime in boilers and resistances.

In Spain, tap water changes a lot from one area to another: in Barcelona or Valencia it is very hard; in Galicia or Madrid, soft. If yours is hard or tastes like chlorine, use a filter pitcher or a bottled water of weak mineralization, with a dry residue of 50-150 mg / L, which is indicated on the label.

A simple trick: make the same coffee with tap water and a soft bottled, and share them. The difference is usually surprising.