Water for espresso: what to check

Start with the manual

Your machine maker may specify parameters for water and filters. These requirements can differ by model and region. Follow those instructions before choosing tap, filtered or bottled water.

Taste and minerals

Water is most of the drink and its composition can affect flavor. Hardness and alkalinity are different properties; a pleasant-tasting water is not by itself proof that it meets the machine requirements.

What a TDS meter cannot tell you

A total dissolved solids reading is one measurement. It does not establish the individual hardness, alkalinity or other parameters a manufacturer may specify. Use suitable tests if your manual calls for them.

Choose treatment carefully

A filter does not necessarily remove or change every property. Check what a specific filter does and when its maker says to replace it. Do not assume distilled water, unmodified reverse-osmosis water or a universal mineral recipe is suitable for your machine.