A cup of espresso is 98% water.

This indispensable element must be potable and flow at a minimum pressure of 1 bar, maximum 4 bar (fit a reducer if the pressure rating is higher).
Potable water is odourless, tasteless and colourless, but must be subject to filtering (>µ 1) through authorised and approved ceramic or activated charcoal micro-filters, which are changed according to the filtering system and the characteristics of the water used. Water hardness, determined by the calcium and magnesium mineral salt content, is measured by French degrees. Essential for a good cup of espresso, hardness should be between 9 - 15° Fr. This measurement varies from one area to another, and should be known before treating the water.

A high water hardness value can at high temperatures lead to:

• residue deposits in internal pipes and on electric heaters
• circulation blockages
• slower temperature transmission

A. IONIC EXCHANGE SOFTENERS
B. REVERSE OSMOSIS

A. IONIC EXCHANGE SOFTENERS
The cationic resins present in these softeners release completely soluble sodium salts, while retaining calcium and magnesium salts.

The resins must be regenerated regularly by washing retained salts (i.e. calcium and magnesium) while adding sodium chloride (coarse cooking salt). The frequency of resin regeneration depends on the hardness of the water and the volume treated.

Some softeners automatically rinse the resins (if configured for this function at the time of installation), though the regeneration of salts must be performed manually. Resins should be replaced every three years, regardless of the water softener type.

ADVANTAGES

The manual model is inexpensive.

DISADVANTAGES

Requires periodic maintenance.
The release of carbon dioxide during chemical reactions makes water acidic and corrosive.

B. REVERSE OSMOSIS

Softening process during which a saline solution is pumped through a diaphragm to separate the water from salts and other substances present.

Separation depends on:

1. the porosity of the diaphragm used
2. pressure

ADVANTAGES DISADVANTAGES

• Softens and purifies water at the same time
• Salt discharge is continuous
• Ensures water quality and safety
• Requires little (though specialised) maintenance

Reverse osmosis scheme: