Coffee and Water - The importance of water quality in the espresso

When we think of a good espresso, we often focus on the blend, the grind, or the machine used. But there’s an invisible, often underestimated ingredient that has a major impact on what ends up in the cup: water.

Since water is the main component of espresso, its quality can be the difference between a mediocre coffee and an extraordinary one. In this article, we’ll explore why water deserves attention, what the ideal parameters are, and how to manage it effectively in a café setting.

Ideal parameters - Hardness, pH, and TDS

Not all water is the same: its composition varies from region to region and may contain minerals, chlorine, limescale, and other dissolved substances that affect coffee extraction.
The three main parameters to monitor are hardness, pH, and total dissolved solids (TDS).

• Total hardness: Water that’s too hard (rich in calcium and magnesium) can cause limescale build-up and alter the espresso’s flavour. On the other hand, water that’s too soft tends to emphasize acidity and reduce body. The ideal range is between 7 and 10 °f (French degrees)
• pH: The ideal pH is around 7 (neutral) to preserve the coffee’s aromatic balance
• TDS (Total Dissolved Solids): This indicates the quantity of dissolved salts in 1 liter of water after evaporation at 180°C
   

Keeping these parameters stable is the first step toward consistently high-quality espresso.

Filters, purifiers, and system maintenance

The use of water softeners is always recommended to prevent limescale build-up, which can damage espresso machines and affect brewing temperature.

Equally important is regular equipment maintenance, including periodic checks and resin replacements. Clean, balanced water not only improves the coffee’s taste but also extends the lifespan of your machinery.

How water affects the taste of coffee

Water doesn’t just impact the technical side of extraction — it also plays a crucial role in the sensory experience. Unbalanced water can highlight undesirable flavours, mask aromatic notes, or distort the perception of body and crema.

• Overly hard water can make the coffee taste flat, bitter, or metallic
• Overly soft water may lead to an espresso that’s too acidic and lacking in balance

To deliver a flawless coffee experience, it's essential to treat water with the same care given to selecting the coffee itself.

Water quality is an invisible yet essential pillar in the espresso preparation.
Paying close attention to its parameters, investing in the right filtration systems, and ensuring regular maintenance are choices that truly make a difference.

A café that wants to stand out and build customer loyalty cannot afford to overlook this key element: high-quality water is the first step toward a truly unforgettable espresso.