Water filter for coffee: how to improve the taste

Why water quality is so decisive for the taste of coffee

A cup of coffee consists of around 98% water. That makes water effectively the most important ingredient, even more important than the coffee beans themselves. Yet most people pay it hardly any attention.

Water is not just a carrier, it's the liquid that dissolves flavour compounds out of ground coffee. This process, called extraction, determines how many acids, sugars and bitter compounds end up in your cup. The composition of the water directly determines how that extraction unfolds. Research by the Specialty Coffee Association (SCA) shows that the ideal TDS value (Total Dissolved Solids, all dissolved substances) for coffee lies between 75 and 150 ppm. Depending on the region, people in the Netherlands get tap water with a TDS of 100 to 400 ppm, which means adjusting it is almost always worthwhile.

At PureFilter, we see that customers who switch to filtered water taste a difference immediately: the coffee tastes rounder, has more aroma, and the crema is fuller and more stable.

Which substances in tap water disrupt the taste of your coffee?

Dutch tap water meets strict standards from the RIVM and Vewin, but that doesn't mean it's ideal for brewing coffee. Various substances negatively affect the taste:

• Chlorine and chlorine residues: water companies add chlorine as a disinfectant. In the cup, this gives a bitter, chemical aftertaste that also masks subtle coffee aromas.
• Excess limescale (calcium and magnesium in high concentrations): hard water disrupts extraction and deposits in the coffee machine as limescale, which leads to malfunctions and a shorter lifespan.
• Lead and copper: in older homes, these metals can be released via the pipes. They give a metallic taste and are harmful with prolonged exposure.
• Organic compounds: residues of pesticides, medicines and other micropollutants can enter the pipe network via groundwater.

Vewin reports that more than 80% of Dutch tap water is extracted from groundwater and surface water that is exposed to agricultural and industrial influences. A good water filter for coffee removes all these disruptive substances.

The ideal water composition for coffee

Good coffee doesn't call for pure H2O, but for water with the right mineral balance. Minerals play an active role in extraction:

• Magnesium helps bring out fruity and sweet aromas from the coffee. It's the most coffee-friendly mineral.
• Calcium gives body to the coffee and contributes to a stable crema.
• Potassium enhances the sweetness and roundness of the taste.
• Bicarbonate buffers the acidity. Too much makes the coffee flat, too little makes it sour.

Inline water filter vs. water jug vs. bottled water: a comparison

There are several ways to improve the water quality for your coffee. Below we compare the three most commonly used options with unfiltered tap water. Still unsure about which water filter suits you? Our pillar page gives a complete overview of the options.

The inline water filter wins on almost every point. The only advantage of unfiltered tap water is that no purchase is needed, but that's amply offset by the benefits in taste, convenience and machine protection.

Why adding minerals makes the difference

Most water filters for coffee only purify, they remove unwanted substances but add nothing back. That's better than nothing, but it's not optimal. Water that loses too many minerals becomes flat and produces a thin, watery coffee.

The PureFilter Mineral+ works differently. After the filtering stage, the water flows past Swedish Mineral Rock, a natural mineral stone that releases calcium, magnesium and potassium in exactly the right ratio. This simulates the process of spring water flowing through limestone rocks, the principle behind the best mineral waters in the world.

The result is water that is not only free of harmful substances, but also actively contributes to better coffee extraction. The SCA guideline of 75 to 150 ppm TDS is achieved automatically this way, even if your tap water is naturally very soft or very hard.

Buying advice: which filter suits you?

If you're looking for the simplest way to brew better coffee, an inline water filter is the smartest choice. You don't have to refill anything, there are no jugs on the worktop, and your coffee machine, kettle and espresso machine are all automatically fed with filtered, mineralised water.

You install the PureFilter Mineral+ in 5 to 10 minutes under the worktop, without a plumber. The capacity is 15,000 to 20,000 litres, enough for an average family for several years. The purchase price is €149.00 including one filter cartridge. Replacement filters are available from €65.00. Feel free to check out the complete range of water filters for home to see which setup best suits your kitchen.

Frequently asked questions about water filters for coffee

Conclusion: the simplest upgrade for your coffee ritual

If you want to brew better coffee, tackling water quality is the smartest first step. Chlorine, excess limescale and other contaminants disrupt extraction and mask aromas. A water filter for coffee solves this, but the best models go a step further by also adding minerals.

The PureFilter Mineral+ combines filtration of more than 100 contaminants with mineralisation via Swedish Mineral Rock. The system is certified to NSF 42, 53, 61 and 372, installs in 5 to 10 minutes and lasts 15,000 to 20,000 litres. Whether you brew espresso, filter coffee or tea: with filtered and mineralised tap water, you get more out of every cup.

Also check out the comparison of the best water filters or read more on the PureFilter FAQ page if you want more information for your purchase decision.