Why water for coffee matters more than ever

Key takeaways

• Water makes up over 98% of a cup of filter coffee.
• Its mineral content acts like salt in cooking, amplifying flavour and depth.
• Baristas and competitors use custom water profiles to adjust acidity, sweetness, body, and clarity.
• Pre-made concentrates are becoming more popular in competitions and high-end coffee shops.

Water is the invisible foundation of pour over coffee. Once overlooked, baristas now can’t overstate how crucial its role in extraction truly is.

“It awakens, carries, and elevates every nuance in coffee,” says Jordan Tachnakian, the 2024 World Cezve/Ibrik Champion and the head of quality at Terres de Café, the French National Winner at the Global Coffee Awards. “Just as each coffee demands its own precise roast curve, it also deserves water crafted with intention.”

Comprising more than 98% of a cup of filter coffee, water does much more than just extract soluble compounds; it actively affects flavour and mouthfeel. “Even small adjustments to its mineral content can noticeably change silkiness vs. crispness, weight on the palate, or the length of the finish on the tongue,” Jordan says.

Competitions, high-end cafés, and industry experts like Maxwell Colonna Dashwood and Christopher Hendon have helped bring water chemistry to the forefront of specialty coffee. As a result, we’re seeing more baristas and competitors use custom water profiles with precise mineral concentrations to enhance sweetness, accentuate body, round out acidity, and tweak flavour profiles.

You may also like our article on how cafés filter water for coffee.

How water mineral content affects coffee

Grind size, water temperature, and agitation are, of course, vital parameters in pour over brewing. But the recent laser focus on water chemistry is a clear sign that science is playing a bigger role in the pursuit of coffee excellence.

Whether tap, bottled, distilled, filtered, or spring, water varies around the world – containing different concentrations of minerals, including magnesium, calcium, and carbonates. The combination of these soluble minerals inevitably influences how coffee is extracted and tastes.

For many years, baristas largely focused on water hardness, which can be broken down into total hardness and carbonate hardness. The first is a measurement of the calcium and magnesium levels in the water, and balanced levels of both are essential for optimal extraction.

Carbonate hardness, meanwhile, is a measurement of how many carbonates and bicarbonates are present in water. These compounds also play a key role in extraction, as bicarbonates act as buffers to maintain pH, ideally between 6 and 8 for coffee.

Optimising water hardness is still essential to extract great pour over coffee. But baristas are now recognising that a wider range of minerals affects coffee extraction and flavour. Potassium, for example, can prolong sweeter flavours in the aftertaste, while chloride can create roundness and balance. Moderate levels of sodium can amplify flavours and reduce bitterness, and sulphate can enhance floral and citrus flavours.

Effectively, baristas understand that water’s mineral content can be used like salt when cooking: controlling how much you add to amplify the flavours already present and create more depth and complexity.

A new wave of water products for coffee

In response to water becoming its own brewing variable, more products are launching that allow baristas to finetune water “recipes”. By adding or removing different concentrations of compounds and ions, they can create customised mineral compositions to achieve specific flavour goals.

Naturally, this trend is most evident at competitions. At the 2024 World Brewers Cup (WBrC), over 70% of competitors used pre-made concentrates – Apax Lab specifically – in their routines. The winner, Martin Wölfl, blended the brand’s Tonik, Jamm, and Lylac mineral concentrates to create a sweet, round, and balanced flavour profile for his anaerobic natural processed coffee.

Coffee shops are also joining the trend. “We worked closely with Simon from Apax Lab to develop our own mineral kit,” Jordan explains. “It was designed to complement both our roasting style and different water profiles.”

This creates more opportunities for interactive experiences with customers – allowing them to taste the coffee before and after adding mineral concentrates.

“If you split your brewed coffee into two cups, add a single drop of minerals to one and leave the other untouched, you will taste the difference – in flavour, texture, and overall expression,” Jordan asserts.

Third Wave Water is another popular product among professional and home baristas. After securing investment on Shark Tank in 2017 and acquiring competitor Perfect Coffee Water in 2025, the brand expanded its range to include different roast profiles, espresso, cold brew, and low-acidity flavour profiles.

“One of the most important differences in mineral content between light and dark roasts is alkalinity,” says Charles Nick, the founder of Third Wave Water. “Generally speaking, and this is key, you want more alkaline water for dark roasted coffee to smooth out flavours and enhance the nutty, chocolate notes.”

Precision as standard

Water chemistry has quickly transitioned from a background variable into a deliberate tool for achieving coffee excellence. Baristas are also choosing to optimise mineral content before and after extraction, opening new avenues for experimenting with sensory profiles.

“It’s an exciting time in specialty coffee,” Charles says, as he notes that more cafés are bypassing traditional filtration systems in favour of fully remineralised reverse osmosis systems. These systems remove up to 97% of mineral content – effectively creating a “blank canvas” for baristas to build custom water profiles.

Creating DIY water recipes offers flexibility, but also comes with challenges. Without the right expertise and guidance, baristas can struggle to achieve the optimal balance of compounds and ions, potentially muting or distorting coffee flavour before extraction even begins.

But accessibility is still important

The slurry of new, pre-prepared products then offers a more accessible entry point into the complex world of water chemistry. Pre-weighed sachets can remove guesswork, while bottled concentrates contain specific mineral blends to hit precise sensory targets.

“These products are like a gateway into specialty water for coffee,” Charles explains. “Start with ‘empty’ water, then add a sachet and brew. You don’t need to be a scientist, just trust that the science has already been taken care of.”

Water’s shift from passive variable to active tool may be one of the most significant developments in pour over brewing of the past few years.

“Water is fundamental to truly enjoying a great cup of coffee,” Jordan says. “Even the finest coffee in the world can taste disappointing when brewed with hard tap water, so it deserves real consideration.”

To many, accounting for water chemistry among numerous other variables can feel intimidating and overwhelming, but new products are making it more accessible.

“There’s no need to overcomplicate things,” Jordan concludes. “A well-designed filtration system, combined with thoughtful mineral adjustment tailored to the coffee, already makes a significant difference.”

Enjoyed this? Then read our article on maximising water quality and consistency.

Photo credits: Terres de Café, Third Wave Water

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