Composing your own coffee water: Filtering, remineralizing, extracting perfectly

Composing your own coffee water: Filtering, remineralizing, extracting perfectly

Your espresso is over 90% water. If your coffee tastes flat, dull, or watery despite a good grinder and a high-quality portafilter machine, the problem almost always lies with the water. The tap water in cities like Zurich and Bern contains too much calcium and bicarbonate – this blocks aroma extraction and causes limescale buildup in your machine. The solution: Filter first. Then remineralize it.

Sounds complicated? It isn't. The simplest way: 1-2 drops of Apax Lab directly into your freshly brewed espresso – that's exactly how we do it every day in our cafés. For those who want to delve deeper, combining a Brita water filter with Apax Lab mineral concentrates allows you to tailor your brewing water to your specific needs. We'll explain both methods here – from a quick start to complete control.

The principle: Two steps to perfect coffee water

Step 1 – Filtering: Tap water contains too many dissolved minerals (high total hardness) and often too much bicarbonate. Before we can build up flavors, we need to remove these uncontrolled impurities. The goal is a neutral, controllable water base. Our recommendation: a Brita activated carbon filter (e.g., the Marella Cool with MAXTRA PRO cartridge), which reduces limescale, chlorine, and taste-impairing substances without completely demineralizing the water.

Step 2 – Remineralizing: Filtered water provides a controlled base. Now you add the specific minerals you need for your desired flavor profile. More magnesium for body and texture, low alkalinity for floral notes, higher calcium for classic espresso character. The tool for this: Apax Lab mineral concentrates – three bottles, three profiles, precisely dosable per liter or directly into the cup.

Why the tap water in Zurich and Bern is problematic

Tap water in Switzerland is safe and drinkable – but rarely ideal for espresso. In Zurich and Bern, the total hardness varies between 18 and 38 °fH (French degrees of hardness), depending on the district. For optimal espresso, experts recommend a range of 3–6 °dH (German degrees of hardness), which is significantly softer than what comes out of most taps.

The consequences of excessively hard water are twofold: First, the taste suffers – aroma extraction is blocked, fruit acids are neutralized, and the coffee tastes flat. Second, the machine suffers – limescale builds up in the boiler, pump, and valves, significantly shortening the lifespan of your espresso machine . Regular descaling helps, but it doesn't solve the aroma problem.

The three Apax Lab profiles: TONIK, JAMM and LYLAC

Apax Lab was founded in Australia in 2023 by Simon Gautherin, who spent six years researching the effects of minerals on coffee flavor and developed over 2,000 water recipes. The result is three mineral concentrates made from demineralized water and analytically pure (AR-grade) minerals – precise enough for world championships, simple enough for everyday use.

Each 100ml bottle is sufficient for approximately 150 preparations. The three profiles can be used individually or mixed – depending on the desired result. There are two ways to do this:

Post-extraction (our favorite): 1-2 drops per espresso, 3-6 drops per milk-based drink, 5-10 drops per filter coffee – directly into the finished cup. This is how we do it in our cafés and at home. No pre-filtering necessary, immediate effect.

Pre-brew: 3 to 4 grams of concentrate per liter of water in the kettle or tank. This method influences the extraction itself and gives you maximum control – ideal in combination with filtered water.

Which setup suits you best?

Post-extraction with Apax Lab – The easiest way to get started (this is how we do it)

This is the method we use daily in our cafés in Bern and Zurich, and which we also use at home: Prepare the coffee as usual, then add 1-2 drops of Apax Lab directly to the finished espresso . Swirl briefly, and you're done. No pre-filtering, no conversion, no additional equipment required. The minerals directly affect the taste of the drink – you'll taste the effect immediately.

Post-extraction works with any setup, any machine, and any water. Dosage is simple: 1-2 drops per espresso (40 ml), 3-6 drops for milk-based drinks (150 ml), 5-10 drops for filter coffee (200 ml). You can directly compare different profiles—pull an espresso, divide it between three cups, and add a different profile to each. The difference is not subtle.

Filter jug ​​+ Apax Lab (Pre-Brew) – For tank machines and small appliances

Ideal for espresso machines with a water tank (most machines from Arkel , WPM , Rocket , La Pavoni ), lever machines like the Flair Espresso , and pour-over setups. You run the tap water through a Brita filter jug ​​(reduces limescale, chlorine, copper, and lead), then add the Apax Lab concentrate according to the recipe and swirl briefly. Done. Less than two minutes per liter. This method combines machine protection (limescale reduction) with aroma optimization – killing two birds with one stone.

In-tank filter cartridges – For engine tanks with Brita adapter

The Arkel Coast and some other machines have an integrated Brita filter adapter in the water tank. You insert a Brita AquaAroma Crema cartridge directly into the tank – this automatically filters and conditions the water every time you refill it. For most users, this is the simplest way to combine limescale protection and improved taste. Those who also want to use Apax Lab can further optimize the filtered tank water.

Reverse osmosis + Apax Lab – For perfectionists

Reverse osmosis removes virtually all minerals from the water, resulting in a near-perfect zero base (0 ppm TDS). From here, Apax Lab allows you to precisely build up any desired mineral profile – magnesium, calcium, and bicarbonate dosed to the gram. This is the level at which world championships are won. The effort is greater, but the control is absolute. For machines with a direct water connection (e.g., La Marzocco Linea Mini ), an RO system can be integrated directly into the water line.

All features at a glance: Water treatment for coffee

Our recommendation: Combine coffee and water

The effect of minerals in water depends directly on the roasting process. Here are our recommendations from our daily experience as a coffee roastery:

For Cozy Chocolate , Nutty Delight , and Very Nutty : JAMM [2] pure or a blend with a high JAMM content. These medium to dark roasts benefit from increased calcium and bicarbonate – this accentuates the chocolatey, nutty notes, gives the espresso body, and produces a dense, stable crema. Pre-brew: 3 g of JAMM per liter of filtered water. Post-extraction: 1–2 drops of JAMM directly into the espresso.

For Bright Cassis and Wild Peach : TONIK [1] with a small addition of LYLAC [3]. Light roasts require water with a low buffering capacity – only then can the fruity and floral nuances develop without being neutralized by the bicarbonate in tap water. Pre-brew: 2 g TONIK + 1 g LYLAC per liter. Post-extraction: 1 drop TONIK + 1 drop LYLAC directly into the espresso.

For milk-based drinks (cappuccino, flat white): JAMM [2] is the first choice. Its creamy texture and pronounced sweetness stand out even when combined with milk – the espresso remains prominent instead of being overpowered. Post-extraction: Add 3–6 drops of JAMM to the finished milk-based drink. Especially when used with Cozy Chocolate and Nutty Delight as a base, it creates a full-bodied, chocolatey milk-based drink.

Frequently asked questions about coffee water

Is a Brita filter sufficient on its own, without Apax Lab?

For machine protection: yes. A Brita filter significantly reduces limescale and chlorine, extending the lifespan of your machine. However, filtering alone isn't enough for flavor optimization – you remove impurities but don't add flavor-enhancing minerals. The combination of filtering and remineralizing with Apax Lab makes a noticeable difference in the cup.

Can I add Apax Lab directly to the finished coffee?

This is actually our preferred method – and the one we use daily in our cafés in Bern and Zurich. 1-2 drops in a finished espresso (40 ml), 3-6 drops in a milk-based drink, 5-10 drops in a filter coffee (200 ml). This post-extraction method requires no special water or pre-filtering. You're directly influencing the flavor of the drink. For beginners and everyday use, post-extraction is the quickest way to better coffee.

How often do I need to change the Brita cartridge?

The MAXTRA PRO cartridges should be changed every 2 weeks – the integrated electronic display in the Brita jugs will remind you automatically. With very hard water or high water consumption, an earlier change may be advisable.

Which type of water is suitable for machines with a fixed water connection?

For machines like the La Marzocco Linea Mini with a direct water connection, we recommend a pre-filter system (Brita or equivalent) installed directly in the water line. A reverse osmosis system with subsequent remineralization via Apax Lab gives you complete control. Visit our showroom – we'll advise you on the right solution for your setup.

Can I purchase Apax Lab products at the Coffee Coaching Club?

Yes. The Apax Lab Set (TONIK, JAMM, LYLAC – 20 ml each) can be ordered directly from our webshop. Delivery throughout Switzerland and Liechtenstein takes 1–2 days. You can also test the profiles live with different coffees in our showrooms in Bern and Zurich.

Roastery tip: Bring your water test results with you.

Water hardness varies not only from city to city, but often from neighborhood to neighborhood. You can find the current values ​​for your location at wasserqualitaet.ch or directly from your local municipality. Even easier: Bring a bottle of your tap water to our showroom – we'll analyze the hardness on-site and recommend the right combination of Brita filter and Apax Lab profile for your setup and your favorite roast.

Combined with a high-quality coffee grinder and an Acaia precision scale , optimized water is the third building block that elevates your home setup to a professional level. Machine, grinder, water – when these three variables are right, you'll taste the difference in every shot.

All products mentioned are available in the Coffee Coaching Club webshop or in our showrooms in Bern and Zurich. Delivery throughout Switzerland and to Liechtenstein takes 2-4 days. Financing is available.