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

Compose Your Own Coffee Water: Filter, Remineralize, Perfect Extraction

Over 90% of your espresso is water. If your coffee tastes flat, dull, or watery despite a good grinder and a high-quality portafilter machine, the problem is almost always with the water. Tap water in places like Zurich and Bern, for example, contains too much lime and bicarbonate – which blocks aroma extraction and limes up your machine. The solution: First filter. Then remineralize specifically.

Sounds complicated? It's not. The easiest way: 1 – 2 drops of Apax Lab directly into the finished espresso – that's exactly how we do it daily in our cafes. For those who want to delve deeper, combine a Brita water filter with Apax Lab mineral concentrates and build up your brewing water specifically. Here we explain both methods – from a quick start to full 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 build aromas, we must remove these uncontrolled interfering factors. 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 lime, chlorine, and taste-impairing substances without completely demineralizing the water.

Step 2 – Remineralizing: Filtered water is a controlled base. Now you specifically add the minerals you need for your aroma 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 Tap Water in Zurich and Bern is Problematic

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

The consequences of overly 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 – lime deposits accumulate 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 effect of minerals on coffee taste and developed over 2000 water recipes. The result is three mineral concentrates made from demineralized water and analytically pure minerals (AR quality) – precise enough for world championships, simple enough for daily 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:

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

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

Which Setup Suits You?

Post-Extraction with Apax Lab – The Easiest Start (how we do it)

This is the method we use daily in our cafes in Bern and Zurich and also at home: Prepare the coffee as usual and then add 1 – 2 drops of Apax Lab directly into the finished espresso. Swirl briefly, done. No pre-filtering necessary, no recalculation, no additional equipment. The minerals act directly on the taste in the drink – you taste the effect immediately.

Post-Extraction works with any setup, any machine, and any water. The dosage is simple: 1 – 2 drops per espresso (40 ml), 3 – 6 drops for milk beverages (150 ml), 5 – 10 drops for filter coffee (200 ml). You can directly compare different profiles – pull an espresso, divide it into three cups, 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 water tanks (most machines from Arkel, WPM, Rocket, La Pavoni), lever machines like Flair Espresso, and Pour-Over setups. You run tap water through a Brita filter jug (reduces lime, chlorine, copper, and lead), then add the Apax Lab concentrate according to the recipe and swirl briefly. Done. Under two minutes per liter. This method combines machine protection (lime reduction) with aroma optimization – two birds, one stone.

In-Tank Filter Cartridges – For Machine 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 filters and conditions the water automatically with every refill. For most users, this is the simplest way to combine lime protection and taste improvement. Those who want to work additionally with Apax Lab can further optimize the filtered tank water.

Reverse Osmosis + Apax Lab – For Perfectionists

Reverse Osmosis (RO) removes virtually all minerals from the water, resulting in a nearly perfect zero base (0 ppm TDS). From here, you can precisely build any desired mineral profile with Apax Lab – magnesium, calcium, and bicarbonate dosed to the gram. This is the level at which world championships are won. The effort is higher, but the control is absolute. For machines with a fixed 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 + Water

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

For Cozy Chocolate, Nutty Delight and Very Nutty: JAMM [2] pure or a blend with a focus on JAMM. These medium to dark roasts benefit from increased calcium and bicarbonate – this emphasizes the chocolatey, nutty notes, gives the espresso body, and creates a dense, stable crema. Pre-Brew: 3 g 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 need water with low buffer capacity – only then can the fruity and floral nuances unfold without being neutralized by the bicarbonate in tap water. Pre-Brew: 2 g TONIK + 1 g LYLAC per liter. Post-Extraction: 1 drop of TONIK + 1 drop of LYLAC directly into the espresso.

For Milk Beverages (Cappuccino, Flat White): JAMM [2] is the first choice here. The creamy texture and emphasized sweetness stand out even in combination with milk – the espresso remains present instead of being lost. Post-Extraction: 3 – 6 drops of JAMM into the finished milk beverage. Especially with Cozy Chocolate and Nutty Delight as a base, this results in full-bodied, chocolatey milk beverages.

Frequently Asked Questions About Coffee Water

Is a Brita filter alone enough, without Apax Lab?

For machine protection: yes. A Brita filter significantly reduces lime and chlorine and extends the life of your machine. For aroma optimization, filtering alone is not enough – you remove interfering factors but do not add taste-enhancing minerals. The combination of filtering and remineralizing with Apax Lab makes a noticeable difference in the cup.

Can I also drip Apax Lab directly into the finished coffee?

That is even our preferred method – and the one we use daily in our cafes in Bern and Zurich. 1 – 2 drops into a finished espresso (40 ml), 3 – 6 drops into a milk beverage, 5 – 10 drops into a filter coffee (200 ml). This post-extraction method requires no special water and no pre-filtering. You work directly on the taste in the drink. For beginners and daily use, post-extraction is the fastest 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 of Brita jugs automatically reminds you. With very hard water or high throughput, an earlier change may be useful.

Which water for machines with a fixed water connection?

For machines like the La Marzocco Linea Mini with a fixed water connection, we recommend an upstream filter system (Brita or equivalent) directly in the water line. A reverse osmosis system with subsequent remineralization via Apax Lab gives you full control. Come to our showroom – we will advise you on the right solution for your setup.

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

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

Roastery Tip: Bring Your Water Values

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

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

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