How does water affect the taste of coffee?

Think about it this way – your morning coffee is 98 percent water. It's the water that dissolves the chemical compounds trapped in roasted beans and extracts the best from them. If you use poor quality water, you will irrevocably ruin the taste of even the most expensive specialty beans.

You probably don't realize that ordinary tap water literally blocks the release of the most interesting aromas. To help baristas around the world, the Specialty Coffee Association (SCA) has developed official guidelines. Thanks to them, you can easily take control of the taste of your brew.

Why should you care about the water quality in your kettle?

Once you master this topic, you will protect your brew from a flat, bland taste and extract the deepest aromas from the beans in a fully controlled manner. Well-balanced water guarantees that your coffee will be clean, sweet, and perfectly balanced.

When you start filtering water, you will quickly get rid of substances that suppress natural acidity and sweetness. Unpurified tap water is full of chlorine and other organic compounds that spoil the taste. Good water will give you much better results than buying the most expensive brewing gadgets and accessories.

What do the official SCA standards say about water?

Specialists from the Specialty Coffee Association have precisely defined the chemical parameters of water that allow the best to be released from the beans. These standards apply to total mineralization, pH, and carbonate hardness. Baristas around the world treat them as their holy grail.

Look at the parameters that determine the preparation of the perfect brew:

• total mineralization (TDS): the ideal level is 150 ppm, although the permissible range is 75–250 ppm,
• general hardness (GH): the recommended value is 50 to 175 ppm CaCO₃,
• carbonate hardness (KH): the optimal level is around 40 ppm CaCO₃, in the range of 40–75 ppm,
• pH: ideal water has a neutral pH of 7.0, with an allowable fluctuation of 6.5 to 7.5,
• sodium: its level should not exceed 10 mg/l,
• chlorine: there should be no chlorine at all in your water (0 mg/l).

These parameters directly affect how water extracts organic compounds from the beans. The slightest change in these proportions will instantly change the taste you experience in your cup. When you keep these indicators at a constant level, every subsequent cup will taste equally good.

How does the TDS indicator change the taste in your cup?

TDS (Total Dissolved Solids) is simply an indicator showing the total amount of minerals dissolved in water. The strength with which water will extract compounds from coffee depends on their concentration. For your brew to be perfectly balanced, aim for mineralization between 120 and 160 mg/l. Any deviation up or down will disturb the natural qualities of the beans.

When mineralization drops below 75 ppm, the brew will seem flat and bland. Very pure water washes out acids too quickly, leading to an unpleasant astringency. On the other hand, water with a TDS above 250 ppm will block delicate fruity and floral notes.

The role of calcium and magnesium in building the brew profile

Calcium and magnesium ions bind with aromatic compounds in coffee. Calcium helps to bring out heavier, deep notes and builds a pleasant texture of the brew. Magnesium, on the other hand, perfectly extracts bright, fruity and sweet accents.

Ideally, the calcium to magnesium ratio (Ca:Mg) should be around 3:1. This balance protects you from the dominance of one flavor. Magnesium very effectively attracts compounds with high aromatic intensity, ensuring the freshness of the brew.

Carbonate hardness as a guardian of acidity

Carbonate hardness acts as a safety buffer that ensures the appropriate level of acidity in your cup. Bicarbonates control how acidic the brew will seem to you. If their level is too low, you will feel an unpleasant, aggressive acidity.

Conversely, carbonate hardness exceeding 75 mg/l will neutralize these good, fruity acids. This will make the brew flat and give it an earthy character. If you maintain the KH indicator within 40 mg/l, you will preserve the natural freshness and juiciness of specialty coffees.

Why is pH so important?

The pH directly affects how quickly delicate acids and essential oils dissolve. You will achieve the best taste when the water has a neutral pH between 6.5 and 7.5. Any deviation from this norm will immediately spoil the profile of your brew.

Acidic water with a pH below 6.5 will make the drink sharp and unpleasantly tart. On the other hand, alkaline water with a pH above 7.5 will greatly slow down the dissolution of flavor oils, and you will feel a bland, metallic, and sometimes even soapy aftertaste.

What happens when the water is too hard or too soft?

Too hard or too soft water will completely change the brew profile and how you perceive it in your mouth. Your choice of water will determine the intensity of bitterness and the level of acidity. Extreme parameters will simply make it impossible for you to properly brew the beans.

See how these extremes affect what ends up in your cup:

• hard water: excess minerals blocks the release of aromas, giving a heavy, bitter, and chalky aftertaste, and at the same time damages your kettle and espresso machine due to limescale build-up,
• soft water: a deficiency of minerals causes too rapid extraction of acids, which makes the drink watery, unpleasantly acidic, and lacking sweetness and body.

Effects of too high water mineralization

An excess of minerals in hard water will block delicate fruity notes and emphasize heavy bitterness. A high concentration of calcium ions will react with acids, neutralizing them and leaving a chalky, rough feeling on your tongue. The drink will seem one-dimensional and flat.

Additionally, hard water quickly leaves limescale inside devices. As a result, the espresso machine will not heat the water sufficiently and the brewing pressure will drop, leading to under-extraction and spoiling the final taste.

What happens with a mineral deficiency?

When there is a lack of minerals in the water, a rapid, uncontrolled extraction of aggressive organic acids occurs. Due to the lack of magnesium and calcium ions, water absorbs low pH compounds too strongly. As a result, you will feel a sharp, very acidic, and tart taste.

Such water will deprive the brew of its pleasant texture and sweetness. The coffee will become watery, and its aftertaste will disappear in the blink of an eye. If you use distilled water or water from a traditional softener, you will completely strip the brew of its depth.

How does water temperature affect the extraction process?

Water temperature directly controls how quickly and to what extent compounds from the beans dissolve in your cup. Too hot liquid will instantly accelerate extraction, releasing an unpleasant bitterness. On the other hand, too low a temperature will not allow the most valuable essential oils to dissolve.

It is best to stay within the range of 89 to 96 degrees Celsius. If you pour boiling water over ground beans, you will burn delicate aromas. Conversely, water below 88 degrees will result in an under-extracted, flat, and tart brew.

Ideal temperature for pour-over methods

If you use a V60 Dripper, Chemex, or AeroPress, the water temperature will allow you to perfectly extract the fruity and floral notes characteristic of light roasts. The best results will be obtained in the range of 90 to 96 degrees Celsius. By precisely adjusting the temperature, you will gain control over acidity and sweetness.

Lightly roasted beans require a higher temperature – ideally around 94–96 degrees Celsius. This will help to open up their hard structure. Darker roasts, however, should be brewed with cooler water in the range of 90–92 degrees, which will help you avoid a burnt aftertaste.

Temperature in espresso and French Press

In pressure and immersion methods, water temperature determines the density of the brew and the release of oils. For classic espresso, choose a temperature of 90 to 92 degrees Celsius. This will allow you to balance acidity with chocolate bitterness.

When brewing coffee in a French Press, choose water at 90–94 degrees. Due to the long contact of ground beans with water, a lower temperature will protect your brew from harsh, earthy aftertastes.

How to effectively filter water at home?

Good filtering allows you to get rid of harmful impurities while leaving essential minerals in the water. Adjust the choice of method to the hardness of the tap water in your home. Water purification is the cheapest way to achieve a huge leap in quality in home brewing.

Remember never to boil the same water twice, as this will deplete its oxygen. Fresh water guarantees the best extraction. Look at the simplest home methods for water treatment.

Carbon filters and popular pitchers

A filtering pitcher with a carbon cartridge is the simplest step – it almost completely removes chlorine and reduces organic impurities. Such a filter significantly improves the smell and clarity of water. This is an incredibly budget-friendly solution for every lover of good coffee.

Activated carbon copes well with compounds that spoil natural aromas. At the same time, it allows calcium and magnesium ions to be retained, provided your tap water is not extremely hard. Thanks to this, you will get a clean brew with great texture.

What do you gain from reverse osmosis?

A reverse osmosis system gives you a completely clean slate – water devoid of any minerals, which you can compose yourself. Osmosis removes almost one hundred percent of dissolved substances. However, for the brew not to taste flat, you must use a remineralizing cartridge.

Professionals often add special mineral sachets, such as Third Wave Water, to osmotic water. In this way, you will create water with an ideal composition, compliant with SCA standards. You will achieve full repeatability with every brew.

Why should you avoid ion softeners?

Avoiding household ion softeners will protect you from a bland and flat brew. Classic central filters exchange calcium and magnesium ions for sodium, which makes the water too soft. Such fluid will drastically disrupt the process of extracting aromas from your beans.

Instead, it is better to choose filters installed directly in the espresso machine's reservoir, such as Brita Intenza or BWT Bestmax. They will reduce hardness in a balanced way, protecting the device from limescale and ensuring a great tasting brew.

See how easy it is to improve the taste of your daily coffee

Water absolutely determines the acidity, sweetness, and aroma of your coffee. When you ensure appropriate mineralization at around 150 ppm and a neutral pH, you will unleash the true potential of the beans. Switching from ordinary tap water to filtered water is the simplest step you can take to instantly drink better coffee.

Do a simple experiment at home – brew the same coffee with tap water and filtered water, then describe your impressions in the comments. Also, take a look at our proven filtration systems in the online store.