There are usually two types of coffee drinkers, the ones who make their coffee with mineral water and the ones who use normal tap water. There are also a few people who use distilled water. The question of which water should be used to make coffee is entirely justified, because around 99% of the popular hot drink consists of this water.
When I was looking for new coffee recipes the other day, I stumbled upon a question that amazed me: Why is distilled water not suitable for coffee? I decided to look into this question further and explore which type of water is most suitable for the perfect cup of coffee. Read on, to find out more!
What is “good water”?
The perfect coffee water brings the full aroma from the coffee grounds into the cup. In our latitudes we benefit from water quality that already offers a high quality through various controls and treatment.
However, since the guidelines of the waterworks are mainly based on aspects such as cleanliness and freedom from harmful substances, these cannot automatically be described as good coffee water. Even high-quality tap water contains various ingredients that influence the taste of coffee.
Even switching to distilled water should not be viewed as switching to good quality coffee-making water. In fact, it is the minor additions of minerals and oxygen that enhance the aroma of the coffee beans in the coffee water.
Soft vs Hard Water
The water hardness has the largest share in influencing the quality of coffee preparation. Hard water possesses the ability to neutralize the fine fruit acids of the coffee bean. If coffee is prepared with hard water and left to brew for a long time, the aromatic components can bind to the minerals and ensure a coffee with no or little aroma.
In addition, there is the mineral aftertaste, which is noticeable as limescale deposits, e.g. in the thermos or the coffee machine. These are also a breeding ground for undesirable bacteria and harmful organisms, which also reduce the quality of the coffee.
Soft water, on the other hand, can influence the taste of the coffee the other way around: While hard water allows too few ingredients to be expressed in the coffee grounds, the soft and therefore acidic water helps the ingredients to achieve greater release and taste dominance.
The result is a very acid-intensive and bitter coffee, which, like the bland variant made from the hard coffee water, is not very suitable for caressing the palate of coffee lovers.
Apart from the fact that distilled water can rarely be bought in stores (mostly it is demineralized or deionized), it is not at all good for the body to drink large amounts of distilled (demineralized) water.
Water in its natural state always has a certain amount of minerals and these are what the water wants. I will spare you the highly chemical-scientific approach. Let's put it this way: water wants a certain amount of minerals. If it doesn’t have it tries to get it. No matter where.
Now imagine your body: full of vitamins, minerals and all sorts of things. And now this distilled water from the coffee comes along and only "wants" one thing: minerals! But don't worry, there are so few minerals that you will lose, you really have to drink a few liters of distilled water to understand the difference. This is not the main reason why you shouldn’t use distilled water in your coffee though.
No, the real reason why distilled water is not suitable for a tasty cup of coffee is another one: Due to the lack of minerals (i.e. tiny particles in the water), the coffee aromas cannot be absorbed by the water during preparation. The flavors of the coffee slide through the water, as if on a slide, instead of being able to work their way through the small minerals. The result is a coffee that does not taste good.
On the other hand, it is true that too many minerals are also not good for making a good coffee. There is a rough rule that may be helpful for advanced users: 150 PPM (parts per million) of minerals should be roughly in the water. If - as I suspect - you don't have an analyser for your water, then just use filtered water.
Other Types of Water for Coffee
Natural mineral water is rich in trace elements and minerals, as well as magnesium, calcium and hydrogen carbonate. Mineral water provides the body with important substances that it needs for daily life and is therefore not a bad choice for making coffee with it.
But be careful: There are also types of mineral water that have an acidic pH value. This is bad for a number of reasons:
- Acid damages the coffee machine
- Water with a sour pH value enhances the sour taste of green coffee
If you still don't want to do without mineral water for making coffee, you can filter it beforehand to rid it of unwanted substances. If you have found mineral water that is neither too acidic nor too basic and also has a balanced number of minerals and trace elements, mineral water is perfectly suitable for making coffee.
When it comes to tap water, the composition of the minerals and the lime content strongly depend on where you live. You can obtain information about the quality of your water from the health department or your local supplier.
Caution is advised if lead or copper water pipes are still installed in your house. In this case, the water should not be drunk and that’s why in some countries or regions people don’t drink tap water.
Tap water has a decisive advantage however: it is significantly cheaper than mineral water. In addition, there is no tedious carrying of water boxes and bottles. At the same time, preparing a coffee with tap water is kind to the environment, as no plastic bottle or other container is required.
All in all, I would not recommend using distilled water for your coffee. My go-to would be filtered mineral water. Well-stocked supermarkets and drinks dealers have also been offering special water for preparing coffee specialties and tea for some time.
The producers advertise that the pH value and water hardness of this type of water are optimally matched to get the best result out of your hot drink. The content of minerals and salts is also only made for making the best coffee or tea. You can achieve the same effect much cheaper with a water filter, which, however, has to be changed regularly.