The right coffee water - the coffee water instructions

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Since your coffee beverage consists of over 90% water and less than 2% dissolved coffee particles, it's worth taking a closer look at the water. Even if it tastes good as drinking water in a glass, there are some criteria that make your drinking water a good starting point for your coffee beverage.

What should good coffee water be like?

Basically, coffee water should be soft, usually softer than what comes out of the tap. There are two measurements:

• Total hardness = Magnesium Mg+2 and Calcium Ca2+
• Alkalinity = Hydrogen carbonate = Bicarbonate = HCO3-

For filter coffee, the best values are:

• Total hardness: 2 – 3 °dH
• Alkalinity: 1 – 2 °dH

For espresso, the best values are:

• Total hardness: 3 – 6 °dH
• Alkalinity: 2 – 4 °dH

Alkalinity is often also referred to as carbonate hardness, which is not entirely correct in the strict sense, but carbonate hardness has become an established term.

This sounds very complicated. Here we explain how you can achieve such good values, as it is highly probable that you will not get such soft water from your tap.

How good is my water at home?

There are several ways to measure water hardness. A conductivity meter, a ppm meter, and a droplet test (the simplest option). In the latter case, 10ml of your water are filled into a test tube and a few drops of test liquid are added. You count the drops, and as soon as there is a color change, you know the water hardness. In addition, you can contact your local water provider or visit their website.

How and what does the table water filter filter?

Tabletop filter devices are inexpensive and widely used. Water is filled in, and up to 50% of the water is decarbonized. The other 50% simply passes through the activated carbon filter of the device.

A short example calculation: From the tap, we have drinking water with 16°dH total hardness and 12°dH alkalinity. After one pass through the water filter, the alkalinity halves to 6°dH, but the total hardness only reduces to 10°dH. Since this is still far from perfect coffee water, we need a second pass.

After the second pass, the alkalinity is at 3°dH and the total hardness is at 7°dH. This is already good, but we only reach the perfect range with the third filtration (1.5°dH alkalinity and 5.5°dH total hardness).

In some cases, therefore, 3 or even more passes are necessary with tabletop filter devices. Quite elaborate!

The water filter with a fixed water connection

A luxury is a water filter with a fixed water connection, meaning a permanently installed under-sink filter. It has a higher and more consistent filtering performance and filters the water directly to the desired value. Decarbonization occurs through ion exchange, which in turn changes the pH value of the water.

But is this luxury necessary? If you have hard water and prepare a lot of coffee, the purchase is worthwhile. 90% of machine defects are due to excessively hard water. Considering the expensive purchase price of a good espresso machine, which you surely want to use for a long time, you should consider such a filter system. As a rule, it is cheaper to buy an under-sink filter than to have your portafilter machine serviced once. In many cases, installation is simple, but can also be carried out by specialists.

Another advantage is the reduced lime content of the water; you will also immediately notice this in your kitchen, as white deposits will hardly be found anymore.

Desalination plants are not an alternative!

In some houses, the drinking water system is connected to a desalination plant. This softens the water through ion exchange (calcium and magnesium are replaced by sodium), but the alkalinity remains. This imbalance leads to a bland and boring taste in coffee preparation, as the interplay of balanced acids and bitter notes does not work. One way out here is to go into the garden, as the water hoses are usually not connected to the desalination system.

Concrete procedure on the way to your suitable coffee water

We are happy to help you achieve the right water hardness at your home. Here's how to proceed.

1. You measure your existing water hardness with a droplet test or ask your water supplier.
2. You estimate the amount of water you need per day.
3. You send the total hardness and alkalinity (carbonate hardness) together with the water quantity and your coffee beverage type to support@kaffeemacher.de
4. We will contact you as soon as possible with a concrete recommendation on how to achieve your target values.