The perfect water for your coffee

Coffee is one thing above all: water. Espresso consists of 90 percent water, filter coffee even 98 percent. The prerequisite for good coffee is, of course, good water. But what is good water? We want to clarify this in this article.

Coffee fans spend a lot of time thinking about the perfect roast, the degree of grinding, the type of coffee, the temperature and the method of preparation. What many people don't know: The water is just as important as the bean. It makes the difference between a normal and a sensationally good coffee. But what does the right water for your coffee depend on? Let's find out in this overview.

Content

What is the perfect water for coffee?
What is hard, medium and soft water?
How does water vary depending on the region?
How does the pH value affect your coffee?
How does alkalinity affect your coffee?
What is the perfect water for my espresso?
What is the perfect water for my filter coffee?
What is third wave water?
How does water emphasize acidity and bitterness?
What is the right water temperature for coffee?
How can I filter water and soften hard water?
How do I test my water for free?
FAQ – The perfect water for your coffee

What is the perfect water for coffee?

Ideally, the water used to make coffee should be soft, i.e. have a low mineral content. Water that is too hard can make the coffee taste bitter and unpleasant. It can also lead to limescale deposits in the coffee machine, which can shorten the life of the appliance.

"When the water is soft, the coffee has a lighter body and is more acidic – possibly so acidic that it tastes sour," says Maxwell Colonna Dashwood in Perfect Daily Grind. "However, if the water is hard, the coffee will have a muddy, thick and chalky consistency and taste flat." Maxwell Dashwood is co-owner and managing director of Colonna Coffee in Bath, UK. He is also the founder of the Peak Water filtration system and co-author of the book "Water For Coffee".

To describe the composition of water and its properties for coffee, we use the terms water hardness, pH value and alkalinity. We will define these in the following paragraphs.

What is hard, medium and soft water?

The standard unit for water hardness in the coffee scene in this country is °dH. This means: degree of German hardness. There are basically three ranges of water hardness. Above 14 °dH, the water is considered hard. From 8.5 to 14 °dH is considered to be medium hardness. And at less than 8.5 °dH, the water is considered soft. Ingredients such as magnesium or calcium ensure greater water hardness.

How does the water vary by region?

Before we look at the importance of water for coffee, it is important to understand that not all water is the same. The composition of water varies by region and can contain different minerals and impurities. These factors can affect the taste of your coffee at home. The following table shows that water hardness varies by region:

Water hardness by region

10245, Berlin, Friedrichshain: 25°dH
70176, Stuttgart, West: 14°dH
80469, München, Ludwigsvorstadt-Isarvorstadt: 20°dH
28217, Bremen, Handelshäfen: 7°dH
20095, Hamburg, Hamburg-Altstadt: 12°dH
Quelle: BWT-Website

How does the pH level affect your coffee?

The second value that is important for the taste of the coffee is the pH value. It depends on the water hardness. The softer the water, the more alkaline the value. The harder the water, the more acidic it is. The scale ranges from 0 (very acidic) to 14 (very basic or alkaline). A value of 7 is a neutral solution, which is what most drinking water has. And a pH value of 7 is ideal for your coffee, as water that is too acidic or too alkaline can have a negative effect on the taste.

How does alkalinity affect your coffee?

The third value that influences the water in coffee is the so-called alkalinity. It indicates how much acid the water can bind. Alkalinity also measures how well the pH value of the water can be kept stable in the event of fluctuations. It is important for the taste of coffee, but is difficult to influence.

Now there are differences between filter coffee and espresso when it comes to the perfect water. We will go into this in more detail in the next few paragraphs.

What is the perfect water for my espresso?

We recommend a total hardness of around four to five degrees German hardness (°dH) for preparing coffee with the espresso machine. This will give you a delicious espresso. The water should also have a pH value of 7.0, i.e. not be too acidic or too alkaline. A medium calcium and magnesium content is perfect for your espresso. We'll explain how to achieve this a little later in this article.

To get the perfect water for your espresso, we recommend a reverse osmosis system from BWT for commercial customers. Basically, the principle is as follows: everything is first removed from the water and then only those minerals are added that are specifically beneficial to the water for coffee preparation. You can read more about this in the article below.

What is the perfect water for my filter coffee?

However, we recommend a total hardness of 2-3 °dH for preparing your filter coffee. As filter coffee consists of over 98 percent water, too much calcium and magnesium will quickly prevent a good taste. For specialty coffee beans in particular, it is important to use good water in order to emphasize all the nuances of the coffee. To do this, the water should have a pH value of 7.0, i.e. not be too acidic or too alkaline. A medium calcium and magnesium content is perfect for your filter coffee. We will explain how to achieve this a little later in this article.

What is Third Wave Water?

Third Wave Water is a mineral blend for the perfect coffee water. Third Wave Water is based on the SCA water profile of the American company and is easy to use and allows you to bring out flavors, reduce bitterness and achieve optimal extraction rates in just a few steps.

The American company offers blends for a classic profile (for filter coffee), for dark roasts and for an espresso profile. Let's assume you want to make espresso. The Third Wave Water pack for the espresso profile contains twelve sachets of magnesium sulphate, calcium citrate and potassium hydrogen carbonate. You take one of the sachets and mix it with 3.8 liters (1 gallon) of distilled water. Now stir carefully and you have the perfect coffee water.

How does water emphasize acidity and bitterness?

Water hardness results from the concentration of calcium and magnesium in the water. The more calcium and magnesium it contains, the harder the water. The basic rule is: soft water emphasizes the acids in coffee, hard water tends to emphasize the bitter notes. More calcium in the water leads to more bitterness. The basic rule is: more magnesium in the water makes for an astringent mouthfeel.

What is the right water temperature for coffee?

Another important aspect is the water temperature. Ideally, the water should be between 92 and 96 degrees Celsius in order to extract the full aroma of the coffee. Water that is too hot can burn the coffee and lead to a bitter taste, while water that is too cold does not release enough aromas.

How can I filter water and soften hard water?

As I said, 98% of your filter coffee and around 90% of your espresso is made from water. To improve the taste of your coffee, optimize the brewing water and protect the material, you should definitely filter the water. There are various treatment methods for use at home.

An inexpensive and very practical tool are the table filters from BWT, which primarily bring out the taste of coffee and tea while filtering unwanted substances such as limescale, chlorine and heavy metals from the water. The basic rule is that the degree of hardness is roughly halved with each filter cycle. Incidentally, still mineral water from the supermarket is not suitable for brewing coffee due to its high sodium and mineral content. Our experience is that Turkish spring water is ideal for coffee.

Incidentally, we use a BWT reverse osmosis system in our cafés especially for coffee. Reverse osmosis is a physical process for treating water. It was originally developed for military and aerospace applications. Reverse osmosis is based on the principle of concentration equalization. Water is forced under high pressure through a semi-permeable membrane that only allows water molecules to pass through and retains impurities. This purifies the water of unwanted flavors and impurities to ensure optimum water quality for coffee preparation. An osmosis system is many times more effective than a conventional fine filter, which uses a simple sieving process.

How do I test my water for free?

Before you order a table filter, you should find out how soft or hard your water is at home. To do this, you can simply on the website www.wasserhärte-deutschland.de or on the BWT website by entering your zip code. Or you can get test strips from a pharmacy or online shop, which you can use to easily determine the water hardness by placing them in a glass of cold water.

FAQ – Das perfekte Wasser für deinen Kaffee

What is the perfect water for coffee?

It all depends on whether you want to make filter coffee or espresso. Ideally, the water used to make coffee should be soft, i.e. have a low mineral content. Water that is too hard can make the coffee taste bitter and unpleasant.

How does the water vary depending on the region?

The composition of water varies from region to region and may contain different minerals and impurities.

What is hard water?

The standard unit for water hardness in the coffee scene in this country is °dH. This means: degree of German hardness. Water with a hardness of over 14 °dH is considered hard.

What is soft water?

Water below 8.5 °dH is considered soft.

How does the pH value affect your coffee?

The softer the water, the more alkaline the value. The harder the water, the more acidic it is. The scale ranges from 0 (very acidic) to 14 (very basic or alkaline). A value of 7 is a neutral solution, which is what most drinking water has.

What is the perfect water for my espresso?

We recommend a total hardness of around four to five °dH. This will give you a delicious espresso. The water should also have a pH value of 7.0. A medium calcium and magnesium content is perfect for your espresso.

What is the perfect water for my filter coffee?

We recommend a total hardness of 2-3 °dH. As filter coffee consists of over 98 percent water, too much calcium and magnesium will quickly prevent a good taste. The water should also have a pH value of 7.0, i.e. not be too acidic or too alkaline. A medium calcium and magnesium content is perfect for your filter coffee.

How can I soften hard water, i.e. filter water?

An inexpensive and very practical tool are the table filters from BWT, which primarily bring out the taste of coffee and filter unwanted substances such as limescale, chlorine and heavy metals from the water. The degree of hardness is roughly halved with each filter cycle.

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written by

Christopher Braemer

Christopher is a trained journalist and works in marketing at Röststätte Berlin. He is passionate about the Röststätte newsletter and the content area. For the blog, he writes about coffee from all over the world, but also about business, politics and sustainability. If you have any questions or suggestions, please send him a message.

Photos: Laura Droße, Constantin Gerlach

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