What kind of water should be used to make coffee?

Where there is water, there is life. From human beings to plants, water is the source of life for all things. Water molecules are composed of oxygen ions and hydrogen ions. It is precisely because of this molecular structure that it is difficult to find pure water in the natural environment. In the process of transforming Rain Water into tap water, water will absorb and decompose a variety of substances that come into contact with it. Therefore, we must pay special attention to the purification and treatment of water so as not to cause damage to machinery and equipment.

Especially for coffee, the purification and treatment of water is particularly important. The coffee machine uses high pressure to raise the temperature of the water and turn it into steam. The water that flows through the boiler flows out of the outlet, extracting cups of espresso as we know it.

At the same time, water may cause damage to the coffee machine, but also affect and destroy the original taste of coffee. In order to extend the life of the coffee machine and make the coffee taste better, we must intervene manually to adjust the material composition of the water, that is, mineral hardness, carbonate hardness, chlorine and pH (pH).

What is the total hardness of water?

The total hardness is the mineral hardness of water. Water contains a large number of mineral elements such as calcium, magnesium, sodium, copper and iron, among which we need to pay most attention to calcium and magnesium, which can improve the ability of water to dissolve organic molecules and make coffee extract more fully.

What is the carbonate hardness of water?

Carbonate hardness determines the ability of water to balance acidity and alkalinity. What determines this ability is the bicarbonate in water, the substance formed by carbon dioxide absorbed by water as it flows through the soil and air.

Bicarbonate is amphoteric and can react with either acid or alkali. Carbon dioxide dissolves into water and becomes carbonic acid. If one proton is lost, it becomes bicarbonate; if multiple protons are lost, it becomes carbonate. If the content of carbonate and calcium in the water is high, they will form calcium carbonate, that is, scale.

Water is very easy to form scale in the boilers and pipes of the coffee machine, especially in a high-pressure environment that accelerates the formation of calcium carbonate. Too much scale will slow down the flow of water and slow down the heating speed of the boiler.

The good news is that we can dissolve the scale by adding acid. When cleaning the coffee machine, we often use citric acid to dissolve the calcium carbonate. In addition, we can also install a water filtration system to remove excess calcium and other minerals from the source to avoid scale. Note, however, that we just mentioned that magnesium and calcium can improve the ability of water to extract coffee. If these two substances are removed too much, the taste of coffee will be insipid; too little will form scale, so we must strictly control the content of calcium and magnesium in the water to find a perfect balance!

About chlorine

Most of the tap water we use contains chlorine, which reacts with magnesium, calcium, sodium and so on to form salt. When the pH value of the water is acidic, the corrosion of chlorine to the metal will be very serious, especially when the metal content of the equipment is not pure. It is worth noting that many water filtration technologies, such as water softening systems, reduce the content of calcium and bicarbonate in the water, weakening the ability of the water to balance pH, which leads to a decrease in the pH value of the water, that is, slightly acidic, which can cause corrosion to the equipment, so we do not recommend using water with a pH value below 6.5, as it will affect the extraction process of coffee.

About pH value

The pH value measures the total amount of hydrogen ions in water. PH value is an important basis for us to judge water quality. The pH value of 7 indicates that the water is neutral; with the addition of additional acid or alkali, the pH value will decrease or increase. When the pH value is lower than 7, the water is acidic; otherwise, it is alkaline. It should be noted that when the pH value increases or decreases by 1, the concentration of hydrogen ions in the water will change 10 times, so the change of pH value will greatly change the properties of the water, resulting in a more intense reaction between the water and some substances.

We just mentioned that bicarbonate can affect this reaction, but it is precisely because of this that bicarbonate also weakens the high-quality acidity of coffee, making the taste of coffee tend to be flat.

The key is balance.

Achieving a perfect balance of all kinds of substances in the water can not only protect our coffee maker, but also make the coffee more delicious. We need to test the water quality regularly in every link to ensure that the content of all kinds of substances in the water is up to the standard.