How does water affect the taste of coffee?

Water is able to extract various substances present in coffee, including acids contained in the grain. Therefore, the taste of the finished coffee depends a lot on its acid-base balance. The use of alkaline water causes bitterness, and acidic water can be immediately recognized by the taste of vinegar. The optimal choice for brewing coffee will be water with a neutral pH level or at least in the range of 6.5 – 8.

Not everyone knows that the preparation of espresso and filter coffee requires water with different characteristics. This is an indispensable condition for achieving a balance of coffee acids and the taste of the cup as a whole. Having understood some of the nuances, it will be easy to get the desired result when preparing any coffee drink.

Dependence of coffee taste on water indicators
The choice of water for coffee should take into account the following parameters:

• Acid-base balance (pH). It is calculated by determining the ratio of acids and bases using a scale from 0 to 14. Where "0" indicates increased acidity, "7" indicates neutral, and "14" indicates the maximum acidity. The percentage of acid content directly affects the taste of coffee. If too acidic water is used, the acidity of the finished drink also increases. The bitter taste indicates that the pH of the water is above neutral.

• Rigidity. Indicates the presence of calcium sulfate, calcium chloride, magnesium sulfate and magnesium chloride in water. These minerals tend to extract coffee flavors and do not form a precipitate when boiling. Their increase ensures the brightness of the drink, and a decrease provokes a loss of saturation.

• Carbonate hardness (alkalinity). It depends on the indicators of sodium bicarbonate and potassium bicarbonate – their excess increases the level of acidity of water. The lack of bicarbonates results in a noticeable increase in the acidity of the drink and the risk of corrosion of the boiler, coffee machine and other devices.

These factors especially strongly change the taste of coffee.
There is such a thing as "perceived acidity of coffee", which also deserves attention, being an important aspect within the framework of the topic under consideration.
The high acid concentration in coffee is due to a decrease in pH due to the ingress of acids into the water. Bicarbonates are responsible for the balance of taste, actively contacting with acids. As a result of the reaction, the acids are neutralized with precipitation, while maintaining the original amount of substances in the cup. In professional language, it looks like this: "The perceived acidity of coffee is equivalent to the amount of acids without taking into account alkalinity."

Water and different brewing methods
The taste of the future drink is largely formed by the level of alkalinity and pH.
The second most important aspect is the ratio of water and coffee (Ratio). It has several names, which are determined by the brewing method:
• Brew Ratio. A classic ratio suitable for drip and immersion brewing. It helps to find out how much coffee you need to take per liter of water. In most cases, 60 grams of coffee beans are taken.
• Beverage Ratio (coefficient). The standard option when brewing espresso, indicating the ratio of the weight of ground coffee and the finished drink.

In simple words, when making espresso, we will need 10 times less water for the same amount of grain, compared to brewing filter coffee. If at the same time the composition of the water remains unchanged, there will be 10 times less bases in the cup that neutralize acids. So, the output will be a drink with pronounced acidity.
To balance the acids in the concentrated version, it is necessary to increase the indicators of bicarbonates in water.
Thus, it becomes clear that espresso requires more alkaline water, which often causes problems in the use of coffee machines.

Way out of the situation
The conflict between the need to use highly alkaline water in the preparation of espresso and its harmful effects on equipment is solved by expanding the parameters of water. Concentrated drink is allowed to be prepared of water containing 150 mg / l of bicarbonate, 20 mg / l of calcium and magnesium. Such figures are considered to be optimal in terms of the ratio of total hardness and alkalinity.

Such strict values are due to the discrepancy between the final value and technical capabilities. To a greater extent, they relate to the water that forms scale in the coffee machine (0.25–0.45 g of bicarbonates per 1 liter of water). Therefore, we have to go to the limit of the norm of carbonate hardness for espresso.
 Fans of experiments with extraction should not worry, even with such water standards.

The norms of calcium and magnesium are not set in accordance with safety regulations, but taking into account taste preferences. This means that the overall hardness parameter allows you to change the acidity of the drink, soften the water to the required level, which is achieved by reducing the content of calcium and magnesium. Thanks to this step, it becomes possible to increase the level of bicarbonates.

There are methods of self-softening water for espresso. But it is much easier to use a special cartridge constructed to filter potassium and magnesium salts without affecting bicarbonates. It protects the internal components of the coffee machine from scum formation and ensures optimal acidity of the finished drink.

Conclusion
Managing the taste of coffee with different methods of preparation is impossible without taking into account the following factors:
• The final taste of coffee is directly influenced by the pH level. Acidic water causes unpleasant acidity, alkaline – bitterness. The ideal pH of water is considered to be 6.5 – 8.
• Coffee contains acids. The adjustment of their perception occurs by changing the pH of water through the content of bicarbonates.• Different brewing methods require different amounts of water, which means also the number of molecules responsible for the neutralization of coffee acids.
• Espresso preparation needs less water in recalculation for each gram of coffee. In this case, the formation of the correct acidity of the cup is achieved by using a more alkaline liquid.
• Water with a high level of alkali forms scum in the equipment. Therefore, the existing standards for concentrated beverages are: 150 mg/l of bicarbonate, 20 mg/l of calcium and magnesium.
• To conduct experiments with espresso extraction and its softening, the amount of calcium and magnesium should be reduced along with the addition of bicarbonates.

The formation of the desired taste of espresso and the preservation of the performance of the coffee machine is possible in the case of self-preparation of water or installation of a filter softener.