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Why Do You Need Different Water for Espresso and Filter Coffee?

The water removes the substances in the coffee, including the acids found in the beans. The acid-base balance (pH) therefore significantly affects the final taste. A beverage made with alkaline water will taste bitter. Acidic water will give the coffee a vinegary taste. The best coffee is made with water whose pH is close to neutral - between 6.5 and 8.

Interestingly, espresso and filter coffee need different water to balance the coffee acids and therefore the flavor of the cup. Coffee chemistry researcher Dr. Marco Wellinger talked about how to get a predictable result when making any coffee beverage.

Water parameters and coffee taste

When choosing water for a drink , they rely on the following indicators:

pH - acid-base balance. It is determined by the ratio of acid and base in water. This indicator is measured on a scale from 0 to 14. Water with pH = 0 is very acidic, water with pH = 7 is neutral, and water with pH = 14 is very alkaline. Acid-base balance affects the taste of coffee. If the water becomes more acidic, the coffee will also be more acidic. If the pH is above neutral, bitterness will appear in the cup.

Total hardness is the content of calcium chloride (CaCl2), calcium sulfate (CaSO4), magnesium chloride (MgCl2) and magnesium sulfate (MgSO4) in mg/l. Calcium and magnesium extract coffee flavors and do not precipitate during boiling. With an increase in their levels, the drink becomes more acidic, brighter and even sweeter. With a decrease - coffee loses saturation.

Carbonate hardness or alkalinity is the level of potassium bicarbonate (KHCO3) and sodium bicarbonate (NaHCO3) in mg/l. The higher the bicarbonate level, the more alkaline the water. Their excess flattens the coffee and leads to scale formation. With a lack of bicarbonate, the drink becomes too acidic, and the boiler of the coffee machine and other equipment components are at greater risk of corrosion.

All these parameters affect the final taste of the drink. In particular, carbonate hardness (alkalinity) affects the perceived acidity of coffee. Let's take a closer look at this concept.

The alkalinity level of the water directly affects the acidity perception of the glass.

Relationship between pH and alkalinity

Measuring the pH of the water shows how alkaline the environment is. This is generally true, but this interpretation overlooks that pH does not indicate how many bases are in the water. The indicator only reports how alkaline the medium is relative to the neutral level (pH = 7). For clarity, let's look at an example.

Consider two benches - wood and stone. Both are standing in the sun in the park. You will not feel hot if you sit on a wooden bench. If you switch to the stone one, you can feel it burning the skin. But if you measure the temperature of both counters with an infrared thermometer, it will be the same.

Due to the larger mass, the stone countertop accumulates heat better - it has a large heat capacity. For the same reason, it will be more resistant to temperature changes - the thermal energy accumulated after sunset will persist for a long time.

It turns out that when choosing a countertop, it is necessary to find out not its temperature, but the heat capacity of its material.

A wooden bench has a lower heat capacity than a stone bench at the same temperature.

A similar comparison can be applied to water: to choose it, you need to know the alkalinity level, not the pH. Similar to the temperature on countertops, pH indicates the current state of the water. And alkalinity tells about the sensitivity of the water's pH to changes. For example, how it will react to contact with acids in a metal cauldron or coffee.

It turns out that pH indicates the property of water - acidic, alkaline or neutral. But it does not report on the amount of substances in it. For example, pH > 7 means that the water is alkaline, but does not indicate its base content.

This is especially important to know in order to achieve the desired coffee taste.

Coffee contains a lot of acid. When they enter the water, they lower its pH and make the drink acidic. The bases, the bicarbonates in the water, help stabilize the taste. They actively react with acids and neutralize with the formation of a precipitate. At the same time, the amount of substances in the container remains unchanged.

Professionals put it this way: The perceived acidity of a beverage is equal to the amount of caffeic acid minus alkalinity (the amount of bicarbonate).

Water and various brewing methods

Alkalinity and pH are the main water parameters that can be used to predict the taste of a future beverage.

Also, the most important factor in this equation is the ratio of coffee to water (Ratio). This parameter is called differently depending on the brewing method:

Brewing Rate. Standard ratio for drip and immersion brewing methods. Indicates the amount of coffee per liter of water. Most often, 60 g of coffee per 1 liter is used.

Beverage Ratio or coefficient. The standard used for espresso. Indicates the ratio of the weight of ground coffee to the finished beverage. For example, 18g of coffee for 36g of finished espresso.

When choosing the composition of water, it is necessary to take into account the method of preparation of the drink.

Ratio for different methods may differ 10 times. Simply

In other words, when preparing espresso, we take 10 times less water per bean than filter coffee. If we do not make any changes in the composition of the water, there will be 10 times less bicarbonate in the glass to neutralize the acids. The acidity of the drink will be extremely pronounced.

This means that the bicarbonate content of the water for espresso needs to be higher than for #filter coffee to balance the acids in a concentrated beverage.

It turns out that espresso water should be different - more alkaline. However, this can lead to difficulties in using the coffee machine.

SCA proposed expanding the water parameters for espresso to account for their differences from less concentrated beverages. Thus, the norm was determined: 150 mg / l of bicarbonate, 20 mg / l of calcium and magnesium. To calculate filter coffee standards, we multiply the Espresso Ratio (2) by 7.3, which is the ratio between filter coffee (14.6).

Optimum total hardness and alkalinity ratio in espresso water

Espresso values ​​turned out to be strict, because the final figures did not coincide with the capabilities of the technique. Basically, they corresponded to the lime-forming water in the coffee machine (0.25-0.45 g of bicarbonate per 1 liter of water). Therefore, the ratio of carbonate hardness for espresso had to be limited.

Such water standards may seem to hinder extraction experiments. But there is a gap here.

The ratio of calcium and magnesium was determined according to taste preferences, not technical safety rules. Thus, due to the general parameter of hardness, you can “play” with the acidity of the drink and soften the water to varying degrees. To do this, reduce the content of calcium and magnesium - so it becomes possible to increase the level of bicarbonate.

You can make your own soft water for espresso. But there is an easier way - install a cartridge that filters calcium and magnesium salts, but does not affect bicarbonates. Such a device will help prevent the formation of scale in the coffee machine and create a positive acidity of the drink.

Things to remember to manage aroma with different brewing methods:

The pH level affects the final taste of the coffee. A drink made with acidic water will become unpleasantly acidic, while a drink made with alkaline water will have a bitter result. The ideal pH of water is between 6.5 and 8.

Coffee contains acid. To regulate their perception, you can change the pH of the water through its alkalinity level (bicarbonate content).

Brewing methods differ according to the volume of water. Hence the number of molecules that neutralize caffeic acids.

Concentrated beverages (espresso) use less water per gram of coffee. This means that the glass has to be more alkaline to create the correct acidity.

Very alkaline water creates scale in the coffee machine. Therefore, espresso standards are strict: 150 mg/l bicarbonate, 20 mg/l calcium and magnesium.

It is possible to experiment with espresso extraction and make it softer: reduce calcium and magnesium and add bicarbonate.

In order to create the desired taste of espresso and not to spoil the equipment, you can prepare the water yourself or add a filter softener.


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