Which kind of water to choose for the preparation of the Perfect Espresso?

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Which kind of water to choose for the preparation of the Perfect Espresso?

Acqua preparazione espresso perfetto

“Let’s drink a coffee?”. Typical daily phrase of millions of Italians.
We drink coffee and have a chat with an old friend, we share the work break with a colleague or maybe we allow ourselves an instant of reflection sipping an espresso.

In reality, even if we forget it, what is served to us in the cup is mainly water: how much, which kind and why we’ll see, step by step.

The water quantity in the espresso: the refractometer
The water quantity in the espresso swings between the 88% and the 92%.
It is enough easy to identify this range, even if a little bit expensive. The instrument used is the refractometer: an instrument which, given a liquid, calculates the percentage of solids melted in the same
trough the light reflection.
In practice, simplyfing, it’s “ shot” a ray of light and the more dense is the liquid (and therefore more components are melted in the liquid), the less will be the refracted light. This number swings usually
between 8% and 12 %, so the presence of water is calculated by difference.

The quality of the water in the espresso
The water has to be neither flavours nor bad tastes, with a ph between 6,5 and 7,5 (ph 7 is neutral, less is tending to acidity, more tends to basicity), possibly with a content of of solids around 150mg/l. The content of solids is the value that in the label of mineral water you find at the item “fixed residue“ and expresses the hardness of the water.

A high fixed residue can result with the time in formation of limestone, this last is definitely a damaging element for coffee machines.

The limestone: enemy of the coffee machines.
The limestone creates from combination among calcium carbonate and magnesium carbonate mixed at high temperatures.
In the water we have calcium and magnesium both in form of base elements that combined with carbon dioxide, which, in turn, creates carbonates of calcium and magnesium. These elements combined among them
in hot water (the water that flows in the pipes of the machine to extract the coffee) fall at the solid state producing that white powder, similar to the gypsum we call limestone, the famous “limescale“.
Consequence is that the machines in which are present these inner limescale don’t result performing in terms of stability, temperature, extraction capacity or in terms of drying of the coffee tablet after the extraction.

The water softener and the regenerating power of the marine salt
The equipment to avoid this formation are different. The most common in Italy is without doubt the water sweetener, whose function is linked to the use of resins which hold the carbonates and release sodium ions.
These resins are regenerated thanks to the power of the marine salt, element which periodically has to be introduced in the device.

In extreme cases we have to use the inverse osmosis , in which the water is completely filtrated through an intrusive mechanical action and after eventually “regenerated”. Luckily in Italy don’t happen many cases in which is necessary the inverse osmosis.

My suggestion
Rely on your trust specialist who knows or can calculate the water parameters and consequently can show you the best indicated system of filtration.
But above all: put the salt in the water sweetener and check it periodically!

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