Posts Tagged ‘Grinding coffee’

How to grind the coffee is a topic sometimes almost mysterious, that seems ruled by bizarre alchemy. I met many old bartenders (sometimes even younger) not allowed to touch their sacred grounding machine, the same for years!
The coffee grinding instead responds to clear and linear rules.
Why, first of all, we grind coffee? The milling of coffee allows hot water to extract the substances that will give body and aroma to the espresso. The hot water is would find difficulties to penetrate the whole grains and would extraxt only the substances on the surface of the grain itself.

As all the baristas know the grinding can be too coarse or too small
If the ground is too coarse the water flows very fast between the large particles of coffee (such as water of a river flowing between big stones) water can not remove all substances and we will have a espresso with a very pale cream, with little body and a thin aroma. In technical jargon this is called an espresso “underextract”

If the grinding is too fine the water takes a long time to go (as water from a river that finds a sandbank). The water extracts so all substances, but tends to ‘burn’ the particles of coffee which remains too long in contact. The result is an espresso with a little cream very dark colored, very dark, with little aroma and  and a bitter and burned taste ‘overextract’
So how can we recognize the grinding?
The right one is when our espresso reach its ideal dose (defined classically in 25 ml) in 22/28 seconds. This is the so-called rule of 25 seconds, and allows you to understand that with a well-set machine, the water will extract all substances of coffee without burning the powder. The result is a beautiful creamy hazelnut color and a fragrant espresso and balanced in flavor.

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