The Pressure bars in a coffee
Pressure bars are a characteristic of coffee machines that often go unnoticed or that is not given the importance that it really has. But in this article, we will try to clarify what for many is a great unknown in the preparation of coffee. Make yourself comfortable in your chair, because we are going to tell you what exactly pressure bars are, what they are for, how many a machine should have, and the importance of pressure bars in a cafe.
Coffee made in a thick machine is easily recognizable due to its distinctive flavor and aroma. Automatic machines give the coffee a distinctive body and aroma that a drip machine can never match. You have never wondered why coffee made in an automatic machine tastes better than a drip one.
The differential factor, which changes everything, is the pressure bars.
How does an automatic coffee machine work?
To understand the incidence of pressure bars in a coffee, we must know how an automatic coffee machine works. We will explain quickly and very briefly how it works.
In automatic coffee machines, the water is heated reaching a lot of pressure, then that water passes through the filter where the ground coffee is located. It is at this point where the magic happens, the water at a very high temperature and under high pressure, extracts all the characteristics of the coffee, turning that water into an espresso. The greater or lesser extraction of the qualities of the coffee is determined by the extraction method or the pressure bars. The higher pressure the water has, the more qualities it will extract. This is why the espressos made in automatic coffee machines have a more powerful aroma, greater body, and a characteristic flavor.
Now, like everything in life, it requires its fair measure, if we go over the water pressure, our espresso will have unpleasant characteristics.
9 bars of pressure for a perfect espresso
After many trials and errors of those in charge of the official certificate of the qualities that an authentic Italian espresso must have, it has been concluded that the pressure bars necessary to make an authentic espresso coffee are 9.
So if only 9 bars of pressure are needed, because the vast majority of coffee machines that you can buy for homes have 15 to 19 bars.
The answer is strictly mechanical. To make espresso you need 9 bars of pressure, which professional machines achieve constantly due to the type of machines and utensils they use to generate that pressure.
Commercial coffee makers: they use rotary pumps. This type of pump achieves a constant pressure of 9 bars, regardless of the water flow available. That is why they can serve more coffees.
Domestic coffee makers: they use vibratory pumps, which are much cheaper, so we can buy coffee machines at a good price instead of spending thousands of euros.
The problem with these pumps is that they lose pressure, so it is necessary that they have more bars, to reach 9 bars of pressure at the end of the process.
The importance of pressure bars lies in the ability to extract more qualities from the coffee. The pressure bars are very important in the final result of a coffee, but they are not the only important thing, the type of grind, the compaction of the same, the temperature of the water … there are many factors that affect an espresso, but perhaps this is one of the least known to the general public.
In short, to make a good espresso you need 9 bars of pressure