Coffee machine pressure on coffee machine pressure on the impact of coffee

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The key to making espresso lies in pressure, and the crema, quantity, and flavor of espresso all come from the influence of stress.

But why is stress so important? How does it affect concentrated formulations? Why is the nine atmospheric pressure the most commonly recommended pressure setting for brewing coffee?

The knowledge of stress

Pressure is measured by atmospheric pressure, and the pressure generated by the atmosphere is usually calculated as an atmospheric pressure at sea level.

The usual nine atmospheric pressure (9 bar) when making espresso is nine times the weight of one atmospheric pressure. Stephen said: "espresso has a very long history, and nine atmospheric pressure is recognized as the most suitable pressure to extract espresso." "

In order to make it easier for you to understand and imagine the situation of tire inflation, the tire pressure of most cars is 32 PSI (about 2.2bar) and that of bicycles is 65-85 PSI (about 4.4-5.8bar).

The 9 atmospheric pressure extracted by espresso is as much as 4 times the normal tire pressure.

Control pressure

Imagine that such a high-pressure flow over coffee powder seems to create a mess, so we have to control and apply these nine-atmospheric pressure, which is at the heart of espresso theory.

How do we control stress? You can control the coffee brewing time by filling and pressing the coffee pressed powder.

First of all, let's take a look at the coffee pressed powder. To avoid the confusion mentioned above, we need something to stop the water from being pushed quickly over the coffee powder.

So the first thing to make sure is that the grinding degree of the coffee powder must be very fine, and any coffee can be made into espresso, but it must be extremely fine ground and filled with pressed powder in the brewing handle. This creates a high-density, flat surface that allows coffee powder to block the flow of water.

Adjust the flavor of coffee

The extraction time of a dose of concentration combined with nine atmospheric pressure is usually between 25 and 30 seconds. If the pressure is low, it takes more time to extract; if the pressure is high, the extraction time needs to be shortened.

Many people also like to change the pressure of extraction: first pre-soak from low pressure, then use 9 bar of high pressure extraction, and then reduce the pressure extraction to the end. Maxwell Colonna-Dashwood advocates the use of 6 bar pressure for low pressure extraction. There are always many new directions to test for coffee, and our idea of extraction continues to evolve.

However, 9 bar pressure extraction is still the most standard setting. In fact, pressure control can only be used on advanced coffee machines with pressure adjustment.