The principle of pre-soaking of espresso how to presoak

Pre-Infusion

The presoaking stage is when the water touches the coffee for the first time. At this point, the goal is not to extract it, but to prepare the channel.

Lauro told me, "in filtered coffee, what you usually have to do is add some water at the beginning of the coffee bed." "this is the beginning of steaming: when water reacts with coffee, the carbon dioxide in the coffee grounds is released as bubbles."

These bubbles disrupt the coffee bed and prevent water from reaching some of the ground. Then they dissipated and the coffee bed settled down again. Therefore, allow steaming to occur before extraction ensures more uniform and consistent wetting of coffee grounds.

The same principle applies to espresso. This is why it is important to deaerate the beans before making coffee. This means that less carbon dioxide is released during brewing.

Just as important, different coffee maker manufacturers have different pre-injection systems. Lauro told me that the Simonelli Group team divided pre-injection into two different stages: pre-wetting and pre-injection. "pre-wetting is usually a function that we activate when we drink very fresh coffee," he said. By opening the solenoid valve, the machine can release carbon dioxide inside the coffee ball.

He added, "if your coffee has been properly degassed, you don't need to remove excess carbon dioxide."

As for the advance injection, he told me that the channel "will get wet, absorb water, release carbon dioxide, and expand."

He stressed the importance of a stable coffee bed in the pre-soaking and pre-wetting process. "it is very important to [use] the right time," he said. "if this happens too fast, carbon dioxide will still be released when the infusion starts.

Another point to consider is the disturbance of coffee grounds caused by the impact of water on the channel. The strength and extraction time of espresso are due to pressure, and many machines extract it at a pressure of 9 bar. However, this may replace the venue.

"it's very important to minimize the risk of channeling," Lauro said. "if the water is hit on the coffee at a pressure of 9 bar during the pre-injection stage, it will disrupt the passage and make it easier for the water to pass through certain areas." In turn, this may lead to uneven extraction.

For this reason, Lauro emphasizes the need for hot water to flow without any mechanical pressure during pre-injection. The purpose of this is to make the passage smooth and wet.

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