What is Pre Infusion – Most of today’s high-tech espresso machines contain functions to generate a pre-infusion procedure. What exactly is pre-infusion?
Let’s compare espresso to another brewing method, manual brewing, to understand better. We can easily change the amount of water we want and the flow rate with the manual brewing method. Blooming is when a small amount of water is poured near the end of the brewing process. The goal of this activity is to assist the coffee in absorbing water quickly and releasing CO2, which will help the extraction process run smoothly later.
Similarly, the pre-infusion technique in espresso is designed to help the coffees soak up the water before being exposed to the machine’s maximum pressure. Typically, an espresso machine’s maximum pressure setting will be between 9 and 10 bar. When the bartender presses the button, the pressure rises from 0 to 9 bar in a short amount of time. If the coffee machine achieves maximum pressure before the complete coffee cake is wetted, a considerable amount of Co2 gas will be emitted, affecting the extraction’s stability.
The longer it takes for the water in the early phases of the coffee cake to soak through, the thicker and tighter it is. The task of the Barista will be particularly interesting for machines that can modify the pressure and amount of water in the Pre-infusion stage when you need to find the formula that balances the pressure, the amount of water, and the cake.
If your machine doesn’t have this feature, grind size and coffee input are two things you should pay attention to if you want to brew more steady and excellent espresso cups.