Espresso
Pre-Infusion
A low-pressure soak phase at the beginning of espresso extraction that gently saturates the coffee puck before full pressure is applied. Pre-infusion promotes even saturation and reduces the risk of channeling.
Em Profundidade
During pre-infusion, water contacts the dry puck at line pressure (1–4 bars) or through flow restriction for 2–10 seconds, allowing grounds to swell and seal gaps. This creates a more uniform bed density before the pump ramps to 9 bars. Machines offer different pre-infusion mechanisms: some use the pump at reduced power, others rely on reservoir pressure or mechanical E61-style preinfusion chambers. Extended pre-infusion is particularly beneficial for light roasts and finely ground coffee, where channeling risk is highest.