The soft start of an espresso shot
Pre-infusion is the gentle first stage of an espresso shot. These notes explain what it is and how pump, lever and plumbed-in machines do it. They also point you to what the maker's manual says about setting it.
All the notes
- What Is Pre-Infusion in Espresso?
What the gentle first stage of an espresso shot is, what it's meant to do to the coffee puck, and how makers describe it in their own words.
- Pre-Infusion Versus Blooming
Pre-infusion and a pour-over bloom both wet the coffee first, but they aren't the same step. Here's how the two terms differ and where each is used.
- How Pump Machines Pre-Infuse
Pump espresso machines make a soft start by pausing the pump or by opening a valve to low pressure. Here's how three makers describe their versions.
- How Lever and Spring Machines Pre-Infuse
What sources say about spring-piston lever machines, and what La Marzocco says about lever position and pre-infusion length on its Leva-X.
- Line Pressure and Plumbed-In Pre-Infusion
Some makers use water-line pressure for a soft start. What La Marzocco and ECM say about line pressure, plumbing in and the reservoir.
- Pre-Infusion Time and Pressure Settings
Examples of the pre-infusion time settings that three makers list in their manuals, and why you should check your own manual instead of copying them.