Kit
What is pre-infusion, and does your machine need it?
Oct 19, 2026 · 5 min
Pre-infusion wets the puck at low pressure before full pressure hits. Why Barista Hustle says it evens extraction, and how home machines do it.
Short answer
Pre-infusion (Barista Hustle writes preinfusion) is a lower-pressure wetting phase at the start of the shot, before full brewing pressure. Barista Hustle’s lesson on preinfusion puts it simply: it gives the puck time to absorb water before full pressure, so the bed wets more evenly and extraction is more uniform.
Why it helps
Barista Hustle notes that dry coffee is hydrophobic: dry spots that remain when full pressure arrives resist flow and can create uneven extraction and channels. Pre-infusion is meant to clear those dry spots. The same lesson says a wetted puck is more permeable, so flow during the main brew can be faster after pre-infusion, which is why some baristas use it to grind finer while keeping a usable shot time. How long full saturation takes depends on grind and flow; Barista Hustle cites 8-10 seconds or more in some cases, longer than many machines allow.
How home machines do it
Barista Hustle lists several machine approaches: open the solenoid without the pump (line pressure only), restrict flow with a needle valve or restrictor, or fill a pre-infusion chamber before full pressure builds. On the Breville Barista Express (BES870), the instruction manual names LOW PRESSURE PRE-INFUSION: low water pressure at the start to gently expand the grinds for a more even extraction, then full pressure. Preset 1 CUP and 2 CUP shots start with that low-pressure phase; press-and-hold on those buttons lets you hold low-pressure pre-infusion until you release, then the shot continues at full pressure. The pressure gauge needle sits in the pre-infusion zone at the start. The Breville Bambino Plus review covers another Breville that advertises low-pressure pre-infusion as a feature; see that review for details.
Machines without a named pre-infusion step
Not every home machine documents a low-pressure wetting phase. If your machine’s manual does not mention pre-infusion, do not assume it has it. What you can still control is puck prep: even distribution and a consistent tamp. How to tamp espresso, the Bambino Plus vs Gaggia Classic Pro E24 comparison, and the Gaggia Classic Pro E24 review are the places for technique and machine tradeoffs.
Does it fix channeling?
Barista Hustle ties leftover dry spots under full pressure to uneven extraction and channels. Pre-infusion is one way machines try to wet the bed first; it is not a substitute for distribution, tamp, and grind. For causes and fixes on the channeling side, use espresso channeling causes and fixes.
Sources
Get gear picks
Occasional shortlists when we update tiers.