The machine, demystified
What nine bars of pressure actually do — 4 min
Espresso is not a bean, a roast, or a flavor — it is a brewing method defined by pressure. Around nine bars of it pushes hot water through a compacted bed of finely ground coffee in 25–35 seconds, producing a small, intense cup crowned with crema.
Why pressure? Ground this fine, tamped this firm, the coffee bed would choke any pour-over. Pressure forces water through anyway, so an extraction that would take minutes happens in under half a minute — and along the way it emulsifies oils and dissolves far more CO₂ than water normally can.
In the app
The rest of this lesson is in the Blend app — with the interactive widget and the practical brew.
Finish this lesson in the app.
The interactive widget, the footnotes, and the practical brew you can taste. Free on iOS and Android.