What is Pump pressure?
Pump pressure (espresso)
Bars of pressure pushing water through the coffee puck — 9 bars is the extraction sweet spot.
Short answer
Steam-toy machines claiming espresso at 3–4 bars produce no crema worth the name.
Pump pressure when buying a coffee maker
Bars of pressure pushing water through the coffee puck — 9 bars is the extraction sweet spot.
Why it matters: Machines advertise 15–20 bar pumps but regulate down to ~9 bars at the puck; below 9 you get sour, weak shots.
Look for: Steam-toy machines claiming espresso at 3–4 bars produce no crema worth the name.
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