Guide · By The Lab · October 12, 2026
15 Bar vs 9 Bar vs 20 Bar Espresso Machines.
In a 15 bar vs 20 bar espresso machine comparison, nobody wins on pressure: both brew at about 9 bar at the coffee, because an over-pressure valve caps whatever the pump could produce. The number on the box is the pump's maximum, not the pressure in your cup — and 9 bar is the figure real espresso is actually pulled at.
So the honest ranking is: 9 bar = 15 bar = 20 bar, as far as your shot is concerned. The difference between the labels is marketing. Here's what each number means, where it can matter, and what to compare instead.
01.What each number on the box means
A quick translation of the labels you'll see. For the full explanation of why 9 bar is correct, read our bar pressure guide.
| Box says | What it actually is | Pressure at the coffee | Real difference |
|---|---|---|---|
| 9 bar | The standard brewing pressure — often a rotary pump or a machine that states its operating pressure | About 9 bar | None — this is the target |
| 15 bar | The maximum a common vibratory pump can generate with the outlet blocked | About 9 bar, once the OPV opens | Nothing you can taste |
| 19–20 bar | A pump rated even higher — a bigger number on the box, not in the cup | About 9 bar on a well-set machine | Marketing |
02.Why the box number is a pump rating
Pump ratings are measured with the outlet closed — nothing flowing, pressure building as high as the pump can push. Once water flows through coffee, the over-pressure valve opens and bleeds off everything above roughly 9 bar. A pump rated 15, 19, or 20 bar therefore brews at the same pressure.
That's why the Gaggia Classic Pro, the Dedica Duo (a 15-bar machine), and the Casabrews (a "20-bar" machine) all aim at the same number where it counts.
03.Where the number can actually matter
On budget machines, the over-pressure valve and the pressurized basket do the real work. With a pressurized basket (see our pressurized vs non-pressurized guide), the resistance comes from the basket's exit hole rather than your puck, so the pressure at the coffee is set by that design, not by the headline bar rating.
A higher-rated pump can also hold pressure more steadily under real conditions — low voltage, a slightly-too-fine grind — and rotary pumps are quieter and steadier than vibratory ones. Those are properties of the pump type, not of the number printed on the box.
04.What to compare instead
Stop shopping on bar rating. Compare temperature stability (PID control or a dual boiler), portafilter size and basket type, pre-infusion (a gentle pressure ramp that wets the puck evenly), and the grinder you'll pair it with — that last one moves your shot quality more than every spec on the box combined.
If a listing leads with "20 BARS OF PROFESSIONAL PRESSURE," it's telling you it has nothing more interesting to say.
FAQ
- Is 20 bar better than 15 bar for espresso?
- No. Both brew at about 9 bar at the coffee because an over-pressure valve caps the pressure. The higher number is the pump's maximum, not what your espresso experiences.
- What pressure should an espresso machine brew at?
- About 9 bar. That's the pressure real espresso is pulled at, and every well-set machine throttles down to it regardless of its pump rating.
- Why do cheap machines advertise 15 or 20 bar?
- Because a bigger number sells. It isn't false — the pump can generate it — but it's not the pressure that reaches your coffee, and the box rarely explains the difference.
- Does a higher bar rating make better crema?
- No. Crema comes from fresh beans and the way the shot is extracted, not from extra pump pressure. Pressurized baskets can manufacture foam, but that's a basket effect rather than a pressure advantage.