A 15 bar espresso machine can at most, force heated water through coffee at 15x the present atmospheric pressure of the earth.A 9 bar espresso machine can at best force heated water through coffee at 9x the present atmospheric pressure of the earth.A coffee machine’s bar number denotes the maximum atmospheric pressure multiplier that the machine can generate as it forces hot water (194☏ - 203☏) through the coffee beans. To answer this question, we need to understand exactly how coffee machines use their capacity of producing the bars of pressure first. How and Why Are The Bar Numbers Relevant? 14.5 psi x 20 bars = 290 psi of pressure (20 bar espresso machine).14.5 psi x 15 bars = 217.5 psi of pressure (15 bar espresso machine).14.5 psi x 9 bars = 130.5 psi of pressure (9 bar espresso machine).Note that since 1 bar is equal to 14.5 psi, when we are pitting 9 bar vs 15 bar vs 20 bar espresso machines against each other, we are essentially comparing coffee machines capable of producing: Whenever you hear or read about a 9, 20, or 15 bar machines, that’s exactly what the bar number on it indicates.įor the sake of simplicity and understanding, the pressure capacity of espresso machines can also be converted into pounds/square inch, aka psi. 1 bar of pressure is also barometrically defined to be almost equal to the earth’s present atmospheric pressure, as would be found at an elevation of 111 meters (59☏).

The Bar is a metric unit of measuring and representing pressure that’s equal to 100,000 Pa (pascal) and 100 kPa (kilopascal). Naturally, they are left with plenty of unanswered questions such as what exactly is a bar? What are 9 bar, 15 bar, or even 20 bar espresso machines? Does a higher “bar” number indicate quality or performance in some way? The list of questions is pretty long, so that’s where we will begin here, before moving on to a detailed comparison of 9 bar vs 15 Bar vs 20 Bar espresso machines. Any coffee lovers out there looking to buy an espresso machine might already have come across terms such as 9 bar or 15 bar espresso machines, but most don’t really know what that means.

Starbucks espresso machine