The pump in an espresso machine is the key to flavor extraction. Here we explain what it means when a machine is rated at 15-bar pump pressure.
Our Espresso machines are calibrated for 15 bars pump pressure which corresponds to 9 bars operating pressure.
When it comes to buying an espresso coffee maker, it’s often hard to decide what you need. Some machines look great but don’t measure up in terms of performance. Others take up too much counter-top space. More still are messy to clean. Oh, the pressure, the pressure. And pressure is key – preferably 15-bar pump pressure and 9-bar operating pressure.
To understand this, we need to go back to basics. Older, piston machines first boil water and then store this water to make up to, say, four shots of espresso. Once the water has boiled, you pull a lever that sends the water through the coffee grounds and brews the espresso. This is the old-fashioned way that gave rise to the notion of ‘pulling a shot’. Newer models, like Tecnora’s Cremiere TCM 106A and even the Classico TCM 107M espresso coffee makers, are pump-driven machines. They come equipped with a precision, temperature-controlled thermoblock that allows you to heat water at two different temperatures: one to brew and another to steam.
When it comes to brewing, the standard recommended pressure is 15 bar. Anything less and you run the risk of getting a weak brew; anything more and you could end up with a very bitter-tasting espresso.
But we’re talking pump pressure here, which is not to be confused with operating pressure. Pump pressure speaks to capacity; operating pressure speaks to consistency. You need 15-bar pump pressure in order to deliver a constant 9-bar pressure throughout the operation. So think of the pump pressure as getting everything started, getting the water hot enough to brew the coffee. Then the operating pressure is what finishes it off, what maintains those 20-30 seconds it takes to brew a perfect shot of espresso and give you the lovely crème on top.