November 13, 2006

What does "15-Bar Pump Driven Espresso Machine" mean?

I have been getting a lot of people writing in asking about what does 10-bar or 15-bar pump driven mean when we talk about espresso machines. First to start out, a "bar" is a scientific term for pressure. It's about equal to an atmosphere of pressure, or about the ambient pressure at sea level (all approximate; we're not in science class here). So, a 15-bar pump will deliver about 15 times the pressure at sea level; it's fairly high pressure. So, when you see 15-bar pump-driven espresso machine, in the description, you should take away that this machine pumps the hot water through the ground espresso at high pressure.

Why is it important to have a Pump Driven Espresso Machine?
There are a couple of kinds of espresso makers out there: Steam driven and Pump driven (there's also manual where you are the pump). Steam driven machines are less expensive, and when the water boils, it develops only 2-3 bars of pressure to push the hot water through the espresso. In order to get the foamy crema on top of an espresso, which is emulsified oil and air, you need the higher pressure of a pump driven espresso machine. So, if you want better tasting, crema topped espresso, go for the pump-driven espresso machines.

We have reviewed a lot of inexpensive pump driven espresso machines as well as some more expensive ones - check out our reviews in our Espresso Machine archive.