How is espresso made?

Picture of Espresso Beans

A pump espresso machine is an apparatus used to produce a small but strong amount of coffee known as espresso.

Picture of Espresso Pour

Why the Fascination?

I suppose my interest was sparked because of my mom, whom could be found drinking the hottest cup of java even on some of the hottest days of summer. Wanting to see what all the fuss was about, I tasted some when I was around six years old. My reaction was probably what you'd expect: BLEH!

It wasn't until I was in undergraduate school that I began to drink coffee regularly out of necessity to stay awake. However, once I became a part-time barista, I was taught how complex the coffee process is and where it comes from.

What do I use?

A popular and recommended brand of pump espresso machine is by Breville called the Barista Express, which is what I recommend to anyone who enjoys espresso but wants a machine that is low-maintenance.

Picture of Breville Machine

What is its function?

An espresso machine produces espresso. Espresso beans are usually a blend of different coffee beans.  Compared to regular coffee grounds, espresso grounds are extremely fine. The finer the espresso grounds, the slower the water is forced through the grounds, thus producing about 30 - 60 mL of condensed caffeine content. The espresso comes out looking very dark with a small amount of crema (foam) on top.

What does it look like?

A pump espresso machine is also known as an at-home espresso machine or semi-automatic. Pump espresso machines are compact and can easily fit on a kitchen counter. Pump machines are meant to produce a shot or two at a time and are not meant for mass production. Pump espresso machines are fairly easy to use compared to the lever espresso machine which requires more barista knowledge. One has to know how to operate the lever properly and read the pressure gauge in order to dispense a proper espresso pour.  Industrial-size espresso machines, like you would find in Starbucks, are very large and can easily produce several shots  all day. They are also semi-automatic.

How does it work?

Pump espresso machines have a water reservoir where, when the machine is turned on,  is heated just below boiling point. The ground espresso is put into the basket of the portafilter (handle) and packed down tightly and evenly with the use of the tamper. This packed-down coffee is known as the puck. The portafilter is inserted into the machine and twisted into a locked-position. The espresso cup is then placed underneath to catch the espresso for when it begins to pour. A button is on the machine's keypad which engages the micro-switch which starts the pump. The pump pressurizes the heating chamber and the hot water to about 15 atmospheres (220 psi) of pressure. This forces the hot water through the ground coffee and out of the spouts. This process occurs within about 25 seconds for an ideal espresso shot.

Below is a link to a video which better explains the process, as told by one of my favorite go-to sites for food technqiues, ChefSteps:


There are multiple espresso machines out there for the espresso consumer. The pump espresso machine is favored in households for its ease of use and minor maintenance. Knowing the correct settings for your specific brand of pump espresso machine will guarantee a near-perfect shot every time.