How Espresso Machines Work

By Melanie Rose

It wasn’t that long ago that I bought my first espresso maker — a small semi-automatic that was a good machine in it’s price range, but not the best espresso machine to be had. I made the decision to craft my own espresso at home due to the fact that I was spending anywhere from $8 to $20 a day at local cafés. I would haul in my trusty laptop and camp for the better part of a day while savoring ambient conversation, sipping rich espresso and taste-testing scrumptious pastries. Between my pocketbook and my waistline it’s hard to say which was suffering the most.

I do have great fondness for a good coffee house. The place I will always love the most usually has the front and back doors open and brave pigeons waddle in to pick crumbs from the floor. The fragrance of brewing coffee and baking delectables permeate the air, mixing with the sounds of people coming and going. Ahhhhh, so sweet. Once or twice a week I still visit the local coffee house and relax or do some work so that I can sunbathe in the warmth and glow of a great café.

But whether you partake at home or at the local café, espresso has a way of pulling you into its rich world. It wasn’t long after buying that first little machine that I was grinding my own beans and experimenting with different blends of coffee. I began conducting all types of research on how to illicit the flawless shot from a machine with understandable limitations.

Along the way I’ve learned a lot, but creating a great shot of espresso is like living the Tao. Elusive, slippery, and an ongoing process. It’s an art form that you can play with for a lifetime, and I guess that appeals to me.

In my search for espresso perfection I’ve run across so much terminology that I found confusing, so I wanted to share what I’ve learned about how espresso machines work, what all that lingo means, and why it’s important if you are a true seeker as I am.

I’ve included some diagrams so that you can have a visual, too. These are very basic because there is so much variation between machines and manufacturers, but they give you a general idea of the workings of an espresso machine.

First Things First

Before I get into describing the inner workings of the machine, I want to run through the process of extracting (aka pulling) a shot. The term “pulling” comes from the old time baristas using their lever machines.

Essentially, the shot is produced by propelling between 1 and 2 ounces of hot, pressurized water through a firm bed of finely ground espresso coffee.

In order to extract the shot from your espresso machine, the first thing you need to do is to check the reservoir tank and make sure that it’s full. Some of the pricier espresso machines can be plumbed into the home, in which case this step won’t be necessary.

Next, you place the ground espresso into the portafilter and tamp it down in order to produce a tightly packed bed of coffee. The portafilter is attached to the machine by twisting it into a unit that contains the gouphead, a component which attempts to evenly distribute the water onto the coffee. The portafilter sits just below the grouphead.

Now you will turn on the machine and [Read more…]