How Do Automatic Espresso Machines Work?
Do you treat your espresso machine like a magic black box? Add water, press button, await glorious caffeinated goodness?
What if I told you it’s to your advantage to know how your automatic espresso maker works? It’ll help you troubleshoot problems, shop wisely in the future, and might even improve your shot of espresso!
So keep reading as we pry open the black box and find out what’s really going on in there.
What defines an automatic espresso machine?
If you’ve ever shopped for an automatic espresso machine, you’ve probably found yourself confused by terminology like automatic, fully automatic, super-automatic, and semi-automatic.
There are slight differences between each of these types of espresso makers, but they all have one thing in common. They all use a motorized pump to generate pressure to pull an espresso.
That’s what distinguishes them from manual espresso makers where the barista needs to pressurize the machine by hand.
Follow the water
The easiest way to understand how your machine works is to follow the water path after you add it to the reservoir. Its first stop is the pump.
There are two main types of pumps. A vibratory pump relies on electric current to move a piston and force water through. A rotary pump uses a motor to spin a disk to generate the pressure. Each has pros and cons.
Vibratory pumps are smaller and less expensive. They’re more common in home espresso makers.. Rotary pumps are quieter, last longer, and produce more consistent pressure. They’re often found in commercial machines.
To the boiler!
Once the water is pressurized, it’s held in the boiler. In there, a heating element gets it to the correct temperature for espresso, around 200 ℉ (1). Most espresso makers have a feedback system using a temperature probe that keeps the water at the right temperature until you’re ready to pull an espresso.
The grouphead: where the magic happens.
The grouphead is where the hot pressurized water meets the tamped coffee grounds in the filter basket and produces the espresso’s sweet elixir. For a great espresso, you need an excellent grouphead:
Great espresso machines remove themselves from the equation by delivering water to coffee at a predictable pressure and temperature.
So, good pressure and high temperature are KING. But that’s not all.
In a semiautomatic machine, you’re responsible for the timing of this stage. You start and stop the extraction. This stage is automated in a fully automatic or super automatic machine—a flow meter gauges when to stop the shot.
A side trip to the steam wand
If you prefer lattes or cappuccinos, your espresso maker probably has a steam/frothing wand.
The hot water used for pulling an espresso shot isn’t hot enough to be steam, so the steamwand complicates things.
There are two leading solutions. In a single boiler machine, the boiler has two thermostats, one for steaming and one for brewing.
That means you can’t froth milk and pull espresso at the same time.
For impatient drinkers, more expensive dual boiler machines have separate boilers for brewing and milk frothing.
I hope that understanding the brewing process and how automatic machines work was entertaining and informative. Go forth with this knowledge. Use it to make smart buying decisions and brew better espresso. Or just impress your friends with your wisdom at the next brunch.
Espresso machines are expensive because makers, especially reputable brands, make sure that the machines have enough precision to deliver stable and reliable temperature and pressure to extract espresso from the ground coffee beans. Also, the span of cost for these machines is pretty broad. So, there’s a machine for everyone’s pocket.
The difference between a manual vs automatic espresso maker is that the former uses a motorized pump to generate pressure while the latter requires it to be done by hand. Clearly, an automatic machine is more convenient, which is why this is the most usual choice for home or office coffee machine.
With a semiautomatic espresso machine, the barista is in charge of shot timing. Compared to a semi automatic, a fully automatic machine uses a flow meter to automatically stop the shot. Super-automatic machines do most of the work for you, including grinding, tamping, dosing, and even milk frothing.
- Easthope, A. (2015, April 8). Brew Temperature and its Effects on Espresso. Retrieved from https://fivesenses.com.au/blogs/news/brew-temperature-and-its-effects-on-espresso/