An Expert Guide to Semi-Automatic Espresso MachinesPublished on 01/06/2023 · 9 min readCoffee & Espresso Expert Jeff Sutton walks through the main types of semi-automatic espresso machines and key features to consider when picking your new machine!
Photo by Tyler Nix
If the thought of replicating a perfect espresso shot from your favorite cafe in the comfort of your kitchen strikes a chord with you, then a semi-automatic espresso machine is the best way to transform that idea into a reality.
What Is a Semi-Automatic Espresso Machine?
Espresso machines these days can broadly be broken down into two categories: semi-automatic and super-automatic. I consider any machine that requires the barista to take an active role in any part of the espresso brewing process, from grinding to distributing and tamping the puck, all the way through the actual extraction, to be semi-automatic.
The line can blur to some degree due to machines with integrated grinders and automatic tamp stations like the Breville Barista Express Impress. However, the barista is still required to have some control over the portafilter and making the drink, so it is still a semi-automatic machine. Some machines will create a shot of espresso from bean to cup but still require the user to steam the milk. Since the espresso process is fully automated, these machines fall into the super-automatic category.
Starter Semi-Automatic Machines
Many people only have a coffee maker at home and are dipping their toes into making their favorite beverages in the kitchen. It is a "dangerous" hobby; once you get into it, you dive in head first to try and find that perfect flavor. However, there are many solid options for someone trying to stop using their coffee machine and start making espresso drinks like their favorite coffee shop but not break the bank.
Most beginner espresso machines under the $500 price point use pressurized baskets. These make the grind size much less important and allow people to pull shots using less expensive coffee grinders or even pre-ground coffee beans. Beginner espresso machines almost always run off of a single boiler (I’ll delve into the differences between boilers shortly) or a thermocoil that requires some wait between extracting espresso and steaming milk. It isn’t the end of the world and only becomes an issue when trying to serve multiple drinks simultaneously.
The differences in semi-automatic espresso machines sometimes relate to how the steam wand operates. Some steam wands on starter units like the Bambino by Breville have one hole in the tip and need to be completely controlled by the barista. Other machines, such as the Bambino Plus, have an automatic steam wand that makes it much easier to get cafe-quality milk froth and allows anyone to begin practicing their barista skills until complex latte art becomes a regular occurrence. An automatic steam wand is seen occasionally on some commercial-level machines. Still, most prosumer and commercial-level machines are fully manual steam wands, allowing baristas to showcase their skills in steaming milk.
The biggest difference in price between espresso machines is the number and type of boiler used by the machine. As aforementioned, a single boiler idea is mostly associated with starter espresso machines and requires a wait time for the boiler's temperature to adjust between steaming milk and extracting espresso. This is fine if steaming milk is a rarity in your world, but it's not an ideal setup if you are making multiple steamed drinks in a row.
The next step up in boiler design is the heat exchange boiler. Often referred to as an HX boiler, it is a two-chambered boiler that simultaneously allows water to be held at different temperatures for steam and extraction. These machines provide the convenience of being able to steam and extract at the same time with a reduced size compared to a double boiler machine. A double, or dual boiler machine, has independent water boilers for extraction and steam functions. However, it is usually seen on the best espresso machines, often included in the commercial and prosumer categories.
Pumps in espresso machines can be broken down into vibratory or rotary pumps. Before the prosumer market, a vibratory or vibration pump is seen on most espresso machines. The vibratory pump is louder than a rotary pump and is designed to run off an attached water reservoir. On the other hand, a rotary pump is more expensive but can be directly plumbed into a water line or run off an attached reservoir, depending on the machine's design.
Machine temperature control is controlled by either a thermostat or a PID (proportional integrative derivative). A thermostat is the most economical option in espresso machines, but it is not the most accurate. A thermostat-controlled machine will click off its heating element when the ideal temperature is reached and kick it back on when it cools down to a set temperature. This can cause fluctuations of up to 10 degrees. Contrarily, a PID is an algorithm run by a computer that keeps the machine’s boilers within one degree of the set temperature at all times. In a dual boiler machine with multiple PIDs, the barista can lower the water temperature for the extraction without affecting the temperature of the steam.
Another aspect of semi-automatic machines that separates the more entry-level options from higher-level machines is pre-infusion. Pre-infusion is wetting the espresso puck at a given rate before the full nine bars of pressure are applied to the extraction. The advantage of pre-infusion in an espresso machine is that the initial soaking of the puck allows for certain flavors to shine, especially when looking to bring out bright notes in lighter coffee roasts. Some machines have a few preset options for the pre-infusion pressure. In contrast, other machines will allow any variation in pressure giving the ultimate control for the barista to dial in the perfect taste.
Pressure Profiling (Flow Control)
Pressure profiling, also known as flow control, takes the idea of controlling pre-infusion one step further. It allows the barista to control the pressure of the water over the entire extraction instead of being run at the standard nine bars of pressure from start to finish. Additionally, it can also include the post-infusion time that lasts for a few seconds when a shot ends. During the finishing moments of extraction, a shot can begin to show more undesirable characteristics that lower-end pressure can control.
A volumetric machine doesn’t depend on the barista to stop and start the shot. Instead, it has a pre-programmed water dose that is released at the push of a button, depending on whether a single or double shot is selected. As a result, these machines are generally easier to use for an uninitiated barista but do take away from being able to dial shots exactly every time.
Manual Espresso Machines
Another type of machine for the person willing to spend the time and wants the quality of a more expensive semi-automatic idea is a fully manual espresso machine. Lever-style machines rely on the barista’s touch to get consistency in the shots and require plenty of practice to master.
How to Choose the Right Semi-Automatic Machine for You
With all the available options on the market, choosing the perfect semi-automatic espresso machine can be quite challenging. Now that I’ve gone over the available semi-automatic options, it's time to determine what would be best for your kitchen. Below I’ve given personas to three types of customers I commonly deal with at Curated that sum up what many people are looking for in their machines.
Nina: Nina is looking to save time and money by stopping daily trips to her favorite cafe for a morning latte. She wants something that won’t be too overwhelming but will still make great drinks. She is willing to put forth some effort in learning, but not an excessive amount. Nina lives alone and rarely has people over for coffee, so it will mostly be one drink at a time. She has a grinder, but it isn’t designed for espresso.
Features Nina should look for:
- A single boiler machine that will suffice her drink needs
- A machine with pressurized baskets, so she doesn’t need a new grinder immediately
- A machine with a simple push-button design
Bradley: Bradley has had a starter machine for the last five years and is looking to dial in more shots. He now makes drinks daily for his wife and daughter, and it is a bit much on the old machine. Bradley is looking to speed up his mornings by pulling shots while steaming the milk for the lattes. He understands that the next level will be more expensive but doesn’t want to go nuts on the machine as he still has his daughter's schooling to consider.
Features Bradley should look for:
- A machine with a heat exchange or dual boiler to steam and extract simultaneously
- A PID controller for better consistency in his shots
- A commercial quality steam wand to ensure quickly-made drinks
Marina: Marina is an espresso aficionado. She has worked in cafes and is now at a point where she can design her dream kitchen. She wants an espresso machine to be a statement piece in her new home, and money is no issue. Marina is unsure if she wants to plumb the machine into a water line but would like to be able to in the future if she decides to.
Features Marina should look for:
- A rotary pump that can run off a tank or water line
- A pre-infusion and PID control for consistent shots
- The highest level of user control via Bluetooth or touchscreen
There will always be amazing coffee shops where you can consistently get high-quality drinks and perfectly pulled shots, which is enough for most people. However, for the person who may want to tweak their preferences over time and dial in espresso drinks to how they feel at any given moment, the real question becomes, “What is the best semi-automatic espresso machine for you?” Let one of the Coffee and Espresso Experts at Curated make the process easy by helping you along the way to find your perfect machine.