Espresso Machine Comparison: Pre-Infusion

"What is pre-infusion?" is a commonly answered question. How it can vary from machine to machine is a bit more complicated. Today we’ll dive into specifics and compare pre-infusion from a few of our most popular machines.

If your machine features pre-infusion, the overall capabilities and workflow might look and feel a bit different depending on your machine. If you’re still searching for your dream machine, we’re here to be your guide and help you find which machine and workflow sound perfect for your morning routine.

Ultimately, the goal with pre-infusion is the same from machine to machine. But if you’re unfamiliar- pre-infusion refers to the gentle saturation of ground coffee within the portafilter before ramping up the pressure inside the group head. This initial soak settles the coffee puck, which minimizes channeling and will give your shot the best chance at a perfectly even extraction for a rich, full-bodied flavor.

Today we’ll review a few different machine styles to understand how pre-infusion works within their specific class of machines. With a grasp on the technical components, pre-infusion will be something you can keep in your espresso toolkit to perfect your shots at home.

First, let’s take a look at our most popular and very traditional machine style — a directly plumbed espresso machine with an E61 group head.

With any E61, the halfway point between the lever full engaged and entirely off is where pre-infusion will occur. With the brew lever halfway opened, the top brew valve inside the group head opens, allowing water to begin filling the chamber just before the lever hits the micro switch on the front of the machine to engage the pump to start your shot. The machine needs to be plumbed in with this style of group head for a true pre-infusion since there’s not much back pressure coming from just the brew boiler alone. With a standard E61, pressure for pre-infusion is not variable or easily changed. The flow is consistent and infinite thanks to the line pressure behind your machine at its water source. We’ll talk about modified E61’s with flow control a bit later. Overall, if a tactile manual workflow sounds intriguing to you, a traditional E61 group head is undoubtedly a reliable route to achieve pre-infusion.

Next, we have these compact vibratory pump machines that only run off their own internal reservoir — machines such as the Lelit Victoria and Lelit Elizabeth, which are affordable and compact. We’ll also include the LUCCA A53 Mini in this comparison, with the optional pre-infusion chamber. In this case, they all operate in a very similar manner.

These machines use an electronically controlled three-way solenoid valve to start and stop water flow to their group head. They also feature an additional chamber or separate pipe reserved for a small amount of water for pre-infusion specifically. With this digital component, pre-infusion is preset with a specific time or volume allotted. This function is different compared to the other styles since you are limited to only a few seconds maximum, but that’s typically all you will need to saturate the grounds thoroughly. If you’re someone who craves precision but prefers to let the machine do all the hard work, a compact machine of this style is an excellent option.

Lastly, the machine style for those who want it all - machines with flow control or pressure profiling used to perform a manual pre-infusion. In recent years, additions have been added to E61 machines to control their group head’s flow rate, similar to high-end commercial machines.

Our favorite machines with variable flow profiles are the La Marzocco GS3 MP and the wildly popular Lelit Bianca, both phenomenal machines with endless amounts of control and versatility. With their manual paddles, you’re able to adjust the flow at the group head to simulate line pressure with a gentle ramp-up in brew pressure. Our go-to with this machine style is typically a 3-4 seconds pre-infusion at 4-5 bars of pressure, then flipping the paddle to the open up to 9 bars to finish our shot. But again, with flow control, the options are endless. If you enjoy a hands-on experience and find experimenting and tinkering with details exciting - you’ll love this workflow.

Whether you’re a novice or experienced barista, a little pre-infusion can easily benefit your daily espresso routine. A gentle saturation with any machine style will help keep your shots consistent and will bring out that delicious full-bodied, rich flavor we’re all trying to achieve. For some, a set it and forget it option works best. Others want options and versatility.

Now it’s up to you to decide what will suit your needs! But of course, our team here at Clive is always here to answer any of your questions and be your guide for all things espresso.