Portafilter - What is important? A guide

luna espressomaschnes unbound

Anyone who wants to perfectly prepare espresso, cappuccino and other coffee creations at home will sooner or later play with the idea of buying a portafilter machine.

The range is huge, terms like brew group, dual-circuit and PID are hotly debated in forums and the overview of which espresso machine meets one's own requirements is quickly lost.

With the Unbound portafilter machine guide, you'll get your perspective back and shine in the next discussion with the knowledge of a professional barista. In our store you will find our LUNA One and Next, as well as the Futura Kikka.

Table of contents

The brew group E61 - Old proven, why actually?

In 1961, the machine manufacturer Faema developed a novel brewing process with the E61, thereby revolutionizing the espresso world.

True connoisseurs know that the term E61 stands for quality and durability. This can be said of the E61 brew group with a clear conscience, because after all, it has been the undisputed No.1 in terms of brew groups for portafilter machines and the first choice of all major brands for almost 60 years.

It is also worth mentioning that the availability of spare parts is ideal and just about any portafilter technician can handle the E61 brew group.

This brewing group is also installed in our LUNA portafilter machines. A durable and timeless achievement of coffee machine technology.

e61 brew group luna by unbound

Pump - Vibration pump vs. rotary pump

The pump in an espresso machine creates the pressure needed to move the water from the boiler through the E61 brew group and into the cup.

Vibration pump (bottom right in the picture):

An espresso machine with such a pump builds up the necessary pressure by means of vibration.

Coffee machines with vibratory pumps emit a slightly louder hum when preparing a coffee.

Advantage: Relatively cheap.

Disadvantage: Pressure is built up slowly and is not kept constant.

rotary pump (bottom left in the picture):

The pressure here is generated by, correctly, rotation.

Advantage: several brewing groups can be supplied with pressure simultaneously and the pressure is kept constant. This has a positive effect on the quality of your coffee. In addition, rotary pumps are much quieter than vibratory pumps.

Disadvantage: More expensive to purchase.

When deciding which pump is the right one for your portafilter, your coffee needs should be taken into account. For connoisseurs of a few espressos a day, a cheaper vibration pump is perfectly adequate and ultimately still guarantees a perfect coffee.

However, if there are caffeine fanatics among our readers, we would like to recommend them to buy a portafilter espresso machine with rotary pump. Our LUNA next is then right for you. 

Vibration pump vs. rotary pump unbound

PID control, electronic temperature control - Why should the temperature be electronically adjustable?

PID stands for proportional - integral - derivative

No idea what that means? We'll explain it to you in a nutshell.


In a portafilter espresso machine with PID control, three states of the boiler temperature are evaluated, simply explained.

The temperature right now at this moment (P), the temperature from past readings (I) and the expected temperature (D). A PID control therefore lives in the past, the present and the future and enables, through its detailed research of the heat level, a constant brewing temperature in your portafilter.

With the PID control, you can set your desired boiler temperature at the touch of a button. 116-120 degrees is the standard. An exact and stable boiler temperature is essential for a perfect espresso.


We think the PID control is great, that's why it's included in both of our LUNA models! However, if you can do without it, the Futura Kikka is definitely the right choice for you.

PID control luna espressomashines

Copper kettle - Why not a stainless steel kettle?

An eternal discussion in which no clear winner can be determined.

In short, both materials can be used very well. We opted for copper kettles for the LUNA portafilter machines primarily because of their greater heat storage capacity. In this way, we are relying on material that has been tried and tested for decades and guaranteed barista pleasure for many years to come.

Copper kettle luna espressomashines

Boiler size: The size makes the difference!

Small kettles require less heating time, but are also less temperature stable. Whether small or large, it is important here again to question your own coffee consumption.

A milk frothing freak who additionally suffers from green tea addiction should definitely handle larger kettles. More power when frothing the milk and the possibility to prepare a cup of hot tea water at any time definitely play a role in such consumption.

However, those whose coffee pleasure of the day is kept within limits, can also feel great joy with a barista machine with a small kettle.

They always say - size isn't everything!

For our LUNA One, we opted for a 1.6 l boiler, whereas the LUNA Next has been given a 3 l boiler.

large boiler - small boiler unbound

Boiler insulated - What is the benefit of boiler insulation?

All our LUNA portafilter machines have been equipped with boiler insulation.

Low energy consumption and a more constant brewing temperature are the advantages of a portafilter with boiler insulation worth mentioning.

In the event that your cups are to be stored on the machine and kept pleasantly warm there, this is not a problem. The insulation of the boiler is open at the top. Thus, the heat of the radiates upwards and keeps the surface of your portafilter nice and warm.


Expensive espresso machines from the catering industry have, in addition to boiler insulation, an external cup heater. This is not necessary in our case due to the insulation that is open at the top. All our LUNA portafilter machines are equipped with boiler insulation.

insulated boiler luna espressomashines unbound

Barista steam lever - What is it? What is the advantage of barista steam lever?

Basically, there are two variants of how you can operate your steam nozzle. Rotary lever and toggle lever control.
A rotary lever, as the name suggests, must be turned up, a toggle lever (barista steam lever), tilted.
It would go beyond the scope of this article to emphasize how much more comfortable a rocker arm control can be. One thing should be said, however - rocker arms simply look much cooler! For our LUNA portafilter machines, we therefore also use oak wood instead of plastic.

Wooden handles oak special - advantages and disadvantages of wooden handles for barista.

While we're on the subject of coolness, our oak handles add the finishing touch to your portafilter coffee maker.
But beware, there is a small drawback. If you want to be cool, you have to suffer, right?
Wooden handles are somewhat more sensitive than handles made of plastic - especially when cleaning with intensive agents, care must be taken not to damage the wood in the process.
However, with a little care, this won't be a problem and the cool look of your espresso machine will last for a long time.

Wood handles luna espressomashines unbound

Luna Design, stainless steel matt - Why is the Luna not shiny? What is the advantage?

The functional parameters of a barista espresso machine are of great importance. Likewise, the design and materials of the device contribute to the ease of use.
On the one hand a piece of jewelry, on the other hand simple to operate - probably the two most important points of a barista espresso machine.
In order to combine these two features in the best possible way, we have chosen a housing made of matte finish for the design of the LUNA portafilter machines. On top of that, our LUNA Next has a frame made of extra-strong stainless steel.
As a result, the espresso machine gains some weight, making the entire device more massive and robust.
Non-glossy stainless steel makes cleaning easier, because as baristas we know: where work is done, chips fall. The matte exterior of our LUNA espresso machines therefore does not need to be treated daily with stainless steel polish.

luna espressomashines by unbound

Single-circuit, dual-circuit, multiboiler - what? 

In single-circuit portafilter machines, a single boiler supplies the steam lance and brew group. 
The optimum temperature for the brewing group is approx. 90°C, but for the steam lance it is over 100°C. Since only one temperature can be set in the boiler, it is necessary to switch between preparing coffee and using the steam lance. Thus, there is an annoying heating time between espresso preparation and milk foaming. 
Dual-circuit portafilter machines allow the simultaneous use of brewing water and steam without annoying waiting times. The steam comes from the boiler, whose general temperature is over 100 °C, perfect for the use of the steam lance. The brewing water is pumped directly from the fresh water tank through the boiler to the brewing group. As it passes through the boiler, the water reaches a temperature of over 100 °C and is brought to the perfect temperature of about 90 °C on its way to the brew group. The two most weighty advantages are the high temperature stability and the low maintenance costs. For the HOME barista as well as for offices, we therefore recommend dual-circuit portafilter machines with a large boiler. The LUNA Next also has enough reserve for smaller gastro locations. 

Multiboiler espresso machines contain two separate boilers for brewing water and steam. Both boilers have their own perfect temperature, which is perfectly matched for the respective purpose (brewing water or steam). However, household machines with multiboiler function need to be careful, because in machines of this size, the boilers tend to be small.  

Thus, they are sometimes less temperature stable than dual-circuit portafilter machines with a large boiler. 
In any case, the multiboiler function is useful for large, multi-group machines in the catering industry. The boilers of machines of this size have a significantly larger filling capacity, which means that temperature stability is not an issue. 

luna espressomashines by unbound

Our portafilter machines:

28,90 €
229,90 €209,90 €