Espresso machines use different types of methods to generate the pressure required for brewing espresso.
The ideal pressure for brewing coffee and espresso depends on various factors, including the type of coffee machine and the desired flavor profile. Generally, a range of 7 to 11 bars is considered optimal for extracting the best flavors from the coffee grounds.
The type of water pump is a crucial component that creates the high pressure needed to force hot water through the coffee grounds in the portafilter during extraction. They can be electric or non electric.
Here are some of the common types of pumps found in espresso machines:
1.Vibratory Pump:
This is an electric pump.
They are the most common type used in small home and commercial espresso machines. They operate by using an electromagnetic coil to move a piston back and forth (up to 60 pushes per second), creating pulses of pressure to pump water through the system. Vibratory pumps are compact, reliable, and relatively quiet, making them popular for domestic espresso machines. They take a little bit longer that rotary pumps to ramp up the pressure.
To the left is an ULKA EX5 Coffee Machine VIBRATING PUMP - 48W 230V 50Hz . It's commonly used in the Gaggia Classic, Krups & Saeco coffee machines.
Vibrating pumps normally operate at one pressure. Also because its vibrating its not going to be a perfect 8 or 9 bars. To control that pressure at the group head what is normally used is a bypass valve. The valve sits past the pump. The pump creates the initial pressure and the valve removes some of that water and passes it back into the reservoir, effectively bringing down that pressure to whatever level you wish to use.
Other machines that use this kind of pump are the Rancilio Silvia, the Breville Barista Express, the Lucca A53, Profitec Pro 300 and Rocket Apartamento.
2. Rotary Vane Pump:
This is a mechanical pump powered by an electric motor.
Rotary vane pumps are commonly found in most commercial espresso & high-end home machines. They operate by using rotating vanes to draw in water and create a continuous flow of pressurized water. The device is a complex mechanism. A motor spins a disc that is offset inside a large, round chamber. The spinning disc is segmented into sections by vanes. As the disc spins, the vanes press against the wall of the outer chamber, diminishing the size of the section, creating pressure. Water enters in during the large phase and is pushed out as the section shrinks.
Rotary vane pumps offer smooth and consistent pressure delivery, making them ideal for high-volume environments where precision and reliability are paramount. Rotary pumps are quieter than vibratory pumps.
They offer more consistent pressure, and generally have longer lifespans.
These kind of pumps can use a reservoir tank or you can plumb them in.
Machines that use this pump include the Lucca M58, the La Spaziale S1,S2,S3 ,Victoria Arduino Prima One, La Marzocco Linea Mini and the Rocket Espresso Milano. These tend to be the top end of home machines.
The reason these aren't on smaller machines is because they are larger and heavier than vibratory pumps.
Two common types of pump are the "Procon" and the "Fluid-o-Tech"
3. Gear Pump:
This is an electric pump.
These are very specialised pumps found in high end commercial & home machines designed for specialty coffee applications. They are used for pressure profiling to emulate any profile curve you want. It uses a pressure transducer to understand the pressure and can then electronically raise or lower the pressure.
You can find these types of pumps on La Marzocco Strada EP and the Rocket R91
Gear pumps use gears to pressurize and move water through the system. They are known for their precise pressure control. Gear pumps offer quiet operation and excellent durability but are less common in consumer-grade espresso machines due to their higher cost.
4. Piston / lever Pump:
This is a non electric pump.
Piston pumps, also known as lever pumps, are less common in modern espresso machines but are sometimes found in traditional lever-operated machines. They use a piston mechanism to generate pressure by manually pulling a lever or handle. While piston pumps offer a unique and hands-on brewing experience, they require more effort and skill to operate compared to other pump types.
The choice of pump type can affect factors such as pressure consistency, noise level, maintenance requirements, and overall espresso quality. Vibratory pumps are the most common choice for home espresso machines due to their affordability, reliability, and compact size. In contrast, rotary vane and gear pumps are favored in commercial settings for their precision and durability. Ultimately, the pump type is an important consideration when selecting an espresso machine, especially for users who prioritize consistency and performance.
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Pressure profiling
Classic espresso extraction has for a long time centered on pumping hot water (85 - 92°C) through ground coffee at 9 bar of pressure to produce around 30 ml of espresso in about 25 seconds. This idea of using a fixed pressure is behind the design of most electrically driven pump machines.
However, fully manual Lever machines give the coffee maker other options.
9 bar is not necessarily the optimum pressure for all coffee blends, and a 25 second extraction time does not always produce the best results.
The aim of profiling is to not accept conventional parameters.
Instead search for alternative pressure, temperature and timing combinations to produce the best results for a particular coffee
Machines that you can use for pressure profiling
(uses a vibratory pump)
+ La Marzocco GS3 MP Manual Paddle Espresso Machine.
+ La Marzocco Strada
+ Decent Espresso machines
+ Sanremo YOU Espresso Machine. ...
+ Synesso MVP Hydra 1 Group Espresso Machine.
+ Synesso MVP Hydra Commercial Espresso Machine.
+ Sanremo Opera 2.0 Volumetric Multi-Boiler Espresso Machine.
+ Fiamma Vela Profile Pressure 1
+ Crem ONE Dual Boiler Pressure Profile Espresso Machine
+ Dalla Corte Mina Espresso Machine
A manual lever offers control over flow rate.
+ Profitec Pro 700 Espresso Machine
with Flow Control
+ ECM Synchronika
+ ECM Classika PID
These are some manual lever machines.
+ La Pavoni Europiccola with added
Pressure Profiling Kit
+ FlairEspresso 58
+ Flair Pro 2
+ Cafelat Robot Barista Espresso Maker
+ Naked Portafilter - Smart espresso profiler
This heat exchanger coffee machine comes with mechanical pre-infusion
capabilities (giving your coffee a proper
bloom before extraction) & pre-set temperatures.
The MaraX can also be upgraded with a
flow control kit.
dual boiler machine with manual espresso
flow control device.
control over both the brew
temperature and steam pressure.
"Low flow" at start and end of shot -
user programmable time.
Programmable pre-infusion parameters
through LCC.... I love this machine .... well worth the 3K price
traditional, lever-operated heat-exchange machine
with manual pressure profiling which lets you experiment \with your shots and get unique results.
Bezzera ARIA
Has adjustable brewing temperature and shot timer chronometer to keep coffee flow under control.
It has a brewing profile paddle control on the group to adjust brewing pressure
It uses induction to heat the coffee.
Pressure profiling, Temp profiling and flow rate profiling are all possible.
Something for the future?
