E61 brew head
E61 is the name of an espresso machine launched in 1961 by the Italian company Faema. This machine ushered in a new era of espresso machines. The E61 was not only the first machine with a heat exchanger, which meant that fresh water was used to make espresso instead of boiler water. It was also the first to integrate a pump to create pressure instead of using a hand-operated lever. E61 is legendary for its brewing group that weighs between 4 and 5 kg. E61 is made of solid brass. The Thermosyphon system constantly circulates hot water through the brewing group and keeps it constantly heated and provides a stable temperature. The importance of the E61 brewing group is the mechanism in the brewing head that makes it possible to saturate the puck before brewing. Through this pre-infusion process, the brewing water is led slowly and with reduced pressure into the portafilter. All this is regulated by a pre-infusion cylinder in the brew head which causes the pressure to rise slowly. The result is a perfect espresso.
A double-boiler machine has a kettle that is used to brew coffee and one to extract steam and hot water. Both boilers are independent of each other and with the help of a PID on each boiler, the temperatures on the boilers can be regulated separately. The brew boiler is usually smaller than the boiler for hot water and steam. The reason why the steam and hot water boiler is larger is because the contents are consumed much faster than brewing boilers as the temperature in the steam boiler is much higher. An espresso machine with double boilers is more temperature stable compared to an espresso machine with a heat exchanger because you can control the two pans separately.
Advantage:Can both skim milk and brew at the same time. You have full control over the bridge temperature and the steam temperature separately with PID. Can produce a larger amount of coffee compared to a heat exchanger.
Disadvantage:More expensive than a heat exchanger
An espresso machine with a heat exchanger means that it has two water circulation systems. Because the boiler is not completely filled with water, steam can be created on the top of the boiler. When brewing, the machine circulates the fresh water through the large boiler where it is heated to the optimal brewing temperature and then led to the brewing group and down to the coffee puck. Thus, fresh water is always used to brew espresso. As an E61 group constantly circulates the brewing water through the brewing head, you get a very temperature-stable brewing water. During milk frothing, the steam that has previously been in the upper part of the boiler is released and rebuilds the steam pressure
Advantage:Cheaper than espresso machines with a double boiler and can both skim milk and brew at the same time.
Disadvantage:Less control over the brewing temperature (Except heat exchangers with PID) and need to exercise a so-called "Cooling flush" before each brewing.
A hand-lived espresso machine is what makes you a real professional.
The biggest difference between other standard espresso machines is the brewing group itself with hand-lever lever which is also called "Boston lever group".
A dipper system is a unique way of brewing espresso. By pulling down the hand lever, the pre-infusion starts where it introduces the brewing water at low brewing pressure to saturate the puck slowly and evenly. Hot water from the boiler flows into the massive brew group and cools down to the right temperature. If you release the lever and allow it to return to its original position, the water flow is closed and a spring with a piston slowly goes up to 9-10 bar brewing pressure then slowly lowers the brewing pressure at the end of the whole cycle. This gives boston handshake espresso machines a unique espresso taste that is often experienced as a softer and sweeter as it lowers the brewing pressure at the end of brewing.
Advantage:Creates espresso that no other type of espresso machine can provide. Provides a unique brewing experience.
Disadvantage:Because it has a long lever, the espresso machine takes up quite a lot of space. It costs more compared to a heat exchanger and some double boilers.
Recommended espresso machine: Profitec Pro 800
Espresso machines with vibration pump
The vibration pump was launched in the early 70's by Ulka Co.
Because it was cheaper than other pumps, it made espresso machines for home use much more affordable. The vibration pump has an output of 15 bar, which can be reduced to between 9 and 10 bar with the help of an expansion valve.
The pressure is built up with the help of the resistance of the coffee puck. Therefore, it is very important to find the perfect grind and to use the right amount of coffee in the portafilter. If any of these parameters are not correct, the correct pressure will not be reached.
Since the vibration pump oscillates a lot during activation, it emits quite a lot of noise and hence the manufacturers have installed the entire machine housing in isolation. The advantage of vibration pump is that it is easy and cheap to repair. The disadvantage is that espresso machines with vibration pumps can not be connected directly to a water source.
Espresso machines with rotary pump
Rotary pump is larger and heavier than vibration pump, and has more power. It can give several brewing groups an even pressure and is most often used in commercial espresso machines. It has a longer life but is more expensive and more difficult to repair.
A unique aspect of a rotary pump is that it is almost silent, which many people appreciate. Espresso machines with rotary pump can also connect directly to the water source.