The term "E61 group" is frequently misused. Some attribute the term to the saucer shaped grouphead, some attribute it to the thermosyphon design, others attribute it to the automated preinfusion. While the first two attributions are common embodiments of the implementation, only the latter attribute is part of the patent claim; see E61 Group Espresso Machine: Is its reputation justified? and Is there a purpose for the E61 middle brew lever position? for more details.
The short answer to "what makes an E61?" is "the alternately seating valves." The familiar grouphead shape and its thermodynamics are just the particulars of an example embodiment of the patent.
Where does that leave solenoid controlled E61 style groups? Since they use a solenoid to close the 3-way when you engage the pump, there are no alternately seating valves. Just a single solenoid that snaps shut. Or is that the defining difference between an E61 and an E61 style group. The E61 has to be manual, no semi or full auto could be classified as a true E61 because there is a single seating solenoid controlled valve.
Pressure profile of Expobar Brewtus, Elektra A3, La Valentina
And the pump makes a difference too:
Two E61 espresso machines, two different types of pumps (vibe, rotary)
I refer to the preinfusion of the solenoid type E61s as "progressive preinfusion". Brew pressure is attenuated by the gicleur and slower pressure ramp of vibratory pumps, but not as much as for a true E61. I've not done a careful side-by-side blind taste test of E61 and E61 solenoid type espresso machines, so I won't argue there's a consequential in-cup difference. My gut feel is that if it exists, it's negligible compared to other significant factors (correct distribution, dosage, temperature, etc.)
espressme wrote:? What makes an E-61? The group is not bolted to the Boiler but tube fed. I believe the maxi is the same. My old 55 mm Salvatore is an HX with a 3way solenoid on the water inlet. What differentiates that type of machine from the E-61?
richard
I believe yours is a "E61 Clone" Richard. Imitation being the sincerest / cheaper form of .....
HB wrote:I refer to the preinfusion of the solenoid type E61s as "progressive preinfusion". Brew pressure is attenuated by the gicleur and slower pressure ramp of vibratory pumps, but not as much as for a true E61. I've not done a careful side-by-side blind taste test of E61 and E61 solenoid type espresso machines, so I won't argue there's a consequential in-cup difference. My gut feel is that if it exists, it's negligible compared to other significant factors (correct distribution, dosage, temperature, etc.)
And I would agree. I think the grouphead/dispersion/shower screen design plays a larger role than most people think. Having both a lever operated E61, and a solenoid operated E61 style machine I prefer the shots of the later. However there are too many differences between the two machines to be able to point to that design difference alone as the cause of the cup difference.
I wonder how many manufacturers distinguish between a true E61 (if there are still any true Faema E61 designs on the market) and a E61 style design in their advertising.
cannonfodder wrote:
I wonder how many manufacturers distinguish between a true E61 (if there are still any true Faema E61 designs on the market) and a E61 style design in their advertising.
Gaggia Espagnol stole the E61 toolings in 1966 and brought out the clone group still found on most of the E61 boxes. Faema gave up on Spanish law courts, and licensed the design to them a few years later. The Wega/Brasilia and Grimac clones are not based on stolen toolings, but the Wega ones are so close that the parts are interchangeable. The various solenoid versions use a similar thermosyphon and group bell, but a gicleur and an empty space, rather than a piston, to get the preinfusion. The timing on these can vary dramatically. For instance, on the Elektra group, it's very short; while the Grimac and Wega built solenoids are nearly as long as the manual groups'.
The "original" E61 went through several iterations as well; the earliest one being a simple bent pipe shape on the outside. The early models had a knob, rather than a bolt, at the very top, but I'm not sure what, if anything, this accomplished.
Since we are on the subject of group evolution, where do the Faema E64 and E66 fit in? Would a solenoid controlled 'E61 like' group be more inline with either of those designs. From the group diagrams I have seen, I don't think they do but I am curious. I think the Faema No-Stop group may be a closer electronically controlled group.
I'll make it simple without a history lesson or any science.
An E61 group is:
A Lever E61
A Solenoid E61
Both based on a a patent that shows thermo syphon and the same water path. How the water is released into the brew path is the only difference. Utilization of the term E61 is the best way to describe this particular group.
HB wrote:The short answer to "what makes an E61?" is "the alternately seating valves." The familiar grouphead shape and its thermodynamics are just the particulars of an example embodiment of the patent.
Faema played with lots of ideas early on -- here's a detail from a '64 Eclipse export on sale on German Ebay at the moment: The left half shows the group with the hood on, right with the hood off. It's half way betwen the manual and the solenoid group. Notice the linkage at the bottom right that activates the pump. Presumably, one could turn the valve part way part way to preinfuse, then activate the pump by turning it completely.
The levetta may be iconic now, but not even Faema thought it a big deal in the early 60s.
mogogear wrote:I believe yours is a "E61 Clone" Richard. Imitation being the sincerest / cheaper form of .....
(BUMP)
Hi Greg,
That I could believe! And, It may not be an E-61 type at all! Only HX!
The reason for the posting is that there are significant differences in HX machines. I would like to understand the differences as the term E-61 is thrown around loosely! The main ones being:
Group fastened to boiler.
Group not fastened to boiler.
Steam saturated group.
Water saturated group.
3way valve in feed line.
Manual valves ( Inflow , pressure release. )
Solenoid valves ( Inflow , pressure release )
+ more I don't even know about.
So it seems an E-61 is an HX but not the opposite?
Thanks for the input so far!
sincerely
richard
