E61 Group Espresso Machine: Is its reputation justified? - Page 2

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E61 Group Espresso Machine: Is its reputation justified?

Yes
117
69%
No
13
8%
No opinion
40
24%
 
Total votes: 170

User avatar
Teme

#11: Post by Teme » Jul 25, 2005, 2:38 pm

In my humble opinion as a consumer - yes, the E61 has earned its rep.

It may not be the be all end all design but it certainly has helped a lot of consumers enjoy their coffee more than they may have done in the past. This may be partly due to the E61's looks (as in getting people to buy a more expensive and potentially superior machine than they initially intended to) and partly due to its technical merits.

Like I said, just my humble opinion and even as an owner of an E61 machine I actually wanted to say no but could not come up with reasoning to overrule the yes vote...

Br,
Teme

lennoncs

#12: Post by lennoncs » Jul 25, 2005, 4:38 pm

malachi wrote:1) Preinfusion is a good thing
2) But I prefer the preinfusion style of a 1 group Synesso or a LM GS (for example) and also the preinfusion style of a Mistral
3) I consider a saturated group to be better for thermal stability than a thermosyphon (personally)

Basically, what I'm saying is that things have progressed since 1961. Not that the E61 is not great, or that it is not important or that it was not revolutionary. But there are better options and solutions to the same problems. The use of the E61 has become a crutch that is holding machines back.
Hi Malachi,

I agree with your position on the E61 but I would also add that the LM machines suffer from fundamental problems in thermal performance also, as would machines based on LM components or concepts. The problem is systemic to the industry not just a particular design. I would like to see some real development in the design of new machines, not just dressing up last years hardware with new controls.

Sean

lino

#13: Post by lino » Jul 25, 2005, 5:18 pm

lennoncs wrote: ...but I would also add that the LM machines suffer from fundamental problems in thermal performance also, as would machines based on LM components or concepts.
... I would like to see some real development in the design of new machines...

Sean

Hello,

Could I persuade you to elaborate on the problems? I'm interested in other's views of what's needed.

ciao

lino

User avatar
HB
Admin

#14: Post by HB » Jul 26, 2005, 8:17 pm

malachi wrote:But I prefer the preinfusion style of a 1 group Synesso or a LM GS (for example) and also the preinfusion style of a Mistral
That reminds me, I would like to plumb an E61 / rotary to allow manual preinfusion under line pressure when the lever is in the midway position.
I consider a saturated group to be better for thermal stability than a thermosyphon (personally)
A few meta-comments:

First, for those who are reading along, a "saturated group" is one where the boiler water fills the group extending all the way to the grouphead. For example, the La Marzocco's group extends out like ET's neck from the boiler and boiler water fills ("saturates") the entire assembly. The benefit is that the grouphead and the boiler are effectively one (and in some models they're welded together), reducing the boiler / group temperature differential. In contrast, a thermosyphon is transferring a percentage of the steam boiler's heat to the group. While its shortcomings with regard to HX flushing are well documented, I've been impressed how well they are tuned on the machines I've tested. The measured in-basket temperature of an idle HX / thermosyphon is in the 195F range and the grouphead zeros in fairly quickly after a few shots, again assuming the flushes are correct.

Back to Chris' point, I assume that a saturated group implies a dedicated brew boiler, i.e., HXs need not apply. Admittedly, if I worked in a cafe, I would prefer a dual boiler because they're easier to operate. But in the low-volume Cafe HB, either design works for me.

PS: This is a CAD picture of Lino's pseudo-saturated E61 group. I never got to see the real thing though...

Image
(click to read article)
Dan Kehn

User avatar
HB
Admin

#15: Post by HB » Jul 31, 2005, 1:41 pm

Lino spent hours measuring his E61 group to input it into his CAD program. Below is one example:

Image

He and I are collaborating on an article to explain in layman's terms how this works. He's working on an animation too. Very cool Lino, thanks! For more pictures, see E61 Group Espresso Machine: Detailed Interior Schematics.
Dan Kehn

default

#16: Post by default » Aug 09, 2005, 7:06 pm

that's one awesome drawing, for an untechnical e61 owner like me to understand.

many thanks.

okaychatt

#17: Post by okaychatt » Nov 10, 2005, 10:23 am

HB wrote:He and I are collaborating on an article to explain in layman's terms how this works. He's working on an animation too. Very cool Lino, thanks!
Dan - When will the layman's terms article be ready? I'm lost, and I want to understand.

Let me be sure I've grasped things so far.

The HX thermosyphon runs through the boiler, which heats the water inside. That water is delivered to the grouphead. Because the water is overheated from the boiler temp, cooling flushes are required.

The saturated grouphead is connected directly to the boiler, making its temp higher than the water delivered from the thermosyphon.

Why is that considered an advantage? Wouldn't it take more cooling flushes than the HX? Is it a matter of stability somehow?
Kay

User avatar
HB
Admin

#18: Post by HB » Nov 10, 2005, 10:52 am

okaychatt wrote:Dan - When will the layman's terms article be ready? I'm lost, and I want to understand.
The proposed article mentioned above would be about the mechanisms of the E61 design, not how it addresses temperature stability, which is already discussed in Espresso 201: Heat Exchangers. In the case of a HX thermosyphon it describes, the grouphead is heated to a percentage of the (steam) boiler temperature by circulating water. Ideally that percentage of heat transfer is tuned such that the grouphead is very near the desired brew temperature. For the machines I've tested, it works surprisingly well with the grouphead idling in the 195-197F range.

As you said, the flush evacuates the overheated water from the heat exchanger, but it also warms the grouphead to brew temperature. Through continual use and attention to correct flushing, the grouphead will zero in on the brew temperature. A very neat, efficient design, however it does depend on the barista managing temperature properly.

The grouphead of a saturated group acts as a direct extension of the boiler:

Image
See Cutaway of La Marzocco saturated grouphead for more details

In this case, the boiler is at brew temperature, not steam temperature. There's not much for the barista to do temperature-wise, since the boiler temperature directly dictates the brew temperature. In contrast, the barista must "surf" an HX machine to the desired brew temperature. This video using the thermofilter demonstrates that managing HX temperature really isn't that difficult, but there's no arguing it's more involved than machines having a dedicated brew boiler.
okaychatt wrote:Why is that considered an advantage? Wouldn't it take more cooling flushes than the HX? Is it a matter of stability somehow?
My above comments cover the operational advantages of a saturated group (i.e., one less thing to worry about) and imply the advantages with regard to exceptional espresso (consistent, flat temperature profile). That's where disagreement begins concerning the merits of a slant-L (flat) temperature profile versus a "humped" temperature profile, the latter being unique to HX machines (*).

I'm firmly in the "it depends" camp. :wink:

(*) ...and many lever machines.
Dan Kehn

User avatar
barry

#19: Post by barry » Nov 10, 2005, 4:07 pm

HB wrote:The proposed article mentioned above would be about the mechanisms of the E61 design, not how it addresses temperature stability, which is already discussed in Espresso 201: Heat Exchangers.

fwiw, there seems to be a common misconception that a "heat exchanger" machine is a "thermosyphon" machine. there are several heat exchanger designs in use on commercial machines which do not use a thermosyphon.

User avatar
malachi

#20: Post by malachi » Nov 10, 2005, 4:53 pm

And I believe that the Amica is a thermosyphon machine that is not a HX machine - right?
"Taste is the only morality." -- John Ruskin