I have a Rocket R58. I have read the posts about the integrated vs. Saturated head and seen the video test of the LMLM which is very impressive.

I see a number of posts around HX post flush consistency .....interesting but a big a variable at play.

Also a number of posts around the idea that the e61 is solid but ultimately older design being supplanted by newer approach.

It could be my search failure, but I would have assumed someone would have run scace tests of a DB E61. I'm not concerned with offset and actual brew temp really. I would like to find some data on consistency of brew temp, shot to shot. Is. Is it +/- 2 C ....vs 0.5 c for more modern design etc.

I suspect it will lose out the the very small variation of LMLM etc ....but what is the real story. With so many E61 DB around .....thought it would be easy to find.

Again....apologies in advance if I just missed / failed the search.

Thanks.

I think you should better directly search for machines you know they are having a e61 head and are are dual boiler.
One example is the Lelit Bianca. Here is a measurement for different flow rates (German, but plot is plot):
https://www.kaffee-netz.de/threads/leli ... st-1663265

Another thing to consider is how ambient conditions impact the brew temperature. Greater (or lesser) heat loss from the group will impact the differential to the boiler. A cold kitchen in the morning, the heat of the afternoon sun, an open window or the air conditioner running creating a draft, ...

Just a draft can be enough to control the temperature creep of an E61 HX (though it might be a relatively strong draft). A guide to managing HX brew temperatures See around Post #16 and later.

Pflunz wrote:I think you should better directly search for machines you know they are having a e61 head and are are dual boiler.
One example is the Lelit Bianca. Here is a measurement for different flow rates (German, but plot is plot):
https://www.kaffee-netz.de/threads/leli ... st-1663265

Translated link https://www-kaffee--netz-de.translate.g ... st-1663265

Thanks for the translated link. It's not perfect translation and quite a long thread ....i'll try to tranaslate more pages ...it seems to only give me one page.

On that page, however, it seems the variation is tiny. If so, why the theory of its relative weakness.

I def get the point about ambient impact which is a flaw of e61 - at least in theory. But in static climate kitchen ....is this a real issue. Would be nice to see more.

Strange that we had to go to Germany to get some data. The e61 is so common, and the debate seems prevalent. . I suppose I could buy/rent a scace, but surprised it's not common thread.

Single or double boiler doesn't really matter here, what matters is "not heat exchanger".

Here are some examples:
SB E61+PID, Episode 2: Tested properly this time, with much better results [note the edited comment and results in this post, SB, thermocouple in PF]

VBM Domobar Single Boiler - PID & thermostat questions [DB, scace]

The second link in particular tells a story that makes sense.....
The heat spilling from e61 means a big delta vs boiler. (I guess the thermosyphon is not very effective?) and hence running shots simply raises the temp in succession.

That makes sense and unfortunate. The question though ( not to create new topic ) is what are the alternatives. I had a La Spaziale. Different boiler hybrid and I understand not significantly more stable.

The LMLM is awesome but a LOT of money. A different class. I don't love my e61 reality but don't see much I could have done in prosumer space. No amount of BDB performance stats or value comparison will get me onboard.

mx125 wrote:The second link in particular tells a story that makes sense.....
The heat spilling from e61 means a big delta vs boiler. (I guess the thermosyphon is not very effective?) and hence running shots simply raises the temp in succession.

To be fair, the variation between first and last shot in the second link was <1deg C... to say it raises the temp in succession is factually correct, but lacking context and misrepresenting the findings.
Yes there is a decent delta between brew boiler and temp at the puck, but does that really matter if you get consistent temps at the puck?

mx125 wrote: The LMLM is awesome but a LOT of money. A different class. I don't love my e61 reality but don't see much I could have done in prosumer space. No amount of BDB performance stats or value comparison will get me onboard.

Nor I, the BDB is just another Breville appliance, none of which remain in my kitchen. I had some of their other products when I first moved out of home as a teen and none of them lasted(some of which cost more than their espresso boxes!). Machines last and are repairable(such as Dualit toasters, not just espresso machines ).

mx125 wrote: That makes sense and unfortunate. The question though ( not to create new topic ) is what are the alternatives. I had a La Spaziale. Different boiler hybrid and I understand not significantly more stable.

I've wondered about what else is out there, but aside from gaining flow control and pressure profiling from another design, I doubt I'd gain much from a machine change without spending a significant amount of money, my temps are rock solid. I'd get far more value from better/more grinders. PID controlled e61 SB (I don't drink milk) serves me well, although it might get manual flow control soon.
The only downside (for me personally) is that it's not a "supported" configuration with the Leva!/ITO device which offers flow control and pressure profiling which can be hidden and done with pump control.

It seems you're not a fan of e61

There are saturated group options, some reviews state the Rancilio Silvia Pro is DB and saturated group - I haven't verified that it is a true saturated group.
I believe ECM, Lelit and Profitec offer saturated group machines if that is what you're after.

Perhaps the most reasonable option is to accept a one or two degree Celsius shot-to-shot variation as "close enough". Even though I could control my E61 HX to within a 1°C range and my current machine similarly, I don't find changes much less than 2°C to make an obvious change in the cup.

There's a balance between cost and performance. E61 castings and parts are dirt cheap compared to engineering and fabricating a new group. There's no need for tight tolerances as there would be with a close-coupled group that needs to mate to the boiler at 9-bar working pressure. A thermosiphon sort of works with the relatively low temperature differential (maybe 5-10°C for a dual boiler, compared to around 30°C below 123°C for a 1.2 bar steam boiler HX), well enough that I don't know any manufacturer that has a circulation pump.

My guess is that the technology will come from two fronts. One, like the BDB, how to mass-produce a temperature-stable espresso machine at a premium, but not outrageous price for the high-end kitchen appliance crowd. The other, I'm guessing, will be energy (cost of operations) savings in the commercial market. Smaller boilers, better-insulated groups, flash heaters, and integrated energy management seem to be a way to get some significant savings for the commercial operator. The VA Eagle One series is, I think, just the first of these. My crystal ball isn't clear enough to know when that will make a big impact on the hobbyist-consumer market. There's still the attraction of decades of posts on the Silvia and E61s coupled with the "that doesn't look like an espresso machine" factor that is a big driver of, I'm guessing, 90-95% the machines out there above the basic, "15 bars" buzz-box level.

Thanks again and all very helpful. Also helpful to get a reality check from your perspective. I actually really have enjoyed my hx e61 and having just bought the db, I would say my inquiry is more theoretical. I will re-read that link as the variable is small and must have misread. Definitely more interested in shot to shot puck repeatability ...,not the profile or boiler to group delta.

I would not likely taste the difference nor am I actually worthy of even the machines I have. Just interesting AND given the very fresh purchase ( and an expensive one for me ) I did some quick reading and had sudden concern / hope that I didn't make a bad ( dumb ) decision based on marketing and old data. However, as we've discussed, I think at the price point and in the realm of prosumer I am in good company at least.

My La Spaz lasted 13 years and still going like new. It is showing some age, however and just never got on with the looks. It was a mini and I really wanted rotary and plumbed ...... and couldn't commit to a new one..... mainly because of the appearance and just desire for a change.