Temperature Stability . . . . from a Heat Exchanger - Page 2

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AndyS

#11: Post by AndyS »

Ken Fox wrote:You are among the most rigorous and conscientious "espresso-scientists" out there, and I really respect your judgement and your observations.
C'mon, Ken. Didn't your parents ever tell you that flattery will get you nowhere? :o
Ken Fox wrote:Could you tell us what if anything you have found on the idea of there being a "sweet spot," a certain band of temps that a machine might be able to pull flat curve shots at, and that the ability to do this declines as one gets to the fringes of this "band?" It seems only logical to me that you can only tune such a system (as an espresso machine) so well, and in the design the engineers would have to decide where they wanted the machine to be the most stable.
Sorry to tell you that I have no data on this. Certainly your point makes sense: the band of temps within which machines will exhibit good thermal performance cannot be unlimited....
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

Ken Fox (original poster)

#12: Post by Ken Fox (original poster) »

AndyS wrote:Sorry to tell you that I have no data on this. Certainly your point makes sense: the band of temps within which machines will exhibit good thermal performance cannot be unlimited....
I bet that Dr. Illy has read every single one of your posts

ken

Ken Fox (original poster)

#13: Post by Ken Fox (original poster) »

lennoncs wrote:Congratulations Ken!

You have found that "DPlot Religion"


nice looking graphs, I am going to ruminate on them a bit before I comment but it looks promising.

Cheers,
Sean
OK, Sean, you've had almost a week to ruminate on these graphs. Whaddya think?

ken
p.s. I don't regard these graphs as the limits of what can be done on this machine as the PID could be reprogrammed and shot and flush temperatures varied. It is just a start and I think it shows that a lot more can be gotten out of a HEX machinne, certainly THIS one, than had been previously assumed. Being as I am in California right now visiting my parents, I won't be able to do any further testing for more than a week.

MJ's Cafe

#14: Post by MJ's Cafe »

I've been reading this site for a while now and need a good lie down as my head is swimming with pid's and hex's and the ramifications. I'm in Taiwan setting up an espresso bar and recently bought a Faema e92 elite due to considerations of service availability in Taiwan and not having a spare internal organ to sell in exchange for a La Marzocco. To my horror I am now presented with 'flushing' options for a HX machine and doing triple backflips with a pike finish to get temperature stability out of my machine. What's going on in the world of espresso machines where we do our best to put all the other factors in place for great espresso only to be let down by machines that fluctuate like butterflies on amphetamines? Can you point me to a few articles/forum chats on this site to try and improve my shots through stabilising my HX machine?
God perfected it, we're playing catch up.

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HB
Admin

#15: Post by HB »

MJ's Cafe wrote:Can you point me to a few articles/forum chats on this site to try and improve my shots through stabilising my HX machine?
How I Stopped Worrying and Learned to Love HXs is geared towards semi-commercial machines, but the principles are the same. Commercial HXs rebound much faster than their smaller siblings, so I use the the flush-n-go technique (or sometimes called the "pro's method") exclusively in their case rather than the rebound method described in the HX Love article.
Dan Kehn

MJ's Cafe

#16: Post by MJ's Cafe »

Thanks for the articles. It feels like I've gone a long way from turning the hissing, spitting tomcat into a friendlier beast. I haven't rigged up a thermometer yet but noticed my shots were coming out a lot steadier, blonding less and also noticed much more crema than I was previously getting. I'm now looking for a good thermometer (may use a similar rig to the one schomer discusses) to really start testing the temperatures in the group. thanks again! :)
God perfected it, we're playing catch up.

mteahan

#17: Post by mteahan »

Keep in mind that without coffee or sufficient restriction in the probed based portafilter, the PI chamber won't be used. The chamber will bleed off 50 or 60cc which will mimic the preflush about which everyone seems to be obsessing.

Michael
Michael Teahan
analogue | coffee

MJ's Cafe

#18: Post by MJ's Cafe »

I've been wondering about that michael. After checking a few articles on how to rig up a portafilter with a temperature probe and the importance of having the head of the probe level with the top of the puck: see Schomer article: (how do i work this bloody url insertion thing?) http://www.lucidcafe.com/cafeforum/schomertable13.html

"After the porta-filter has heated up thoroughly in the group head grind a shot and pack it over and around the bead probe. It is crucial that the bead just shows on top of the packed coffee. If the bead is sticking up too high it may contact the metal dispersion screen and create an erroneous reading. If it is buried inside the packed coffee it will take 10 to 15 seconds to obtain a true reading of what the machine is doing as brewing water permeates the packed coffee."

Schomer advocates packing the shot 'over and around the bead probe'. How do I do that and 1) avoid damaging my tamper on the head of the bead and 2) ensure the shot is as close in consistency as a normal shot would be without packing around the bead? I was going to have a go and use my ol' friend trial and error but thought to ask you guys first and avoid the potential of a few hours of frustration, hair pulling and tantrum throwing.

cheers, mark.
God perfected it, we're playing catch up.

Ken Fox (original poster)

#19: Post by Ken Fox (original poster) »

MJ's Cafe wrote:I've been wondering about that michael. After checking a few articles on how to rig up a portafilter with a temperature probe and the importance of having the head of the probe level with the top of the puck: see Schomer article: (how do i work this bloody url insertion thing?) http://www.lucidcafe.com/cafeforum/schomertable13.html

"After the porta-filter has heated up thouroughly in the group head grind a shot and pack it over and around the bead probe. It is crucial that the bead just shows on top of the packed coffee. If the bead is sticking up too high it may contact the metal dispersion screen and create an erroneous reading. If it is buried inside the packed coffee it will take 10 to 15 seconds to obtain a true reading of what the machine is doing as brewing water permeates the packed coffee."

Schomer advocates packing the shot 'over and around the bead probe'. How do I do that and 1) avoid damaging my tamper on the head of the bead and 2) ensure the shot is as close in consistency as a normal shot would be without packing around the bead? I was going to have a go and use my ol' friend trial and error but thought to ask you guys first and avoid the potential of a few hours of frustration, hair pulling and tantrum throwing.

cheers, mark.
Then was then and now is now. If you really want accurate measurements, get a Scace Thermofilter and either a Fluke datalogger or another datalogger. The Scace device was developed because of the severe limitations of the Schomer basket technique. You will drive yourself crazy with the Schomer technique, and your readings won't be worth anywhere as much, nor be repeatable, like the Scace device readings. You will also end up with hot coffee sprayed all over your clothing, and your kitchen, if you use the Schomer technique long enough.

kne

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HB
Admin

#20: Post by HB »

Follow-on discussion split to WBC standards don't reflect real world usage...
Dan Kehn