gscace Senior Member Joined: 19 Dec 2001 Posts: 237 Location: Laytonsville, MD USA Expertise: I live coffee
Espresso: La Marzocco Linea 2AV, Astra... Grinder: 3 Mazzers Robur, Kony,... Vac Pot: Cona D, Hario Nouveau Drip: Technivorm Roaster: Has Garanti 1kg. electric
Posted Wed Oct 19, 2005, 6:22am Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
strugs Said:
Greg - curious what bolier pressure you are running. I am not familiar with the Astra specs, but what size boiler does it have?
gscace Senior Member Joined: 19 Dec 2001 Posts: 237 Location: Laytonsville, MD USA Expertise: I live coffee
Espresso: La Marzocco Linea 2AV, Astra... Grinder: 3 Mazzers Robur, Kony,... Vac Pot: Cona D, Hario Nouveau Drip: Technivorm Roaster: Has Garanti 1kg. electric
Posted Wed Oct 19, 2005, 6:27am Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
randyr Said:
Greg, do you have extra pipes so you can change the temperature for different espresso? ;)
Haha! Actually I gots a drawer with a few pipe configs. I should just tape em on the side of the machine and label them "malabar Gold", Decatur Stree Blend", etc just to yank the cranks of geeks who drop into my office.
It might surprise you that I think the plumbing in my Astra is in the good enuff category and I don't change it at all. My method for fine adjustment to different coffees is to support the machine by the pressurestat adjustment screw and then rotate the machine in the appropriate direction.
Posted Wed Oct 19, 2005, 10:40am Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
gscace Said:
It might surprise you that I think the plumbing in my Astra is in the good enuff category and I don't change it at all. My method for fine adjustment to different coffees is to support the machine by the pressurestat adjustment screw and then rotate the machine in the appropriate direction.
Interesting that you mention this. I find that in periods of high humidity, it helps to orient the machine so that it is facing South. In the dry summertime, a Northerly orientation seems to work better.
On a serious note, after a few days of playing around and drinking WAYY too much coffee, I am finally pretty adept at controling actual brew temps through varying flush volume and rebound times.
Say the target brew temp is 198 F. If I want a flat brew profile, I flush to 196, then pop the basket into the PF and hit the brew switch. Delay between ending the flush and brewing is approx 10 seconds. The brew temp quickly ramps up to 198 and stays there (+/- 1 F) for the entire 26 seconds.
If I want a more typical "humped" E61 style profile, I flush to 195, then wait 30 to 45 seconds before I hit the brew switch. The brew temp quickly shoots up to 200, then slowly settles down to 198 by the 12 second mark and stays pegged at 198 for the remaining 24 seconds.
So far, the humped profile seems to give me a better tasting shot, but my latest batch of beans was not up to its usual standard, so more experimentation is definitely in order.
Ozark_61 Senior Member Joined: 18 Dec 2004 Posts: 395 Location: Springfield, MO Expertise: I love coffee
Espresso: ECM Giotto Grinder: Mazzer SJ Roaster: SC/TO, Poppery I
Posted Fri Oct 21, 2005, 10:12pm Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
Awww... shucks.... no big deal... nothing compared to strugs' project... it's just that... I'm just obsessed like the rest of you! Hey, if Norman Bates had an espresso machine, we'd be all over it. I would love to see some more examples of temperature vs. flush time & vs. recovery time, such as Dan had in his HX love article on HB. I think the PID would be helpful since the flush seems to be the largest variable since recovery should be fairly constant-ish.
Nor-man! Where's my double ristretto!!
.... Coming mother....
jakethecoffeelover Said:
Holy shit! That's gotta be the best idea I've ever heard!!!! Is that your own idea? That would do wonders for commercial HX owners. They could press a button before they grind and the PID would activate. It would flush until the water in the HX was at a certain temperature and flush again if it starts to heat and so on so that it's ready to brew as soon as the barista locks in the portafilter... Wow, that would be HUGE!!! It's so simple, too. A normal PID and SSR that activates the pump instead of the element (but reverse, I'm pretty sure most PIDs figure that out).
Posted Sun Dec 18, 2005, 3:46pm Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
Very cool work. While it doesn't make any difference if you're looking at how the espresso tastes, if you're thinking about absolute temperatures or profiles, you should keep in mind that the stainless probe has a time constant that's non-trivial with respect to what you're measuring. When I asked Omega about that, they said that a 1/16" stainless type K probe had a time constant of about three seconds. I.e. if the actual temperature changed instantaneously, the probe would register two-thirds of that change three seconds later, two-thirds of the remaining three seconds after that, etc. I'm not sure what Greg used in the thermofilter, and what its time constant is, but I'm sure he knows. Greg?
Posted Sun Dec 18, 2005, 11:56pm Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
DavidMLewis Said:
Very cool work. While it doesn't make any difference if you're looking at how the espresso tastes, if you're thinking about absolute temperatures or profiles, you should keep in mind that the stainless probe has a time constant that's non-trivial with respect to what you're measuring. When I asked Omega about that, they said that a 1/16" stainless type K probe had a time constant of about three seconds. I.e. if the actual temperature changed instantaneously, the probe would register two-thirds of that change three seconds later, two-thirds of the remaining three seconds after that, etc. I'm not sure what Greg used in the thermofilter, and what its time constant is, but I'm sure he knows. Greg?
You are correct, and I am glad you brought this up, as the discussion about absolute temperatures has been discussed on this forum before, just not in this thread. The system in my machine is in no way capable of measuring absolute temperatures. In addition to the probe's time constant you refer to, there are many other factors (such as the delta between group and water temperature) that renders the system unable to tell me that brew temperature is precisely X degrees. Even my cheap Fugazi Fluke digital temperature meter is off by a significant margin (registers temp of boiling water as 206 F). However, what I believe is really important is consistency and repeatability. In other words, my taste buds tell me that my usual espresso blend tastes great when my meter tells me that the water is at 193 F. Even if I assume that the 6 degree difference at boiling point is constant throughout the upper temp range, I would never tell anyone that Hines espresso tastes best when brewed at 199 F.
I believe that Greg used a "Type T" TC in the thermofilter, which is much more responsive than the "Type K" TC I am using. I would love to get my hands on a Scace devise and run it parallel with my onboard probe just to see the differences and/or similarities. Espresso Dom has a TC installed in his E61 bolt and he did some testing with a Scace device, and reported that the temps were different, but the profiles mirrored each other throughout the brew cycle. Since the probe in my machine is that much closer to the brew head than the E61 screw, I would expect similar if not better correlation on my rig.
For those looking for an update on my mod, everything is still running flawlessly. The probe has never leaked or given me any kind of trouble. It is so simple to ensure that I brew at my target temperature. However, I am still amazed at the amount of flushing that my machine needs to get down to proper brewing temps. After the initial 9 to 1oz flush after a long idle, I am still having to flush 6 or 7 oz between shots (approx 3 minutes between pulls). The probe reads a temp of 220F after a long idle period, which seems to be high compared to other machines. I have even played around with the water level in the boiler to see if I can lower the group temp, but even at its lowest level, the group still reads 219 F at idle). Since water level does not seem to be the cause of the high group temp, I am still planning on lengthening the HX feed tubing to see if this helps. However, this involves some plumbing work and I a bit leery of jumping into it without doing some serious homework. My biggest worry is that the hardware on the group is all metric, and I will not be able to match it up with the typical north American tubing and fittings. Anyways - it will be a while before I get enough time and courage to do this next mod.
Posted Sun Sep 10, 2006, 12:12am Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
Hi,
Dr. FrE61nkenstein here again.
You may recall that my first foray into the realm of E61 surgery did not go well. Lots of leaking and broken thermocouples. The second attempt under the guidance of Mr. Scace went very well and I have been enjoying the real time temp monitoring device for months. Well, I recently decided to proceed with FrE61nkenstein Version 3.0.
As I mentioned previously in the thread, my beloved WEGA machine seems to run extremely hot. When my boiler pressure was set at its factory setting of 1.1 bar (high side), a 12 oz flush was required to obtain a proper brew temp. I was also having to flush 6 to 7 oz of water between successive shots to obtain optimal brew temps. After dialling the BP down to 0.8 bar, I only need to flush 8 or 9 oz after machine has been idling, but this still seems excessive (plus my steaming pressure is more anemic).
To rectify the problem I set out to install a gicleur valve (basically a copper washer with a small hole) in the thermosyphon loop. After disassembling the top and bottom copper feed lines to the grouphead, I discovered that this would be difficult to do. The connections between the tubing and the grouphead are tapered so that it would be impossible to put in a washer with a small diameter. If I could not restrict the flow, I thought I would take the next available option and extend the thermosyphon line. After my last successful surgery I thought, "how hard can that be?" Well - all I can say is that my machine has been torn apart and I have been Cappuccinoless for about 6 days now. I cut the thermosyphon line (the one that goes from the top hole in the grouphead to the boiler) with a pipe cutter, then bought some 3/8" tubing and compression fittings at the home dept. The I learned a valuable lesson - what looks like 3/8 tubing is not necessarily 3/8 tubing. The compression fittings from HD did not fit on the WEGA's thermosyphon line. Turns out the OEM tubing is metric and despite the fact that I live in Canada, metric tubing and fittings are not available. Since I am a sore loser and cannot tolerate personal failures, I did make an attempt to make the parts fit, but despite finally "massaging" the SAE fittings onto the metric pipes, the system leaked like the proverbial sieve when I installed it and pressurized the system. I included a picture of my patented leaky top tube system at the bottom of the post. The fittings nearest each tapered end (before the elbows) were the source of the leaks.
I have a replacement top tube coming to me from espressoparts, but I guess I am back to the drawing board with my excessive heat problem. Ideally, I would like to have a tube with a ball valve so that flow could be adjusted from from a full flow to a minimal trickle, but in order to do that I would need to source a metric ball valve and some 10mm compression fittings. Also, would it not make more sense to restrict flow from the boiler to the group (the line going into the bottom hole in the grouphead) rather than vice versa?
Luca Moderator Joined: 27 Jan 2004 Posts: 2,639 Location: Melbourne, Australia
Espresso: H: Maver W: FB-80 Grinder: H: Super Jolly W: Brasilia... Vac Pot: Hario TCA-2 Roaster: Sample Roaster at Work
Posted Sun Sep 10, 2006, 4:32am Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
strugs Said:
Ideally, I would like to have a tube with a ball valve so that flow could be adjusted from from a full flow to a minimal trickle, but in order to do that I would need to source a metric ball valve and some 10mm compression fittings. Also, would it not make more sense to restrict flow from the boiler to the group (the line going into the bottom hole in the grouphead) rather than vice versa?
My local roastery had some awesomely tweaked WEGA polarises on the bench about half a year ago. Almost no cooling flush and milk steaming up the whazoo. Not sure how they restricted the thermosyphon, but have you checked to see if standard gicleurs are available from WEGA or EPNW? The variable thermosyphon idea would be damned sexy. I wonder if one of the original e61 valves would fit? If the flushing thing really is a hugeass problem, why not just crimp the tubing?
Does it really matter where you restrict the flow on the thermosyphon? I mean, it's a closed loop, so a bottleneck anywhere will slow it down everywhere ... right? Or am I completely off track?
Posted Sun Sep 10, 2006, 9:54pm Subject: Re: Real Time E61 HX Brew Temp Mod aka FrE61nkenstein Part 2
Luca Said:
have you checked to see if standard gicleurs are available from WEGA or EPNW? The variable thermosyphon idea would be damned sexy. I wonder if one of the original e61 valves would fit?
I asked Terry Z from EPNW about this last week when I ordered the replacement tube, and he said slowing down the thermosyphon MAY actually increase the idle temp... Seems to be against the common thinking in this thread and in alt.coffee, but TZ knows more about these things than most people. I have to call him again tomorrow anyways, so I will see if he knows about the E61 valve.
Luca Said:
If the flushing thing really is a hugeass problem, why not just crimp the tubing?
I thought about this option a while ago, but the question becomes - how much of a crimp to put in it? It is not an adjustable (let alone reversible) mod, and there is also the possibility of stressing the tube to the point that it springs a leak.
Luca Said:
Does it really matter where you restrict the flow on the thermosyphon? I mean, it's a closed loop, so a bottleneck anywhere will slow it down everywhere ... right? Or am I completely off track?
That makes sense. Shouldn't matter where the restriction is located within the system. My bottom thermosyphon line (running from the lower hole on the back of the grouphead) is much longer than the top, and would be more suited for splicing in a ball valve. I was thinking a bit more about the whole issue today, and I may call ASTRA tomorrow to see if they have any metric to imperial adapters. If I recall correctly, I have seen pics of their "made in USA" parts having to be mated to the OEM E61 plumbing.
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