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Thread: New Coffee Machine Advice...

  1. #1
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    New Coffee Machine Advice...

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi All

    I am after a new coffee machine. The budget is set to 2000-3000. What I am looking for is PID with Heat Exchange and a very good brand. Would love to have dual boiler but they all seems to be over 3000....

    Now brands and models... my father in law have Rocket R58 which looks awesome and making great coffee so I was looking a rocket one but also found Profitec brand
    The models I looked so far are Rocket Mozzafiato and Profitec Pro 500.. Looking at the reviews and features as well as brand reputation,, both seems to be similiar as per reviews etc... These two are about 3K which is higher mark and I am willing to pay but I was wondering if there a cheaper machine out there whcih same features and from a reputable brand... Would not mind if I can some some money...One of my friend was recommending Isomac brand and they seems to be around 2500ish range.. but not sure about quality and features etc...



    Any help would be awesome... Thanks heaps in advance..

  2. #2
    Senior Member artman's Avatar
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    Once you get into this $ territory in "traditional" machines, IMO they are all great machines (I'm talking traditional machines, not specced up Breviiles etc) and the limiting factor in producing a ripper brew would be your technique and ingredients (assuming your grinder is semi decent, dont forget the grinder has a big impact). Almost all should be decent quality.

    The rest is mostly what you find appealing in looks and layout. Many machines look almost the same (say most E61s), but its the small details that define them.

    Best bet would be to go to a sponsor or two and see and feel them in the flesh and preferably have a play.

    Cheers
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    R58 is over $3K, especially if you need a grinder.

    I was in your position recently and settled on the Expobar Office Leva.

    It's been making a dozen or more coffees a day for a few months without any issues except for some adjustments required out of the box (which the retailer could have done if I had asked them to).

    I prefer HX, the water doesn't sit in a boiler.
    Dual boilers aren't better machines, just different.

    You'll first have to also yourself what your requirements are imo.
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  4. #4
    Senior Member rusty888's Avatar
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    I’ve learnt. Buy once buy right. If you love the R58 perhaps save a little more. If your budget is 2-3k and a R58 is about 3.7k it’s worth saving some more. Look at second hand perhaps.

    Only reason why I say that I went through this and went breville dual boiler to heat exchanger to ecm synchronika dual boiler to linea mini. I should of just bought the one I wanted to start with.

    As was mentioned once you get to that 2k mark it’s mainly just down to looks and personal preferences.

    If I was you send a quote request on the site and see what demo machines are out there if you want. Maybe someone has a demo R58
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  5. #5
    Senior Member woodhouse's Avatar
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    yeah, buy once cry once. if you want a dual boiler, save up for one. otherwise every time you look at your HX you will sigh just a little bit until upgrade-itis takes you.

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    iffarukh;

    Check this one, https://dibartoli.com.au/profitec-pr...ys-collection/ think is in your buget, we have sold few of then everyone is happy

    Regards

    Renzo

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    An R58 is $2K more than the Expobar and, for my use case, wasn't better, no faster either.

    I think the advice to pay a whopping $2K more for a 'better' machine 'could' be bad advice.

    The difference in cost is a very, very nice grinder which would make all the difference vs virtually no difference for the machine upgrade.

    If it wasn't clear, I advise to very closely asses your use case, is your palette going to taste the difference between HX and DB? Mine can't and I've run coffee shops and been drinking for 35 years, some will and justify the extra cost though, so do the work to taste the difference.

    Otherwise you're wasting $2K and that's not something you should just go ahead and do without any testing imo.

    Actually, now that I compare my notes, I preferred the Expobar taste very slightly. My budget would have stretched for the R58 but I put a good amount into my grinder (modified M7D) instead of the machine and I'm very happy I did.
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    Experience tells the story here - don't cheap out by just a few hundred....a solid E61 will probably outlive you, so do some research based on those features that are important to you, then go get it. Many believe there's no real diff between a heat exchanger and a dual boiler, but they are incorrect in that line of thinking. Yes, both have the capability of making a great espresso and milk based drinks but that comes at a price in terms of the coffee making process you will have to go through. Sure the heat exchanger will cost less but there's a reason for that. You don't want to buy the wrong machine and then in a few years go buy yet another one.

    A heat exchanger only has one boiler, the hot water/steam boiler, so there's a cost savings right there as compared to a dual boiler. The heat exchanger uses a separate tube that runs through the boiler for its coffee water. Since you need a very high temp in the boiler to get steam, the coffee tube that runs through the boiler gets too hot for making coffee. So, when you lift the brew lever in a heat exchanger machine, you need to let the water run through the brew group and into the drip tray in order to decrease its temp by virtue of new cooler water flowing into the coffee tube. Some people add a thermometer that screws into the E61 head in order to know when you have the right coffee temp, others just wait till the water coming out of the head stops spitting and sputtering and then connect their portafilter and brew. Once you have made your coffee and lets say you have to make four coffees, by the time you dump the spent grounds from the first coffee, grind and prepare your portafilter for your next coffee, prepare the milk if people want a latte or cap, the water temp has risen again and you have to do another cooling flush, if you remember! Its just a pain in the ass.

    My brother in law has a nice heat exchanger E61 machine but I can tell you that both he and I forget to do the cooling flush on a regular basis. I don't know why, we just forget to do it. Your busy with the process, maybe talking to people while doing it, whatever. The espresso doesn't taste good when brewing it at 265 degrees! Plus, its just a sad waste of water if you ask me. A PID based dual boiler solves that issue since it has two boilers, one for coffee with its own temp and one for the hot water/steam at its own temp. You pay more to get the second boiler, but its worth it. You will have more control over your boiler temperatures with a PID dual boiler.

    Now, don't forget that a mediocre grinder will be a sure way to waste any amount of money on any kind of espresso machine so be sure you have a proper grinder before spending $$ on a nice espresso machine.

    ps: You can buy new E61 based dual boilers for $3K and even a little less.
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    I was down this road just a couple of weeks ago and ended up purchasing the ECM Technika V for $3300+

    My reasoning was behind the rotary pump which is quieter and supposedly lasts longer plus being able to plumb it in later when i choose to.

    Now I have had it for only a week and getting used to the steaming and now starting to get a feel for the quality and build of the machine. I havent used other prosumer machines but I can definitely recommend ECM.

    PSX_20190801_222128.jpg

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    Senior Member level3ninja's Avatar
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    jksniper if you think the Technika is good now wait till you feed it with a proper grinder
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    level3ninja i was looking at getting just the eureka mignon e for now

    out of budget hehe

  12. #12
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    Quote Originally Posted by jksniper View Post
    level3ninja i was looking at getting just the eureka mignon e for now

    out of budget hehe
    There is a second hand Atom in the for sale section
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  13. #13
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    My set up, using the Eureka Atom, a very nice midrange grinder that doesn't lose its grind setting when taking it apart to clean it. Its fast and pretty dang quiet, meaning you can grind while talking with someone. Its programmable to two settings.

    IMG_6983.jpg
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    Quote Originally Posted by Martino View Post
    ...

    A heat exchanger only has one boiler, the hot water/steam boiler, so there's a cost savings right there as compared to a dual boiler. The heat exchanger uses a separate tube that runs through the boiler for its coffee water. Since you need a very high temp in the boiler to get steam, the coffee tube that runs through the boiler gets too hot for making coffee. So, when you lift the brew lever in a heat exchanger machine, you need to let the water run through the brew group and into the drip tray in order to decrease its temp by virtue of new cooler water flowing into the coffee tube. Some people add a thermometer that screws into the E61 head in order to know when you have the right coffee temp, others just wait till the water coming out of the head stops spitting and sputtering and then connect their portafilter and brew. Once you have made your coffee and lets say you have to make four coffees, by the time you dump the spent grounds from the first coffee, grind and prepare your portafilter for your next coffee, prepare the milk if people want a latte or cap, the water temp has risen again and you have to do another cooling flush, if you remember! Its just a pain in the ass.

    My brother in law has a nice heat exchanger E61 machine but I can tell you that both he and I forget to do the cooling flush on a regular basis. I don't know why, we just forget to do it. Your busy with the process, maybe talking to people while doing it, whatever. The espresso doesn't taste good when brewing it at 265 degrees! Plus, its just a sad waste of water if you ask me. A PID based dual boiler solves that issue since it has two boilers, one for coffee with its own temp and one for the hot water/steam at its own temp. You pay more to get the second boiler, but its worth it. You will have more control over your boiler temperatures with a PID dual boiler.

    Now, don't forget that a mediocre grinder will be a sure way to waste any amount of money on any kind of espresso machine so be sure you have a proper grinder before spending $$ on a nice espresso machine.

    ps: You can buy new E61 based dual boilers for $3K and even a little less.
    There are many HX machines available in Australia which do not need a cooling flush before extracting espresso. If in doubt, ask your retailer or get a demo - the group head should give you water rather than spluttering with steam and water even if the machine has been on all day without being used. However, many can justify the extra expense of a dual boiler due to faster heat up and control of the brew temperature.

    charlie
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  15. #15
    Junior Member FedeBarista's Avatar
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    Iffarrukh,

    Why are you locking a HX with PID?

    I have a HX and I like this kind of machines. But I believe that a PID is more useful in SD, DB and Thermoblock machines.

    The PID usually controls the boiler, not the HX.

  16. #16
    Member Martino's Avatar
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    Quote Originally Posted by JetBlack_Espresso View Post
    There are many HX machines available in Australia which do not need a cooling flush before extracting espresso. If in doubt, ask your retailer or get a demo - the group head should give you water rather than spluttering with steam and water even if the machine has been on all day without being used. However, many can justify the extra expense of a dual boiler due to faster heat up and control of the brew temperature.

    charlie
    Can you explain how it works then without a cooling flush, this is the first I've heard of it. Interesting.

  17. #17
    Senior Member Jackster's Avatar
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    There is a restrictor in the top pipe from the hx. So it blends the too hot water from the top of the hx, with the too cool water from the bottom of the hx. Result is perfect temp brew water and no cooling flush

  18. #18
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    It must incorporate some type of smart mixing valve in order to set the brew temp then, otherwise its pot luck. What are a couple of these machines, I'd like to look them up and read about them. Thanks

  19. #19
    Senior Member Jackster's Avatar
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    My Musica is fine without cooling flush. But it's a bit touch and go as I don't know the start group temp.
    I have a Diadema junior extra. Has Eric's group thermometer, so once it's up to temp, it's right on the money. No cooling flush needed

  20. #20
    Senior Member Jackster's Avatar
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    The restrictors are called gicleurs, if these are fitted and tuned and the boiler pressure is also tuned, it shouldnt need a flush. Maybe a little purge to stabilise the temp and wet the pf...

  21. #21
    Senior Member Lyrebird's Avatar
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    Quote Originally Posted by Jackster View Post
    There is a restrictor in the top pipe from the hx. So it blends the too hot water from the top of the hx, with the too cool water from the bottom of the hx. Result is perfect temp brew water and no cooling flush
    To my knowledge, that's not how the flow restriction in an Hx thermosiphon works. The water only flows one way, the rate of flow is driven by the cooling of the water in the grouphead so the more heat the head is losing the more water flows, supplying more heat. The restrictor serves to limit the flow rate so this balances near the desired temperature under normal conditions.

    When a shot is being pulled the water that is already in the HX comes out first, followed by water that is actively heated by passage through the HX. The water that was held in the HX will be too hot but it will be cooled by passage through the grouphead if the grouphead is at the right temperature (as above). The water that passes through the HX and the (now heated) grouphead will be at a lower temperature.

    The result is a reasonable approximation of desired brewing temperature, usually declining a bit across the shot.

    As I understand it, on a standard E61 Hx machine the gicleur is in circuit for the preinfusion stage but is bypassed when pulling a shot, this being what the mushroom does.
    Last edited by Lyrebird; 6th August 2019 at 08:50 AM.

  22. #22
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    Quote Originally Posted by Jackster View Post
    My Musica is fine without cooling flush. But it's a bit touch and go as I don't know the start group temp.
    I have a Diadema junior extra. Has Eric's group thermometer, so once it's up to temp, it's right on the money. No cooling flush needed
    Lyrebird has a firm grip on how heat exchangers work and what the gicleurs orafice is for. All heat exchanger machines will produce water temp that is too hot to brew coffee, it needs to be cooled down first. The one and only boiler in a heat exchanger machine is to produce hot water and steam. The water used for brewing comes through a separate tube/pipe that is embedded in the steam boiler, water just passes through this tube and is passively heated as it either sits in its tube or flows through it. Steam boiler temps are in the 250-270 range when the machine is sitting idle, otherwise you would not have sufficient steam pressure. As you use the machine, the ambient water entering the heat exchanger, tends to be what cools the brew water down, hence the "cooling flush". If you make several extractions consecutively, you only need to run a cooling flush for the first one since new ambient water is coming into the boiler to replace the water used for the extraction. If you hesitate between extractions long enough, the ambient water rises in temp to match that of the boiler, thereby requiring another cooling flush. If you were to lift the brew lever and just let water flow and flow and flow, its temp would drop before coffee brewing range because it didn't spend enough time in the steam boiler to be properly heated.

    Ok the gicleur is a flow restrictor, noting more. It isn't there to mix or change the temp of brewing water. Its useful in any E61 group to slow the flow of water to a manageable level. Yes, it can have a slight cooling effect if it restricts the flow enough. It could be possible that some manufacturers, Diadema for example, try to balance the flow of brew water to the mass of the E61 group coupled with their boilers heating element's power and recovery such that brew temps are in the 200 neighborhood. However, without proper PID's all bets are off in terms of anything being at the right temp for anything. Without some way to measure the water temp and then feed that temp info back to the machine, the water temp will reach the capacity of the heating elements design and mass.
    To keep costs down, a manufacturer can probably design the heat exchanger boiler heating element such that when coupled with the lifting of the brew arm, prioritizes the brew temp over the steam temp to strike a certain balance. This of course is a compromise and my guess would be that steam pressure would hover around one bar and little more in reality and probably be good enough for one steaming session before needing to stop to allow the pressure to rebuild. However, this might be ok for a more entry or even mid level priced machine.

    This is why the more expensive machines will have a PID, maybe two or three in order to monitor and constantly adjust temps in the boilers as well as the E61 group, which is what I believe Bezzera is doing in one of their Duo machines that uses an electrically heated brew group, I think that might be the Duo DE IIRC.

    Here's a pic that may help.. ..

    E61-heat-exchanger.jpg

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    Quote Originally Posted by Martino View Post
    Lyrebird has a firm grip on how heat exchangers work and what the gicleurs orafice is for. All heat exchanger machines will produce water temp that is too hot to brew coffee, it needs to be cooled down first. The one and only boiler in a heat exchanger machine is to produce hot water and steam. The water used for brewing comes through a separate tube/pipe that is embedded in the steam boiler, water just passes through this tube and is passively heated as it either sits in its tube or flows through it. Steam boiler temps are in the 250-270 range when the machine is sitting idle, otherwise you would not have sufficient steam pressure. As you use the machine, the ambient water entering the heat exchanger, tends to be what cools the brew water down, hence the "cooling flush". If you make several extractions consecutively, you only need to run a cooling flush for the first one since new ambient water is coming into the boiler to replace the water used for the extraction. If you hesitate between extractions long enough, the ambient water rises in temp to match that of the boiler, thereby requiring another cooling flush. If you were to lift the brew lever and just let water flow and flow and flow, its temp would drop before coffee brewing range because it didn't spend enough time in the steam boiler to be properly heated.

    Ok the gicleur is a flow restrictor, noting more. It isn't there to mix or change the temp of brewing water. Its useful in any E61 group to slow the flow of water to a manageable level. Yes, it can have a slight cooling effect if it restricts the flow enough. It could be possible that some manufacturers, Diadema for example, try to balance the flow of brew water to the mass of the E61 group coupled with their boilers heating element's power and recovery such that brew temps are in the 200 neighborhood. However, without proper PID's all bets are off in terms of anything being at the right temp for anything. Without some way to measure the water temp and then feed that temp info back to the machine, the water temp will reach the capacity of the heating elements design and mass.
    To keep costs down, a manufacturer can probably design the heat exchanger boiler heating element such that when coupled with the lifting of the brew arm, prioritizes the brew temp over the steam temp to strike a certain balance. This of course is a compromise and my guess would be that steam pressure would hover around one bar and little more in reality and probably be good enough for one steaming session before needing to stop to allow the pressure to rebuild. However, this might be ok for a more entry or even mid level priced machine.

    This is why the more expensive machines will have a PID, maybe two or three in order to monitor and constantly adjust temps in the boilers as well as the E61 group, which is what I believe Bezzera is doing in one of their Duo machines that uses an electrically heated brew group, I think that might be the Duo DE IIRC.

    Here's a pic that may help.. ..

    E61-heat-exchanger.jpg
    This is almost ... completely incorrect.

    Charlie
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  24. #24
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    Feel free to rewrite it Charlie, I'm certainly open to constructive criticism.

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    The short version: The water in the HX circuit reaches an equilibrium temperature (ET) that is below the boiler temp and this ET is set by the design of the whole HX/thermosyphon/E61 system. It is possible to achieve a ET that is anywhere from 80 degrees C to well over 100 C. When it's over 100 C it is obvious because the group head will hiss and spit steam if the group head has not been used for some time ("some time" is also a function of the design parameters of the HX system). One factor which may help explain how this is possible - consider that the water constantly circulates through the HX (or boiler in a DB/SB E61) and group head in an E61 equipped machine and the E61 is a heat radiator (effectively cooling down the brew water). It's this cooling that causes the brew water to be below the temperature of the water in the boiler.

    A properly designed HX-E61 machine requires no cooling flush and the brew water temperature will be right where it needs to be from first shot to last shot (as long as the machine has had enough time to reach it's ET).

    charlie

  26. #26
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    It is physically impossible for the water in a thermosyphon to be in equilibrium when the thermosyphon is working. The disequilibrium is the driving force.

    The thermosyphon reaches its operating point when the heat loss from the group head balances the heat gain from the flow of water through the Hx. At this point the water coming from the Hx is hotter than that returning from the group head. If we draw the system boundary around the HX / grouphead loop that system is indeed in equilibrium with its surroundings, perhaps this is what you meant.

    If we now force water out of the grouphead by pumping in to the bottom of the Hx, the water at the group will change temperature as it flows. The degree of variation will depend on the flow rates but it can never be zero so the water cannot be at a constant temperature.

    Consider the following: Call the flow rate through the thermosyphon Ut and the flow rate when pulling a shot Us. If Ut does not equal Us then the heat loss from the Hx to the grouphead will be different between the two conditions, so the temperature of the water will change as the shot is pulled.

    If Ut does equal Us then the heat provided by the Hx will vary because the makeup water from the pump is colder than the return water from the thermosyphon. In this condition the water temperature will again change as the shot runs: the flow rates are equal so for a finite heat exchange capacity the final temperature will also be lower.
    Last edited by Lyrebird; 6th August 2019 at 10:08 AM.
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    Not to take anything from the above posts, but my observation has a slightly different insight.
    The gicluer will do little to the flow of the thermosyphon, as this flow will be quite slow.
    But when brewing, the pump pressurised both the upper and lower hx pipes equally, so the flow is blended with reverse flowed water from the lower pipe (that has already cooled the group) and the water that is coming out of the hx inside the boiler (that is hotter than the group temp).

    I have just had a Diadema junior extra on the bench. It had a scaled hx, and the gicleur was near blocked with scale. It would not come up at the group head (no more than 180f), and the brew temp was way to low. It was taking it's brew water from the bottom cooler pipe and almost none through the blocked gicleur.
    I diagnosed the fault by temperature gauges on the top and bottom pipes, and could clearly see the flows by the temperature change. With the top temperature stalled by the blockage, the bottom pipe temperature dropped also, as the cold water into the bottom of the hx was going straight out of the hx and into the bottom hx pipe, up to the group
    Obviously, if I removed the gicluer, then the machine would need a cooling flush, and the brew temp would be acquired by blending freshly drawn cold tank water into the hx and using it before it gets too hot.
    With the gicleur cleared, and brew selected, the top pipe increases in temp with the additional flow from the top of the hx, and the bottom pipe reduces in temp.
    The orifice size balances the hotter/cooler mixing by the ratio of the flows.

    My Musica has 2 gicleur, one in the top hx pipe, and one in the bottom pipe.

    There was a link that Mal gave but it wasnt directly about hx temp control. But it had a awesome engineering view of the hx temp control. They were basically bagging the dual boiler setup as being too easy, and removing the romance/engineering from machine design. It was one of the very expensive machine websites- van deer Kees, maybe...

  28. #28
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    Quote Originally Posted by Lyrebird View Post
    It is physically impossible for the water in a thermosyphon to be in equilibrium when the thermosyphon is working. The disequilibrium is the driving force.

    The thermosyphon reaches its operating point when the heat loss from the group head balances the heat gain from the flow of water through the Hx. At this point the water coming from the Hx is hotter than that returning from the group head.
    I think we're now arguing over semantics. There is a thermal gradient in the HX system which drives the thermosyphon. And after a sufficient heat up period, the brew water won't get hotter even if you leave the machine on all day. This is the temp I'm calling ET. Design the system so this temp is, say, 93 degrees and you have a HX which is a breeze to use and enjoy. No cooling flushes required.

    charlie
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  29. #29
    Senior Member Jackster's Avatar
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    Ok, it was Kees, im going to rip it straight from them, and post the link. I hate that in 10yrs time the links don't work, and the info is gone...
    Im a bit wrong in my post, but close.. Kees explains very nicely.
    Link:
    https://keesvanderwesten.com/mirage/construction/

    THERMO-SYPHON LOOP AT WORK
    The water in the HX is heated by the hot water and steam surrounding the HX in the large boiler. This is an extremely quick way to heat water, thanks to the massive energy in the 125 degrees C. steam boiler and the fast heat transferring capabilities of the copper. It is far more efficient than a heating element. The capacity of the HX therefore may remain relatively small. We use HX`s of 450cc per group.

    Heat always wants to go up: the heated water becomes lighter and moves upwards. This flow of hot water leaves the HX, enters the thick tube attached to the top of the HX, then runs towards the group. The group is installed slightly higher than the top of the HX. The group is a massive piece of almost 4 kg of brass. Brass being a very good heat transferring material, soaks up heat from the water when this enters the 35cc chamber at the rear of the group.

    The group becomes hot, the water losing much of its heat becoming heavier and starts to sink through the lower thick tube, running from rear of group to the bottom of the HX. Arriving there, the water re-enters the HX, heats up again and all starts anew. The temperature inside the HX is much higher than the normal operating temperature for the group. Capacity to heat the group is thus ensured very well.

    This thermo-syphon loop, travelling up from HX to group, then returning to bottom of HX, is driven solely by the heat inside the large boiler. There is no pump or any other device. When the machine is on and at idle (no coffee being made), the thermo-syphon loop is flowing constantly all by itself. As heating the water inside a closed system also means pressure will rise, there is an expansion valve installed. This is adjusted at the workshop to start releasing drops at 11-12 bar. The group solenoid valve has a rating of 15 bar and may act as a secondary expansion valve for extra safety.

    SYSTEM AT IDLE
    The group sitting at the very end of the thermo-syphon loop is a vitally important stabilizing factor. It is after all the last part water travels through before hitting the coffee, during brewing. Its temperature therefore is important and should be very close to the desired temperature of the brewing water.
    The temperature of the group body can be adjusted simply by having more or less hot water flow through its rear chamber. The temperature inside the HX being quite a bit higher than the desired temperature for the group, the thermo-syphon loop needs to slow down, needs to be restricted.
    With the Mirage we adjust the boiler to 125 degrees Celsius. To get the group body temperature at low nineties we install a standard restrictor at the top of the HX with a passage of 1.5mm.

    With different restrictors installed it is quite possible to operate one machine with temperatures adjusted differently from group to group, for example to accommodate for the use of lighter and darker roasted coffees. As an option we offer adjustable restrictors.

    One also may attempt to change the group temperature by changing the boiler temperature, but this method is limited because fairly large boiler temperature changes are needed to realize just a little effect at the group. Also the steam or hot water capacity of the boiler may be affected that way. With the proper restrictor one can for example easily combine the extremes of 1.5 bar high steam power with a low 88 degrees C. brew temperature.

    BREWING
    The challenge of the thermo-syphon system is to get water of low nineties temperature to the coffee, provided by a HX that stores water at 125 degrees. The extra heat is needed to keep the group at its perfect temperature, the remaining heat is needed to deliver brewing water of the correct temperature. To start the brew process the group solenoid valve opens the path from the thermo-syphon system towards the coffee in the filter holder. At the same moment the pump starts to run, keeping the pressure at a steady 9 bar, everywhere between pump and coffee.

    The sudden exit, provided by the open solenoid valve, has a drastic result. All water will now flow to that exit, pushed out by the pump pressure. The flow in the lower tube changes direction, it flows upwards to the group, instead of downwards to the bottom of the HX. The flow in the upper tube remains the same. The crucially important second function of the restrictor now becomes clear. The flow through the upper tube towards the group is severely restricted by the1.5mm orifice of the restrictor. The lower tube does not have any restriction, it has an inside diameter of 8mm. This full-flow 8mm, compared to the 1.5mm, means 99% of the water reaching the group arrives via the lower tube.

    This suits the requirements very well, since this lower tube contains the cooler water (generally 88-92 degrees, compared to the upper tube 115-125 degrees). To get the most out of this, we install a very long lower tube in the Mirage, containing 30cc. The remaining water comes directly from the HX. All water leaving the HX is replaced simultaneously by fresh cold water. The hot water leaves the HX through the lower tube, from bottom of HX. The cold water enters the HX also through the bottom. The cross flow of outgoing hot and incoming cold water is used to help each other. As there is just a 1mm copper wall between these 2 flows, the outgoing hot water is cooled down considerably, losing its heat to the incoming cold which starts to heat up right away. The cold water is forced to travel to the top of the HX via a long injection tube.

    When leaving the top of the injection tube it needs to travel down again to the bottom of the HX, during brewing. This ensures the heating capability of the HX is used to its full capacity. Naturally, the cooling down of the water from HX to lower tube by the crossflow is not a very precise process, as the temperature of the cold water can vary because of climate, location, season, etc. It will however be a major drop to well below 100 C. Travelling upwards through the long lower tube offers a good start to further stabilise. When entering the big brass group body the temperature of the water will be easily stabilized to the correct temperature of the group.

    To facilitate this temperature stabilization process we changed the insides of the group to increase the contact of water with the group body as much as possible. During brewing the water first passes the 35cc chamber in the rear of the group, then runs to the solenoid valve from where it re-enters the group. It fills the infusion chamber, passes through the passages towards dispersion fitting and finally is pressed through the group membrane- type screen.

    The stabilizing ability of the mass of 4kg brass is impressive. Even after taking a bucket of hot water from the main boiler, causing this to cool down for a short while during re-filling with cold water, the energy stored within the brass ensures enough shots of the correct temperature to allow the boiler to regain its standard temperature. When starting a shot, we recommend to draw a short flush: 30-45cc. Never flush more, because the water runs much faster through the entire system during a flush. When flushing longer the inherent stability of the system can easily be ruined, requiring at least 5 minutes to completely restore.

    CONCLUSION
    55 Years after its creation the E61 thermo-syphon system can still very much be considered a technically highly elegant system. Especially the thermal efficiency impresses and easily surpasses the popular multi-boiler systems. In comparison, the double, or multi boiler system, can technically be regarded as rather run of the mill.

    It is a great pity the Italian espresso machine industry, although widely adopting the thermo-syphon idea, did for about 40 years not take any initiative to keep on developing. Instead, it finally took the easy way, went back in time and grabbed the previous old idea of separate boilers for steam and coffee production. As a tiny company we could only follow. We do our best to offer the finest of either system.
    Dimal, Tusk, Martino and 1 others like this.

  30. #30
    Junior Member FedeBarista's Avatar
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    Quote Originally Posted by Jackster View Post

    CONCLUSION
    55 Years after its creation the E61 thermo-syphon system can still very much be considered a technically highly elegant system. Especially the thermal efficiency impresses and easily surpasses the popular multi-boiler systems. In comparison, the double, or multi boiler system, can technically be regarded as rather run of the mill.

    It is a great pity the Italian espresso machine industry, although widely adopting the thermo-syphon idea, did for about 40 years not take any initiative to keep on developing. Instead, it finally took the easy way, went back in time and grabbed the previous old idea of separate boilers for steam and coffee production. As a tiny company we could only follow. We do our best to offer the finest of either system.
    Jackster, your text is very interesting and I agree with your conclusion, HX is a great technology and it could be improved.

    But I believe that the Italian espresso machines for shops, such as Victoria Arduino, Simonelli, La Marzocco are HX, could you confirm that? or these companies are selling DB machines for shops too?

    Althought, I'm sure that DB is a trend in the prosumer segment.

  31. #31
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    Interesting and informative read, thanks for posting! Kees van der Westen certainly makes some far out looking machines but are not our typical made-for-home equipment. I think the Mirage goes for around $12K US. In reading through their write up, they mentioned a couple times that they modified their Hx/E61 system to improve upon it and gain brewing temp stability but I don’t think our common household Hx machines get this level of mod when we pay $1,500.
    The article mentions a short cooling flush, 30-45cc which is pretty small but as I think back to E61 Hx machines I’ve used, that’s in the range I recall the flush to be, only takes a few seconds and yes, if you dwell too long, you will need to wait a few minutes before brewing to allow the temp to get back to brew temp.



    Thing is, a lot of people buy mid level prosumer machines and spend a lot of money but end up making milk based drinks in which case, did they over spend? ha ha Yeah, I know I did. I had planned on drinking mainly espresso but my wife likes latte’s and in order to get a nice microfoam froth, I need to use enough milk for two and I don’t like to just throw the extra away, so I cave and drink latte’s with her most of the time. Oh well, I like my machine anyway even just to look at it :-)

  32. #32
    Senior Member level3ninja's Avatar
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    Martino have you considered using a smaller milk jug?

  33. #33
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    Ha ha, in fact I have played around with a few diff sizes. The one I use now when I make two latte's holds a total of 480ml, I only fill it to 230ml and our latte's are small, only 6 ozs (177ml). This rather small size produces a nice deep coffee flavor with just the right amount of foam for us. Sometimes when at a cafe, they put so much milk in that its hard to taste the coffee and you get filled up with milk....the beauty of making it at home is you make what you like.
    I have the Synchronika steam boiler set for 1.5 bar and it produces a wet paint silky froth that feels great in the mouth and makes nice latte art (when I'm in the mood :-) When company is over, I use a larger jug with probably 50% more milk and I crank the steam boiler up to 2 bar. Works great. The Synchronika, even at 1.5 bar steams quite quickly and I have the process timed so by the time the shots are done, so is the frothing and everyone gets a nice hot drink.

    If I use less milk, and sometimes when my wife pours the milk she'll put less in the jug, the steam is so powerful that it produces a lot of bubbles and if you aren't careful, you'll zip right past the stretching phase and into the heating phase and ruin the froth. My Synchronika has the joystick controls which I love but they are more of an on/off than rotary controls. No complaints here, its all about practice and patience. Oh, yeah, milk too...the type of milk makes a huge difference in its ability to create microfilm. We only use 2%, don't care if its organic or not but it does greatly depend on which brand we buy. Some simply don't work I have learned.

    All that said, I do make straight espresso's once in a while, its just not as often as I had imagined I would. I also like macchiato's. My in laws were here staying with us for a couple of months, since there were four of us for coffee, I would steam a bit more milk, like 250-260ml, make the two latte's for the girls and had enough milk left over for two macchiato's. I rather enjoyed that and that is what I drink when we go to Italy.

  34. #34
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    Quote Originally Posted by Martino View Post
    ... In reading through their write up, they mentioned a couple times that they modified their Hx/E61 system to improve upon it and gain brewing temp stability but I don’t think our common household Hx machines get this level of mod when we pay $1,500. ...
    Quote Originally Posted by JetBlack_Espresso View Post
    There are many HX machines available in Australia which do not need a cooling flush before extracting espresso.
    For example, the Lelit Mara 62S is temperature stable. That is, no cooling flushes are required and the brew water is at the correct temperature for espresso whether you are making back to back shots or the machine hasn't been used for hours.

    charlie
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  35. #35
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    Charlie,
    re: Lelit Mara 62S...Can you set the temp for coffee water yourself as well as change it if you want to?

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    The Lelit Mara 62S brew water temperature is set by the design of the HX, so is not changeable by the user. The Lelit Mara 62T has a PID which controls the steam boiler temperature and therefore also the brew water temperature (indirectly).

    charlie

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    Quote Originally Posted by JetBlack_Espresso View Post
    The short version: The water in the HX circuit reaches an equilibrium temperature (ET) that is below the boiler temp and this ET is set by the design of the whole HX/thermosyphon/E61 system. It is possible to achieve a ET that is anywhere from 80 degrees C to well over 100 C. When it's over 100 C it is obvious because the group head will hiss and spit steam if the group head has not been used for some time ("some time" is also a function of the design parameters of the HX system). One factor which may help explain how this is possible - consider that the water constantly circulates through the HX (or boiler in a DB/SB E61) and group head in an E61 equipped machine and the E61 is a heat radiator (effectively cooling down the brew water). It's this cooling that causes the brew water to be below the temperature of the water in the boiler.

    A properly designed HX-E61 machine requires no cooling flush and the brew water temperature will be right where it needs to be from first shot to last shot (as long as the machine has had enough time to reach it's ET).

    charlie
    hi Charlie, quick question, is the ECM Technika V one such machine? I’m looking into coffee machines and grinders now and you seem to know your stuff

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    so many opinions and so much technical data. I own an ecm giotto and recently upped the boiler pressure to 1.3 bar which in turn ups the temperature. my reason for this was the temp at the group wasnt high enough for proper espresso extraction and I was never getting the desired result. when I upped the pressure I installed a restrictor to the group head to keep the group from over heating. now I have only tasted with my tastebuds however the change in espresso is incredible. the flavour profiles are so different and not just noticeable with espresso but also my wifes capachino and the odd latte. I read all the data but at the end of the day the data doesnt taste good in my mouth. the coffee in the cup has really been a game changer. highly reccomend if your boiler is sitting below 1 bar. up it to 1
    2-1.3 add a restrictor and change your life

  39. #39
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    Charlie's explanation is correct and note his last sentence/caveat. I found wbroadhead’s post quite interesting and believe it demonstrates what I will say here.

    There's no reliable/repeatable way to know what the coffee brew water temp is on a Hx machine without some sort of measurement/gauge because even with a PID controlled Hx machine, such as the new ECM Technika V Profi with PID, the temp setting and monitoring of its temp is for the steam boiler, not the coffee brew water. As you adjust the steam boiler temp in an attempt to raise or lower the steam pressure the water temp inside the Hx (your coffee water) raises or lowers as well, it has to by design. Reference ECM's chart below to see ECM’s correlated temps, their chart is derived from their machine design. The typical brass ECM E61 group head weighs 3.6kg. That sucker is a huge mass and as Charlie said, its a radiator and part of the auto recirculation system of an E61. Personally, I think coffee brew temp is more important than steam pressure (just ask wbroadhead) and would experiment with the machines PID steam temp till I got the desired coffee brew water temp for the beans you’re using and then live with the resultant steam pressure, which should surely be adequate.

    The default boiler temp for the Technika V Profi PID is 120C which yields about 1-1.25 bar. From their user manual: The PID control of your TECHNIKA V Profi PID allows you to regulate the steam temperature and thus the boiler pressure for steaming milk. The steaming temperature is factory pre-set to 120°C (248°F). Inherent to the design of the machine, when modifying the steaming temperature, not only the boiler pressure but also the extraction temperature of the coffee changes.


    Per ECM.. .. The PID temp sensor is located at the steam boiler, there is no temp measurement at the group head or Hx. The table below indicates the set steam temperatures and the resulting “expected” extraction temperatures according to a measurement series with consistent parameters. At the time of coffee extraction, the machine has been on for 20-30 minutes.
    This table should only be used as a general guidance. Please note that the temperature values indicated in the table may differ from the actual temperature values due to variables such as ambient temperature, time of use of the machine since it has been switched on, extraction time of the coffee, possible lime residues etc. This is where the properties of a Hx machine come into play. You can approximate and calculate what the coffee water temp will or should be but you won’t know for sure without a way to measure it.
    Technically, the boiler temperature can be set between 80° and 128°C (between 176°F and 262°F). In the table, only the recommended boiler temperature interval from 120 to 124°C (from 248 to 255,2°F) is indicated.

    Boiler temperature at the measuring point/display ° C 120,0 121,0 122,0 123,0 124,0
    Extraction temperature at the brew group ° C 93,4 93,9 94,8 95,5 96,2

    Here’s a video, maybe you have already watched it, where Espresso TV is at ECM near Heidelberg as they reveal the new [COLOR=var(--ytd-video-primary-info-renderer-title-color, var(--yt-spec-text-primary))]ECM Technika V Profi PID this past June. If you pay attention to the timeline, you will see the machine spitting/sputtering at the [/COLOR]2:37 mark. The machine has been on for a while but not being used so that gave time for everything to heat up. While we don’t know the temp of the water coming out of the group head, my experience is 93C doesn’t spit and sputter. You will also notice a short flush done at 7:54. Ok, this short flush may be done via habit but I personally believe its good practice on a Hx machine for reasons stated above. No one is going to take constant note of how long the machine has been sitting between extractions, they are just going to use it.

    https://www.youtube.com/watch?v=MFOxjpgpx14

    This new ECM Technika V Profi PID machine looks to be a fantastic Hx machine and should serve you quite well. Its one of the closest Hx machines to a no cooling flush as you will get.






    Attached Images Attached Images

  40. #40
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    Quote Originally Posted by Sleeprequired View Post
    hi Charlie, quick question, is the ECM Technika V one such machine? I’m looking into coffee machines and grinders now and you seem to know your stuff
    It is .

    However, if you'd like a specific brew temperature at a certain (say higher) steam pressure then that's where a HX calibration may help

    charlie
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    Quote Originally Posted by Martino View Post
    Charlie's explanation is correct and note his last sentence/caveat. I found wbroadhead’s post quite interesting and believe it demonstrates what I will say here.

    There's no reliable/repeatable way to know what the coffee brew water temp is on a Hx machine without some sort of measurement/gauge because even with a PID controlled Hx machine, such as the new ECM Technika V Profi with PID, the temp setting and monitoring of its temp is for the steam boiler, not the coffee brew water. As you adjust the steam boiler temp in an attempt to raise or lower the steam pressure the water temp inside the Hx (your coffee water) raises or lowers as well, it has to by design. Reference ECM's chart below to see ECM’s correlated temps, their chart is derived from their machine design. The typical brass ECM E61 group head weighs 3.6kg. That sucker is a huge mass and as Charlie said, its a radiator and part of the auto recirculation system of an E61. Personally, I think coffee brew temp is more important than steam pressure (just ask wbroadhead) and would experiment with the machines PID steam temp till I got the desired coffee brew water temp for the beans you’re using and then live with the resultant steam pressure, which should surely be adequate.

    The default boiler temp for the Technika V Profi PID is 120C which yields about 1-1.25 bar. From their user manual: The PID control of your TECHNIKA V Profi PID allows you to regulate the steam temperature and thus the boiler pressure for steaming milk. The steaming temperature is factory pre-set to 120°C (248°F). Inherent to the design of the machine, when modifying the steaming temperature, not only the boiler pressure but also the extraction temperature of the coffee changes.


    Per ECM.. .. The PID temp sensor is located at the steam boiler, there is no temp measurement at the group head or Hx. The table below indicates the set steam temperatures and the resulting “expected” extraction temperatures according to a measurement series with consistent parameters. At the time of coffee extraction, the machine has been on for 20-30 minutes.
    This table should only be used as a general guidance. Please note that the temperature values indicated in the table may differ from the actual temperature values due to variables such as ambient temperature, time of use of the machine since it has been switched on, extraction time of the coffee, possible lime residues etc. This is where the properties of a Hx machine come into play. You can approximate and calculate what the coffee water temp will or should be but you won’t know for sure without a way to measure it.
    Technically, the boiler temperature can be set between 80° and 128°C (between 176°F and 262°F). In the table, only the recommended boiler temperature interval from 120 to 124°C (from 248 to 255,2°F) is indicated.

    Boiler temperature at the measuring point/display ° C 120,0 121,0 122,0 123,0 124,0
    Extraction temperature at the brew group ° C 93,4 93,9 94,8 95,5 96,2

    Here’s a video, maybe you have already watched it, where Espresso TV is at ECM near Heidelberg as they reveal the new [COLOR=var(--ytd-video-primary-info-renderer-title-color, var(--yt-spec-text-primary))]ECM Technika V Profi PID this past June. If you pay attention to the timeline, you will see the machine spitting/sputtering at the [/COLOR]2:37 mark. The machine has been on for a while but not being used so that gave time for everything to heat up. While we don’t know the temp of the water coming out of the group head, my experience is 93C doesn’t spit and sputter. You will also notice a short flush done at 7:54. Ok, this short flush may be done via habit but I personally believe its good practice on a Hx machine for reasons stated above. No one is going to take constant note of how long the machine has been sitting between extractions, they are just going to use it.

    https://www.youtube.com/watch?v=MFOxjpgpx14

    This new ECM Technika V Profi PID machine looks to be a fantastic Hx machine and should serve you quite well. Its one of the closest Hx machines to a no cooling flush as you will get.






    wow that’s a truly comprehensive reply. Hmmm I’m planning to automatically turn my machine on every morning and it seems if I forget to purge I’ll waste/burn coffee/time. I see what you’re getting at thank you for your input.

    im learning...

  42. #42
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    Quote Originally Posted by JetBlack_Espresso View Post
    It is .

    However, if you'd like a specific brew temperature at a certain (say higher) steam pressure then that's where a HX calibration may help

    charlie
    just saw this thanks Charlie. So this will mitigate the differences between the double boiler and the Hx? It does bring the unit $250 closer to the dual boiler though...

  43. #43
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    There are a few ways you can get a quasi handle on a Hx coffee water brew temp. The Hx Calibration kit, just using the manufacturers cross ref chart (like the ECM one), experimentation and/or you can install a digital thermometer into the E61 group head. Once such thermometer is the Vidastech E61 Group Head Thermometer -https://www.amazon.com.au/Vidastech-...0624931&sr=8-1

    You can read a few posts on this here - https://coffeesnobs.com.au/brewing-e...roup-head.html

    Keep in mind, its not the end of the world if you forget to do a cooling flush, buy a good machine and while you may notice a slightly different coffee flavor if you forget, it will probably still be drinkable and who knows, you may not even notice a flavor diff on the ECM Technika V Profi PID. No matter which technique you use, out of the above, in reality, you will turn the machine on in the morning and it will probably stay on for long periods of time during the day, especially on the weekend. You will not want to wait for it to heat up when you're in the mood for a coffee so you will leave it on. You will not know for sure when the machine has reached equilibrium and you'll be busy having a life so its doubtful you will pay attention to all the variables that come into play for its coffee water temp. You will probably get into the habit of doing a quick cooling flush and not even think much about it. We form habits over time.

    The ECM you are looking at has a PID that also allows you to set the number of minutes of non use before it goes in standby mode. I have this on mine as well so I just have the machine turn on via an electronic timer in the morning, its up to temp when we're out of bed, I make our coffee's, about an hour later I make another set of coffee's and then let the machine go into standby mode till early afternoon when I use it again. The timer turns it off at a certain time or I can use my phone to turn it on and off at will. If the machine goes into standby mode, the PID display will tell you that and you will see the boiler pressure gauge at near zero. If at that time you want a coffee, you will power cycle the machine, it will restart the boiler and you will need to wait for it to come back to temp, doesn't take long and the PID display will tell you when the steam boiler is back to temp and if you have a thermometer in your E61, that will tell you as well.

    If you are trying to fit a machine and a grinder into a set budget, a Hx type machine will help over a Dual Boiler. I think one of the points made in the coffee snob link above is that people use the E61 thermometer to get an understanding of their machine, how long it takes to recover the temp after a brew, what the temp can get up to when letting the machine sit for a while, etc. Once they learn the characteristics of their machine, they set their process. If the variability in brew water temp is slight, you may not worry if you forget a cooling flush.
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