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  • Martino
    replied
    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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  • Sleeprequired
    replied
    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...

    Leave a comment:


  • Sleeprequired
    replied
    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...

    Leave a comment:


  • JetBlack_Espresso
    replied
    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

    Leave a comment:


  • Martino
    replied
    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.






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  • wbroadhead
    replied
    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

    Leave a comment:


  • Sleeprequired
    replied
    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

    Leave a comment:


  • JetBlack_Espresso
    replied
    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

    Leave a comment:


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

    Leave a comment:


  • JetBlack_Espresso
    replied
    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. ...
    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

    Leave a comment:


  • Martino
    replied
    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.

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  • level3ninja
    replied
    Martino have you considered using a smaller milk jug?

    Leave a comment:


  • Martino
    replied
    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 :-)

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  • FedeBarista
    replied
    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.

    Leave a comment:


  • Jackster
    replied
    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.

    Leave a comment:

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