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Digital pre-infusion module for L-R

Hi all, after extensively using the new digital pre-infusion module (https://londiniumespresso.com/store/espresso-machine-parts/p-271-digital-pre-infusion-kit) I can say I'm very happy with it.

It expands the versatility of the Londinium L-R machine as it allows a flexible and precise adjustment of the pre-infusion pressure up to 6 bar.

Now, dark roasts can be gently extracted at a relatively low pressure, avoiding the 'burnt rubber' taste and on the other extreme of the pressure spectrum, light 'nordic' roasts and even those meant for filter coffee can be extracted as regular espresso.

Especially that "high pressure" functionality makes it feel like I got a completely new machine.

Before I would just give away bags of beans that were on the very light side and a friend who does drip / pourover methods would enjoy these beans a lot.

Now I can just slam the higher pressure on and boom, there's a full bodied rich regular espresso. I purchased three bags of beans from a nearby roaster whoi is well known for his light roasts. One was even exclusively roasted for filter but it got turned into a fine espresso all the same.

Meanwhile I'm back to my usual 3bar setting but it's very nice to be able to swiftly adjust the pre-infusion pressure and, in consequence, the infusion temperature and the start of the pressure profile.

At the high end, the lever, when lifted, grabs just below horizontal, when the spring is very powerful.

https://kostverlorenvaart.blogspot.com/2018/12/taming-light-roasts-with-digital-pre.html

https://kostverlorenvaart.blogspot.com/2018/12/taming-light-roasts-with-digital-pre_13.html

https://kostverlorenvaart.blogspot.com/2018/12/taming-light-roasts-with-digital-pre_15.html

So if you feel like treating yourself to a whole new ballgame, I advise picking up this nifty and (at current exchange rate) affordable innovation for your L-R...
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Comments

  • Frans, I presume you are getting quite high EY from these coffees due to fine grind, high piston pressure and high brew water temperatures. Have you measured them?
    Matt
  • Matthew Hoffman post=15252 wrote: Frans, I presume you are getting quite high EY from these coffees due to fine grind, high piston pressure and high brew water temperatures. Have you measured them?
    Matt

    I have not measured the TDS and therefdore also not calculated the extraction yield with teh VST app, but I enjoyed the full bodied espresso out of the very light roasts. I did not grind extremely fine. When I did in the beginning, assuming that would be necessary, I choked the group and had to leave it for minutes to drip out. When grinding at the fine end of the etzMAX spectrum (able to grind fast with the relatively small motor) and dosed 1-2g extra, that was enough. No extra long pre-infiusion time needed. The relatively high extraction pressure compressed the puck enough to get a fairly normal flow.
  • Frans Goddijn post=15253 wrote: [quote=Matthew Hoffman post=15252]Frans, I presume you are getting quite high EY from these coffees due to fine grind, high piston pressure and high brew water temperatures. Have you measured them?
    Matt

    I have not measured the TDS and therefdore also not calculated the extraction yield with teh VST app, but I enjoyed the full bodied espresso out of the very light roasts. I did not grind extremely fine. When I did in the beginning, assuming that would be necessary, I choked the group and had to leave it for minutes to drip out. When grinding at the fine end of the etzMAX spectrum (able to grind fast with the relatively small motor) and dosed 1-2g extra, that was enough. No extra long pre-infiusion time needed. The relatively high extraction pressure compressed the puck enough to get a fairly normal flow.

    Maybe the extraction levels were more normal then. As I inderstand it, from reading Matt Perger, the main point of grinding finer for light coffees is to increase the surface area of the coffee grinds exposed to the brew water. In any event, the proof is in the taste and your results are interesting.
  • With LR default setting I get usually over 20% with light roast (La cabra, Tim wel) with ratio around 2:1 in VST 18 - dose 17.5g.
    The better prep the higher you can go with extraction. I usually don't like below 19%...

    For darker roast I usually stop at 30grams...
  • Thanks for taking the time to report! Much appreciated. The upgrade is something I intend on doing, but have only had the R for about a month. It's my first lever so still going through a learning curve, and prefer to learn on the stock machine and with minimal variables.

    I do enjoy med to med/dark roasts from time to time so I think I would benefit from it.

    Thanks!
    TonyM
  • How long are your preinfusion times?
  • Jonathan Shneidman post=15262 wrote: How long are your preinfusion times?
    Usually, between 7-15s. Though lately it seems to keep around at 15s.
    Tried longer too but saw no improvements...
  • Since it's fun and propductive to tweak the pre-infusion once the digital module is installed, I frequently find myself trying out a new setting.

    With the module behind the right side panel, this involves a few steps:
    1) switch off machine
    2) take off reservoir lid
    3) take off top panel
    4) take out reservoir
    5) take off side panel
    6) adjust setting
    7) attach side panel
    8 ) attach top panel
    9) insert reservoir
    10) put on reservoir lid

    Taking off the reservoir / tank is necessary for me because getting on the top panel with the reservoir in place involves precision wriggling which I like to avoid.

    A downside of this is that frequently removing and re-inserting the reservoir can get dust / grease on the water level sensor and this causes the "i have no water" alarm to go off. Also I find that keeping the reservoir where it is prevents a situation where the pump is gasping with air instead of water, since re-inserting the reservoir opens/closes the connection where one wants air to keep out as much as possible.

    To make module adjustment easier, the future optional wireless app is an idea but for me that's introducing high tech in a machine that's so beautiful in its simplicity.

    An alternative would be a nice bracket at the back / side of the machine to mount the module on, and a slit in the back panel to lead the wires from the module through. This would involve some work to make the bracket look real good and to keep the wires protected.

    Then I thought of simply removing the nipple from the top panel that catches the side panel.

    I removed it (simple with a small 10mm spanner) and now I can quickly

    1) take off the side panel,
    2) change settings, observe the result and
    3) re-attach the side panel.

    No need for a complex mod! And the top panel and tank/reservoir can stay where they are.



    image
  • brilliant - thx Frans
  • Hi Frans,
    Thank you for this simple and elegant solution. This makes removing the panels and performing pre-infusion adjustments much easier. Also, thank you for your many posts here and elsewhere. I have read many and have always found them to be quite insightful and helpful to my coffee exploration.
    Would you please answer a question and help me understand the LR a bit better? Now that I have the pre-infusion module in place, an adjustment up or down will produce changes in extraction temperature, correct? How does a pressure-stat adjustment (the screw under the yellow plastic cap) interact with the pre-infusion module? Why would one change one vs the other?
    Thanks for your insights.
    Kind regards,
    Rick
  • hi ricky

    we have chosen to regulate the pre-infusion pressure in order to provide a wide range of inlet water temperatures into the brew chamber, rather than regulate the inlet temperature directly because whilst a PID to measure temperature is 'precise' the readings go all over the place whereas pressure is constant, or at least stable, at any given point in the circuit

    moving the pressure in the boiler is as good as useless as significant movements in the boiler pressure produce very small movements in temperature in the boiler and elevated boiler pressures will very quickly produce flash boiling in the thermosiphon circuit, which presents as a loss of thermal stability in the group temperature so please never change the boiler pressure from a maximum value of 1.0 bar

    when i was using the L3 in the early days i discovered that changing the inlet pressure on the cold water line feeding the L3 had a drastic impact on the taste in the cup. this lightbulb moment was understanding that this was because we had water at very different temperatures in relatively close proximity in different parts of the system; in the core of the heat exchanger the temperature was around 125C yet a short distance away the surface temperature at the group was only 87C

    when you increase the pressure in the pre-infusion circuit you are 'blowing' the 'hot' water in the core of the heat exchanger out to the puck much more rapidly and so the group has less time to suck heat out of the water and so it arrives at the puck at a higher temperature (and pressure obviously)

    this increase in heat and pressure transforms the thin citrus (lemon, lime) taste of many light roasts into a pleasing sweetness and creates a lot of body

    why did we move from a secondary pressure switch to regulate the pre-infusion pressure to a pressure transducer?

    primarily reliability: the static pressure present in the system when it is idle is too great for the pressure range that we needed the pressure switches to operate within; the original Ceme was 0-6 bar, the first Mater was 1.5-4.0 bar, and the last Mater we used was 2.0-6.0 bar but the static pressure tends to run around 9 bar and over time it blows all three switches. in comparison the pressure transducer we are using now is rated to operate to 30 bar so it eliminates this issue at a stroke

    secondly the pressure transducer allows you to change the pre-infusion pressure by a known amount with no tools required to make the adjustment or to check the post adjustment pressure

    for a darker roast you might want a pre-infusion pressure of around 1.0 bar, a medium roast around 2.3 bar, and a super light nordic style lemon juice roast can be transformed into something really remarkable and pleasant with 6.0 bar of pre-infusion

    the offset value compensates for the drop in pressure between where the pressure transducer is place and the pressure at the puck and -1.0 bar seems to work well; you can verify this offset yourself with a pressure gauge mounted in a portafilter but please be careful as you need to flush out any air or you will obtain an artificially low pressure reading and it is very easy to spray near boiling water all over yourself

    you can adjust the time interval that the pump activates in response to the pressure reading; this helps you to stop the pump chopping in repeatedly in an erratic fashion which is a bit irritating and probably not that great for the pump either

    if you have further questions please ask

    kind regards

    reiss.
  • Hi Reiss,

    Do you have any plans to design new side panel with easy access to change the preinfussion settings (small window, flap, etc.) or your final decision would be to focus on app and wireless module?
  • In my view removing the one nipple makes access very easy. The added costs of other alternatives would not be worth it, in my opinion. The Research & Development for the module went directly to the effect of improved versatility in making delicious coffee. The rest would be investing in looks, one of those extras that 10 guys say they want but if it's finished and ready to order most will say "wonderful, so happy I can get it, I might get it sometime next year, maybe" ;-)
  • Paweł Walczak post=15271 wrote: Hi Reiss,

    Do you have any plans to design new side panel with easy access to change the preinfussion settings (small window, flap, etc.) or your final decision would be to focus on app and wireless module?

    Hi Pawel

    the wireless module is already in the pressure transducer kit - all that is missing is the app and i would anticipate that being available in february/march

    kind regards

    reiss.
  • Thanks for your thorough reporting, as usual, Frans. After corresponding with Reiss a bit, I decided the timing was right for me and I just placed my order for the digital pre-infusion module for my L-R. I am looking forward to experimenting with different settings as they relate to varying roast profiles. I intend to take advantage of your side panel modification tip for easier access and will also be looking forward to taking advantage of the app once it is developed. Good times. :)
  • I'm excited to get my digital pre-infusion box up and running. Does anyone have advice on getting the blank nut off the junction? It's proving a much tougher nut to crack than any of the others.
  • hi ben

    can you please provide an image of where the trouble is?

    kind regards

    reiss.
  • This bad larry right here is giving me some trouble. The spanner-and-hammer treatment worked fine on everything else, but this one refuses to budge. I'm thinking maybe I just need something that can provide more torque, like a socket wrench.


    image
  • hit it harder with the hammer

    if you have got an assistant to hold the manifold for you so not too much strain goes onto the water tank carrier bracket that would be helpful

    dont be afraid to strike it hard

    perversely just pulling harder and harder on the end of a wrench with your hand is what turns soft copper pipes inside out; the shock of the hammer is your friend in this particular situation, this is what will free the thread

    kind regards


    reiss.
  • My pre-infusion module arrived yesterday and I installed it last night. I can attest that the hammer method does work. I struggled just a bit at first, too. I'm really glad I watched the video. Speaking of the video, my kit did not contain the 'olive' part mentioned in the video as it shipped with a larger diameter copper tubing for this part, so the 'olive' part was not required. I did spend a couple of minutes looking for the 'olive' until I realized the difference in size of the tubing. All went well with the install. I took my time and it was very satisfying once completed. One minor issue I noted on my control module was with the display. Once the settings are saved, I cannot really read the top line, clearly, which, from the video, I believe to be the 'bar' reading. The text is displaying a bit too high in the window. I can see the second line, the set value, clearly. I don't know if there are any adjustments for that? If not, no big deal as I can clearly see the text during the critical times when configuring / saving the settings.
  • hi terry

    i think you can lift the adhesive sticker and reposition it

    alternatively you could open the casing and reposition the display by a millimetre or similar

    we are now using a different fitting on the pipe you mention, so no olive

    kind regards


    reiss.
  • Reiss, thank you for the tips regarding the display window. I'll have to take a close look next chance I get.
  • Reiss Gunson post=15317 wrote: hit it harder with the hammer

    Thanks, this worked perfectly! When it doubt, bang it harder.
  • Firstly, my thanks to Frans for suggesting the removal of the front/right bayonet fixing pin such that the right-hand side panel can be easily removed, in order to access the PI module. It was that idea that prompted me to go digital in advance of the App and, it works a treat.
    Although at first, I ordered the upgrade kit, Londiniumitis got the better of me and I ended up ordering a brand new machine. :)
    As expected, the L-R has produced some great coffee from the get-go.

    I do however have a question which I would imagine is, best directed at Reiss.
    There are several references here on the site to keeping the Offset value set at -1.0 and it is a point stressed in the retro-fit installation video. My machine has arrived with an Offset of -1.4 Is there any reason why this would not have arrived factory-set at -1.0 and, should I now reduce it ?

    Tony
  • Tony Cordery post=15324 wrote: I do however have a question which I would imagine is, best directed at Reiss.
    There are several references here on the site to keeping the Offset value set at -1.0 and it is a point stressed in the retro-fit installation video. My machine has arrived with an Offset of -1.4 Is there any reason why this would not have arrived factory-set at -1.0 and, should I now reduce it ?
    Tony
    For what it's worth, mine shipped with the same default setting of -1.4. I had the same question in my mind but deferred to the video instructions and made the adjustment to -1.0. I will be watching to see what Reiss has to say.

    P.S.
    I am really enjoying the pre-infusion module. Before, I never bothered trying to adjust this setting as I was fearful of messing something up and not being able to back out of it. I tried Frans' preferred setting of 3.0 and, anecdotally speaking, could tell the difference in water temperature and taste---water temperature seemed cooler in the shot, and it tasted more fruity. For my taste and this specific coffee, Kenya AA, Otter Specialty Coffee Roasters, with a Full City+ (medium-dark) roasting profile, I did revert back to 3.5. Fun stuff.
  • hi tony

    its a good question and i expect you are going to be slightly disappointed with the short answer which is: i am not yet certain

    the long answer is hopefully slightly better received:

    i am still running a pre-production version of the pressure transducer kit in which i have the pressure transducer threaded into the fitting that the Mater was previously occupying

    in my setup i observed elevated levels of static pressure cycling as the heating element cycled. it was pushing up close to christmas and i was determined to launch it prior to 31/12 so i worked with an engineer at the manufacturer via WhatsApp at some fairly anti social hours and he knew that the range of the static pressure cycling would be reduced if we moved the pressure transducer further away from the boiler. it obviously only took a moment to look at all the unused ports on the inlet manifold and think, right, lets try it there

    we moved the pressure transducer to the inlet manifold and that drastically reduced the range of the pressure cycling that was measured by the pressure transducer, which allows the expansion valve to be set to a lower setting

    the purpose of the offset parameter is you get a pressure drop from the location of the pressure transducer out to the puck. when the pressure transducer was in the location where the Mater used to sit i measured this pressure drop as 1.0 bar, and this is how the offset value of -1.0 bar came to be used in the installation video

    as a result of moving the pressure transducer further away from the puck the pressure differential should be greater. the engineer at the manufacturer has obviously set yours to -1.4 bar, which should be correct

    having said that i am not yet in a position to measure that new difference myself, but as soon as i bring the new kit down here i will do so. perhaps one of you has a portafilter with a pressure gauge mounted on it and is able to verify it? when you have the offset correct, when you pull the lever down and have the pressure gauge on the portafilter and bleed the air out of the portafilter you should then get the 'bar' value on the pressure transducer kit to equal the pressure shown on the pressure gauge at the portafilter. as always with these kind of exercises make it a best of three event

    for the meantime probably run with the assumption that -1.4 is the correct number and leave it at that. happily with this setup these things are so easily and precisely changed

    kind regards


    reiss.
  • what i'll do is pull the production bits i need to upgrade my father's machine on DHL Express to new zealand this week and then i can use that machine to verify that -1.4 bar is the correct offset value for you by the end of this week.
  • Hi Reiss,
    Thanks for the response so far and I look forward to clarification once you have had a bit of a play.
    In the meantime, I will keep the Offset at -1.4 and the Pump Delay at 1000ms

    I have not yet done much with the digital PI unit other than familiarise myself with the control panel but, here are my very limited observations. In fact, they are so limited they are probably of no value whatsoever :)
    The delivery pre-set of 3.0 Bar gave me a great result with a Guatemala Washed SO, so I stuck with that for a while.
    Then I changed out to a medium roast blend and with all else being equal, got an improvement in the cup by changing from 3.0bar to 2.5 Bar
    I did notice that at 2.5 Bar that the pump blips in, at the 1 sec Pump delay interval, more than it did with 3.0 Bar setting.

    Immediately after removing just the rhs panel, the static pressure was cycling, on average, 6.0 : 8.4 Bar
    After a short while, I assume due to the lack of a side panel and therefore running cooler, it was cycling 4.5 : 7.0 Bar
    A similar differential but within different ranges.

    Tony
  • Reiss Gunson post=15327 wrote: what i'll do is pull the production bits i need to upgrade my father's machine on DHL Express to new zealand this week and then i can use that machine to verify that -1.4 bar is the correct offset value for you by the end of this week.

    Reading this, I have changed my control settings from -1.0 bar to -1.4 bar. I will be staying tuned to this thread. Thank you, Reiss (and Tony).
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