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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...
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...
Comments
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.
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.
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...
I do enjoy med to med/dark roasts from time to time so I think I would benefit from it.
Thanks!
TonyM
Tried longer too but saw no improvements...
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.
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
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.
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.
can you please provide an image of where the trouble is?
kind regards
reiss.
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.
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.
Thanks, this worked perfectly! When it doubt, bang it harder.
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
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.
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.
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
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).