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  • Originally posted by AndyGr View Post
    I have found an interesting article on the La San Marco website stating that their lever machines "brew the coffee at a temperature of around 120 °C, as against the 95 °C of electronic models".
    https://www.lasanmarco.com/lever-world.php

    Is it a mistake? The brew temperature of 120 °C seems to be way too high. My understanding is that the temperature in the boiler is PID-controlled in the range of 120 °C - 128 °C. Then it cools down to 92 °C - 98 °C or so in the group head, depending on the boiler temperature. Shouldn't 120 °C burn the coffee? Since the Izzo Alex Leva uses exactly the same LSM group head, has someone actually measured the brew temperature range for different PID settings?
    Andy,

    Sometimes the internet isn't your friend. Combine that with Italian to English translation and confusion reigns!

    Think about it for a second, group head brew water at 120C... its not water... its steam...

    Cheers

    Antony

    Comment


    • Barry O'Speedwagon
      Barry O'Speedwagon commented
      Editing a comment
      So, AndyGr, I was simply trying to be conciliatory, and to reconcile your thoughts with those of the other chaps...but it seems that you are in this to tell Grandma how to suck eggs. Perhaps I'm wrong, and I apologise if that's not the case. Regarding the researchgate article (which I note contains the caveat 'not peer reviewed') that you cite and ask me whether this is also a mistake...could you kindly cite where in that article the authors explain precisely how their temperature references are obtained. The authors do use the phrase 'brewing temperature' to describe the measure applied in their tests, but there's bugger all in the article that inspires confidence that the authors know what they are talking about regarding the temperature of water that hits the puck. So yeh, I reckon it is also a (well-intentioned) mistake.

    • Caffeinator
      Caffeinator commented
      Editing a comment
      No problem whatsoever to brew coffee at 128+ deg C. All you have to do is get the whole setup into an environment of 3 atmosphere- give or take... You might need to drink it in that environment as well. Do you let it cool or just go the whole hog and call the burns unit in?

      Anyone have a spare hyperbaric chamber handy?

      128 deg C of Alex Leva at the PID delivers roughly 96 deg of brew temp at my place. 93 deg at the PID would actually deliver SFA as there would be no steam pressure to make the dipper operate. Pull espresso at much beyond 128 deg and you will be doing it with steam as Antony correctly stated in the original response to Andy's.

      Sadly 20 different ways of stating precisely the same thing- utter waste of time. Year 7 Science fail.

      Where's that faceplam emote?
      Last edited by Caffeinator; 13 August 2020, 11:36 PM.

    • 338
      338 commented
      Editing a comment
      Andy, I must take you to task here, your comments to Barry O are simply unacceptable.

      I have read his post, to me it seemed a mixture of information and conciliatory comments, he even apologised to you in the middle if he misinterpreted you. You clearly read it differently, let's put that down to a bad night, either way your comments were unacceptable.

      There are a lot of wise and experienced people on the forum and in this thread. I consider all know more than myself about coffee and coffee machines, so I always hope to learn. It is OK to ask questions, debate, discuss or dispute but we don't have to inult each other personally.

      Let's stick to the subject of does 128 degree brewing exist and debate the subject not the individual.

  • Originally posted by 338 View Post
    The ACS Vostok is a dual boiler with the same group head...
    Not really in this case. The Vostok employs cartridge heaters to a modified LSM group to achieve PID controlled brew head temps. What you see is what you get. It's a bonus of the dual boiler configuration where you run the brew boiler cool and then allow the cartridge heater to post finish temperature at the group.

    The others are either dipper or variations on the theme of HX. Whether dipper or HX, any PID which is displaying brew temp will be programmed with an offset to display boiler temp - x deg C.

    Offsets are hit and miss in that they vary according to ambient temperature. Ultimately for a traditional group regardless what temperature might be displayed, palate is the determinant of whether the chosen set temp be it it raw boiler (120 deg. C) or thereabouts or offset (raw boiler - x deg.) which is being used.

    Comment


    • 338
      338 commented
      Editing a comment
      Caffeinator thanks for the extra info, had no idea the Vostok used cartridges. Quite an advanced setup

  • In my original post, I was wondering whether the LSM claimed 120°C would make sense at all or just a mistake:
    https://www.lasanmarco.com/lever-world.php

    The German research paper was secondary, just a reference of high temp brewing. So, I asked both LSM and the research team of University of Applied Sciences Albstadt-Sigmaringen for the clarification. Yesterday, I received a reply from Dirk Lachenmeier:

    "The temperature setting of the coffee boiler of the ECM synchronica can be adjusted in the range of about 80-130°C (the boiling point of water depends on the pressure, therefore at 2 bar and 120°C, the water should be still liquid and not steam).
    At the setting of 128°C, we measured about 115°C at the portafilter (scace device).

    The La San Marco apparently used pressures up to 14 bar, at which you would have a maximum possible boiling point of about 180°C.
    In our experience, such high temperatures lead to considerable overextraction, and we would not recommend them (at least not with the ECM Synchronica).
    However, the electronic extraction looks interesting."

    So, this topic raises a few key points: (a) whether it is even possible to have a brewing temperature over 100°C, as many people argued that we will get only steam instead of water; (b) what's the point to raise the brewing temp so high as the coffee should burn and get undrinkable; and (c) the LSM reference of brewing at 120°C on lever machines - is it a mistake (marketing trick) or not,
    1. Brewing under a high temperature of over 120°C is possible under a high pressure, since the water boiling point will increase. We already have a high pressure in the brew chamber above the portafilter - so it is not an issue at all. Here is another question - if we have a high temperature around 120°C above the puck, why don't we get only steam out? It is because of the pressure drop, which causes a drop in temperature. You may calculate the temp drop exactly, based on the pressure drop from ~9-12 bar to 1 bar.
    2. Yes, the coffee will be undrinkable under a high brewing temp; however, it applies to constant pressure machines. For lever machines, in my opinion, it depends on the pressure profile, i.e. how rapidly the pressure/temperature drops.
    3. While I am waiting for a clarification from La San Marco, I don't think the reference of 120°C brewing temperatures for the LSM manual lever machines is an error. Perhaps, a rapidly declining pressure and temperature in lever machines doesn't result in overextraction and burn coffee. Again, this is just my opinion as I could not find any sources analyzing temperature change in spring group heads.
    There is another source from Slayer dated back to 2007 that in lever machines the water hits the coffee under the temperature less than 235F, but certainly hotter than 204F, i.e. more that 100°C. I guess, the assumption is right - a high initial temp on the lever doesn't lead to overextraction and burn coffee due to a rapidly declining temp profile.
    https://slayerespresso.com/lever-esp...%93%20245%20F.
    Last edited by AndyGr; 4 weeks ago.

    Comment


    • Caffeinator
      Caffeinator commented
      Editing a comment
      The outright stupidity and patent lack of understanding as to what they were actually doing especially with the LSM beggars belief. The fact that it was actually published is astonishing.

      Yep you can get 12Bar extractions with a spring leva using water either via a HX or dipper via a boiler at a maximum of 1.5Bar. Whilst the theoretical boiling point of the water might be 180 deg at that pressure within the body of the group, it ain't happening with with water that never was within a bulls roar of that- and that's before consideration the heat losses that occur at the group.

      This journal article it best nailed to the door of an outback dunny lest the loo roll expire. Regardless, I wouldn't wipe my arse with it.

      Next time the want to publish, they can do it in a single sentence: "Burned coffee tastes like crap". Thereafter they can hit the pub. Idjuts.

  • AndyGr I moved your post to here as it continues the argument that was started here and to drag it into another thread is extremely bad form.

    Originally posted by AndyGr View Post
    ...but certainly hotter than 204F, i.e. more that 100°C.
    Uuuummm...100°C=212°F i.e. 204°F is not more than 100°C.


    Java "More like 95.56°C" phile
    Toys! I must have new toys!!!

    Comment


    • Finally, my Izzo Valexia has been fixed, thanks to Antony from Casa Espresso and the Di Pacci's service team! I need to say that Antony has provided a really exceptional level of services - a rare commodity these days. The first inspection visit was organized the same day as I notified the vendor. Next day, the replacement parts had been shipped from Melbourne to Sydney by express courier. Two days after, the machine was fixed.Thank you, Antony - highly appreciated!

      Comment


      • Well, my first trial shots are totally undrinkable... extremely bitter and smell like burned rubber. Someone should have seen my wife's face I tried a dark blend, Elephant Bean Blend from Withams. This is what I have tried so far (all 18 g in -> 35-40 g out):
        1. 125°C - too bitter,
        2. 119°C - too sour and bitter at the same time. I could not even think it is possible.
        3. 120°C - the sourness has gone, bit still too bitter and hardly drinkable. Time: 32 sec, 40 g out.
        The puck turned out very dry, no moisture and no channeling. One of the problems I see is that after 25 sec or so, the flow dries out - actually, no flow, but separate drops (clear blonding). Assuming the it is over-extracted, I need to grind coarser, but it will reduce the time even more. Please correct me if I am wrong. Otherwise, should I grind finer to increase time and remove the cups before the blonding point?

        I would appreciate some suggestions!

        Comment


        • 338
          338 commented
          Editing a comment
          Hi Andy, I would check with Casa Espresso for a definitive answer but worth reading this article which details how the Profitec dipper lever works. Alex Leva is also a dipper. https://www.home-barista.com/reviews...ew-t44660.html

        • AlMac
          AlMac commented
          Editing a comment
          Andy, what a saga you’ve had.

          How long is your Alex on when you are pulling your shots?
          Is your group head full heated? I think this takes 40 minutes at least.

          I have my PID set to 118. Have been as high as 121. All produce great espresso. I use light-mid roasts. I have used dark but never had acceptable results, relative to lighter roasts. Go lighter and see how that goes.

          Ignore time and volume for now (or forever, which is what I’ve done). Just focus on taste. I have never found the time and volume rules to be of any help whatsoever. You are pulling shots for taste.
          I judge my shots only by flow rate and colour (drip, drip, drip, then a slow pour stream and dark brown sugar colour which lightens throughout the pull).
          I pull my cup aside if the colour is getting too light - you’re just dumping sour/bitter/unpleasant flavours into your shot.
          I do think you want a slower pull on the Alex than on a pump machine.
          If your puck is dry I think your flow rate is too high. 30 seconds is too fast a flow rate for this machine. I think 40 seconds plus is where it’s at.

          Pre-infusion - the water valve is open while the Leva is down and only closes on the return.
          I find 10 seconds about right to pre-infuse but don’t think it makes much difference at the grind I use.
          I don’t think you need to worry about getting more water volume into the group head when you pull your shots.

          Stop holding the Leva on the return after you feel resistance. When you push the Leva up let go once it’s under pressure. If you hold it you’re just reducing the brew pressure.

          The max volume from a standard pull is around 50-60ml per shot.

        • AndyGr
          AndyGr commented
          Editing a comment
          Thanks AlMac! Having played with different roasts and different grind/time/temp settings I have learned one thing - to focus on taste rather than on brewing 'rules'. Lowering the temperature to 119-120° definitely helps a lot to reduce bitterness. Today, I have switched beans and run the first test shot of the Ethiopian Limu, medium-light roast. Based on the classic espresso recipes, the flow rate was too high: only 24 sec (including 7 sec preinfusion), 18.6g in - 41.7 g out (1 :2.2 ratio). So, it was supposedly a horrible shot to be discarded; however, it tasted absolutely delicious despite a wrong ratio & timing.

      • My Alex Leva is back to it’s usual tip-top functionality after some downtime with a boiler refill fault. After a frustrating, expensive game of chase with an authorised Sydney repairer where no fault in the machine was replicated in over a week of bench testing I went down the water supply path as suggested by the Melbourne vendor. I replaced the Brita filter (and head) earlier than it needed but the fault persisted. I then added in pressure gauges pre and post-filter (only pre shown in pic) and sure enough the inlet/outlet pressure was only 270KPa. The fault originated from the Brita integrated PLV inlet hose.
        I changed to a nice Italian (naturally) Caleffi adjustable PLV and SS braided hoses instead of the Brita one and the pressure is perfect now. (I removed the post filter gauge after confirming it just for simplicity under the bench however it can be reconnected if there’s any issue in the future.) The machine is back to it's usual flawless operation & I'm a little older, chastened but wiser from the experience.

        I hope my shared experience may spare another CS member a similar journey down a rabbit hole


        Click image for larger version  Name:	IMG_2102.jpg Views:	0 Size:	107.3 KB ID:	839282

        Comment


        • Thanks for sharing... this could save someone a lot of pain.
          I am very suspicious of my PLV, for a while now the boiler refill has slowed down.. if i am in a hurry i can speed it up by operating the filter tap momentarily which seems to increase demand and open up the PLV. If it gets any worse i like the idea of an adjustable one like yours

          Comment


          • The PLV we had used to occasionally clog up with fine particles caught by its inline gauze sediment filter.
            Easily fixed by removing, disassembly and cleanup...

            Mal.

            Comment


            • ^^ You make a good point Mal however (unfortunately) that wasn't the problem with mine. The adjustable one I have now has a removable basket for servicing too. Total cost of parts (PLV/hoses/adapters etc) was less than $100.

              Comment


              • I have had my leva 4 yrs now... its been awesome. Thinking i better prepare to change the piston seals... i’d Rather have a crack at doing it myself than try to ship this beast somewhere.
                ive seen the how to posts here and on home barista..just wondering where to get the parts (seal kit?) in Oz. And are there any options worth trying out? Like silicone?

                Comment


                • Hi Sinkcut
                  The site sponsors will have them -CoffeeParts, Casa Expresso and probably Talk Coffee
                  I bought mine from CoffeeParts (parts numbers- 700466 Teflon Gasket and 700466 Gasket)
                  Mine was a pain the first time to get the Piston off the thread as it looked like the sealer that was used had hardened and locked it on. Eventually I took mine to an engineer friend.
                  Cheers
                  Dave

                  Comment


                  • Thanks Dr Dave, I think your recommendation led me down the Alex leva path years ago... and your still helping out

                    so I think you mean 700466 and 700467

                    I already have some dowe 111 lube.

                    Do you think i need anything else on standby? (Not including my Aeropress )

                    Comment


                    • Hi Sink,
                      Thank you for kind remarks
                      Yes, my mistake - they are 700466 and 700467
                      I have just sent you a pm also
                      Cheers
                      Dave

                      Comment

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