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Bezzera Duo DE Dual Boiler

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  • #61
    Wouldn't it be pretty similar to the integrated brew groups of Breville Dual Boiler or Linea Mini? They're both pretty hard to beat for temperature stability and have relatively tiny brew boilers. Way easier to control something with a smaller thermal mass.

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    • #62
      Hi level3ninja,

      I agree with you completely; except one thing I don't know is the location of the thermocouple in a typical saturated head - on the boiler or near the group head? The boiler is probably insulated and the jacket and head are not, so the head is lossy compared to the boiler. There is also some differential from the top to the bottom of the boiler. These drive the thermosyphon action to circulate the boiler water through the jacket to the head. So the boiler is (a bit) hotter than the head. If the thermocouple to closer to the head then less the need for an offset. You are right that we are talking about small temperature deltas. I'm certainly not needing to justify my machine. I was totally surprised when I measured the BZ stability. To get that for a $4800 machine compared to the expensive big boys is impressive. PS I have no connection with Bezzera.

      Just for balance, I agree with noidle22 that the Duo DE's pre-infusion is rubbish. I almost thought that it was misleading to describe the Duo DE and Matrix DE 5-second wetting as pre-infusion. But then after investigation and confirming with an 'expert' mate, I'm told that the Gaggia and Bezzera have well-document 'pre-infusion' and it can be implemented by either by (1) low pressure for a duration (eg E61 pre-infusion at the pressure generated by the thermosyphon, or line pressure for a duration (typical 4bar) or (2) full pressure for a short period and then a delay at zero pressure prior to full-pressure extraction. The Duo applies full pressure for one second then waits for up to five seconds (settable). It does a lousy job.

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      • level3ninja
        level3ninja commented
        Editing a comment
        From memory it varies and the newer the design the more likely it is to be at the group head.

    • #63
      Just waiting for my DE to arrive today. Upgrading from an Alex Duetto 2 after 13 years of good service-it is plumed in with severe flow reduction, nowhere near the 6 bar the DE can take...lucky to be 1.
      My question is about "pre-infusion". If machine set to plumed does it use the pump for pressure or switch to using Mains pressure. If the latter I will need to change all my plumbing as the current low pressure line goes under floor across room.
      Cheers

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      • #64
        Correct that current pressure is 3.5 bar- 350KPA

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        • #65
          Just did some more searches and figure the John Guest tubing is rated to 15 Bar. Just purchased Apex FMP600 pressure reducer and backflow prevention to replace current lower version. Should be all good.
          Still interested in an answer to my original Q re pre-infusion.

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          • #66
            Re Duo pre-infusion, it's not what we might assume. Pre-infusion is all about wetting or soaking the puck prior to extraction. Most assume that pre-infusion is at low pressure, say 4 bar, roughly line pressure. That's how many machines produce low pressure, but line pressure is only available if you are mains connected. E61 produces a bit of pre-infusion from the pressure driven by thermo-syphon. Not sure what level of pressure that is. The Duo, in an attempt to provide pre-infusion does not use line pressure because they want to market the machine as having pre-infusion from either line or tank by simply applying full pump pressure (say 9 bar) for one second, then waits for the set 'Pre-Infusion' time (settable up to 5 seconds) and then applies full pressure for extraction. So the question is, "is there any difference between high-pressure and low-pressure pre-infusion?" I can't tell. So I'm happy. I actually set the pre-infusion to zero seconds ie no pre-infusion. Then I simply load the portafilter and then run the pump for about 2 seconds (2 seconds completely wets the puck without losing any extracted coffee through the OPV). Then I wait for as long as I like (say 10 seconds) then extract my shot for the programmed volume. It works beautifully.

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            • #67
              Greetings from Switzerland!

              I bought the Duo DE a few weeks ago to replace my Sage Dual boiler system.
              Although bought in Dec 2020 the box indicated manufacturing date Oct 2019. Afraid that I still had the initial display, with its humidity problems, I contacted and phoned the Bezzera HQ in Milan.
              They did not want to talk to me and send me to the Swiss distributor who indicated the following:

              The last main board software version is the 2.4 (the machine in your photo has the 2.2 version). The screen already has the latest software version (2.2).

              With the screen having the latest software I assumed I had the updated display and decided not to return the machine.

              I also noticed that when the machine comes from stand by it is NOT showing the actual temperature, is this common for everybody in this forum or would updating to firmware 2.4 fix this?

              Other question, did anybody already update the firmware themselves?

              Pedro


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              • #68
                Hi there,

                Thanks to all who have posted in this thread. I have just upgraded to a Bezzera Duo DE so the information has been very helpful.

                I am a long-time Bezzera user (20+ years), having owned two BZ99's, a Magica and now the Duo DE. I am really enjoying the volumetric dosing and the auto-clean function. And it is so fast to heat up.

                pp61 - Hi Pedro. When I first switch mine on, the screen shows TFT: 2.2 FW: 2.4 and it shows the actual temperature. However I am not sure what it shows from standby. Will check that tomorrow.

                One thing I have struggled with is using the single shot portafiller, i.e. getting the dosing right. It seems the difference between having too much coffee (hard up against the head) and not enough (resulting in a weak shot) seems very small.

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                • #69
                  Originally posted by PeterW View Post
                  pp61 - Hi Pedro. When I first switch mine on, the screen shows TFT: 2.2 FW: 2.4 and it shows the actual temperature. However I am not sure what it shows from standby. Will check that tomorrow.
                  pp61 - I have checked this morning and confirm that from standby, the digital display only shows the set temperature (i.e. target), not the actual temperature, so you have to look at the coloured lines below the number and wait until they have turned grey. I agree that this is not ideal and could be improved.

                  Comment


                  • PeterW
                    PeterW commented
                    Editing a comment
                    Just to add regarding the operation of the display on the Duo DE... I recently watched a Bezzera factory tour on Youtube and Luca Bezzera mentioned possible upgrades to the firmware in the Duo and Matrix. So I sent some feedback via the Bezzera website today about the temperature display. Hopefully they will read it and consider it.

                • #70
                  Relatively recently I had the unfortunate experience of having my composite granite bench cracked by the super heated water from my Duo DE and wanted to warn other users to be alert to this possibility. I had programmed the TP-Link Kasa smart switch to come on every morning at 05:50 to ensure the machine is hot and ready to go for 6am....ish, start to the day. More like 06:10 - 06:15. This unfortunate morning, I was greeted by a flooded scullery and a cracked bench...20 minutes after it had switched on (it is plumbed in). The Hot Water Valve had locked in the On position. The machine was 5 1/2 months old when it happened. The hot water valve had been faulty, as evidenced by random acts of dripping and running. In fact, I had to adopt the habit of toggling the lever to ensure it was in the off position. Clearly, this morning the valve had stuck open, though the lever was not in the up/locked position.

                  The boiler was set to 127 degrees for the steam pressure. The heat of the water coming out, under sustained pressure, cracked the granite bench. Suffice to say, I no longer trust the smart switch approach. The supplier kindly and immediately replaced the faulty valve unit under warranty and the replacement is behaving perfectly. I now leave the hot water wand, at end of use, pointing in to a plastic container I keep under the Portafilter AND take extra care to toggle the lever so as not to have a repeat episode if I am away from the machine.

                  By the time I had a service agent swap the valves over, the machine was 7 months old. Coincidentally, the Group head gasket (#7496097) was starting to leak. I hadn't realised, also, that this gasket/seal needs replacing every 6 months. It had become extremely hard and brittle. Hot tip number 2, make sure you have a spare seal. I'm not sure whether there is a better replacement seal that the one issued, but Mike has said, in an earlier post, that he likes the fact that this one seals quickly and easily. They are about $8.00 each.

                  Otherwise, I remain really pleased with the machine and would buy it again in heart beat

                  Click image for larger version

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                  Last edited by quester; 22 February 2021, 11:06 AM. Reason: Trying to shift photos to end of text

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                  • #71
                    Thanks for the info quester!! I was unaware that the valve could be locked open with the lever being in the off position!!

                    I am curious as to why you use the Kasa switch as opposed to the machine's own scheduler.

                    I was going to set up the scheduler on my machine but when I read somewhere that it disables the standby function, I decided against it. Prior to getting the Duo DE, we had a Magica and as my wife has been working from home the past year, the machine would be switched on at 7am and was still on when I got home at 6pm, boiler running all day, water tank in need of filling, etc. She would just forget to turn it off after her second coffee. I love the fact that the Duo goes into standby. I've found that the Duo heats up so fast that I don't really need to use the scheduler anyway.

                    Thanks for the tip on the group seal. I will order one to keep spare.

                    I have had my Duo for about a month now and absolutely love it. I still need to tinker a bit with the volumetric settings but it's making great coffee. I ordered some additional kit to go with the machine too - a naked Bezzera portafilter with wooden handle and the Bezzera tamper station with wooden handled tamper.

                    Comment


                    • #72
                      PeterW You'll be rapt with the naked PF. When the valve was replaced it came with the plastic black handle and it was easy to switch that for the wooden one. Love the aesthetics.

                      I can't explain the valve being open either other than the faulty one seemed to have been having problems sticking and the new one doesn't stick at all. The person servicing the machines lubricated both valves and fine tuned the ball cup water and steam hose joints etc and these now swing around much easier. So worth getting someone tending to this who knows what they were doing!

                      Re the Kasa, I agree the Duo has a scheduler but, from memory, it was to do with the Standby function and not being able to override it. I think Mike addressed this in an earlier post. Do read all his entries, they are invaluable. In the meantime I still use the Kasa switch but have scheduled it to turn off the machine at set times. ie I turn the machine on manually by tapping the TP-Link switch button and let it switch off according to schedule. It would probably be fine programme to turn on as well but my bench is expensive and I can't afford to risk another incident, even if this time it is human error. eg someone accidentally leaving the lever up and no-one noticing. As I said, I now am paranoid and leave the Hot water lever over the water tray area rather than over the bench as a matter of procedure.

                      Plumbing the Duo in was another useful thing to do and manually draining is no problem.

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                      • #73
                        Thanks quester. I haven't plumbed my machine in. We make between 6 and 8 cups a day and find the tank is plenty large enough. I probably only refill it every second day.

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                        • #74
                          I'm very interested in this machine and I wish to have more details about the volumetrics function. As I read this is not as simple as it seems. What I'm expecting is when the dose is saved it will push always the same amount of water in the group whatever the grind settings , the dose etc. If it's not the case whas is the point of this feature?

                          Thanks in advance

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                          • clubbi4
                            clubbi4 commented
                            Editing a comment
                            Yes, When you setup your volumetric dose, it will always dispense the same amount of water. The thing is, if you setup 45ml in the cup with 18gms of coffee, it will always drop 45mls. If you dose 24gms coffee, the coffee in the cup will be less cause the amount of coffee you have dosed is more and thus absorbing more water in the puck so you might get 40ml in the cup.

                            Hope I explained that properly for you.

                          • quester
                            quester commented
                            Editing a comment
                            My experience with the volumetrics on the Duo De is different to clubbi4's, below. The theory is as c4 explains. In practice, I programmed one of the buttons for 40gms/mls which is the most frequently used. Typically I run, say, 9gms through the Bezzera single shot basket and it will pour 50 mls. I then switch baskets to the 16gm basket for my 18.5gm dose and the same button/programme puts out nearer 38mls/gms. This happens consistently. There is clearly a difference in resistance. Probably, if I were to programme a different button for the single shot to the double shot, the problem would be solved.
                            Re volumetrics, as Mike has earlier referred (from memory) you can still manually run as much as you like by pressing the Programming/Continuous dispensing button, so you get the best of both worlds.
                            I too short listed the Bezzera Duo DE with the Crem One. Faced with the same decision today and having owned the Duo for 15 months I would get the Bezzera again.

                        • #75
                          Thanks a lot Clubbi4. I m looking to replace my Sage oracle touch and was interest on the Bezzera Duo Top or the new Crem One profile. For the one that have this machine do you still recommend the Bezzera?

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