I know I’m perhaps the outlier here, but I don’t buy that a dual boiler is more temp stable than a single boiler for brewing. The bigger the boiler the higher the stability as incoming water has less impact on the temp, and a PID gives better control than a thermostat, but one vs two boilers has no impact. I think it’s more that quite a lot of the single boilers are aiming at the low cost end of the market.

The real advantage on a dual boiler is they’re quicker for back to milk drinks. I think it really depends on the use case. If you’re only doing espressos or one/two milk drinks there isn’t much difference. If you’re doing lots of milk drinks a double boiler is a clear winner.

Assuming you’re ok with a minor wait to hit steaming temp (usually no longer than it takes to clean the portafilter and weigh out the milk) then single boilers have some definite advantages:

  • cheaper to buy (or you’d expect better components)

  • cheaper to run, as for steaming you’re only heating the water by about 40°C, from brew temp to steam temp, not from ambient. As an example:

  • Single boiler flat white with my Silvia (all energy figure based on no loses and 20°C water tank, not accounting for the reheating the water from the shot as this should be the same, real world figures in both cases would be higher)

    • Heat 300ml brew boiler to 90°C [24.4 Wh]
    • Heating the 300ml from 90°C to 130°C for steaming [197.2 Wh]
    • Total for the Silvia = 221.6 wH (or 0.2 kWh). At 50p per kWh electricity prices this would cost 11p in electricity.

  • Same as above but with a Minima (clearly a great machine, chosen just to demonstrate the difference)

    • Heating the 800ml of water in the brew boiler from 20°C to 90°C [65.2 Wh]
    • Heating the 2.3L of water in the service boiler from 20°C to 126°C [1694.2 Wh]
    • Total for the minima = 1,759.4 Wh [1.8 kWh or 88p]

  • obviously if you make more drinks the difference decreases as the large boilers will stay warm, but if you have one flat white a day the Minima will be £281 per year more expensive to run in electricity alone.

  • Single boilers are usually easier to descale as well, so you don’t have to be as careful with water, a further saving.

Obviously people have to decide the right compromise for them, but I think it’s very tempting to default to a dual boiler because why not, without thinking what the impact actually is.

    There’s also the single boiler Vs hx thing

    Most dual boilers you can have the steam boiler off.

    Your still moving temps about Vs staying stable. It’s just more convenient

    Esp when there’s £100 difference between a mara and liz

    If you look at the profitec go for instance it’s a right faff for a milk drink.

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    hornbyben

    That’s a really informative reply, thank you.

    You have basically iterated what I thought - but my knowledge isn’t great of the matter so I thought maybe I’m wrong.

    My primary drinks are for me, espresso, add water from the kettle, and add milk straight from the fridge. This is how the machine will be used probably 90% of the time. On the occasions when my sister comes over, she will need the use of a steam wand to froth her milk.

    I want a machine with a small physical footprint, with absolute solidly stable brewing temperature, temperature that I can control reliably, with the added ability to be able to steam milk (at the very bottom of the priority list but I do need it). I hadn’t considered pre-infusion but after reading about it now (because of the Elizabeth), I feel like it’s something that I would use - but I want it to be easy to use. Shot profiling I’m extremely unlikely to ever use.

    Based on that, can the Mara X / ECM Classika PID be contenders? They must be more expensive than the Elizabeth for a reason? What’s the reason?

        Mara is out of stock atm, it’s £40 less than the Elizabeth

        The ECM you’re paying for ‘better’ build, is it better I don’t know

        The mara is smarter than the ECM.

        I just don’t understand paying dual boiler money for a machine that’s not as good that’s all

        You could go all out and ignore the milk

        https://bellabarista.co.uk/collections/espresso-machines/products/ecm-puristika-1

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          Cuprajake

          I can’t completely ignore the milk unfortunately.

          So if I’m understanding you correctly, or if the Elizabeth, Mara, ECM, you would say the Mara suits my needs the best?

            Cuprajake

            That reduced machine, on the sure they don’t indicate the size of it. Hope just bigger is it than a Mara? Is it a good machine?

              No idea but quickmill have been around along time

              Take your pic any of those will do you

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              DrForinor personally, based on your stated requirements I wouldn’t go for the MaraX, as this is a heat exchanger machine. It’s undoubtedly a good one, and a lot of people are happy with it, but they are less stable as the brew water temperature is set by it flowing through a coil in the steam boiler. Flow faster and the temp is lower, flow slower and the temp will be higher. To be fair, the MaraX is pretty sophisticated and controls this well, but the main advantage of a HX is allowing steaming and espresso brewing without delays, while saving cost versus a double boiler as you only need a single boiler.

              I have no direct experience of the ECM, but from what I’ve read they are a very high quality manufacturer and this, plus brand value is why it is more expensive. The classika looks like a nice machine, and with a 750ml brew boiler should give very stable temperatures. Obviously from an energy point of view this will be inbetween my previous examples:

              • 750ml from 20 to 90⁰C is 61 Wh
              • 750ml from 90 to 130⁰C is 493 Wh
              • Total 554 Wh (0.5 kWh) or approx 25p

              It’s probably worth having a look on YouTube and seeing if you can find a video that shows how long it takes to go from brew to steam temp, to make sure you’re happy with the compromise. From a quick Google it looks like it has a 1200 W heating element, which if it’s 100% efficient should take 2 mins and 3 second to heat to steam temp (for comparison the same calculation for my machine is 1 minute 4 seconds due to the smaller boiler and similar power of 1100W). I have no doubt this will be annoying if you’re doing more than 3 milk drinks (as for 3 I’d pull the shots and th we do steam a single larger batch of milk), but is probably a reasonable compromise based on what you expect to use it for.

              I hope that helps

                  hornbyben

                  I hear what you’re saying about the time to wait for the frothing, but I won’t be using it that often (once I end up getting it, I’ll probably need it more often).

                  Cuprajake

                  Haha you truly feel the Elizabeth is still the best for my requirements?

                  Given I want very stable temperatures, is it safe to say either a single boiler or a dual boiler would be best for me rather than a HX?

                      Well personally I’d go for the minima as it has bigger boilers, and you can add flow control

                      And easily turn the steam boiler on or off. But you’d have to order from acs in Italy so will be in for a wait.

                      I went minima as the Liz is a bit to sage appliance for me 😐😂

                      What I’d do is have a good look at people using said machines to make drinks not reviews, real world use and see if that’s what you want.

                      I know you don’t do milk drinks all the time, but th day you have to make 4 or 5 milk drinks for say friends and family a dual boilers worth it’s weight in gold.

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                        The Elizabeth is clearly a good value machine, but personally the looks don’t do it for me.

                        Each to their own though. Unfortunately, there is no “right” answer. Just the balance of compromises that works for you.

                        If you do decide you want to play with for control this is easy to do on the ECM classika too, as this is a standard e61 group.

                          I have no experience with the other machines, but I have an Elizabeth, and for your use case, it seems ideal. It has been just wonderful for me. I have had mine about a year now. Flawless. Great temperature stability. You can leave the steam boiler off if you want, but if you need it, it heats very quickly. It has been a very easy machine to live with. Small footprint and easy cleaning has been great. Add to that good additional documentation on use from DaveC’s stuff and you have a winner.

                            Cuprajake

                            Thank you. I have ruled out the Minima as it’s simply too large for the space in my kitchen - which is why I keep going back to the Mara/Elizabeth (and why I even considered the ECM Classika).

                            hornbyben

                            Honestly I really am not a fan of the looks of the Elizabeth. I was so hoping for a machine with the classic E61 style appearance to be the choice for me. But I have always been the kind of person to go for function over form - hence why the Elizabeth is even a contender for me. I’m extremely unlikely to ever think about flow control. But if the ECM Classika can provide better temp stablity than the Mara/Elizabeth then it wins for me.

                            dndrich

                            Thank you for chiming in. How do you use yours? What sort of beans do you use? And your drinks? Have you had any issues? Or any concerns to think about?

                                    Forget the ECM

                                    In theory if you’re going to milk say 5% of the time then there’s very little between them

                                    E61 do take longer to warm up though 20-25mins minimum.

                                    Fwiw I didn’t find the minima that large.

                                    At a £1000 point mark you can’t really go too wrong with any option

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                                      Cuprajake

                                      Why do you say forget the ECM? He didn’t really have much bad to say about it?

                                      Sorry you’re right, the Minima isn’t large per say, but in order for me to accomodate an E61 style machine (so basicaly anything but the Elizabeth), I’ll have to sit it sideways (sitting a corner, the back of the machine to the wall left of me, the right of the machine sitting to the wall in front of me). With any of the other machines the steam wand can still be accessible, but because of the cutout on the Minima, it will make it extremely awkward for me to access.

                                      Regarding warm up, I’ve just purchased a smart plug (so I can switch the machine on at any time remotely, or time it via an app), specifically for this purpose - so I am prepared for that. I have to leave my Gaggia on for 30mins prior to using anyway so it’s new thing to me.

                                        Predictive - ment to say ‘forgot’

                                        As in I forgot to add it to the rest of the vids

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                                          Cuprajake

                                          I did notice in that ECM video, after he’s finished the shot, the temperature that had initially been set dropped - is that lack of temperature stability throughout the shot?