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Thread: Decent Espresso Machines (DE1) - Any thoughts?

  1. #201
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    Quote Originally Posted by noonar View Post
    Do the bars have to have a round cross section? Can they be triangular? Just a thought regarding the beading issue.
    Interesting idea. I haven't come across triangular bars. They would likely bead much less on top, but hugely more on the bottom, since there would be a flat surface on the bottom.
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    News on some Decent Espresso accessories.

    - our portafilter stands (separate models for spouted vs bottomless-only) are being finished at the factory, and should be in stock later this week. https://decentespresso.com/portafilter_stand

    - we've finished the design of our home knockbox and I'm finalizing my choice between two companies to manufacture it for me. In about 70 days we'll have these in stock. https://decentespresso.com/knockbox

    - the mechanical engineering for our scale is almost complete: I'm finishing up the the battery compartment and usb lead. The firmware is done. We're probably about 80 days out from having these in stock. https://decentespresso.com/scale

    - we're stocking Scott Rao's books and working with him on printing his currently-only-an-ebook latest "Espresso Extraction" book. https://decentespresso.com/books

    - our barista kit and tamping kit is (sigh) still not shipping. We have everything but the foam, and that's delayed because everything we sampled was really smelly, and I do not want strong smells getting attached to accessories used for making coffee. We've just finalized and ordered a new kind of foam: fairly thin (4mm) and dense EVA foam, moulded to shape (not thick) and covered with a thick black nylon fabric. We'll have this in 3 weeks, and if we like it, we'll do the same for the barista kit and finally be able to ship our "*-kit" suitcases.

    22105_screen_2017-02-20_at_12 copy.jpgdecent_scale.jpgrao-cover-all3_960.jpgknockbox_grey.jpgpf_stand_spouted_grey.jpg
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  3. #203
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    Keep going with all the good work. I'm keen to give the scales a go.

  4. #204
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    Espresso machine update

    We ordered all the parts to be manufactured (CNCed or bent sheet metal) for Beta 7 last week, and they should arrive this week, we haven't yet built beta 7, because we're waiting for the custom parts to come in.

    For beta 7, we pushed the innovation farther than we had planned, redoing virtually all the water connectors to be "clip connectors", which required visits with manufacturers (to supply us with different valve, heater and pump connectors) and also redoing the mixing chamber. In the end, we removed the need for 15 connectors, which greatly reduces the number of things that can go wrong.

    I also decided to take the time we had to refine a few things, including:

    a) creating and testing new ideas for a splash-free pressure release system http://www.home-barista.com/marketpl...0.html#p514330

    b) solving a wet puck & drip-after-shot issue http://www.home-barista.com/marketpl...0.html#p516716

    c) working on a new drip tray cover design that would require less cleanup http://www.home-barista.com/marketpl...0.html#p514929

    d) moving the tablet forward and designing our own bracket for it, positioned above the group head http://www.home-barista.com/marketpl...0.html#p517460

    I have posted links on each of the points above to conversations on Home Barista about each change, in case you want to read more.

    On a different point, we're continuing to extensively test our beta 1 through beta 6 machines, and we identified a failure mode, where one of the valves fails to open (ie, you can't make espresso) if it gets too warm, which happens when you're pulling shot-after-after for hours for a 20-person crowd of the Hong Kong Coffee Club. I also experienced this one once on tour (hello London!). It took us a while to isolate the problem, which we did two weeks ago, and we discussed it with two valve vendors (our current one, and a prospect). We're getting new valves next week from our prospective new vendor now.

    Our new valve maker (ODE solenoid valves & pumps) is explicitly in the espresso business, and we spent hours face to face with their engineers last week, so we have much greater confidence in them. They have dual HQs in Italy and Hong Kong, which is amazingly helpful for us. Picking our parts suppliers well, and beating the heck out of each part to make sure they're good, is really important if we're going to achieve the reliability we want.

    secondary_mixing_chamber.jpg


    This photo shows the parts for our new side-panel idea. With this new approach, much of the espresso machine assembly takes place on those side panels when the machine is disassembled, making it both easier to build, but also easier to repair.

    oarts.jpg
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    Following closely with interest..
    Many questions, but to start with..
    Is the tablet likely to suffer from heat or steam up above the group head ?
    Are any mains power timer functions included ?
    Can you confirm the hardware differenced between DE1 and DE 1+ .
    Can the DE 1 be upgraded to 1+ spec ?

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    Quote Originally Posted by blend52 View Post
    Is the tablet likely to suffer from heat or steam up above the group head ?
    We were also very worried about this, and many people have voiced this concern. We've tested this for 18 months without problems. The main reason we're likely OK is that the tablet is sealed on the steam-wand side, with all apertures appearing only on the opposite (left) side of the tablet.

    Quote Originally Posted by blend52 View Post
    Are any mains power timer functions included ?
    screen 2017-02-28 at 2.32.55 PM.jpg


    Quote Originally Posted by blend52 View Post
    Can you confirm the hardware differenced between DE1 and DE 1+ .
    Hardware wise, the + adds a temperature and pressure sensor on the group head, and a flow meter. Together, these extra sensors enable a more powerful physics model on the firmware, and enable two significant features: temperature profiling (auto-reactive to actual infusion temperature in the group) and flow profiling (pressure automatically adjusted to achieve flow goals).

    Quote Originally Posted by blend52 View Post
    Can the DE 1 be upgraded to 1+ spec ?
    [/QUOTE]

    It cannot, sorry! It's not just software.

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    Thanks for the quick response ,...but i am now a little confused...
    your video shows the DE1 circulating brew water in the group head until it reaches a chosen (adjustable) temperature. It goes on to explain how to set the extraction profile on the DE1 by altering the pressure / time profile and the temperature of the water,...but If the DE 1 does not have the temp and pressure sensors in the group head, how is that possible ?
    Thanks in advance for clarifying something you have probably explained a few times already !

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    Quote Originally Posted by blend52 View Post
    your video shows the DE1 circulating brew water in the group head until it reaches a chosen (adjustable) temperature. It goes on to explain how to set the extraction profile on the DE1 by altering the pressure / time profile and the temperature of the water,...but If the DE 1 does not have the temp and pressure sensors in the group head, how is that possible ?
    Indeed, the lines between the models can be hard to discern. so let first spell it out in terms of features.

    1) on the DE1 and DE1+ you can set the water temperature for the entire shot. There is a temperature sensor in the mixing chamber that does this. This way of doing water temperature effectively emulates a boiler: what matters here is that the water temperature exiting the water mixer be within 1C of your desired water temperature.

    2) the DE1+ has an additional sensor in the group head, in the chamber above the dispersion screen, providing feedback to the system, so that the water mix temperature can be quickly adjusted. This allows the DE1+ to focus on the temperature at the puck, and automatically vary the "boiler temperature" to compensate for the cooling effects of the grounds and metal portafilter. The DE1 acts like a boiler, with water temperature at the water mixer output being the goal.

    3) the DE1 uses PID to mix the water temperature, and the PID function controls the mix of cooler (50C) water into the too-hot (98C) water. The DE1+ adds a flow meter, so that we can control flow according to goal, by controlling the pumps, while still giving you the water temperature mix you asked for. On the DE1 we also understand flow, but as a function of pump cycles, rather than by measuring it directly with a flow meter. The pump cycles method so far has ~30% error margin, which is why we add a flow meter to the DE1+.

    ps: the only place feature currently demonstrating precise flow control is our preinfusion step. In the coming weeks, I'll be implementing a flow profiling GUI to the tablet, so that you can specify the flow rate you want, and pressure will be adjusted to achieve that flow rate.

    I also need to add a "no flow" feature, so that you can put pauses into your espresso recipe, for example after preinfusion, to copy what La Marzocco and Slayer can do. My goal with the DE1+ is to be able to emulate most other espresso machines from history, but also to do so with transparency, so you can see what happened in the puck, and then adjust accordingly.
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    Quote Originally Posted by decentespresso View Post
    2) the DE1+ has an additional sensor in the group head, in the chamber above the dispersion screen, providing feedback to the system, so that the water mix temperature can be quickly adjusted. This allows the DE1+ to focus on the temperature at the puck, and automatically vary the "boiler temperature" to compensate for the cooling effects of the grounds and metal portafilter. The DE1 acts like a boiler, with water temperature at the water mixer output being the goal......
    thanks again, im beginning to understand i think ..!
    ... However, you did not explain the pressure control/adjustment in the DE1, which presumeably needs a pressure sensor to control the pump speed ?

    Not intended as a criticism, but i am also struggling with the concept that a temp sensor above the dispersion screen (upstream of the puck) , is able to detect temperature changes in the brew water in the puck/PF.
    Previously Its been shown that a sensor in the puck is the only accurate method of registering temperature variations in that area.?

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    Quote Originally Posted by blend52 View Post
    ... However, you did not explain the pressure control/adjustment in the DE1, which presumeably needs a pressure sensor to control the pump speed ?
    Indeed, well spotted, there is a pressure sensor in the group on both the DE1 and DE1+. The pressure profiling features are the same between the DE1 and DE1+. Both let you draw pressure curves to be followed during a shot.

    Quote Originally Posted by blend52 View Post
    i am also struggling with the concept that a temp sensor above the dispersion screen (upstream of the puck) , is able to detect temperature changes in the brew water in the puck/PF. Previously Its been shown that a sensor in the puck is the only accurate method of registering temperature variations in that area.?
    I don't think there is an optimal place to put the temperature sensor. If you put it in the grounds themselves, you create channelling, and thus bad coffee, and also you need a custom portafilter, generally with a wire sticking out of it. Not great for daily use.

    We're calibrating our sensor against a Scace, and it seems that because water fills up in the entire pressurized group head, and the puck is fully saturated with water, that the entire chamber more-or-less has the same temperature.

    I write "more or less" because the temperature (and pressure) will drop as you go from the top of the puck to the bottom, so all temperature and pressure measurements are approximate and local.

    Even when we put a sponge into a Scace, to simulate the effect of coffee grounds, our temperature sensors gives almost identical readings as the Scace probe is giving.

    I'm 100% open to any suggestions of a better place to put the temperature probe. The only better place I can think of would if the screw holding the dispersion screen were a temperature probe, because then it'd be in contact with the coffee material itself.
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  11. #211
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    Quote Originally Posted by decentespresso View Post
    I'm 100% open to any suggestions of a better place to put the temperature probe. The only better place I can think of would if the screw holding the dispersion screen were a temperature probe, because then it'd be in contact with the coffee material itself.
    It just needs to be easily removable and replaceable as they do fail and probably would have a pretty hard life located there, but should be cheap enough and easy enough if the thermocouple and connectors to control unit are easily accessible.

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    Quote Originally Posted by decentespresso View Post
    I also need to add a "no flow" feature, so that you can put pauses into your espresso recipe, for example after preinfusion, to copy what La Marzocco and Slayer can do. My goal with the DE1+ is to be able to emulate most other espresso machines from history, but also to do so with transparency, so you can see what happened in the puck, and then adjust accordingly.
    Now you made me curious . Could you elaborate a bit on this? When you say after preinfusion do you mean before or after the coffee has started to drip out? I'm thinking the "no flow" will cause a (slight) drop in pressure if it's introduced after the coffee has started to flow out. Out of curiosity, which Slayer/Marzocco feature do you refer to that is similar to a no flow?

    In my opinion another useful feature would be to have a button that you can tap to introduce a manual "no flow" (or more like "hold flow") at any time during the shot. That way you can preinfuse until you see the first drops of coffee, then un-pause manually to continue the shot.

    I would really like to see a UI that make manual pressure/flow profiling as easy and smooth as possible. Preset profiles are nice and good once you figured out what profile best suits your coffee but when you're experimenting with a new coffee I think manual profiling makes it easier as you can make instant changes based on what you can see getting into the cup.

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    The way preinfusion is implemented on my GS/3 is "seconds of water (1s-5s)" followed by "seconds of pause (1s-5s)"

    Now, regardless of whether you think this a good idea or not, or if you even think this should not be called preinfusion, this is how LM does it, and I think it's cool to be able to emulate it. FYI on my GS/3 this preinfusion happens at a ~6ml/second flow rate.

    will cause a (slight) drop in pressure
    I'm not sure there will be any pressure loss, because with 5 seconds on, you're looking at a max of ~33ml of water, which will soak up also immediately into the puck. A 15g dose of coffee would be fully saturated, but more would not be. No back pressure will ever have been made. In other words, LM doesn't give you the setting to have preinfusion last long enough to fully saturate the puck.

    Now, onto Slayer, whose preinfusion features are in a whole different universe of subtlety. I have to preface what I'm writing with I HAVE NEVER PULLED A SLAYER SHOT and my understanding is only on what I've read or been told.

    My understanding is that with Slayer, you can have a very, very slow preinfusion, for instance 60s to introduce 30ml of water, and you can then pause the shot for some number of seconds, and then ramp the pressure up. Even if I'm not right about Slayer being able to do this, it sounds pretty nifty, and I'd like the DE1+ to be able to do this.

    Because the DE1+ can stop any stage in the espresso based on pressure, flow or water volume dispensed, you should be able to do something like "put 30ml of water in at 1ml/second, then pause 30s, then ramp up to 9 bar and decline to 6 bar over 30s".

    re: In my opinion another useful feature would be to have a button that you can tap to introduce a manual "no flow" (or more like "hold flow") at any time during the shot. That way you can preinfuse until you see the first drops of coffee, then un-pause manually to continue the shot.
    Currently, the way to do that is to set the preinfusion to end when a certain pressure is reached, and this works fairly reliably, within about ~2s variability.

    Secondly, I haven't yet implemented it on the tablet (nor in firmware yet), but there's a grey "control strip" currently in the GUI, where you can stick your finger, and manually control flow or pressure or temperature, in real time. That will let you do what you describe wanting. We're planning on this being implemented by the time we release.

    I would really like to see a UI that make manual pressure/flow profiling as easy and smooth as possible.
    I agree, and that's why I put the grey "control strip" in. However, I have a bit of experience in audio engineering, and so I am thinking of this all in terms of a "mixing board" that records your movements and can then play them back.

    Ideally, we'll be able support connecting several bluetooth controllers, such as the Griffin bluetooth powermate, assigning each controller to a separate variable (temperature/flow/pressure) and letting you "mix" a shot in real time, with recording enabled. That's the vision, and if I don't get around to it, I hope that my gui being open sourced will motivate others to do it (or do it in different ways).

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    Quote Originally Posted by decentespresso View Post

    Because the DE1+ can stop any stage in the espresso based on pressure, flow or water volume dispensed, you should be able to do something like "put 30ml of water in at 1ml/second, then pause 30s, then ramp up to 9 bar and decline to 6 bar over 30s".

    Currently, the way to do that is to set the preinfusion to end when a certain pressure is reached, and this works fairly reliably, within about ~2s variability.

    Secondly, I haven't yet implemented it on the tablet (nor in firmware yet), but there's a grey "control strip" currently in the GUI, where you can stick your finger, and manually control flow or pressure or temperature, in real time. That will let you do what you describe wanting. We're planning on this being implemented by the time we release.

    I agree, and that's why I put the grey "control strip" in. However, I have a bit of experience in audio engineering, and so I am thinking of this all in terms of a "mixing board" that records your movements and can then play them back.

    G'day John

    I have been following this thread quietly, with a lot of interest. I will be almost certain to get one of your machines later as it does a lot of things that espresso machines should have been doing for the last 10 years or so. As a former "messy divorce separated" 110V & 220V GS3 plus an Electra manual lever (with a specially weakened spring so I could "feel the shot") owner I would offer the following.

    Preinfusion: A few roasts needed very, very slow preinfusion followed by a pause of up to 45 seconds to fully prepare the shot. I could never trick the GS3 into doing that properly and you have just explained why - thanks. The Slayer would probably be able to emulate the manual lever much more closely (only ever pulled a handful of "standard Slayer shots", never played with it in anger). Your "grey strip" is a magic idea - especially if you can use it like a mixer and then "save and tinker" - which should finally get an "automatic configurable machine" to achieve the same result as a manual lever with only a fraction of the grief. Naturally other roasts (usually darker - the major plague holding the industry's traditional gear designers back) need more minimal preinfusion so many options are essential.

    Milk: My background in "high temp steam" is exactly nil. At normal steam temperatures there is very little correlation between getting the texture correct and actually getting about "half a teaspoon of sugar's worth" of sweetness by also breaking down the lipids in an orderly / correct manner (refer to "Lilly - Espresso Coffee: the science of quality" if you are not aware of this issue). Both are achievable together, however virtually all multi hole wands and more powerful steam setups are a miserable fail in terms of sweetness - and often all too successful in scalding the milk beyond death.

    The only question I have about the milk frothing is whether you can pick up the extra sweetness by using such high temperature dry steam? Hopefully your machine can do both easily.

    Good luck with your endeavours.


    TampIt

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    Quote Originally Posted by TampIt View Post
    Preinfusion: A few roasts needed very, very slow preinfusion followed by a pause of up to 45 seconds to fully prepare the shot. I could never trick the GS3 into doing that properly and you have just explained why - thanks. The Slayer would probably be able to emulate the manual lever much more closely (only ever pulled a handful of "standard Slayer shots", never played with it in anger). Your "grey strip" is a magic idea - especially if you can use it like a mixer and then "save and tinker" - which should finally get an "automatic configurable machine" to achieve the same result as a manual lever with only a fraction of the grief. Naturally other roasts (usually darker - the major plague holding the industry's traditional gear designers back) need more minimal preinfusion so many options are essential.
    Thanks for the coffee-centric advice, and the 'use case' for a big pause.

    It's "for the future" but another reason I wanted a bluetooth scale in our ecology is so the espresso machine knows when the 'first drop' hits the cup and can act accordingly (pause, or ramp up pressure, as desired).

    Quote Originally Posted by TampIt View Post
    Milk: My background in "high temp steam" is exactly nil. At normal steam temperatures there is very little correlation between getting the texture correct and actually getting about "half a teaspoon of sugar's worth" of sweetness by also breaking down the lipids in an orderly / correct manner (refer to "Lilly - Espresso Coffee: the science of quality" if you are not aware of this issue). Both are achievable together, however virtually all multi hole wands and more powerful steam setups are a miserable fail in terms of sweetness - and often all too successful in scalding the milk beyond death. The only question I have about the milk frothing is whether you can pick up the extra sweetness by using such high temperature dry steam? Hopefully your machine can do both easily.
    So far, our taste tests are finding our milk steamer to go in the opposite direction: of maintaining more of a raw, buttery flavor, and not really creating a custardy/dolce-de-leche flavor at all.

    We don't yet have the ability to implement different "emulations" of how other espresso machines do steam. I like to think that we might get there with more research, but we're not there now.

    We're typically around ~150C with our steam, compared to the GS/3's max of 128C, but we're at half the flow rate (much drier steam). Our microfoam is extremely stable over time, suprisingly so to new observers.

    In no way am I saying our steam is superior to anybody else's, I think we're just different. In time, I hope to figure out why, and I'm hoping that our DE1CAFE machine can do "steam emulation", if we crack that nut.

    As to Illy's book and sweetening milk, my experience is that milk chemistry varies immensely across the world.
    - USA milk is very sweet, as it's mostly fed corn and is thus high in corn sugars. It caramelises.
    - In Hong Kong, we're using Meiji Deluxe high fat milk, which is quite low sugar, as I like the creamy/buttery flavor it gives, especially since I lean toward chocolatey medium espresso roasts rather than grassy/fruity lighter roasts, when mixing espresso with milk.
    - Australia's O'Lait has a similar flavor profile to Meiji Deluxe, and we might switch to it.

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    G'day again John

    Thanks for the heads up. Appreciated that you have taken the time.

    Milk is something that I do know a fair bit about. When growing up I was blessed with a farm over the back fence with a herd of Jersey, Guernsey and Brahman's in a mostly Frisian dairy farm area. I fully appreciate (and concur) that the various milks (including other countries, different diets, seasons etc) make a huge difference to the taste. My point is that any cow milk (and most other animal variants for that matter - I have done the same with sheep, goats, llama, alpaca etc) has a fairly high lipid content, and if my experience (and Illy's chemistry) is correct then breaking them down "properly"* can add a little sweetness (not custard - yuk) to the cuppa. Most of my friends have from one to three teaspoons of sugar in their coffee - except when I make it and "none" is their usual. The natural flavour of the milk barely alters, it just comes out sweeter. The way you described your milk is exactly what it should do when frothed up properly (Yay!).

    "properly"*: Whatever that means. I just know how to do it with a single hole wand tip on virtually any espresso machine, irrespective of the power. Microwaving it and / or using those ubiquitous "milk frother gadgets" are always a fail.

    A side note - I thought your steam was 170 Celsius not 150? Not that I am concerned apart from the result in the cup... Or is that also configurable these days?

    Thanks again


    TampIt
    PS: I am off the "maintenance payments" hook in August this year. Your machine is top of my list to purchase and have a play with. Not having a presence in Oz is no barrier to that in my view. I also agree that marketing it directly may be a good move - my own IT company found word of mouth was way more effective than any other advertising means of spreading the news. I also congratulate you on your transparency - a real breath of fresh air.
    Last edited by TampIt; 3rd March 2017 at 02:21 PM.
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    Quote Originally Posted by TampIt View Post
    Milk is something that I do know a fair bit about. When growing up I was blessed with a farm over the back fence with a herd of Jersey, Guernsey and Brahman's in a mostly Frisian dairy farm area. I fully appreciate (and concur) that the various milks (including other countries, different diets, seasons etc) make a huge difference to the taste. My point is that any cow milk (and most other animal variants for that matter - I have done the same with sheep, goats, llama, alpaca etc) has a fairly high lipid content, and if my experience (and Illy's chemistry) is correct then breaking them down "properly"* can add a little sweetness (not custard - yuk) to the cuppa. Most of my friends have from one to three teaspoons of sugar in their coffee - except when I make it and "none" is their usual. The natural flavour of the milk barely alters, it just comes out sweeter. The way you described your milk is exactly what it should do when frothed up properly (Yay!).
    I have to confess to not making it through all of Illy's book, even having paid a small fortune for the ebook version of it. Can you write a bit more about lipid chemistry, and how one would "break down" a fat (that's what a lipid is, I believe) into something that is sweet (a sugar?)? This isn't immediately intuitively obvious.

    I'd think that making milk sweeter would happen if you broke down long-chain sugars into shorter chain sugars that taste sweeter, such as what is done to make "lactose free" milk (breaking lactose down into the sweeter tasting glucose). Intense heat would likely do that to lactose.

    Sweetness from lipids, though, is something I don't understand.

    Quote Originally Posted by TampIt View Post
    A side note - I thought your steam was 170 Celsius not 150? Not that I am concerned apart from the result in the cup... Or is that also configurable these days?
    Well spotted! I "mis-wrote" and meant to put in 160C. Yes, you can set the steam heater temperature to as high as 170C, but we're not able to -- when the steam is actually running -- sustain 170C throughout the entire steaming process. Part of the problem is that we have a 180C "overheat" protector, and as you get nearer to that temperature, our gain is pull back, to avoid accidentally tripping it. So, as part of being transparent, I want to report that we can sustain 160C steam consistently, but 170C, not at the moment. We'll be studying this more when we rework steam for the PRO models this summer.

    During my UK sales trip, the "overheat protector" slightly unglued from the steam heater, and then we were hitting 175C steam constantly, which was honestly, a bit terrifying strong (giggles were overheard during the demos).

    Quote Originally Posted by TampIt View Post
    PS: I am off the "maintenance payments" hook in August this year. Your machine is top of my list to purchase have a play with. Not having a presence in Oz is no barrier to that in my view. I also agree that marketing it directly may be a good move - my own IT company found word of mouth was way more effective than any other advertising means of spreading the news. I also congratulate you on your transparency - a real breath of fresh air.
    Thanks for your kind words and thoughts on this approach.
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    Quote Originally Posted by decentespresso View Post
    I have to confess to not making it through all of Illy's book, even having paid a small fortune for the ebook version of it. Can you write a bit more about lipid chemistry, and how one would "break down" a fat (that's what a lipid is, I believe) into something that is sweet (a sugar?)? This isn't immediately intuitively obvious.

    I'd think that making milk sweeter would happen if you broke down long-chain sugars into shorter chain sugars that taste sweeter, such as what is done to make "lactose free" milk (breaking lactose down into the sweeter tasting glucose). Intense heat would likely do that to lactose.

    Sweetness from lipids, though, is something I don't understand.
    I am not a chemistry professional in any way. My understanding is similar to your comment - longer lipids break down into shorter sugars (plus a few other things which provide the "microfoam" & a few other compounds). Done correctly, the milk flavour doesn't vary much, it just picks up a little more sweetness. In the case of Jersey & Guensey, make that a lot more sweetness.

    What I do know is that (so far) any animal milk I have tried in raw / pasteurised / "minimally processed" form will go into microfoam + extra sweetness without much effort in a normal espresso machine with a single hole wand. Most cow milk scalds at around 74 Celsius, you only pick up the extra sweetness 2 to 3 degrees before the scalding point - so a bit of judicious work is required at the barista level. Another issue (which may add another configuration item to your milk temp setup) is different animal milks need widely varying "break down / scald milk temperatures" - about a 15 degree Celsius range if I remember correctly. How the breakdown "non cow milk temperature" copes with your higher "steam wand temperature" I confess ignorance.

    Quote Originally Posted by decentespresso
    Thanks for your kind words and thoughts on this approach.
    I don't do "kind words" - I just call it as I see it. Glad if it helped you.

    TampIt

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    Quote Originally Posted by blend52 View Post
    Not intended as a criticism, but i am also struggling with the concept that a temp sensor above the dispersion screen (upstream of the puck) , is able to detect temperature changes in the brew water in the puck/PF.
    Previously Its been shown that a sensor in the puck is the only accurate method of registering temperature variations in that area.?
    Where would the variability come from if not the inlet temperature? You will never have constant temperature in the puck for the *entire* shot (unless the grounds are preheated to the inlet temperature).
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    Quote Originally Posted by decentespresso View Post
    My understanding is that with Slayer, you can have a very, very slow preinfusion, for instance 60s to introduce 30ml of water, and you can then pause the shot for some number of seconds, and then ramp the pressure up. Even if I'm not right about Slayer being able to do this, it sounds pretty nifty, and I'd like the DE1+ to be able to do this.
    If we're talking about the preinfusion stage then I agree, there should be no pressure drop when you "pause". You said after preinfusion in your post, that's why I asked for clarifications.
    BTW, is your scale sensitive enough to detect the first coffee droplets for the purpose of detecting the end of preinfusion? My Brewista scale doesn't detect the first few drops, it needs some quantity of coffee before it reacts.

    Quote Originally Posted by decentespresso View Post
    I agree, and that's why I put the grey "control strip" in. However, I have a bit of experience in audio engineering, and so I am thinking of this all in terms of a "mixing board" that records your movements and can then play them back.
    I take it the gray "control strip" is some sort of a virtual slider? Ideally it will have some markings on it to allow the user to jump straight to certain discreet values. For example if I want to do a 3/7/5 bar extraction my preference would be to tap on the 3, then 7 then 5 rather than having to move a slider. I find touchscreen sliders to be slightly slow and a bit annoying to use although others may like them.

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    Quote Originally Posted by roburu View Post
    BTW, is your scale sensitive enough to detect the first coffee droplets for the purpose of detecting the end of preinfusion? My Brewista scale doesn't detect the first few drops, it needs some quantity of coffee before it reacts.
    Every scale I've seen has a noise filter, displaying 0g of weight until some threshold is passed, otherwise ambient vibrations would cause the scale display to blink annoyingly between 0g and 0.1g. Ours is no exception, in the same way that Acaia and Brewista do.

    However, at the bluetooth level, our scale's firmware is sending the weight 10x per second, without a noise filter. The first drop doesn't show up as a weight, but rather as a shock wave, a very quick transient spike on the load sensor. Since the scale is being read by our tablet over bluetooth, we can detect that noise, even if the display still reads 0g.

    So, yes: we can detect the first drop.

    Now, I know this for sure because I've written a flow meter for an earlier iteration of the scale, (video at https://www.youtube.com/watch?v=-arEs5jq09A) and a later version of that app (not in the video) had charts on it. In that software, I had two lines: the 10x a second weight, and a moving-one-second-average line.

    What was really interesting in those lines is that channeling appears to show up as increased noise on the load cell, because the spurts of water shoot out with force. I haven't figured out the maths yet, but I think there's a way for scale software to understand the "evenness of an extraction", ie an absence of noise.

    In theory, a less noisy espresso shot should taste better.

    If this is true, we'll have a very interesting tool. I am trying to plan a future where we have an "espresso nanny" software program, that is tracking commercial espresso machine use at a caf, and with the software having some idea of the coffee drink quality being produced at the caf, moment by moment. While I might package up these insights into a commercial software program, I will also share and discuss the metrics, and how they're obtained, in forums such as these, for other enthusiasts to play with. There's no shortage of arduino hackers on the coffee forums. I do think that one big thing holding espresso progress back has been a lack of objective measurements, which is why the Scace was such an important step. More can be done still, and we can hopefully figure this out together.

    Quote Originally Posted by roburu View Post
    I take it the gray "control strip" is some sort of a virtual slider? Ideally it will have some markings on it to allow the user to jump straight to certain discreet values. For example if I want to do a 3/7/5 bar extraction my preference would be to tap on the 3, then 7 then 5 rather than having to move a slider. I find touchscreen sliders to be slightly slow and a bit annoying to use although others may like them.
    My hunch is that real-time control of the espresso will be "laggy" for several reasons. The imprecision of the screen, gui lag, and the fact that moving a finger on a screen is not ergonomically idea, will mean this this way of doing things will be neat, fun, but not ideal.

    In software, it's inexpensive to add lots of functionality, and to try experiments with things. That's what we're doing near term, and that brings a lot of interesting functionality to a larger market.

    For real-time production use, we're planning on adding some sort of continuous controller strip, like a ribbon controller (picture below), that will be wired directly to the DE1. There's an RJ45 plug in back of the DE1/DE1+, with pins that go directly to the i/o ports of the cpu, so that the espresso machine firmware could be updated to talk to the controller. With direct access, and a hardware controller, I expect the experience to be much more real-time and more satisfying.

    hqdefault.jpg
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    Quote Originally Posted by MrJack View Post
    Where would the variability come from if not the inlet temperature? You will never have constant temperature in the puck for the *entire* shot (unless the grounds are preheated to the inlet temperature).
    If you refer bact to decentespresso's previous posts, he states..
    ....the DE1+ has an additional sensor in the group head, in the chamber above the dispersion screen, providing feedback to the system, so that the water mix temperature can be quickly adjusted. This allows the DE1+ to focus on the temperature at the puck, and automatically vary the "boiler temperature" to compensate for the cooling effects of the grounds and metal portafilter. The DE1 acts like a boiler, with water temperature at the water mixer output being the goal.
    ....so he is saying the temp variability Is coming from the cooler grounds and portafilter.
    The brew water feed from the group head chamber should be at a constant controlled temperature.
    My point was,..how well does a sensor above the dispersion screen detect those temperature fluctuations in the puck below when there is a constant flow of brew water downwards ?
    I am however, happy to accept DE's experience from Scace comparisons.
    Also, i suspect that Preheating the Portafilter ( as normal ?) and a decent pre-infusion time, may well minimise those temp differences. ?

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    Quote Originally Posted by blend52 View Post
    My point was,..how well does a sensor above the dispersion screen detect those temperature fluctuations in the puck below when there is a constant flow of brew water downwards ? I am however, happy to accept DE's experience from Scace comparisons.?
    You're absolutely right to call that as an unknown variable. The physics going on inside the saturated & pressurised group head are complicated and fairly opaque. Sensors have to be robust enough to survive the environment, but they also have to be invisible to the process or they'll change the thing you're trying to test.

    When I visited Synesso in Portland a few months ago, they tested the DE1 with their home-made Scace-like thing, which held a coffee puck and placed a temp sensor inside the puck itself. I held my breath, and ... it measured us at only 0.2C over the goal temperature.

    My point is not to pat myself on the back, but rather to end this story with caveat: this portafilter temperature test at Synesso made absolutely terrible espresso, with channeling and too fast a flow rate.

    All of us in the espresso machine industry struggle with what to measure and how to do it.

    The bottom line for me, is "does it make a delicious drink, repeatedly" and as I was almost ready to leave, Mark made me a fall-on-your-ass espresso shot on one of their machines. There's the proof behind the measurements.

    Quote Originally Posted by blend52 View Post
    Also, i suspect that Preheating the Portafilter ( as normal ?) and a decent pre-infusion time, may well minimise those temp differences. ?
    We run about -1.5C too cold on our first shot upon powering up, which is why I always run a 20s shot without coffee before my morning espresso. This heats the basket, portafilter, valves and tubing, and I don't know any substitute to hot-water contact with the entire espresso path.

    When a shot starts, it takes the DE1+ between 3 to 8 seconds to get the puck temperature to the set point goal. However, if you use a Mythos, with warm grounds, the time collapses to 2 to 4 seconds. It's pretty impressive to see the effects of that great grinder.

    -john
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    Quote Originally Posted by blend52 View Post
    If you refer bact to decentespresso's previous posts, he states..

    ....so he is saying the temp variability Is coming from the cooler grounds and portafilter.
    The brew water feed from the group head chamber should be at a constant controlled temperature.
    My point was,..how well does a sensor above the dispersion screen detect those temperature fluctuations in the puck below when there is a constant flow of brew water downwards ?
    I am however, happy to accept DE's experience from Scace comparisons.
    Also, i suspect that Preheating the Portafilter ( as normal ?) and a decent pre-infusion time, may well minimise those temp differences. ?
    If the brew water feed temperature is constant, then you simply will not get "fluctuations" (i.e. irregular change in the temperature). You will get a progressive heating of the puck, by the water, until the shot is ended or they come to equilibrium (which will occur at the top of the puck before it does at the bottom). A picture (and a model) is worth 1000 words: Espresso extraction temperature - DIYCoffeeGuy.com

    You could probably shorten the time it takes to reach equilibrium, by starting with an inlet temperature which is higher than your target (increasing the rate at which the puck heats) and then progressively lowering it to the target temperature (which is perhaps what the DE1+ does) - but you will never, ever achieve a constant temperature in the puck for the entire shot.

    It is simply not thermodynamically possible (unless you preheat the grounds to the and ignore heat of solution). I think people in the espresso world get a little hung up on things being "constant" or "even" - the real world is rarely either.
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    Quote Originally Posted by MrJack View Post
    You could probably shorten the time it takes to reach equilibrium, by starting with an inlet temperature which is higher than your target (increasing the rate at which the puck heats) and then progressively lowering it to the target temperature (which is perhaps what the DE1+ does)
    Yes, that's exactly what we're doing on the DE1+ : there's a feedback loop between the over-the-puck thermometer and the water mix temperature. The goal is to reach the set point temperature on the puck sooner than if the water temperature were left constant.

    Theoretically, this vary-water-temperature-approach would result in a better espresso shot, since more of the espresso's ~25s-35s was spent at the "optimal extraction temperature" of your choice.

    However, it's also possible to theorise that a rising infusion temperature might make the best espresso, on the principle that the remaining coffee material is harder to extract, and thus a higher temperature is needed.

    And then there's Scott Rao, who's put forward the argument to me that a declining temperature will make the best espresso.

    What's needed is a tool that can do these different temperature approaches (ahem), and blind tastings to see what people like best.
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  26. #226
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    Quote Originally Posted by decentespresso View Post
    Every scale I've seen has a noise filter, displaying 0g of weight until some threshold is passed, otherwise ambient vibrations would cause the scale display to blink annoyingly between 0g and 0.1g. Ours is no exception, in the same way that Acaia and Brewista do.

    However, at the bluetooth level, our scale's firmware is sending the weight 10x per second, without a noise filter. The first drop doesn't show up as a weight, but rather as a shock wave, a very quick transient spike on the load sensor. Since the scale is being read by our tablet over bluetooth, we can detect that noise, even if the display still reads 0g.

    So, yes: we can detect the first drop.

    Now, I know this for sure because I've written a flow meter for an earlier iteration of the scale, (video at https://www.youtube.com/watch?v=-arEs5jq09A) and a later version of that app (not in the video) had charts on it. In that software, I had two lines: the 10x a second weight, and a moving-one-second-average line.

    What was really interesting in those lines is that channeling appears to show up as increased noise on the load cell, because the spurts of water shoot out with force. I haven't figured out the maths yet, but I think there's a way for scale software to understand the "evenness of an extraction", ie an absence of noise.

    In theory, a less noisy espresso shot should taste better.
    I wasn't go to comment on these thoughts, however it may save you some time / grief or at least exclude another possibility.

    The idea that channeling could potentially be identified as "shot noise" is a (welcome) revelation to me. About time someone stated how two similar shots on the same gear can be so radically different in taste.


    Quote Originally Posted by decentespresso View Post
    (taken from the DE Grinder thread)

    - If your grinder is junk, you won't be able to make good espresso, even with the DE1. Thus, I want my customers to be able to buy an affordable grinder that I know will allow them to make good espresso.

    - if you're a beginner and you don't weigh your grounds, you're going to have trouble achieving consistently good espresso

    - the Baratza Sette: there are things I like about the Sette, and for the size, styling and price, I think it's unbeatable. However: our use of the Sette with the DE1+ finds that if you dose directly into the portafilter with the Sette, you will get bad channelling. Dosing into the Sette's plastic hopper, shaking, and then tipping that into the portafilter, produces quite good shots on the DE1+. This is fairly objective, and repeatable, as we can see the channeling as loss of pressure throughout the shot.

    - if you are willing to dose into the Sette's plastic hopper, then the Sette is a fantastic choice, and I would not want to offer a product to compete with it. The grind-by-weight feature, in my experience, is mostly accurate to within 0.2g, which is impressive.

    I was taught in the late '70's to set gear up by putting about 2mm of "coffee fluff" in the ("home made naked") portafilter and lightly (2 to 3Kg downforce only) tamp. Care should be taken that the first tamp should be absolutely level, with no signs of breakup in the puck.

    Repeat every 2mm of "coffee fluff" / lightly tamp until the dose is correct. Redistribute if there is any sign of crevices in the puck.

    Polish the final one and pull the shot. Whether polishing actually does anything I will leave to others to prove / disprove. Given decent gear the shots always taste brilliant. Oh, the shots channel slightly about once every blue moon.

    Then Schomer came out with his 30lb / 13Kg single tamp. It never really worked for me. Sprayed everywhere too often for my comfort and tasted a lot worse than my usual tamping method.

    Then there was an experiment with a 300lb / 135Kg tamper which showed that even at such an extreme pressure it was only the top 1/4" of the puck that was compressed. That made sense, as the lower 50% (roughly) of the grounds were a free for all which could channel freely.

    Then LM came out with the swift grinder - which (more or less) tamps in 1mm stages at 8lbs / 3 Kgs force. The output from a swift channels slightly about once every blue moon.

    So, John, I suggest you try my tamping method and see whether it removes the shot noise you detected.

    Hope this helps (or at least gives you something else to play with).


    TampIt

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    De1 progress report

    Hi guys, we're basically in "tying up all the details" mode here, with lots of things that still need to be finalized:
    - vibration dampening technique for the pumps
    - rubber foot design
    - final material of the drip tray & water tank (ceramic is really, really heavy, like 2kg, which is terrible for us since we're air-shipping these : it's +$20 in shipping for those, +$18 to make them. Too expensive.)
    - testing new mixing chamber design that has integrated almost all connectors into it, testing new "ultem" material
    - testing new approach of "clip connectors" everywhere for the water path, no more compression fitting or expensive (and failure prone) quick connects
    - new design for thermometer probes so they look clip connector compatible
    - on the firmware side, lots of hard work around implementing a file system and a firmware update system, and some crypto to prevent chinese copying of the firmware. Almost done with that, needs to be tied into the GUI.
    - on my end, finalizing the gui, which involves increased polish, support for multiple DE1s in a location, support for load/save of profiles, translating it, and skin support. I also have a few things to do on the DE1+ gui based on what I have learned about our espresso making workflow with our gui in the past 4 months of making shots daily.

    Below is the DE1 settings gui, for changing the pressure profile, and for a variety of other settings. This week I should make good progress on load/save of profiles.


    screen 2017-03-08 at 4.12.49 PM.jpg

    screen 2017-03-08 at 4.12.52 PM.jpg
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    That's good to hear. Any rough estimates on how long it will take to get the first non beta version out?

    Also one quick observation on the timer, a bit more flexibility would be useful (please ignore if it's already planned). I used to have my machine on a timer and I had 2 timers for week days: 6 am to 10 am and 4 pm to 10 pm. For weekends I had just one timer from 7 am to 9 pm.
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    Quote Originally Posted by roburu View Post
    That's good to hear. Any rough estimates on how long it will take to get the first non beta version out?
    We're still looking at June for these machines to be manufactured and released in non-beta.

    Quote Originally Posted by roburu View Post
    Also one quick observation on the timer, a bit more flexibility would be useful (please ignore if it's already planned). I used to have my machine on a timer and I had 2 timers for week days: 6 am to 10 am and 4 pm to 10 pm. For weekends I had just one timer from 7 am to 9 pm.
    I had an earlier version of this with a kind of grid, where you could set on/off at any interval during the day (and multiple intervals) and I can see how that would be useful. For now, though, I need to cut back on features and complete what we do have. The kind of timer I just described (as well as your request) should be doable as a plugin, and that'll motivate me to get the plugin architecture done.

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    Here's a short movie of us testing the button interface to our upcoming Decent Scale: https://decentespresso.com/scale



    The idea is for one button to control the timer (on the right) and another button to control the tare weight feature.

    There are a few button presses too many on the timer, and the "weight currently changing" LED should stay on for a second longer (since espresso can drip in slowly), but otherwise this is close to OK for me.

    Any comments?
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    Quote Originally Posted by roburu View Post
    one quick observation on the timer, a bit more flexibility would be useful (please ignore if it's already planned). I used to have my machine on a timer and I had 2 timers for week days: 6 am to 10 am and 4 pm to 10 pm. For weekends I had just one timer from 7 am to 9 pm.
    As it stands now, there's one interval. I've had 3 other people ask for a weekday/weekend scheduler. At the same time, I'm trying to keep the initial feature set down as much as possible, to essentials, so that we can ship this machine. The tablet software will have successive versions, where I can add things that are 'nice to have' but not essential. With a 5 minute warmup time, I was thinking that a power on/off timer was already kind of inessential.

    For the eventual power on/off feature, I had already designed about a year ago something which let you have multiple on/off times in one day, and a different schedule for each day even.

    Below is the design mockup.

    You can see that it's a lot more powerful, but it's also more work for me to program. So.. this is my intended (maybe version 3) scheduler.

    22105_large.png
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    Quote Originally Posted by decentespresso View Post
    Here's a short movie of us testing the button interface to our upcoming Decent Scale: https://decentespresso.com/scale

    The idea is for one button to control the timer (on the right) and another button to control the tare weight feature.

    There are a few button presses too many on the timer, and the "weight currently changing" LED should stay on for a second longer (since espresso can drip in slowly), but otherwise this is close to OK for me.

    Any comments?
    It looks like:
    • 1st press: Start
    • 2nd press: Stop
    • 3rd press: Reset


    Would it be less complicated to use a press for start/stop (i.e. pause/unpause) and press+hold for reset?

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    Quote Originally Posted by MrJack View Post
    It looks like:
    • 1st press: Start
    • 2nd press: Stop
    • 3rd press: Reset


    Would it be less complicated to use a press for start/stop (i.e. pause/unpause) and press+hold for reset?
    I'd rather not require people to learn to hold a button down for a while to have a different action. In my ideal world, one button does one thing.

    My plan, though, is to change the 3rd press into a reset. The workflow then becomes:

    1st press: timer LED turns on and starts counting time
    2nd press: timer stops, LED stays on, final time is displayed
    3rd press: timer is reset, and starts counting time (ie, step 1)

    In other words, the timer button is a START-AT-ZERO/STOP button. There is no feature to unpause, since I think this is not a very used feature.

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    designing a decent knockbox

    About two weeks ago, we finalized the design for our Decent Knockbox https://decentespresso.com/knockbox and sent it off to a CNC service to make us one.

    This one prototype costs about $120 to make. It's expensive, because it's carved out of a solid block of aluminum with a computerized drill. However, it's invaluable as part of the design process, because it lets us hold and use something that is very close to what the final factory-manufactured good will be like.

    Instead of plastic, we opted for 2.5mm thick aluminum, with a black anodized finish. The goal is for it to be sturdy, really dishwasher safe (which plastic often isn't) and to not have that cheap "thonk" sound when used. Anodizing provides a similar surface to teflon, though it's more durable and less slippery.

    Design wise, the goal was the deeply carve out the front so that a portafilter could be held level as it knocks. Some knockboxes don't have this feature and require you to tilt the portafilter forward or risk banging your knuckles. The back of the knockbox is scooped up to capture "splash". The bar is pushed forward because the spent pucks pile up in the back, and when I used knockboxes with bars in the middle I found that I filled the knockbox up when it was only half full, because the pucks didn't spread out in the container.

    We'll be testing this prototype this week and next with different types and thicknesses of foam glued onto the bottom. The "knock bar" on this prototype is borrowed from another knockbox, as we don't have a way to make a prototype of that part without making a silicone mould.

    Once we're happy with this, we'll send it the final specs to our factory, and in about 80 days we'll have them in stock.

    Below are two photos of the real object, along with a computer-generated render. It's always interesting to compare the idealized perfect version off a computer to the real thing. In this case, they're not too different.

    decent_knockbox_prototype.jpg

    decent_knockbox_prototype2.jpg

    knockbox_grey.jpg

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    New drip tray design

    The new design for our drip tray cover came in today from our CNC manufacturer. This version is a hybrid of types "1 and 2" in that from above it behaves like round metal wires, but viewed from the bottom you can see that it's flat. There is no coating on this, nor has it been polished, so it's likely more water retention-friendly than a final product might be.

    I poured water all over the top, to see what droplets would stick the top.

    The ability of this design to repel from the top is fairly good:

    IMG_6014.jpg IMG_6006.jpg

    but viewed from the bottom, the water droplets do like to cling:

    IMG_6013.jpg

    however, this is still much better than our previous design, which I photographed today:

    IMG_6012.jpg

    My feeling is that the performance of this design is likely good enough, and if we were to spray the bottom with a water-repelling coating, that behavior might be improved too.

    A big caveat, though, is that we don't yet know if this design can actually be manufactured at a reasonable cost. This CNC prototype cost us $80 to make. We're going to talk to factories over the next few weeks, and we might end up with a related design, of welded 3mm stainless wires inside a metal frame. The appearance of a drip tray with that approach will be similar to this CNC prototype, from the top, but from the bottom we would get less droplet retention if the wires were round on the bottom too.

    WHAT DO YOU THINK OF THIS DRIP TRAY DESIGN?

    IMG_6010.jpg
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  36. #236
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    Quote Originally Posted by decentespresso View Post
    About two weeks ago, we finalized the design for our Decent Knockbox

    Below are two photos of the real object, along with a computer-generated render. It's always interesting to compare the idealized perfect version off a computer to the real thing. In this case, they're not too different.

    decent_knockbox_prototype.jpg

    decent_knockbox_prototype2.jpg

    knockbox_grey.jpg
    I like the computer generated one.

    Not a lot of scope for originality with knockbox shape I suppose, but that one would look fine next to my machine.

    With such a narrow base is it stable on the bench?

  37. #237
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    Quote Originally Posted by gc View Post
    Not a lot of scope for originality with knockbox shape I suppose, but that one would look fine next to my machine.
    We searched far and wide for inspiration, but it wasn't easy, because at its root a knockbox is a rubbish bin with a bar across it.

    When I started looking at Champagne coolers I found designers trying to communicate the sexiness of champagne in their forms, and I was really floored by this design for Moet Chandon by Jean-March Gady: Jean Marc Gady for Moet & Chandon (NOTCOT)

    Our design uses many of same design tropes that Gady's does, though implemented differently (we don't need a lifting handle, for instance).

    moetshine2.jpg

    moetshine4.jpg


    Quote Originally Posted by gc View Post
    With such a narrow base is it stable on the bench?
    That was a very real concern with this design, but looking at the physics, we thought we'd be fine, since the force of the "thump" channels toward the center with this shape. If the bar were further back (ie, in the center) that could have caused a problem. In use, so far today, the knockbox hasn't "rocked" from use, but I'm definitely watching for that as a problem.

  38. #238
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    Quote Originally Posted by decentespresso View Post
    We searched far and wide for inspiration, but it wasn't easy, because at its root a knockbox is a rubbish bin with a bar across it.
    Looks quite similar to a knockbox I used to have, can't remember the brand, however I found a photo of a similar one: http://www.espressoworkshop.com/imag...300.jpgWM.jpeg . Your rounded design looks nicer though.

    Quote Originally Posted by decentespresso View Post
    In use, so far today, the knockbox hasn't "rocked" from use, but I'm definitely watching for that as a problem.
    I found the wide base on mine was useful as without it I'm pretty certain I would have spilled it a couple of times. Spilling a full or nearly full knockbox is a pretty big thing especially if you have carpet near the coffee preparation area as I (unfortunately) do.

  39. #239
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    Quote Originally Posted by decentespresso View Post
    WHAT DO YOU THINK OF THIS DRIP TRAY DESIGN?

    IMG_6010.jpg
    It's pretty decent
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  40. #240
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    HEATED GROUP HEAD and the question of a PLASTIC VS METAL GROUP HEAD COVER

    Jeremy from Blossom coffee, who is consulting for us, expressed concern about the long-term reliability of our using Calrod tube Calrod Heater - Heater Elements - Wattco.com to heat our group head.

    This is what a Calrod looks like:
    183615-10830315.jpg

    Probably, we're ok, because they only really heat up when the DE1 powers up, but the problem is that it is hard to shape the heating tube to exactly fit into the group head's moulded channel, so that a lot of heat transfer paste is needed to mate them, and that if this isn't done right, or the tolerances are too far out, the Calrod tube will slowly fail over the course of a few years.

    However, besides the "probably ok" there's the inefficiency of the heat transfer that's been bugging me for a while. We're heating the group heat, to indirectly heat the water path.

    So, instead, I decided that we should spend two weeks on switching to directly heating the water path, with a much smaller heater that will be mounted directly on the brass "shower assembly" where the water actually ends up, right above the espresso puck.

    Here is what a ceramic heater looks like:

    pg_pbn_element.jpg

    A few benefits from this approach:
    - we can use less electricity (200W vs 800W) to heat the DE1 to ready
    - we should be able to heat up faster (less mass to heat up now)
    - we will have much less waste heat (less radiating off the group head)

    Which means that we no longer need to use plastic to make the group head cover an insulator around the group head. There won't be enough heat radiating off it to burn yourself on.

    So, four things going on this week:
    - some group head internals redesign to move off of a calrod heater, to a ceramic heater (mechanical engineering, David)
    - electrical calculation changes and some software programming to support the change (electrical engineering, Ray)
    - design thinking into what a stamped metal group head cover should look like. (industrial design, Joao)
    - getting pricing to manufacture this part (Alex and Johnny)

    From a designer's standpoint, I've never been happy about having a big blob of simulated-metallic-finish plastic on the group head, right where everyone can see it, especially since we spent so much time and money using metal and wood everywhere else, to produce a high end machine.

    So, in our next rev this will change to metal, and in the next 2 weeks I'll be able to post here a design for that group head cover, which we can make in metal.

    IMG_5850.jpg

    As an aside, another little sourcing detail for us has been how to tidy up that USB charging cable on the tablet, and where should the cable go.

    This week Jeffrey found a supplier for flush mount charge-only USB cables. They're virtually invisible, and look like this:

    31zQMaBG-ML.jpg

    We need to have a custom cable made for us, and either snake it through a slot in the front panel, or through a screw hole. That'll be much cleaner looking.
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  41. #241
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    Looks like some great feedback and design updates/tweaks there! Ceramic heating looks like a good win. Hope that's works out well. Improved energy efficiency and warm up time are excellent improvements.

    Nice touches on the tablet USB charger/mounting too!

    DE team kicking goals.

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    Quote Originally Posted by decentespresso View Post

    - design thinking into what a stamped metal group head cover should look like. (industrial design, Joao)

    From a designer's standpoint, I've never been happy about having a big blob of simulated-metallic-finish plastic on the group head, right where everyone can see it, especially since we spent so much time and money using metal and wood everywhere else, to produce a high end machine.
    G'day John

    All looking good - well done so far.

    FWIW, I reckon you should retain something close to the current shape as no other coffee machine looks similar. Always a good thing to look different as long as it is still esthetic (and that basic cylindrical shape is).

    TampIt

  43. #243
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    Quote Originally Posted by TampIt View Post
    G'day John

    All looking good - well done so far.

    FWIW, I reckon you should retain something close to the current shape as no other coffee machine looks similar. Always a good thing to look different as long as it is still aesthetic (and that basic cylindrical shape is).

    TampIt
    +1 to the above comment.

  44. #244
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    Quote Originally Posted by TampIt View Post
    G'day John All looking good - well done so far. FWIW, I reckon you should retain something close to the current shape as no other coffee machine looks similar. Always a good thing to look different as long as it is still esthetic (and that basic cylindrical shape is).TampIt
    Agreed on the cylindrical shape, but a quick googling for "espresso group head cover" finds a few companies doing aesthetically nice things with this part, so I think there's room for improvement with ours.

  45. #245
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    Designing a group head cover

    For the past two years, we've had a moulded plastic cover on our group head. It's been made in plastic to keep you from burning yourself if you touched it. We've recently figured out how to keep the heat in, so we can use metal to make the cover, which will be classier looking and more durable. We're thinking about using stainless steel, though we haven't decided between brushed (resists fingerprints) or shiny (very classic).

    So, we're taking the opportunity to rethink this design, and below you'll find some initial concept sketches for ideas we have.

    Which one do you like?

    designall.jpg
    design1.jpg
    design2.jpg
    design3.jpg
    design4.jpg
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  46. #246
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    Weight shots -- just came up with a much better idea

    File this under the WHY JOHN SPENDS SO MUCH TIME ON INTERNET FORUMS category, I had a "holy cow" moment this morning where I put a 3D mockup of our upcoming Decent Scale under the drip tray, rather than on top of it. This was a suggestion made last week on HB (apologies, I forget who came up with it), and I realized that this is so much more logical than putting the scale on top of the drip tray cover.

    With the scale on top, you lose a lot of espresso cup height, and you also have to worry about water getting into the scale, and it's another thing to clean up. A usb micro charger cable isn't really possible in this configuration.

    Under the drip tray, it's out of the way, you don't lose any cup height, and there is no cleanup to worry about. Plus, you can plug the usb power into the scale in a way that isn't even visible.

    And, totally by accident, my design of putting the LEDs and buttons vertically, makes this idea possible. This wouldn't work with most other scales, since they all face upwards.

    To see if this would work, I put the maximum amount of water into the drip tray, I picked the heaviest mug (IKEA) I have and i put 100ml of water (a lungo espresso shot). Good news: we're still 200g short of the 2000g capacity of our scale, so this should work.

    I'll need to make sure that our scale has enough clearance that it doesn't touch the espresso machine when it's on the scale, but otherwise this idea should be straightforward. Since we haven't finalized the ceramic drip tray mould, now is the time to nail this idea down.

    On the DE1+ I can make the tablet software tare the scale automatically when you tell it to start making an espresso, and then "gravimetric" automatic shot-off becomes really easy to code.

    scaleunderdrip.jpg

    fullyweighed.jpg
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  47. #247
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    Thats awesome

  48. #248
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    Quote Originally Posted by Melbroaster View Post
    Thats awesome
    Thanks! We're making good progress on the timeline for finishing our upcoming Decent Scale https://decentespresso.com/scale

    The firmware is done, and we're testing different types of translucent plastics to let the weight LEDs shine through but have it all look like a solid black black front when it's powered off.

    The top LED gives the weight, while the bottom LED stays off by default, and becomes a timer if you tap the [] button to start it.

    preview-full-IMG_1874.JPG
    preview-full-IMG_1875.JPG

  49. #249
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    I like design #2

  50. #250
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    Question: With the weight of the driptray water, drip tray and mug on the scale (ie 1.5kg- would you expect that the accuracy of the scale to reflect each extra gram added to the scale to be as consistent as each gram added to the scale starting from a zero load?
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