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

  1. #451
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    Preinfusion for circa 4 seconds, quick ramp up to 9bar (actually 9.2 in my case) and then maintain a constant flow (well, a very, very slight decrease over the time, but near enough) for the next 25ish seconds. Dead stop at the blonding point (a manual "hard turn off" with a pressure drop to near zero would do that easily). That is a close match for the majority of roasts in my Electra manual lever - mind you a way better grinder and different baskets these days and those may now be way off target.

  2. #452
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    I manually control my Bezzera BZ99S (bypass needle valve) - I have found the best results with low flow (needle valve open) until I see espresso appear across all of the bottom of the basket ("pre-infusion"), then I shut the needle valve over about a second to direct all of the flow to the puck (which open the OPV once the pressure rises to about 9 barg) -usually leaving it there until the end of the shot.

    I have experimented with shorter / longer preinfusion and slow ramp to full flow, or shots at low flow (i.e. low pressure) but I found it negativley impacted crema.

  3. #453
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    Quote Originally Posted by TampIt View Post
    Preinfusion for circa 4 seconds, quick ramp up to 9bar (actually 9.2 in my case) and then maintain a constant flow (well, a very, very slight decrease over the time, but near enough) for the next 25ish seconds. Dead stop at the blonding point (a manual "hard turn off" with a pressure drop to near zero would do that easily). That is a close match for the majority of roasts in my Electra manual lever - mind you a way better grinder and different baskets these days and those may now be way off target.
    That's super interesting to me, because at the moment, only lever dudes (and those with Paddle-based pro machines) can do a constant flow rate.

    There are two pieces of data that would help me emulate this shot:
    1) for what duration of time is espresso flowing into your cup
    2) what is the total weight in cup at the end.

    With those two pieces of information, I can work out what your "constant flow rate" is, and do the same.

    Quote Originally Posted by MrJack View Post
    I manually control my Bezzera BZ99S (bypass needle valve) - I have found the best results with low flow (needle valve open) until I see espresso appear across all of the bottom of the basket ("pre-infusion"), then I shut the needle valve over about a second to direct all of the flow to the puck (which open the OPV once the pressure rises to about 9 barg) -usually leaving it there until the end of the shot. I have experimented with shorter / longer preinfusion and slow ramp to full flow, or shots at low flow (i.e. low pressure) but I found it negativley impacted crema.
    It sounds like you're doing a straight 9 bar shot, after doing a slow preinfusion which you end visually. Is that right?

    Could you tell me:
    1) for how long do your shots run after preinfusion ends
    2) what's your final in-cup weight
    3) what your espresso dose weight is
    4) what how long preinfusion typically takes.

    That will let me more-or-less figure out what your preinfusion flow rate is, as grounds hold about 2x their weight in water.

    Thanks!

  4. #454
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    Flow rate change graphed

    Below is a screen picture of the DE1+ tablet GUI that I'm working on.

    This is Scace shot, 30 seconds long, 5 seconds preinfusion, rise to 9 bar, hold for 5 seconds, then decrease to 6 bar over 20 seconds. We've found that our Scaces "open up" with time and have a faster and faster flow rate, which is why this doesn't look so much like an espresso shot (which would compress down to a lower flow rate).

    Screenshot_2017-05-27-22-52-04.png

    I've added James Hoffmann's suggested "flow rate change" information. I've been struggling with how to display this, because it can be a positive or a negative number. I don't want to make a new chart for this data, and changing the Y axis to go to -6 ml/s would halve the visual resolution.

    I decided that a flow rate increase is very different information than a flow rate decrease. A decrease would tend to be caused by the DE1+'s desired profile, though clogging could also cause this. A flow increase is generally caused by temporary channeling.

    For this reason, I decided to draw flow rate increases from the bottom, moving up. And flow rate decreases are from the top, moving down.

    I'm not 100% sold on this approach, but it's the best I've come up with for now. Changing how this works is very easy, and alternative skins can be offered, as I've coded support for a half dozen alternatives, in coming up with this.

    Screenshot_2017-05-27-22-52-04 copy.png

    I've also changed the "data card" on the right around, so that it's more useful (I hope). There are a ton of usability improvements too, from what I've learned making espresso for 5 months with this software.

    The Y axis for temperature is now auto-generated based on data, so before you think you're having big temperature swings, be sure to look at the Y axis label. This Scace shot started about 0.90C too cold and within 10s hovered around 0.25C too hot. The data card on the right now shows you how far off the brew temperature is from your goal, and it also tells you how many C over/under the goal we're putting into the group head, in order to reach the goal quickly.

    Also new to the DE1+ is a consolidated "zoom mode" that combines flow and pressure on a single chart, doesn't zoom temperature, so that you can see your shot in great detail.

    I think an argument can now be made that "pressure change" should also be displayed, and I might do that eventually too.

    Screenshot_2017-05-27-22-51-56 copy.png
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  5. #455
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    Quote Originally Posted by decentespresso View Post
    That's super interesting to me, because at the moment, only lever dudes (and those with Paddle-based pro machines) can do a constant flow rate.

    There are two pieces of data that would help me emulate this shot:
    1) for what duration of time is espresso flowing into your cup
    2) what is the total weight in cup at the end.

    With those two pieces of information, I can work out what your "constant flow rate" is, and do the same.


    ... after doing a slow preinfusion which you end visually. Is that right?
    To give a more complete answer
    1) Preinfusion: varies massively by the particular roast characteristics. I strongly suspect it is mainly matched to solubility*. I drink light to medium roasts, darker roasts need a different setup. The lightest roast, hardest bean combo I have dialled in successfully (Ethiopian "original Mocha" beans - not the Yemen port) took 40 seconds preinfusion. Most roasts take about 3 to 6 seconds preinfusion, some dark roasts / softer beans actually go backwards with any preinfusion at all. I NEVER count preinfusion time as part of the shot (IMO, it isn't - try to get a coherent shot time with 40 seconds preinfusion!). FYI, your preinfusion detection posts (first drop hitting scales / slight pressure drop) is probably on the money. When using any manual lever worth using (i.e. one you can actually "feel the shot"), whenever the preinfusion is complete you can feel a slight pressure drop. I actually put a significantly weaker spring in my Electra to get a better feel.
    2) The actual shot time for a "mythically average" light / medium roast using my grind/dose/tamp would be from 22 seconds to 35 seconds before it blonds (less soluble takes longer, increasing the pressure too much kills the taste so the flow rate must be lower for the longer shot). The blonding is way, way more critical than the time. No way have I ever "felt" the blonding point despite many others claiming they can (good on them if true). That is why I asked for a hard cutoff which drops the pressure to near zero rather than an end time. A "default end time" of say 35 seconds would be fine, as long as there is a "cutoff button" to end the shot immediately at blonding via human eyeball. Saving that setting for the next shot but allowing a minor tinker would be awesome.
    3) That "blonding cutoff" always gives me almost exactly 60g in the cup from 16g of grounds (measuring via ml is useless given the amount / height of crema). BTW that is a pretty standard, balanced, "normal shot" - not either a ristretto or lungo.
    A note on flow rate - the decrease in flow "after the start up ramping" would be minimal. That is (mostly) how I balance the shot with the lever. Maybe a 10% drop over the whole shot time (more like 5% I suspect).

    Hope this helps.


    TampIt
    solubility*: Some beans are a lot harder / less soluble than others both before and after roasting. After roasting, generally the darker roast is more soluble.
    PS: Your wide variety of configuration options are exactly why I will get one of your machines. Once a roast is optimised, the Decent1+ should be able to pump them out all day with virtually no effort. Hopefully it can equal a manual lever in cuppa quality without the concentration and grief...T.
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  6. #456
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    Quote Originally Posted by decentespresso View Post
    Below is a screen picture of the DE1+ tablet GUI that I'm working on.

    This is Scace shot, 30 seconds long, 5 seconds preinfusion, rise to 9 bar, hold for 5 seconds, then decrease to 6 bar over 20 seconds. We've found that our Scaces "open up" with time and have a faster and faster flow rate, which is why this doesn't look so much like an espresso shot (which would compress down to a lower flow rate).

    Screenshot_2017-05-27-22-52-04.png

    I've added James Hoffmann's suggested "flow rate change" information. I've been struggling with how to display this, because it can be a positive or a negative number. I don't want to make a new chart for this data, and changing the Y axis to go to -6 ml/s would halve the visual resolution.

    I decided that a flow rate increase is very different information than a flow rate decrease. A decrease would tend to be caused by the DE1+'s desired profile, though clogging could also cause this. A flow increase is generally caused by temporary channeling.

    For this reason, I decided to draw flow rate increases from the bottom, moving up. And flow rate decreases are from the top, moving down.

    I'm not 100% sold on this approach, but it's the best I've come up with for now. Changing how this works is very easy, and alternative skins can be offered, as I've coded support for a half dozen alternatives, in coming up with this.

    Screenshot_2017-05-27-22-52-04 copy.png



    I think an argument can now be made that "pressure change" should also be displayed, and I might do that eventually too.

    Screenshot_2017-05-27-22-51-56 copy.png
    Really interesting stuff! Rather surprised that both flowrate and pressure are falling (unless you are manipulating pump speed during that shot?)

    I'm not sure how useful the numeric value of the rate of change in flowrate (which would be mL/s2 ) or pressure (bar/s) would really be. Its also a measurement very sensitive to error in my experience.

    However, if you want a simple visualisation, perhaps consider colour? Changing the background colour of the chart - say, red for increasing flow and green for decreasing, with colour saturation (or alpha?) representing the magnitude of the deviation might be useful for highlighting sudden changes?

    Something else to consider, have you ever tried plotting flow on the x axis and pressure on the y axis?

  7. #457
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    Flow profile editor (1st peek)

    FLOW PROFILE EDITOR

    This weekend I got a first pass at a flow profile espresso editor working. Here's a picture of it below.

    Matt Perger stopped by Decent HQ today, and suggested that moving the "6 bar start" option into a separate "compress" step would be more logical. I think he's right, and will make that change tomorrow. The steps will then be "Preinfuse, compress, hold, decline".

    Another idea Perger proposed was to be able to program a volumetric espresso shot in steps, so that you can say:
    1) preinfuse at 4 ml/s until the puck is detected as being saturated
    2) run 30ml of water at 1.5ml/second, and then end the shot.

    In theory, the in cup weight should be 30ml. The DE1+ firmware can currently do this sort of thing, but I haven't yet programmed the tablet GUI to make it possible. I think Perger's idea is a good one, so I'll make sure that my software can do what he's described.

    screen 2017-05-29 at 6.50.13 PM.jpg
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    filling the water tank

    I've been asked many times "how do you fill the water tank on the decent espresso machine?" So I made a movie today showing how.

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  9. #459
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    Quote Originally Posted by MrJack View Post
    Really interesting stuff! Rather surprised that both flowrate and pressure are falling (unless you are manipulating pump speed during that shot?)
    Yes, that's exactly what's going on. The "dotted line" on the graph shows what the espresso machine is intentionally doing, so if the dotted line is falling, that's because the shot was programmed to lower pressure (or flow, depending on the program).

    Quote Originally Posted by MrJack View Post
    I'm not sure how useful the numeric value of the rate of change in flowrate (which would be mL/s2 ) or pressure (bar/s) would really be. Its also a measurement very sensitive to error in my experience.
    I agree, that sensor noise is something to be wary of, which is also why we're now charting both flow rate and pressure on the same chart. They're different physical phenomena, measured differently, but they're generally inversely correlated to each other.

    Thus, if you see a blip down on pressure, and a blip up on flow, you can be fairly sure something real happened.

    In the charts above, which were our first attempt, we found that we didn't have enough bits of accuracy to be able to meaningfully display "flow rate change". In two day's work, we've added more precision to those reported numbers, and the flow rate change blips are a bit more meaningful.

    Here's a flat-9-bar-shot on a Scace with a very slow (0.3 ml/s) preinfusion:
    Screenshot_2017-05-30-18-35-08.png

    To note:
    1) you can see several blips between 10 and 22 seconds, on the bottom X axis. Those are quick flow rate increases.
    2) looking up to the green line, you can also see blips on pressure at those points. Thus, I think that those blips are meaningful data.
    3) ps: this isn't a useful shot for espresso, we're doing these settings because the Scace doesn't emulate coffee compressing, so preinfusion doesn't really graph right with a Scace.

    Quote Originally Posted by MrJack View Post
    However, if you want a simple visualisation, perhaps consider colour? Changing the background colour of the chart - say, red for increasing flow and green for decreasing, with colour saturation (or alpha?) representing the magnitude of the deviation might be useful for highlighting sudden changes?
    I agree, there's more work to be done to help the graphs lead to better espresso. Top of my list is having the software understand more about what's happening, and then put call-out labels at those points, perhaps "channelling? -->" for example, where we think it occurred.

    Quote Originally Posted by MrJack View Post
    Something else to consider, have you ever tried plotting flow on the x axis and pressure on the y axis?
    I haven't tried that, but wouldn't I need a time series to make it meaningful? Alternatively, I could do a 3D graph with time/flow/pressure on it.

    Lots of ideas to occupy me for the years to come...
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  10. #460
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    Quote Originally Posted by TampIt View Post
    To give a more complete answer ... Hope this helps.
    Yes it does, super interesting, but your message also conclusively demonstrates to me that
    a) trying to emulate what you do, with a "click & make an espresso" would utterly fail
    b) you're the kind of person who will be programming your own shot profiles, not using the existing profiles, except perhaps just to learn what other people are doing.

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    Our first flow controlled espresso shot

    As of today we’re able to make flow controlled espresso shots.

    I don't know of any other espresso machine able to do this, so this could be a world premiere.

    The screen shots below are the results of our first real (coffee, not Scace) fully flow controlled shot, which just occurred a few minutes ago.

    Pressure was never a goal in the shot. This was a 4 ml/s pre infusion, followed by a 1.8 ml/s hold, with a flow rate declining to 1.0 ml/s. Look at the green pressure curve, it’s really interesting to see what kind of pressure curve fits this kind of flow rate.

    I've recorded video of this and will put a movie out shortly, explaining this further.

    settings.png shot.png zoom.png
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  12. #462
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    Quote Originally Posted by decentespresso View Post
    Yes it does, super interesting, but your message also conclusively demonstrates to me that
    a) trying to emulate what you do, with a "click & make an espresso" would utterly fail
    b) you're the kind of person who will be programming your own shot profiles, not using the existing profiles, except perhaps just to learn what other people are doing.
    a) I hope there is a standard profile close to that. If not, there soon will be...
    b) I will start the same procedure I use to set up a cafe - begin with a close guess as to the beans characteristics and then tinker to taste.

    What I gave you is pretty close to a "standard manual lever profile", which is probably an oxymoron given the that whole idea of manual levers is to match a beans requirement exactly on the fly.

    Flow rate: Awesome, that is where I suspect we manual lever guys have been trouncing semi autos forever. Good luck with whatever further developments strike you as a good idea.

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    Quote Originally Posted by decentespresso View Post
    As of today we’re able to make flow controlled espresso shots.

    I don't know of any other espresso machine able to do this, so this could be a world premiere.

    The screen shots below are the results of our first real (coffee, not Scace) fully flow controlled shot, which just occurred a few minutes ago.

    Pressure was never a goal in the shot. This was a 4 ml/s pre infusion, followed by a 1.8 ml/s hold, with a flow rate declining to 1.0 ml/s. Look at the green pressure curve, it’s really interesting to see what kind of pressure curve fits this kind of flow rate.

    I've recorded video of this and will put a movie out shortly, explaining this further.

    settings.png shot.png zoom.png
    Most importantly how did the shot taste in comparison with other profiles?
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  14. #464
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    Quote Originally Posted by TampIt View Post
    Flow rate: Awesome, that is where I suspect we manual lever guys have been trouncing semi autos forever.
    I agree: in my presentations of emulating the history of espresso machine, I present the appearance of flat-pressure semi-auto machines as a step backward in drink quality.

    Quote Originally Posted by mentasm View Post
    Most importantly how did the shot taste in comparison with other profiles?
    It's only been two days since we've had this feature, and I'm both not qualified, and too biased. I shouldn't be opining on drink quality.

    I'm meeting up with Scott Rao tonight for several days, and then spending time with James Hoffmann on Saturday and Sunday (just arrived in London this morning), I prefer to leave the taste opinin to them. I'll be at World of Coffee in Budapest next week with this machine.
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    How is it possible to have a 4ml/sec flow for 10 seconds? Wouldn't an 18 gram coffee puck be over saturated at 4ml x 10 sec? Am I wrong to think that 40ml of brew water be too much for the coffee puck to hold it in? Is something else in play like the excess water draining out somewhere during pre infusion?

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    Quote Originally Posted by JojoS View Post
    How is it possible to have a 4ml/sec flow for 10 seconds? Wouldn't an 18 gram coffee puck be over saturated at 4ml x 10 sec? Am I wrong to think that 40ml of brew water be too much for the coffee puck to hold it in? Is something else in play like the excess water draining out somewhere during pre infusion?
    Well spotted!

    You're right, it isn't possible, which is why there is a "4 bar start" choice (in the hold section) feature. When the pressure reaches 4 bar, the preinfusion stage exits, regardless of how many seconds of preinfusion you set.

    In the shot above, you'll see a vertical gray line drawn around 6.5 seconds, and this indicates the end of preinfusion, at around 26ml total water put into the puck. Preinfusion ended there because 4 bar of pressure was detected. In that shot, preinfusion was cut short 3.5 seconds early.

    The reason for that feature is so that:
    1) you can set preinfusion flow rate to whatever you like
    2) but preinfusion exits if a desired pressure occurs, otherwise the preinfusion lasts the number of seconds you indicated
    3) this also allows Slayer-style preinfusion, so that you could (for instance) do 1 ml/s for 25, require 4 bar of pressure, which would cause the puck to compress before switching back to flow control mode. Without this puck compression step, you could end up not having any pressure at all. Note that if you want to do that, you still can, you just set the "start pressure" to 0.
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    News: final proof of sheet metal, Ultem, brass pieces.

    We're about to receive the final sheet metal "factory proofs" for our chassis, and all the Ultem and brass pieces too. We need to check these all for final accuracy before we give approval for mass manufacture.

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    Quote Originally Posted by decentespresso View Post
    As of today were able to make flow controlled espresso shots.

    I don't know of any other espresso machine able to do this, so this could be a world premiere.

    The screen shots below are the results of our first real (coffee, not Scace) fully flow controlled shot, which just occurred a few minutes ago.

    settings.png shot.png zoom.png
    Had a bit of a look at the data from this shot last night (extracted from the images using WebPlotDigitizer). Made a few different plots (including some with derived / aggregate variables). The result was rather interesting!

    Would be very keen to see some more (in particular one with a fixed pump speed).

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    Quote Originally Posted by decentespresso View Post
    I've been asked many times "how do you fill the water tank on the decent espresso machine?" So I made a movie today showing how.

    Thanks for posting. Does the drip tray lock in or is it just sitting there and subject to movement or knocking?

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    Quote Originally Posted by JMcCee View Post
    Thanks for posting. Does the drip tray lock in or is it just sitting there and subject to movement or knocking?
    It passes by very quickly in the video, but at 0:01 you can see that there are large "dimples" in the bottom front of the drip tray.

    These fall into cut outs in the leg rails and thus lock it into place.

    Here's a screen picture and I've put an arrow to them.

    screen 2017-06-03 at 2.25.54 PM.png

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    flow profile editor evolution

    The Flow Profile shot editor is undergoing rapid change at the moment, because I took my first attempt at it to London, where I'm here with Scott Rao, and he immediately poked holes in some of my assumptions.

    Below is today's iteration, trying to address Rao's points.

    Even though this is a flow controlled shot, there is
    (a) an optional exit during preinfusion if a given pressure is reached, and
    (b) an option for a guaranteed minimum pressure after preinfusion, in case you want flow control, but you want to make sure the puck was compressed.

    Scott and I are with James Hoffmann tomorrow, who I'm sure will poke more holes in our assumptions.

    Hopefully, with all this expert advice on what we're doing, we'll be able to find a happy compromise between power and simplicity. It's a work in progress at the moment. My goal is to have something relatively well thought out for next week's World of Coffee conference in Budapest.

    screen 2017-06-03 at 6.28.26 PM.jpg
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    Quote Originally Posted by decentespresso View Post
    It passes by very quickly in the video, but at 0:01 you can see that there are large "dimples" in the bottom front of the drip tray.

    These fall into cut outs in the leg rails and thus lock it into place.

    Here's a screen picture and I've put an arrow to them.

    screen 2017-06-03 at 2.25.54 PM.png
    I like it. Thanks for clarifying.

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    Quote Originally Posted by MrJack View Post
    Had a bit of a look at the data from this shot last night (extracted from the images using WebPlotDigitizer). Made a few different plots (including some with derived / aggregate variables). The result was rather interesting! Would be very keen to see some more (in particular one with a fixed pump speed).
    Here are two shots, zoomed and not, with different grind settings, both set to provide a 1.6ml/s flow rate. It looks like I had different preinfusion timings on the, which you can see by the vertical grey line indicating the end of preinfusion.

    On one, the grind is fine enough to reach a 8.7 bar pressure, and the pressure stays constant. In the other, the grind is too coarse to create much pressure, and so pressure slowly ramps up over the shot to end around 3.5 bar. What's interesting about this shot is that it still tasted good and had plenty of crema.

    Screenshot_2017-06-04-09-23-38.png Screenshot_2017-06-04-09-23-29.png

    Screenshot_2017-06-02-08-32-11.png Screenshot_2017-06-02-08-31-22.png

    I'm working today on a "historical shots" feature, automatically saving every shot to a history/ directory, with all temp/pressure/flow and settings. These will be text files, and if there's any shot I do that looks interesting, I can post the raw data behind it. I often have trouble recreating a shot that I really liked, as I fiddled with settings afterwards, and I'm hoping that helps with that problem.

    Regarding derived data, the dotted line on the bottom is the flow rate change, but only the positive component of it. Loss in flow is not currently charted, as it didn't seem useful enough to warrant the added visual complexity.
    Last edited by decentespresso; 4th June 2017 at 09:10 PM.
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  24. #474
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    Quote Originally Posted by decentespresso View Post
    I'm working today on a "historical shots" feature, automatically saving every shot to a history/ directory, with all temp/pressure/flow and settings. These will be text files, and if there's any shot I do that looks interesting, I can post the raw data behind it. I often have trouble recreating a shot that I really liked, as I fiddled with settings afterwards, and I'm hoping that helps with that problem.
    I'm going to really appreciate this feature as I am sure I'm going to have the same trouble - as I already do when I'm trying to use a notepad for the same job.

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    Quote Originally Posted by gc View Post
    I'm going to really appreciate this feature as I am sure I'm going to have the same trouble - as I already do when I'm trying to use a notepad for the same job.
    Since it's not much data (about 4kb) for a shot, I decided to
    (a) save all the historical pressure/flow/temperature data, but also
    (b) all the settings that were in place for every shot
    (c) able to chart historical shots, and leave that historical shot charted in place as you make the new shot, so you can compare
    (d) able to load any historical shot, with all settings intact.

    Essentially, every historical shot becomes a "profile" that can be brought back.

    At the moment, I've programmed (a), (b) and (d). I'll get (c) done after my European tour, in a few weeks.

    screen 2017-06-06 at 3.57.08 PM.jpg
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  26. #476
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    Four engineering interns started this week

    Because they're all engineering students, we can put them to work on fairly sophisticated tasks. We have them designing stations to automate testing of our components, and we're also having them create CAD drawings of standard parts that we buy off the shelf (that therefore have no drawings).

    Man Yi turned around the drawings below in an hour, which is really impressive, so it looks like we're going to give her more things to draw.

    interns.jpg
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  27. #477
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    Quote Originally Posted by decentespresso View Post
    Four engineering interns started this week

    Because they're all engineering students, we can put them to work on fairly sophisticated tasks. We have them designing stations to automate testing of our components, and we're also having them create CAD drawings of standard parts that we buy off the shelf (that therefore have no drawings).

    Man Yi turned around the drawings below in an hour, which is really impressive, so it looks like we're going to give her more things to draw.

    interns.jpg
    It's a good thing you're in Hong Kong.

    Millennial interns in Australia would have spent the first hour asking when they could start their company funded mba and then join the exec team before becoming ceo.

    They would spend the second hour comparing paleo bread and civet coffee from the local cafes.
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  28. #478
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    Quote Originally Posted by decentespresso View Post
    Since it's not much data (about 4kb) for a shot, I decided to
    (a) save all the historical pressure/flow/temperature data, but also
    (b) all the settings that were in place for every shot
    (c) able to chart historical shots, and leave that historical shot charted in place as you make the new shot, so you can compare
    (d) able to load any historical shot, with all settings intact.

    Essentially, every historical shot becomes a "profile" that can be brought back.

    At the moment, I've programmed (a), (b) and (d). I'll get (c) done after my European tour, in a few weeks
    Will there be an easy way of renaming/grouping/tagging the logged settings file that's created with each shot setting? eg "a really great shot#1xxxdate". I realise this can be done with any file manager once save location is known, but within the app would be nice
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  29. #479
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    Quote Originally Posted by gc View Post
    Will there be an easy way of renaming/grouping/tagging the logged settings file that's created with each shot setting? eg "a really great shot#1xxxdate". I realise this can be done with any file manager once save location is known, but within the app would be nice

    It'll be logged under God Shot :-)

  30. #480
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    Quote Originally Posted by Shortyesquire View Post
    It's a good thing you're in Hong Kong.

    Millennial interns in Australia would have spent the first hour asking when they could start their company funded mba and then join the exec team before becoming ceo.

    They would spend the second hour comparing paleo bread and civet coffee from the local cafes.
    Internships are generally illegal under Australian law... 🤔
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  31. #481
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    Quote Originally Posted by gc View Post
    Will there be an easy way of renaming/grouping/tagging the logged settings file that's created with each shot setting? eg "a really great shot#1xxxdate". I realise this can be done with any file manager once save location is known, but within the app would be nice
    +1, simple nickname and favourite functions would vastly improve the usefulness of this feature I reckon.

  32. #482
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    Quote Originally Posted by Magic_Matt View Post
    +1, simple nickname and favourite functions would vastly improve the usefulness of this feature I reckon.
    Agreed, as well as a scoring system, maybe even tasting notes. I've got a lot of feature requests on my plate, so for now we're just saving every shot and enabling you to bring it back, but over time I will add more to this section. Ideally, you'd be able to indicate when kind of beans, grind setting and dose weight to the tablet as well, so that you can track some of the more important variables needed to recreate a a great shot.

    Re: GOD SHOT, yes that's exactly what the "background drawn reference shot" is. In lighter colors, your reference shot is charted, and ideally I'd like to give you a "how close to God were you?" score for each shot you pull. Where this is most helpful is in adjusting your grind to compensate for weather and bean aging.

    re: Interns. Our interns are paid AU$8.50 per hour, and our internship program was certified/approved by a professor, so that the interns also earn school credit for their summer work. They also get money to buy lunch. We bought of them a new chromebook. We treat them well, not only because it's the right thing to do, but because we want a good relationship with the local engineering universities.

    My goal is to roboticize much of the DE1 assembly over the next two years, and we'll need clever people to help with that.

    DBiaSZPUIAAq0a4.jpg
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    Here are a few visualisations I produced using data extracted from the images that John posted.

    1.
    The first shows plots of flowrate, pressure and a calculated volume parameter (i.e. cumulative sum of flowrate * timestep) for all three shots.
    These profiles were quite different to what I've seen before, which were from lever machines and had volume profiles resembling exponential growth.
    Decent Espresso Shot Comparison (stacked).png


    2.
    The second is the same three shots, but this time I plotted pressure (which is equivalent to pressure drop) against flow. This is an indicator of the total resistance to flow (a function of viscosity, puck depth and grind size).

    This plot clearly shows three distinct "phases" during the shot, where the slope of the curve changes. I suspect the phases are:
    1) filling the piping / group prior to water reaching the puck (pressure drop driven by frictional losses in piping)
    2) saturation of the puck (pressure drop increases relative to flowrate as water moves further into the puck)
    3) extraction post-saturation (pressure drop decreases relative to flowrate as espresso becomes less concentrated / viscous.

    Looking forward to seeing some video of the shots, to corroborate my assumptions.
    Decent Espresso Shot Comparison - P vs Q.png


    3.
    The third plot is an estimate of viscosity during the shot, based on Darcy's law, with several assumptions (i.e. 58mm basket, 20mm thick puck and a constant puck permeability of 10^-14 m^2, which is at the lower end of reported measured values. I was extremely surprised to see the estimated viscosity was within the ballpark of what I have seen reported in scientific papers (0.5 - 1.4 mPa.s)!
    Decent Espresso - Viscosity Estimate.png

    4.
    Last (but not least) is an aggregate plot of all of the above, for the first shot only. There is additional information encoded in the colour of the scatterplot markers (as indicated on the individual plots).
    Decent Espresso - Three-way Plot.png
    Last edited by MrJack; 8th June 2017 at 02:24 PM. Reason: Fixed images and added some comments.
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  34. #484
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    Quote Originally Posted by decentespresso View Post

    re: Interns. Our interns are paid AU$8.50 per hour, and our internship program was certified/approved by a professor, so that the interns also earn school credit for their summer work. They also get money to buy lunch. We bought of them a new chromebook. We treat them well, not only because it's the right thing to do, but because we want a good relationship with the local engineering universities.

    My goal is to roboticize much of the DE1 assembly over the next two years, and we'll need clever people to help with that.

    DBiaSZPUIAAq0a4.jpg
    Australian graduates would have wanted beard trimmers and moustache wax rather than a chromebook...

    Seriously though, I'm super excited for you. Once I start lining up our new house there will be a de pro or cafe finding a new home.
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  35. #485
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    We've upgraded to a high end "pick and place" machine to make our own circuit boards for our espresso machine. We like the control it gives us, to know that every part on the board is the one we chose. It lets us make short runs and also create small circuits for specific tasks (such as for a testing station) . Even better, the machine pays for itself with the first 1000 espresso machines we make, bringing the per-espresso-machine board cost down from $90 to $50.

    We're calling this machine "Peter", as in "Peter Piper picked a shed load of components almost 500 and made them into PCB boards".



    Here's a picture of a Very Happy Jeffrey with his new toy. You can see the puny old machine we previously used, to its right.

    IMG_4100.jpg
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  36. #486
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    Following on from the images in my last post, I was thinking about the relationship between pressure drop and puck permeability this morning and thought I would plot the viscosity of water (at 90C) against the estimated viscosity based on Darcy's law (assuming constant permeability). Another surprising result!
    Decent Espresso - Viscosity Estimate.png
    Last edited by MrJack; 12th June 2017 at 11:14 PM.
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  37. #487
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    So what does this mean?
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  38. #488
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    Viscosity tells us something about how much coffee is dissolved in the water in the puck. So, it potentially offers a window into the real-time extraction rate! There are a number of factors (temperature, CO2 evolution & changing permeability) which would have to be accounted for though.

  39. #489
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    Quote Originally Posted by MrJack View Post
    Following on from the images in my last post, I was thinking about the relationship between pressure drop and puck permeability this morning and thought I would plot the viscosity of water (at 90C) against the estimated viscosity based on Darcy's law (assuming constant permeability). Another surprising result!
    Decent Espresso - Viscosity Estimate.png
    I think perhaps the relationship is not a simple linear relationship. I think there may be two factors:

    1: A square term relationship to flow rate due to fluid inertia. Perhaps Darcy–Forchheimer applies?

    2: Whether there is a puck at all (coffee grinds swirling around and not yet settled, vs untamped but settled, vs tamped)?

  40. #490
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    Quote Originally Posted by MrJack View Post
    Viscosity tells us something about how much coffee is dissolved in the water in the puck. So, it potentially offers a window into the real-time extraction rate! There are a number of factors (temperature, CO2 evolution & changing permeability) which would have to be accounted for though.
    I think you'd need to account for a lot more than temp, CO2 and the change in physical conditions of the bed during extraction to be able to extrapolate any info about the extraction rate from viscosity. There are way too many other variables for this to be of any real use.

  41. #491
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    My back of the envelope calculation puts the Reynold's number for fluid flow in the coffee bed at around 500 times the flow rate in g/s. Darcy's law is generally only considered appropriate at low Reynold's numbers (less than 10). I think "normal" flow rates range from 1 to 6 g/s when making espresso.

    It is possible my calculation is wrong. Any attempts to double check me would be appreciated. :-)

  42. #492
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    If it's not yet evident to those on this forum, Ray Heasman (who just joined this forum) is the internals engineer / inventor at Decent Espresso.
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  43. #493
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    budapest demo & manufacturing

    Here's a short video Jasper Coffee took of yesterday's DE1+ demo with Scott Rao in Budapest. Best coffee shots so far on this machine, but that's because it was Scott's own Kenyan roast beans. Both the flow profile at 2.2 ml/s and a 9-bar-flat shot delivered good (but different) results.
    https://www.facebook.com/jaspercoffe...0586847650013/

    and meanwhile in Hong Kong, we're taking over 3000 sq ft (about 300 sq meters) of new space next door, to dedicate it to manufacturing, because our first space space (R&D, accessories, lunch!) is now crammed full.


  44. #494
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    Large Ceramics are Difficult

    We've been working for the past 4 months with a ceramics factory to make our water tank and drip tray out of porcelain. The sample they made for us were great, and the price was good (about $7 for both parts). Unfortunately, they've now tried twice to make the parts using the "mass production process" and both times, what we've received has been warped enough that they won't slide into the metal rails of our espresso machine.

    The problem, and we've seen this before, is that samples are often made using a process for one-offs (pressure casting), but after you order, a different manufacturing process is used for quantity (slip casting). You don't necessarily get the same result.

    We had a much more expensive bid from another company ($23.70 for both parts) that we'd passed on previously, but their quality was great, so we've gone back to them. We've decided to use them now, so that we don't add more delays, and keep working with "slip casting" ceramics companies to see if someone can make our vessels well and cheaply with that process.

    The lead time of this new company is 60 days, which unfortunately means that the ceramics will arrive mid-to-late August. That's going to (sigh) put out our DE1 deliveries until then, since an espresso machine that has no water tank is of limited use.

    With luck, this will be the worst delay we encounter, and everything will have arrived by then, and we can just slip the ceramic parts in.

    Sorry for the bad news, guys. Manufacturing is not easy.

    WechatIMG441.jpeg WechatIMG439.jpeg

  45. #495
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    This is the first photo I've posted of our new internal design as a real machine. We totally reconceived the insides after we found our November machine wasn't at a high enough evolutionary level.

    In this photo, you can see (1) the machine opens up quite easily for complete access (2) the silicone insulated hot water and steam heaters (3) totally redesigned and much lighter group head [for faster temperature change responsiveness] and quicker warmup (4) much more internal space and reduced complexity.

    We still have some work to do to organize the tubing better, to test and re-test everything again before we "pull the trigger" on the sheet metal order (which FYI takes 35 days to manufacture) and the mixing chambers (which have been refined to lower mould costs).

    chassis3.jpg
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  46. #496
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    Florence : Caf ditta artigianale (stories from the road)

    IMG_6836.JPG

    These past few weeks, I've been on the road with my DE1+, starting in London, then 3 cities in France, then the "World of Coffee" show in Budapest, and finally a week in Italy. I've got 10 days to myself now in France, so I can focus on finishing the programming of the DE1+ tablet software and then I'm back to Hong Kong. My partner Bugs Harpley can then take a short holiday (she'll also be exhibiting at the Berlin coffee show) while I run things.

    This past wednesday, I got to spend a few hours with Francesco Sanapo Francesco Sanapo | Il blog di Francesco Sanapo the owner of cafe/roaster Ditta Artigianale, seen as one of (if not the) top cafe in Italy. The other Francesco (Masciullo) FRANCESCO MASCIULLO is Itay's top barista and Italy's candidate for this year's WBC in Seoul.

    Francesco Sanapo was quite taken with flow control, as he told me that he regularly talks to La Marzocco and Nuova Simonelli to add user control over flow. They tell him that it's possible with hardware changes, but not as an end user. He invited me to share his booth with two DE1+ machines at HOST Milan http://host.fieramilano.it/en - the most important coffee trade show in Italy. Very flattered, I accepted, and if booth space and schedules permit, we'll do it!

    At Ditta they use a La Marzocco Strada with a paddle to make their shots, and Scott Rao had visited a few weeks earlier to tweak their profile for even flow. Scott had created a rise-to-9-bar-then-lower-to-7-bar profile by visually trying to maintain constant flow. It turns out he did a good job, because with my DE1+ was set to create a constant-flow profile, and we watched what kind of pressure curve was needed. In the shot below, the pressure rose to ~8.9 bar and decline to ~7.4 bar : very close to Scott's settings.

    Screenshot_2017-07-05-14-26-29.png

    In the caf they use a Mythos grinder, which is my favorite, but for this demo I had to make do with a spare Mahlkonig K30 grinder. Every shot we pulled that used the K30 grinds had a characteristic jitter of pressure variation between 13 and 20 seconds, which you can see above (this shot also had a channel briefly opening at 23 seconds). The pressure rampup is smooth, though, with the K30. My apologies that I forgot to take screen pictures this past week when I had access to a Mythos, so you'll have to take my word for it, for the time being, that curves of shots pulled from Mythos grounds are very smooth.

    My way of comparison, here's what a flow profile shot looks like when using grounds from my Lyn Weber EG-1. Quite smooth.

    Screenshot_2017-06-04-09-23-29.png
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  47. #497
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    Why are we Silicone Dipping our Heaters?

    Steve Single asked about our choice of Silicone as an insulator, and our interns are confused about how to test the physics of the thing, so I wrote the message below for them, and also for anyone especially interested in why we're dipping our heaters in silicone, something which has not been done in any other espresso machine that we know of.

    All insulators (except for a pure vacuum) will eventually reach temperature equilibrium with the thing they are insulating.

    The piece of data we want is the "rate of heat loss" that silicone provides, and this is called the "r value". Read about this concept here: https://en.wikipedia.org/wiki/R-value_(insulation)

    Silicone is sold as an insulating material, and its r-value compared to other insulators is given here: GEK Wiki / Insulative Products

    I attach below an excellent academic paper ("New Advances in Silicone-based Thermal Insulation") that discusses various kinds of types of Silicone products for insulation. Here is an important consideration:
    "Thermal conductivity of silicone foam is about half the value of pure silicone rubber. ". We have not yet found a source for foaming silicone that we can use, as we have a very strict requirement that the silicone be odorless even when heated to 160C.

    Thus, if we can find a foaming silicone product that "doesn't stink", we will double the insulation and lower the weight and material use. We've got 9 interns here, all engineering students, so we've manpower to throw at this! At the moment we are using non-foaming silicone, which works well, but it's heavier and less insulating than if we could get a foamed variant.

    I also attach a PDF explaining all the properties of silicone, but here is the important part for our use:
    "Silicone rubber withstands high and low temperatures far better than organic rubbers. Silicone rubber can be used indefinitely at 150C with almost no change in its properties. It withstands use even at 200C for 10,000 hours or more, and some products can withstand heat of 350C for short periods. Silicone rubbers are thus suitable as a material for rubber components used in high temperature environments."

    From a safety perspective, we also like that silicone is an electrical insulator. Should a water leak be spraying inside our espresso machine, silicone will not absorb the water and cause an electrical short. Our double-electrical failover components on both heaters are prewired and totally embedded inside the silicone. Chemically, even fully submerged, silicone will absorb no more than 1% of its weight in water.

    PDFs:
    https://imageserv5.team-logic.com/mediaLibrary/99/InsilThin_Technical_Paper_1.pdf
    https://www.shinetsusilicone-global.com/catalog/pdf/rubber_e.pdf
    IMG_4279.jpg IMG_4281.jpg
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  48. #498
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    I have purchased a DE1+ and have a question about steam tips:

    I usually make piccolo's in a 300ml jug and had to modify my existing steam tip down from 4 nozzles to one to ensure enough time for proper texturing of milk. Will there be optional steam tips available with different steam jets on the DE1+ ? (I wasn't able to source an alternative with my existing HX machine with the same thread size.)

  49. #499
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    Quote Originally Posted by gc View Post
    I have purchased a DE1+ and have a question about steam tips:

    I usually make piccolo's in a 300ml jug and had to modify my existing steam tip down from 4 nozzles to one to ensure enough time for proper texturing of milk. Will there be optional steam tips available with different steam jets on the DE1+ ? (I wasn't able to source an alternative with my existing HX machine with the same thread size.)
    The steam tip that comes with the DE1 models is a single hole, as that works really well with the existing amount of pressure we generate. We also have a four hole tip available to us. While it's overkill for the DE1, I expect that we'll use it for the DE1CAFE and have it as an option for the DE1PRO.
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    Building the de1 : What we're working on

    Back in Hong Kong at our factory, we're building two "final release" machines (110V and 220V) in order to catch any last remaining mechanical issues before building the 300 "early access" machines. Having Interns doing the work has actually been helpful, as they build things "naively" and have caught some remaining problems we've been blind to.

    The list of problems is not so long, but we do need to solve them.

    ---

    PROBLEM #1: the temperature probe in the group head requires too much skill to mount perfectly, resulting in imprecise temperature readings. This was not caught previously because our machines were built by Jeffrey, and "he's too good". Our interns aren't as good as him.

    SOLUTION: stop using a temperature bead and our own design mounting, and switch to using the same ready-made temperature probe we use everywhere else in the DE1.

    probe copy.jpg

    We haven't yet nailed this, as putting the probe there does alter water flow characteristic, and even water flow on the coffee puck is an important goal for us. We may have as much as two more weeks design work on this before we can have a sample made for real testing.

    ---

    PROBLEM #2 : the water flow meter connectors are about 2mm thicker than we expected. This makes it quite hard to get the tubing on. Again, Jeffrey managed but the interns had trouble. This was not caught before because the supplier had not provided us with technical drawings.

    SOLUTION: switch to a new flow meter, from our favorite supplier (ODE, an Italian company), who also make our pumps and valves. Their parts are found everywhere in professional Italian espresso machines.

    preview-full-Mismatch of diameter.jpeg topview copy.jpg

    We've also gone through several iterations of our mixing chamber (the brown-colored part in the drawing above), because the one we had designed turned out to be very expensive ($85 each) to manufacture. The size is now much reduced, so we can injection mould the part, thus greatly lowering the per-piece price. We are awaiting a sample of our new design so we can test it before paying for the mould to be made.

    ---

    PROBLEM #3: sharp bends required of the tubing, which could cause failure:

    SOLUTION: enlarge the hole and the size of the rubber gromet as well.

    preview-full-Limited space for tuning L-shape connector.jpeg

    ---

    That's what we're currently working on, so we can make our first batch of machines.
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