nah, not spending more time on this nonsense, sry.

The grinder is working the way it should be. End of story.

Move on, buy a different grinder. No problem.

    Hmm let’s see here. 18.4 in and 18.4 out and with rdt too.

    Given my country humidity is practically always high, i don’t RDT.

    Once you familiarise yourself to the work flow, there is practically zero retention.

    The higher RPM will cause a higher differentiate pressure difference holding more grounds in the funnel, however most of the it falls upon turning off the grinder. Usually for higher RPM, i will start/stop the grinder once or twice to allow for the last few 0.1 g of coffee to fall. The additional step is not needed at lower RPM say 600 and below.

      Newdent if there’s an intentional pressure difference then that means that suction is holding the grounds in place, correct (but surely impossible)? Or basically, if it’s simple to explain, can you explain how this differential is created and why it does what it does please?

      mackerel nah, not spending more time on this nonsense, sry.

      Newdent it’s easy to talk yourself into thinking everything is fine when you’ve invested a lot of money in something.

      No intention to offend anyone, but as someone just following this thread, the above is what I see. The Deva may or may not be a fantastic grinder, but some of the claims made - just as for other products - simply do not stack up with physics, or if they do they deserve a clear explanation (not necessarily by forum members, but I found none on the Kopi Concepts website). They say:

      Our patent pending design creates a small pressure difference between the burr chamber and the exit chute, encouraging air flow through the grind path to help the pursuit of zero retention. [Kopi’s emphasis]

      While there is a resemblance between the shape (at least the exterior one) of the Deva and that of an expansion exhaust for a 2-stroke engine (which does have the effect Kopi mention… in an engine), I respectfully am very sceptical that the same pressure phenomena (scavenging) observed in a fairly homogeneous gas moving in laminar fashion at speeds of several tens m/s, propelled by temperature differences of several hundreds K and pressures of tens of bar, apply to a highly disorganised “fluid” comprised of coffee beans at various states of grind and air, moving chaotically at a few mm/sec down a chute, propelled by gravity. Yes, it’s patent pending, rather than patented, which could explain some caution in disclosing the “secret ingredient” - then again, it may be patent pending because it’s basically unpatentable.

      ETA: If the ‘pressure differential’ isn’t generated by the shape of the grind path (which is my assumption here), Kopi doesn’t explain what it’s due to. All the descriptions above are consistent with behaviour I observe in commercial grinders (Mazzer and Ceado), that certainly do not make claims about pressure differentials holding the grounds up.

              CoyoteOldMan zero retention is the important factor to me. Pressure differential….is it marketing jargon to claim a unique design? I wouldn’t know how to test it. I could say it’s not true but that would just be my opinion and nothing more.

                  spivechild Which is more than fair enough - I’m genuinely glad if your Deva gets zero retention and you are happy with it. I’m just quite annoyed at the marketing spin (which is not at all your or Mackerel’s fault). Enjoy your coffee!

                      if they say it works this way and i experience it just the way they say it is, as you can see in the video, I do not care if anyone calls it a marketing spin. I am just glad i don’t need stupid bellows.

                      I have hands on experience with a lot of grinders and the way the Deva accomplishes zero retention is unique to me.

                      And it is not about me talking myself into the purchase. I couldn’t care less what other people think, as i am happy with the results i get from the Deva.

                      It’s more that i appreciate the effort, the work and the transparency the Deva team put into the project, that i think they don’t deserve false information or dissing of their product.

                      Feel free to visit Brandon in the workshop and he will answer your questions and give hands on experience like he did with the other guy somewhere above in this thread.

                        CoyoteOldMan I share your annoyance, not just with coffee grinders but with many products. We all know it when we see it and read it. Unfortunately it’s all become quite customary. In some cases companies straight up lie and deceive consumers which can cause real harm.

                          mackerel Feel free to visit Brandon in the workshop

                          Which I would, if I lived anywhere near (I can’t find an address beyond “UK based”). I don’t think promoting magical thinking is in any way transparent or a good marketing practice, but I doubt they are interested in talking through the magical pressure differential with someone who is not interested in buying - including the magic.

                              mackerel

                              Don’t think you need to be so defensive about it,

                              Any new product in a highly competitive market like the single dosing grinder market is going to be highly questioned.

                              I’m glad you’re happy with it, but some people like to go into the technicalities of products which sadly seems in this industry often falls on deaf ears.

                              Decent De1pro v1.45 - Niche Duo - Niche Zero - Decent is the best machine ever made -

                                CoyoteOldMan magical pressure differential with someone who is not interested in buying - including the magic.

                                But lets be fair, has it been proven to be “magical” Is what they state regarding pressure differential based on the design completely impossible?

                                    Am glad Jake posted his observations. Every one of us is happy if the new owners are happy with the Deva. It is ok if some isn’t.

                                    Our forum is known as friendly; open-minded; knowledge sharing; and, genuinely helping / aiding those who have concerns, issues, require more clarity and would like to go into finer details.

                                    It is equally ok for members to freely express their views and challenge the status quo of a product. We can question the views, challenge them in turn and never attack a person personally.

                                    Perhaps, some members can articulate well and others cannot. A lot of members are unlikely to have sufficient technical expertise to understand.

                                    We here to help each other, where ever possible. If we can’t, it is equally ok to otherwise.

                                    But, we must draw a line and not be dismissive of the other person as they are asking too many questions.

                                    Sorry, this is a general observation, nothing personal and thanks to every one for making this an important and an interesting read. 😊

                                    CoyoteOldMan I observe in commercial grinders (Mazzer and Ceado), that certainly do not make claims about pressure differentials holding the grounds up.

                                    Is it possible the same pressure differential is happening with these grinders too… regardless if it’s claimed or not?

                                        spivechild But lets be fair, has it been proven to be “magical” Is what they state regarding pressure differential based on the design completely impossible?

                                        Completely impossible - no, however I struggle to understand how this would happen, and more so in a way that is unique to the design of the Deva.

                                        The funnel at the top and the chute at the bottom are open, at atmospheric - thus equal - pressure. As far as I can tell, there is no ‘pressure-retaining’ mechanism or device inside the grind path, just the axle and its supports, and the burrs. This means that - including the “fluid” that is the coffee-and-air mix in its various states of grind - all of the grind path is at the same pressure when the motor is not running. When the motor runs, there will be some ‘pressure’ (air speed) generated by the burrs (they can look a bit like turbine vanes, if you think about it), centrifugal forces that push the coffee/air mix, and some viscous drag around the axle - not different from any other flat-burr grinder.

                                        spivechild Is it possible the same pressure differential is happening with these grinders too… regardless if it’s claimed or not?

                                        I have observed that in my Ceado E37S used as a single-doser there is a ‘spurt’ of ground coffee when the last few beans are through; I have seen the same phenomenon occur in a Super Jolly used as single-doser. I think this is because whatever ‘low pressure’ was being generated in the centre of the grinder by centrifugal forces to push the beans (and some air - that’s why they are fluffy) through the burrs is being replaced by atmospheric pressure as the air can get through completely unobstructed. This however is a general ‘truth’ for any grinder that uses centrifugal force as a means (the main means, for a single-doser with flat burrs) to push the beans through the burrs. Claiming it as a patentable innovation strikes me as… well, marketing-speak, to be charitable.

                                              Unless I have missed reading, has it been tested using light and medium light? Thx