ez4prez Thank you for asking - and reporting back! So in reality the pressure differential has nothing to do with lowering retention. Read between the lines, and what they say is that because the exit chute is all around the lower burr, unlike in ‘traditional’ grinders where the grinding chamber has a floor and an exit hole, there is no (or lower) retention.

Is that patentable? I doubt it - there is plenty of prior art in terms of grinders that have no grinding chamber floor (the Weber EG-1 for example). Does it matter? Not in the least, as long as it works.

    So as I predicted, what people are experiencing is caused by static. Thanks for clarifying.

    “…the retention of our grinder is within 0-0.2g of remaining coffee grounds. This is in line with a low retention grinder…”

    It would be close to a miracle if it were true.

    There isn’t a hard definition of ‘zero retention’ but Mark Prince suggested it was within +/-0.5g and this seems reasonable enough.

      6 days later

      MWJB Been using it non-stop for the last 2 months and for the first four times I cleaned it I had less than 0.3g of grind showing on the scale.

      I believe them.

          Otaibimn 0.3g is more than 0.2g.

          Do it another 6 times and post the weights for each of the 10 samples.

          I tend to think that dose consistency (every time you use the grinder) is the more useful measurement than retention (only when you clean the grinder) and that is seemingly very, very difficult to get below +/-0.2g.

              MWJB There is retention and there is exchange.

              Retention is basically how much the grinder will hold each time it grinds… but this is subjective.

              Since some will be exchanged with the current grind.

              You find grinders having 0.2g worth of retention each time… but in reality you are exchanging 1-2gs worth of coffee and that will be effecting the flavor.

              So when I say the grinder holds only 0.3g worth of grounds in it’s assembly… the exchange will be much less than that and the retention will be lower.

              This is impressive gentlemen.

                  Otaibimn You find grinders having 0.2g worth of retention each time… but in reality you are exchanging 1-2gs worth of coffee and that will be effecting the flavor.

                  You’re forgetting the third parameter, dose consistency…which this is…….

                  Contact me

                      DavecUK

                      what dose inconsistency is to expect from weighing beans for single dosing?

                          It’s worth noting that a lot of 0.1g resolution scales don’t actually go up/down in 0.1g increments, so if you have 0.1g scales and beans in and grounds out weights match up, I wouldn’t go looking for a problem.

                          But to measure consistency to 0.1g you rally need another decimal point on the scales.

                          Me, I just check in an extra bean or two anyway, trim the dose, then I don’t need to have those last few 0.1g’s of chaff in each grind. But if you just want to weigh once & brew high dose consistency makes for an easy life.

                          7 days later

                          So, the button replacement finally arrived. Was simple to swap it in for the old one, which was bent. Here are a couple pix. Not sure how it got bent, apparently in shipping, that zip tie is suspect…

                            Meanwhile, bigger problems. My touch point is 6.2 - I can’t get the grinder to grind beans at less than 7. Honestly, it’s pretty hard at 7, takes 20 seconds at least to get the first grinds. Grinds great at 10, but even 7 is way too coarse for espresso. I’ve put about 450g through it so far, but still looking for my first cup. Have tried misting but no improvement. Any tips for first time user? And at 7, it will grind through about 9g, and then stop. I have to start and stop the grinder about 6 times to knock out the remaining 9g. Hoping this is just lack of seasoning. Appreciate your advice.

                              Wow, that’s not the best is it.

                              Wondering if you just got a Friday grinder.

                              I’d be tempted to ask for an exchange unit.

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

                                powderhorn Not sure how it got bent, apparently in shipping, that zip tie is suspect…

                                Shipping my left foot; the zip tie done it in the assembly.
                                I may be wrong, but I think it’s repairable - possibly with a bit of epoxy resin; if nothing else you have a spare.

                                  What beans? Btw

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

                                  Contact kopi and get some feedback.

                                  powderhorn Are the burrs concentric and parallel, or is there misalignment between the top and the bottom?

                                  Also - what beans are you grinding? Perhaps try grinding some ‘cheapo’ darkish roast to season the burrs, as they will be softer.

                                  All this said, I’m inclined to agree with Cuprajake

                                      powderhorn

                                      these are my settings.

                                      I grind Espresso between 6.2 and 6.6.

                                      This worked from the first grind. Do you tighten the thumb screw to lock the burrs?

                                      Or maybe the burr touching point is noted incorrect. Check your actual burr touching point this way:

                                      Turn on the KOPI Deva, and press the start/stop button. Select the slowest burr speed using the RPM Dial. Loosen the thumb screw, and rotate the upper burr carrier towards FINE until you can hear the burrs touch (a chirping sound). Press the start/stop button to stop the burrs, and turn off the KOPI Deva using the power switch. Note the grind setting at which this happens.

                                      Contacting the Deva team should be usefull anyways.

                                        Update: I took off the funnel and cleaned the insides, and took off the bottom burr and cleaned it and the top. Inside he funnel were lots of grinds, but burrs seemed ok. So, starting with a clean machine, I ground 18g of French Roast (dark, fresh, a bit oily) on medium speed (i think a couple of you smelled this out as contributing factor).

                                        On 6.5 setting, i got 14.5g out. So i took off the funnel again. and there it was, my missing 3.5 grams. I brushed that out into the dosing cup, packed a filter, and brewed a cup. I got to say, damn, that was good. Big step up. And still room to improve, 6.4 would be better I’ll bet (it brewed in 24-25 sec). Still enjoying now as I write. But anyway, I gotta fix this wiper issue, i can’t be bothered to take the funnel off every time.