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.
