I experimented with single dosing on the Ceado - I built a ‘very small hopper’ made with a piece of stainless pipe and an ‘augmented’ tamper (weight 700 grams) to simulate a full hopper’s weight/pressure on the small amount of beans. Because of the way in which I built the two parts, they are almost air-tight, and can be used as a sort of bellows.
As it’s also used to prevent pop-corning and weight pressure directly on the beans, I can only use it at the end of the grinding process, lifting the tamper up and gently releasing it a couple of times while the grinder is running empty (it also has a rubber sheet on the bottom, so it doesn’t dent any parts of the grinder). It’s quite effective at pushing air through the system, and dislodging grounds: it does get retention on the Ceado down from >2.5 grams to about 0.3 or less - which I think is tolerable for single-dosing, but I wouldn’t recommend anyone builds something like that!
If I single-dose nowadays, I use the Omega…
JHCCoffee Does the bellows just push out what’s in the chute or also the grinds that are in burr crevices?
It will push out ‘anything’ that is a) on the air path, and b) not stuck down with sufficient force. Where that happens precisely is largely unpredictable from grind to grind on the same grinder, never mind in different grinders.
JHCCoffee Would adding a bellows to my NZ work? Is it a good idea?
It might work, but I doubt you’d be making a big difference on something that is designed from the start to be very low retention (and I think - from my recollection of the Niche - it’s going to be difficult to put bellows on it - no straight surface). Just as I doubt that 0.3 grams will make any difference to anything; if you start worrying about things like these, then you’d need to take apart the grinder every time you grind and clean it thoroughly; the 0.3 grams that are retained are clearly staling. 😈 I’d just tap the grinder smartly a couple of times, while it’s running.