First off -- this is sweet and you should be proud.
Without data, I'm skeptical of the claim
> that gravity does most of the work to reduce retention
Naively, I'd guess that the increased surface area from the cylindrical burr increases the retention rate since it's mostly caused by static cling. There's mention of a built-in knocker, but even with the dissected machine photos, I can't tell where that knocker is housed or how it would function.
It is definitely true that larger burrs have more surface area to retain grounds. In general, I think most people consider the tradeoff worth it in terms of flavor, especially because in my experience the coffee that builds up in the burr of any grinder is likely to stay there whereas coffee that sits in nooks and crannies around the chute is likely to get cycled each time.
The knocker is actually hidden within the hopper itself, you twist and release it and it knocks into the burr. The basic idea for the design is that you have 3 rings, and each of them is a touch point, the bottom turns it on, the middle adjusts the size, and the top is the knocker.
Every burr grinder I've owned over the years (Cuisinart, De’Longhi, Braun, Black+Decker) had that awful static cling problem, although my newest, a KitchenAid KCG8433DG conical, is notably cleaner and quieter than all of the others were. For comparison, I'd like to see some real life on-the-counter evidence after a Velofuso grind.
BTW, there are a few different means of reducing static cling problems, including stirring the beans in the hopper with a moistened spoon before each run.
That clip is showing the filter coffee brew function, not espresso. Brewing filter coffee in an espresso machine actually sounds like it'd be nice on occasion. Side note -- I find it funny that you'd assume the guy that designed an espresso machine and grinder doesn't know what espresso looks like; on the flip-side, why no espresso pull money shot???
That’s a charitable take. There’s a picture at the end of the page that shows coffee dripping with much lower flow rate in the „filter mode”. The upper one however looks like low pressure attempt at an espresso, which makes me question whether the machine can actually do the advertised 10 bar.
I've snorkeled at Electric Beach -- underwater you could hear the buzzing from the powerplant. Somewhat surreal and I'm surprised it didn't bother the marine life.
Without data, I'm skeptical of the claim > that gravity does most of the work to reduce retention
Naively, I'd guess that the increased surface area from the cylindrical burr increases the retention rate since it's mostly caused by static cling. There's mention of a built-in knocker, but even with the dissected machine photos, I can't tell where that knocker is housed or how it would function.