Willinak wrote:I'm no help as I have yet to produce what I consider a good pull after a couple of weeks with the Robot. Here is my story: I did observe this morning that the first flow is around the edges, and eventually in the middle. My shots are fast, well under 20 secs, and pressure rarely gets into the red zone. With the naked PF, I sometimes get a spray over the sides, so I'm doing a lot wrong.
Where does your flow come in and what are you times and pressures like?

My shots easily get in the red zone, I suppose it's mostly a matter of how fine you grind, and didn't notice any splattering. Didn't time my shots yet, but the timing seems ok to my semi-trained eye. I think I pre-infuse for about 5-10 seconds, then slowly raise to 6 bars for about half of the shot, and then gradually lower to 4 bars towards the end.

I'll film a slow-mo tomorrow and post it, in order to provide accurate timing for the applied pressure.

ojaw wrote:Sorry, misread you.
How long are you preinfusing?
I'm often into the 20-30 second range but it depends on how saturated things are looking underneath the portafilter.

Didn't accurately measure yet, but I estimate 5-10 seconds.

I did try to preinfuse longer, but I never seem to get a nice uniform saturation before more then a few drops start to fall. I suppose that I should grind finer if 20-30 seconds preinfusion is something acceptable (For now working with medium-dark roasts).

ytm wrote:Thanks, I'm not preinfusing for 2 seconds, but at 2 bars. I doubt WDT is needed, since the Niche produces very few (if any) clumps, and I always break those apart anyway with a 'cork-with-needles' (Is there a name for it?) tool.

I'll try tamping with less force though.

Thanks!

Cork-with-needles sounds like a WDT tool

Right, mixed it with RDT.

ytm, may have missed it but didn't see your dosage. Assuming you're using fresh coffee about a week or so off roast, try a slightly finer grind and start with 17-18g doses. If the Robot chokes, back off the grind a bit. And can't recall who offered the tip earlier in this thread, but WDT only in the top half of the bed, settle the grounds, and then level and tamp on the light side before inserting the screen. FWIW, we've found that doing a full WDT to the basket seems to make the coffee bed more prone to defective distribution, at least with the Robot, and the partial works better. Thanks to whomever suggested that!

Looking forward to your progress reports!

I'm currently using 15g, which is my preferred dose. The beans I'm using are fresh enough, as I'm pulling quite nice shots with them using my Bianca, and having only a couple of hours of experience with the Robot, I have to assume the most likely culprit for my channeling issues is the human element. I'll up the dose though, as you suggest.

Also, as you suspected, I'm doing full WDT. Given the consistent nature of how it channels, that sounds like a very promising lead, as this is something I didn't change between any of my shots. I'll try this tomorrow and post my findings.

Tamper is a fairly tight fit and the basket is deep, pull up gently, or tilt it a bit before pulling up fast.

Channeling in same spot each time? Humm, could you possibly be pressing harder with one handle? Honestly not sure if this would make a difference or not, but it could explain the fact that the channeling is happening in the same place especially if the channeling is always to the side rather than front or back.

Also, try spinning the basket 180 degrees just before inserting the porta filter and see if the channeling moves with it. Maybe your prep is so consistent and the channeling might move with the spin??

Both extreme long shots, but no harm done.

Ken

Ken5 wrote:Also, try spinning the basket 180 degrees just before inserting the porta filter and see if the channeling moves with it.

That's what I was going to suggest.

Is it a single stream but just not in the exact middle? Could it be that the Robot isn't on a level surface or you are inadvertently tilting it during the pull?

Came to suggest the same as jpender - I took a level to my counter and realized my butcher block slants towards the front, while my other counter is dead level. I've changed which counter I use for the Robot

jpender wrote: That's what I was going to suggest.

Is it a single stream but just not in the exact middle? Could it be that the Robot isn't on a level surface or you are inadvertently tilting it during the pull?

Single stream, but more than 'just not in the exact middle'. But it does seem the Robot is not level, at least during pull.
As was suggested, I turned my basket 180 degrees after puck preparation, and it's the same area, so that proves there's a tilt, probably by my hand, as I have my machine on the far side of that counter, and it doesn't exhibit any tilt.

Anyway, thanks everyone! I still need to work on my pressure profile to get nice and consistent shots, as I have no experience with levers whatsoever, but at least I think I'm in the right direction.

There's a little bit of play where the base meets the legs, perhaps that's why ytm experiences off center pours. Doesn't have to mean the extraction itself isn't even.