Channeling

Michael Hart

Hello all,

I have had my machine for a while and I just installed the new seals. The last couple of days I have noticed that I am getting significant channeling at the 6 o'clock mark on the portafilter basket.

I took the portafilter out and pulled the lever down to see if anything was wrong and I noticed that it looks like I have a "leak" in my shower screen. Water was rushing out of this one part more than the normal spray. I have had an IMS screen on for a while so I decided to change it back to the OEM screen.

Still having the same issue. I have a monolith flat grinder and I do all the recommended steps when I prep my puck. Have multiple tampers and it still is occurring.

I will try to grab a video of this when I get a chance.

Thanks,

Michael

Reiss Gunson

hi michael

i dont that 6 o'clock, or any other position, is significant when it comes to channelling (just a general comment) - its just channelling - i.e. i dont think channelling from position A means anything relative to if it was channelling from position B

my first question is probably, at what angle is the lever grabbing?

and my second question is what duration of pre-infusion are you using?

kind regards

reiss.

Michael Hart

Hello Reiss,

1) the lever actually grabs around the 45 degree mark

2) I get drips of coffee almost instantly after pulling the lever. Same spot every time. The rest of the puck looks like it is saturated evenly.

When I take the portafilter out, the 6 o'clock mark on the shower screen has a jet of water coming out of it (both screens) that's why I mentioned the position. Thought that was weird.

Reiss Gunson

ok, so how many seconds of pre-infusion? (before you let the lever come up)

Michael Hart

I usually do a 5-6 second count before releasing the lever.

The other part of the basket does not have any coffee coming through the screen until the lever is released.

Thanks

Michael

Reiss Gunson

it is almost certainly a distribution issue

i haven't used the kafatek, but by all accounts it is the new benchmark in single dosing in the home

so, with that in mind (and other kafatek owners should wade in here as they are in a much stronger position) i would suggest you dose a single cone of coffee into the centre of the PF, then use a cake skewer or similar ( a straightened paperclip would do) held vertically and run around in the coffee in a random manner prior to tamping - if you are using a paper clip the end of it will scratch the base of the basket, so take care to keep the paperclip a faction above the base of the basket so you dont damage the basket

take care to tamp level

if you are grinding fine enough you dont need to tamp like a gorilla

the instant gush is evidence of poor distribution, but i would also suggest you grind a little finer to compensate for it

once you eliminate the instant gush then you can increase the pre-infusion time, perhaps to 10 seconds, which will reduce the probability of channelling occurring once the load of the spring comes on

let us know

reiss.

Michael Hart

Thanks Reiss.

Denis actually provides a tool to WDT, which I do for every shot.

I have the five star tamper and the kafatek level tamp as well.

I will keep working on it, but I haven't had this issue until just recently. Multiple types of coffee as well.

Thanks again!

Reiss Gunson

step one would be to grind a little finer then.

Michael Hart

Pulled a couple of shots this morning with a finer grind and the channeling wasn't as dominant. Thanks for the suggestion Reiss!

Reiss Gunson

a bit finer still

then, lengthen the pre-infusion time

Dan Tochterman

Hey Michael,

how much are you dosing into the basket? if you are dosing around 18g, i would also check to see if your technique is disturbing the puck when you insert it into the group. you can check this by taking the portafilter out after inserting it into the group (without extracting anything). if the puck is disturbed, then that could be your problem. lower dose to 16.5 and see if that helps.