Hi,
I am new lever user with a millenium La Pavoni Pro and Niche Zero.
I have been struggling since i got the LPP with consistent channeling.
I upgraded with IMS shower screen and basket + bottomless portafilter.
So far tried at least 10 different quality and fresh beans and all shots have had obvious signs of channeling of two distinct types:
1. Classic channeling 2-3 holes always on the same spot around 3 o'clock


2. "Strange" signs that look to me as caused by the flash boiling water.


I have tried varying dose, grind and tamp throughout the spectrum up to both extremes and sometimes shots turned out quite good (not yet excellent), but channeling signs never disappeared.

I have also tried different temp management techniques, but this is much leas objective and consistent to effectively track and reach conclusions.

I am waiting for my group head temp strip, hope it will help.

I know there are plenty threads for the same, but never found discussions on the second type of channeling, so i will appreciate any ideas on how to deal with these.

PS my other machine is heavily tuned Silvia. Each bean i try on La Pavoni, i also try on the Silvia and i can easily make consistent excellent shots, so beans are always good and i have a good baseline for what to expect from the shot taste wise.

A couple of questions:

How much is your boiler pressure? The range, roughly. Mine is 0.95 a 1.05 roundabout, which may be too high.

What is your usual grouphead temperature? I go with around 85C

How exactly do you pull? I am mostly interested in how you pull the lever up (need to go slooow) and how/if you preinfuse.

I think you should try with the stock double basket, the IMS might be more finicky. Also the grind does not look very uniform but I might be imagining.. the roast looks light so my advice would be to go very fine grind and do careful blooming and preinfusion.

Let me know if I'm completely off the track here.

Mine idles between 0.75 and 0.9. You are right that looking at the pics grinds seem quite inconsistent, but probably its a visual thing. When its freshly ground it looks very consistent and i can also pull excellent shots on the Silvia.
I should have started by saying that i have read all relevant threads here, as well as youtube videos, so i pretty much have the theory, but probably not the required experience.
I always raise the lever to almost top, then put portafilter, then very slowly and gently raise to the top letting the water in. PI time - usually wait for first drops or at least visual saturation of the basket bottom that happens within 10-15 sec depending on grind.

I dont so Fellini moves yet, as I feel they are a next advanced step - no point in doing it if i cant do a proper standard shot.

As for grouphead temp i dont know yet, as thermostrip is not yet installed.

An outside consideration...

One of my grinders is a Monolith FlatSSP. That grinder is MUCH more prone to channeling than my others unless I grind into a vessel first, then stir the grinds like crazy before depositing into the portafilter. After that, I get beautiful pours.

Not familiar with the NZ grinder but I would try what I suggested to see if it helps. Two of my machines are Pavonis too BTW. Love them.

-Peter

Actually with NZ you get that by default sticking to the standard workflow. I grind in the niche SS cup, stir with wooden stick in the cup, then carefully transfer in the PF with dosing ring and stir again with WDT tool.

What's your routine with the Niche Zero? WDT? Any sorr of distribution in the niche cup or portafilter?

Here are some iphone pics of grinds.
I do stir heavily both in niche cup (wooden stick) and in basket (WDT tool + funnel)

Another potential issue might be the tamper. I am using a dodgy tamper that looks like almost 1mm smaller in diameter than what i actually need. But if that was so much of an issue i would expect side channeling on the very edge of the puck, but i am always seeing it on the very same spot at 3 o'clock.

Hi Blazarov,
I recently acquired a pre-millennium la pavoni professional and I've seen exactly the same dent pattern occurring in my pucs, irrespective of grind or tamp.
What I noticed is that in my case the dents don't firn channels through the puck but appear to be more superficial disturbances. (Also managed to get a few very good shots)
I had the same routine of raising the lever almost to the top, locking the portafilter and then slowly raising the lever to let the water flow in.
After a few trials with different grinds and tamps I decided to check how the water flows by pulling a shot without the portafilter.
At that point I noticed that if you raise the lever slowly there is a single stream of water on the 3 o'clock position before the full shower starts at a slightly higher lever position. Lifting the lever faster somehow avoided this single stream. (I'll try to make a movie of this)
I then tried pulling a live shot by lifting the lever sightly faster after locking the portafilter which resulted in a much smoother surface on the puck.
I'm curious to hear if your machine has the same behaviour.
Best!,
Rob