Thanks again for the suggestions.
My summary of the last 2 weeks would be its been a bit 1 step forwards 2 steps back! Initially I thought I’d cracked it as I managed to get better looking shots (not perfect but much improved) that more importantly tasted considerably better than I had been getting.
This was using a medium roast coffee from Monmouth (Monmouth) that I rested for about 7 days before using it and using the tamping technique recommended by Dave (plus a quick stir with a chopstick pre-transfer to portafilter). I also stopped using the leveller tool and switched to pouring into the portafilter (rather than flipping over) and doing my best to level by tapping the side of the portafilter and one bang on the surface at the end to level. So I was hoping the change to technique and/or using a different coffee solved or at least reduced the problem.
Unfortunately, over the last few days I’m struggling again and I’m not entirely sure why. This is leading to shots that are tasting pretty harsh and where it looks like there’s a fair bit of channelling going on. I made 5 shots this morning and couldn’t get rid of the issue despite trying to take care to follow a set procedure (shot time moved around between about 24-28s to get the same yield of around 2:1).
A number of people suggested a magnetic funnel and I’m going to order one of those now. If nothing else it will make it a lot easier to keep coffee in the portafilter when transferring from the dosing cup and levelling by tapping.
I suspect my issue is still with my levelling/tamping technique and I may also try WDT if I’m still having problems after adding the funnel.
Any other suggestions welcome.
I’ve pulled about 200 shots so that’s at least 3.5kg of coffee through the Niche grinder now so I don’t think it should be anything to do with that. I guess the coffee is now approaching 3 weeks from roasting but again I would not expect that is the main problem.
One other thing I’ve noticed is that I’m getting a fair bit of coffee residue on the shower screen after pulling a shot. I’m not sure if this is normal or not? I am weighing 18g in the stock Lelit double basket (16g-18g) so I didn’t think it was an issue of overfilling the basket but thought worth checking. This has been the case with all coffees I’ve tried not just the current one.
Can share another video later if helpful