A couple of months ago I had done my monthly maintenance on Cremina. After cleaning the shower screen and the bottom of the piston along and then applying some Dow 111 on the cylinder wall, I decided to try a tip that I had read on HB. Each time after that maintenance, when I prepared my basket, I placed a wet aeropress paper filter on top of the portafilter before loading it into the group. The same paper filter was reused for a week before replacing it with a new one (about 30 uses per paper filter). This technique provided several advantages:

Kept fines out of the shower screen and bottom of the piston (when I went to do my monthly maintenance, the shower screen was pristine and the bottom of the piston was nearly what it looked like after my last maintenance)

Shots tasted as good or better than before using the paper filters

There was a notable positive change in channeling

I no longer needed to flush the group after a shot which also allowed me to get an additional 4 shots from the boiler before having to refill it when making drinks for guests

The only disadvantage was the extra steps of properly placing the wet paper filter on the puck before loading and then rinsing the paper filter after pulling the shot. It has become an integral part of my routine that I plan on continuing.

Amazon carries the aeropress paper filters. You can get 350 filters for under $10.

I just tamp a dry aeropress filter on top of the puck and its disposes itself it the knock box when I am done (I do not have the patience to resuse them). I used mine to keep the fines from the boiler on my La Pavoni's. Even with new seals I would still get some fines in the boiler. I just continued the same process on the Cremina.

It is a time saver, I have not noticed any negative results either.

This morning I tried tamping the aeropress paper filter to puck using my Elektra basket. The edges of the filter turned up along the sides of the basket and made it difficult for my tamper to get in the basket so I took the aeropress filter off and tamped and then placed as usual on top of the portafilter and pulled my shot as usual. For my next shot, I remembered that I have an Olympia basket that has a slightly wider diameter than the Elektra one. I had stopped using that basket as I always got a better tamp with the Elektra one and the Olympia one often had a doughnut extraction even with nutating. The second shot with the Olympia basket was magnificent. I can now go back to using that basket.

My 54 mm tamper for my Olympia Maximatic has always been too small for the Olympia baskets making good extractions difficult. I will give the tamped aeropress paper filter a try in that basket tomorrow morning. Thanks to forbeskm for the tip on tamping the paper filter.