You guys are talking lever machines, I think, has anybody tried this with a pump machine? In theory, the use of a filter above the puck would have the same effect as preinfusion. A filter below the puck would not really do any thing in either a lever or pump machine with the right grind would be my guess.

yakster wrote:I've read of people using Aeropress filters in espresso prep, both below and above the puck for all sorts of reasons including filtering for cholesterol (below puck)....

although that's not the topic of this thread.

With my Faemina, I don't see any coffee washing back into the boiler, but I do see coffee coming out of the cylinder when I flush if I don't use the Aeropress filters.

I do need to eventually tear down my Faemina and check, lube, and possibly replace the seals and clean the screen from above, but I haven't geared up to do this yet and I doubt that it would really prevent the issue with coffee getting above the screen.

I think that the filter helps keep the puck more intact, an unexpected benefit.

It's amazing how well it works. I forgot to put the filter paper on top this morning. To compound the problem, because the room was very noisy, I must how let water into the chambe too quickly. I got a lot of channeling and the top of the puck was terribly dimpled.

Normally, the top of the puck is mirror smooth. I hardly have to clean the group gasket even.

yakster wrote:I've read of people using Aeropress filters in espresso prep, both below and above the puck for all sorts of reasons including filtering for cholesterol (below puck), dampening the effects of the water from the screen or dispersion block and just keeping the group clean and in some cases preventing coffee fines from entering the cylinder of levers, but now that I've been consistently using a filter above the puck on my 1950's Faema Faemina I can say that it has really helped me in keeping the grounds from getting up in the group. I've had a persistent problem with coffee grinds appearing when I flush (was hoping they were just coffee grinds) and now that I'm consistent it's resolved itself. It also keeps the group cleaner and the puck looks less disturbed by divots so I'm sold.

With an Aeropress it's often recommended to rinse the filter before use. Do you do the same with your Faemina?

Yes, I always rinse my filters first.

I have used them on my Pavoni for a few years now. Even with new seals it still sucks some fines back to the boiler so I started with one aero press filter on top. Works great, no taste difference here. I don't wet the filter, I just tamp it on top.

I do the same with my Cremina out of habit, not sure it's needed but it's more of a pain to dump the Cremina upside down than a Pavoni so I stuck with it.

FirstBetta wrote:You guys are talking lever machines, I think, has anybody tried this with a pump machine? In theory, the use of a filter above the puck would have the same effect as preinfusion. A filter below the puck would not really do any thing in either a lever or pump machine with the right grind would be my guess.

I just tried this, but without finding this thread first. I recently got an EP HQ 14g (double) basket, which is relatively deep compared to the Rancilio double basket. After extraction the surface of the puck is noticeably uneven, probably due to the distance between the screen and the tamped puck and the turbulence created when extraction first begins. With the highly uneven surface, I reasoned that this should result in under-extraction since the pressurized water will find the path of least resistance through the puck.

I thought I might improve this situation by putting a washed aeropress filter above the puck to even out the pressure distribution. I've tried it exactly once so far, but it worked quite well: the surface of the puck was smooth after extraction (no holes), and the weight of the double-shot was reduced by about 20%, given the same grind and the same extraction time. As noted by other posters, it has the added benefit of keeping the group head clean.