I tried a search..no luck..sorry if this is old hat.

Is the value of bottomless PF's the same with levers as pump machines?

From what I can gather tamping is less critical and I'm wondering at the reduced pressure if the feedback on distribution etc..is going to be as helpful on the lever.

I imagine after pulling shots for years with the bottomless PF I'm going to eventually have to chop off the bottom of my new PVL but as for my initial learning shots I'm wondering if I should not worry about it or is it an ASAP priority to take care of while learning.

On levers, it is important especially if you are practicing multiple pulls/pumps. You will have feedback on whether you fractured the puck or not.

Is it crucial you have one? No!

I like them mostly because of the cleanup. It is just so much easier to clean just the basket and not nooks and crannies of spouted portafilter.

I think they are very valuable on levers. If they aren't as valuable as on pumps, it is certainly close. I chopped my Pavoni portafilter and have certainly never regretted it.

Alright..

Looks like I'll be figuring a best plan of attack on chopping down the PF as soon as it gets here.

I did my last one in a moment of haste and it looks the part. Hopefully I can get a better result this time around,

Super important on lever machines, when it comes to dialing in the grind, etc. I would personally call it indispensable myself - at least on my La Pavoni. I know that machine is super sensitive to grind, as well as initial starting pressure of the pull (i.e. to avoid channeling).

Ray

A word of warning, my first experience with a bottomless PF on my Cremina was disheartening. It showed me all the things I was doing wrong (that the regular PF was covering up). Suddenly being behind a learning curve for something I'd been doing for years was discouraging...and trying to fix that at 6 am nearly switched me over to French press.

I have a bottomless (Penney) portafilter for my lever, and it has been completely valuable. With the bottomless, I have a much more direct window into how my pull pressure affects the flow. For a while now, I've been adjusting my pull pressure to create a few different basic profiles:

1) consistent flow rate : I believe this is a declining pressure profile, in that it takes less effort over the duration of the pull to maintain a visually consistent rate of flow

2) increasing flow : consistent pressure profile, similar to what a vibe/rotary pump can produce, affecting a slightly increasing rate of flow

3) decreasing flow : more a variant of 1), but declining pressure at a faster rate to slow down the rate of flow

It's as consistent as any other manual method, which is to say that it's pretty inconsistent compared to a programmable pump, but I am able to fairly reproduce these profiles in a given shot. I'd imagine that any machine capable of pressure profiling (spring lever, manual lever, electronic pump AKA Strada and Hydra) would benefit from the same transparency, even if the Strada/Hydra class are less practical in a home setting than anything else.

My La Peppina spring lever has spouts on the portafilter. It's a bit difficult to go bottomless on the La Peppina unless your willing to forgo the portafilter handle, but it can be done. I've thought about getting a second portafilter and having it chopped, but so far I've resisted. I've been happy with the shots from the La Peppina and I think that I've worked out my technique without the bottomless portafilter. With the La Peppina, all the pressure is from the spring or your assist, it's an open kettle so there's no pressurized water feed, only gravity feed.

When I got my Gaggia Factory, it came with a bottomless portafilter already. While working out proper technique on the Gaggia Factory (forgetting what I'd learned for the La Peppina and starting from scratch) I noticed some pretty clear indications of donut extractions, channeling, spritzers, etc. I also dropped my filter basket in the dirty frothing pitcher along the way. I think the feedback is valuable, but it could be disheartening to a beginner. I've been paying more attention to dose, leveling and tamping and have seen improvement in the shots.

I got the Factory for the challenge, fully expecting it to be more difficult then the La Peppina, and I haven't been disappointed. I've been rewarded with microfoam from the steam wand and some very nice shots which is nice when learning a new machine. I guess with a full manual, you could get up into the pressure range of a pump machine, where with my spring lever, I'm not that close.

The possible drawback with the Gaggia Factory (or a La Pavoni Europiccola/Pro) if you use the portafilter to cool the group head for temperature management may be that there's less mass with the bottomless portafilter, but so far I haven't had any problem with multiple shots, I think because the thermostat came set on the low side and it also included a temperature strip on the nose.

I'd say that it can be worth it to get a bottomless portafilter, especially on a manual lever and it does make it much simpler for cleanup. The portafilter also sits flat on my silicon tamping mat instead of having to balance it on the spouts so that's another possible advantage.