I just went bottomless on my La Pavoni...

Two main advantages seem to be that I can dose higher with the larger elektra a leva basket than the stock double and cleanup is a lot easier.

Looking at the extraction is a bit hard when I have to pull the lever...and the problems I have seen seemed to be mostly caused by using the wrong dose for my new basket.

I appreciate the contrarian viewpoint, but for me I always use the naked PF in my Pavoni. I adjust my force as I watch the first beads appear and the tail develop, and stop it when I start to lose the darker streaking, but mostly, I just like to watch. It's a thing of beauty, part of the Zen of pulling a shot. Like others, I keep a little shaving mirror next to my machines.

For those that want naked, but also want the mass of a standard PF you have the option of using a Richard Penny bottomless. You can get it in stainless or brass. Even if you have a chrome machine you might consider brass because of its thermal characteristics. I've never thought that PF mass was a major concern, always use group cooling methods to manage shot temp.

For me, it seems like I make better shots with a bottomless filter since there's an instant feedback on what's going on. With a spouted PF, you only see if the pour between the two spouts are balanced or not. With bottomless, you'll see evenness of flow, channeling(if there are any), color change, etc.

I've been using my "kinda naked" portafilter for a number of months now and definitely feel that the visual aspect of monitoring the extraction is super important. Here's the thread, with a video, for those who are curious:

Not so naked portafilter

I think being able to monitor how the shot begins (on the bottom of the basket) is super critical. With that said, the smaller amount of mass in the PF does result in a noticeably hotter final shot (which I don't like).

With my setup, if I'm pulling a shot of espresso, I usually cool down the little spout part (as well as the entire portafilter) in cold water first. This still allows me to monitor how the shot is coming along, but yields a cooler final shot in the cup.

When I'm making a Latte or an Americano, then I typically don't bother with the spout, since the starting temperature of the shot doesn't have as much impact on the final result.

Anyway, lever machine or not, there's no way I could ever go back to using a portafilter where I couldn't monitor what's going on in real time.

Ray

I will relate my own personal experience:

I used a PonteVecchio Export, spring lever machine for five years with a stock portafilter. My shots started out good, got better, and over the years became consistently better than 99% of the cafes I've been to (even without using a 64-mm conical burr grinder). In fact I liked the espresso so much that I bought a second Export last year.

The second Export came with a bottomless PF. I followed my 5-year routine, and I often, but not always, got great, solid-center extractions. It took a few months of daily use to achieve very consistent (95%) great pours. There are a lot of very subtle changes in routine that can be perfected by using the bottomless portafilter. Not the least of which is dialing in a new bag of beans. I use the same blend for weeks on end, and it is very easy to see that each batch needs fine adjustments, and changes over time. These would be much more difficult to make with a stock portafilter.

All that said, ignorance is bliss, and there is a lot to be said for just pulling a shot and not worrying about perfection all there time.

PC

Without intending to repeat what was already written in the Caravel thread, for a lever machine that produces small shots, a bottomless portafilter is very, very valuable.

drgary wrote: Advantages of a stock portafilter:
- Helps cool the group more effectively than bottomless with more metal mass
- No need to fuss with another PF or OE heat sink first. Just plug it in to adjust temp and pull the shot for a more efficient routine
- Dual spouts allow split shots (and yes, they can also get in the way)
- Less hassle at 6 a.m.

I agree with Gary about the advantages of standard portafilters. In many ways they are better. For example, I got a bottomless portafilter for my Cremina 2002 and used it only a few times. It helped me diagnose my shots and then I stopped using it. I removed the screw-on dual spout from the original portafilter: It gains more space underneath and I can readily see when I have a centered extraction.

That said, the bottomless portafilter for the Cremina 2002 was my second portafilter. I used it when making multiple full-sized shots. That is a good reason for getting one.

Many aftermarket bottomless portafilters are considerably more robust (additional metal, higher quality or denser materials used) than stock portafilters, so heat dissipation might not be as much of an issue as it seems. In my experience, there is no significant difference.

The original post sought advice on the advantages for lever machines when compared to lever machines. I think the overwhelming answer is yes. I can confirm from my own trials. The bottomless portafilter for my semiautomatic Bezzera BZ02 was used only a few times. After using it, I felt it was a frivolous expenditure. There was not much I could do to impact flow and quality beyond playing with tamp and grind. Temperature surfing and timing do not require bottomless portafilters.

coffeehorse wrote:I think you need to be careful for the bottomless portafilter not to be your only portafilter. Espresso often tastes better with spouts, lever or no lever. Actually - that's derived wisdom, I think the reality is that bottomed but not necessarily spouted portafilters give different extractions

John, I would be very interested to learn more about this. Do you have any specific evidence to suggest there is a difference one way or another?

Converting the Portafilter to Bottomless

On my pre-Millennium La Pavoni Europiccola, which has two power switches and no PSTAT, I control the temperature by toggling the switches on and off. My main reason for keeping the portafilter stock was as a heat sink, so that reason disappeared. Over time I found the double spout on the bottom of my portafilter a hassle, and it was just impossible to remove. After following directions elsewhere on this site it wouldn't budge. I took it to Christopher Cara and he couldn't remove it either without fearing he would break it. The double spout was extra wide, it required using a larger cup and limited clearance underneath the group. After a brew session I typically insert a small sponge in the portafilter and run a blank shot through the group for a mild backflush, as suggested by Richard Penney. The dual spouts would spray water sideways so I couldn't do this without wrestling a small steam pitcher underneath. And the spout made it impossible to rest the portafilter on a tamping pad while filling an inserted basket. My only remaining hesitation was the idea that the portafilter bottom may percolate the coffee a little longer by forming a semi-enclosed brew chamber. That wasn't enough reason. So this afternoon I freed the portafilter from its nasty spout.

Cutting it was a little tricky. Thanks to Ray Johns who told me that if I use a hole saw, expect to chip away the metal rather than smoothly grind through. He recommended using grease but I didn't have any and it worked fine. The hole saw cost me about $18 at Grainger. It needs to be fastened to a drill bit, and even then it would work its way loose. But I worked carefully, wore protective thick leather gloves and a face mask.



I fastened the spout in a vise and started chipping away and would have to adjust the set screw in the hole saw to re-grip the drill bit. It broke through the bottom of the portafilter at one place at first, so I would redirect it until the bottom and spout were removed.



This left some nasty burrs and an uneven edge on the bottom.



But I used a rotary tool with a heavy duty cutting wheel to remove the burrs, then used a few different grinding wheels to smooth and even up the edges and got it done! It created a few scratches on the outside of the portafilter because I need to be more careful positioning the bit when grinding.



I tried a shot of decaf and was able to much more clearly see when it started to go blonde, so I pulled the shot. This will make a worthwhile improvement in shot quality.

I'll still leave the portafilter on my Millennium machine stock because I actually use it as a heat sink to control temperature.

drgary wrote:Converting the Portafilter to Bottomless
Cutting it was a little tricky. Thanks to Ray Johns who told me that if I use a hole saw, expect to chip away the metal rather than smoothly grind through. He recommended using grease but I didn't have any and it worked fine. The hole saw cost me about $18 at Grainger. It needs to be fastened to a drill bit, and even then it would work its way loose. But I worked carefully, wore protective thick leather gloves and a face mask.

Nice work Gary!

As far as the grease comment, I don't recall that off hand - unless it was perfect in relation to using a hole saw that has a diameter which is very close to the portafilter (so that you don't risk binding as much). The hole saw I have used it much smaller than the PF diameter, so it's not as big an issue here.

However, I do remember mentioning that the cutting action is more of a chipping than sawing deal. The hole saw method does work pretty well though. The teeth of the hole saw (and the entire cutting bit of course) rattles around a lot as you cut. There's always a lot of chatter, so it pays to go slow and not attempt to rush matters. As long as you don't let the chattering panic you, then you can make it through the brass without a lot of problems.

I've cut them on the lathe also, which is more precise, but also a bit more time consuming. The two I cut for TomC were done on the lathe and came out really nice. The one I did for myself and also the one I did for a local bakery were both done using the hole saw routine, followed by sanding attachments and some die grinding and hand filing.

To really do a good job, there's as much hand finishing with a file as anything else. I always try to put a flat lip around the bottom edge after doing a little blending and radius on the lower lip, also.

Anyway, a little grease around the outside of the cutting bit wouldn't hurt. The other thing is to make sure you protect the un-cut surfaces with duct tape or 3M blue tape. It's easy to miss with the sanding or cutting tools and leave nicks and/or scratches in surfaces where you don't want them.

Again, nice work there!

Ray

Hi Ray,

Glad you caught this post. It went pretty much as you described and the hole saw was a good fit in my 49mm portafilter. Afterwards I took your lead from what you did for Tom and finished it off with a sanding wheel on my rotary tool. Next time I'll tape the surfaces I don't want dinged. But after pulling a few shots this morning with the feedback I can get with a bottomless portafilter, it's seeming less likely I'll crave a Cremina.* The shot quality on this vintage Pavoni paired with a Pharos is getting better and better.

* Of course my posts on this thread support the adage, "Never say never."

Yeah, the naked portafilter does allow you to really fine tune things. I have my routine down on the La Pavoni to where every single shot is amazing. Using good quality beans helps a great deal of course too

Ray