Diffuser Screens

Beginner and pro baristas share tips and tricks for making espresso.

#1: Post by BaristaBob »

I've been seeing some aftermarket companies selling "diffuser" screens. These are the ones that you place on top of your puck in the portafiler. So once you WDT, level, tamp, etc...then you place the screen on top. They report better water transfer through the puck to increase extraction. I'm all for that...but do they really work?

Bob "hello darkness my old friend..I've come to drink you once again"

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#2: Post by Jeff »

The BPlus screens were "discovered" by the DE1 community a couple of months ago. BPlus was surprised at the uptick in sales, and responded promptly. The Flair 58 screen is said to be the same product with different branding. Either way, $43 and up (delivered) is, at least for me, not something that is cheap enough to "just try". Thankfully, there have been a couple "group buy" opportunities to help with the shipping cost. I have the BPlus screen.

What I can say, from personal experience, that it does is that it keeps the group head a lot cleaner and the pucks come out of the basket more cleanly.

Before continuing, I consider this a tweak.

If your puck prep isn't excellent to start with, I don't think this is going to fix that.

It may well be that the reported improvements are smaller than the variance that your (speaking generically) puck prep allows in the cup. If you've got money burning a hole in your pocket and don't have a good WDT tool, comparable or better than the LeverCraft tool, I'd definitely spend there instead.

Many people, myself included, start with getting a reasonably homogeneous, void-free, and level bed of grinds, drop the screen on top, and tamp it in place. The screen will scratch a tamper face. I use a Robot filter that dried out with a bit of a curl to it to protect the face of my tamper. If you tamp and then drop the screen, I found that it could land a bit unevenly and mess up the tamp. I remove the screen after a shot by pressing down on one edge with the back of a spoon. It will be hot, so have a place to put it down quickly!

A few people have tried preheating the screen. Stainless steel has a relatively low thermal capacity for a metal. Some measurements of temperature above the screen done by others suggest that the drop is small (0.5°C or less) and of relatively short duration. I don't know of any measurements with a thermocouple below the screen. For me, that measurement and the hassle of preheating the screen and then handling it, wondering how much it cooled during tamping and on the way to the machine, was enough for me to drop following that path.

Since the screen is around 1.8 mm thick, it changes the headspace height as well as volume. This makes comparisons past "used screen" and "didn't use screen" a bit of a challenge. Would one have gotten similar results with a basket that was 1.8 mm shorter or a 1.8 mm "spacer" on the group screen?

Some of the observations from others include slightly higher EY% than without and a bit of belief that it leads to more uniform wetting of the puck. EY% isn't taste, but at least it isn't a subjective measure. I haven't measured the EY% change myself. My cleaner pucks suggest to me that the puck may be wetted and extracted more evenly.

I continue to use mine for the cleanliness aspect. If it is making my coffee taste better, that's a bonus.

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BaristaBoy E61

#3: Post by BaristaBoy E61 »

Jeff wrote: EY% isn't taste

Sounds like it would wind up being another contribution to my box of, 'Bought and Never Used' & 'Bought But No Longer Used' due to the PITA Factor.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

BaristaBob (original poster)

#4: Post by BaristaBob (original poster) »

BaristaBoy E61 wrote: Sounds like it would wind up being another contribution to my box of, 'Bought and Never Used' & 'Bought But No Longer Used' due to the PITA Factor.
Well I greatly appreciate the detailed explanation from Jeff on the portafilter dispersion screen. It might make its way into my routine but agree it could end up in the "tried it didn't like it" bin. :?
Bob "hello darkness my old friend..I've come to drink you once again"


#5: Post by Eiern »

I very much like the clean machine I get with a paper filter, and I do think the extractions benefit a little bit, so I have a metal screen on the way to try out.

But there are a lot of things one can do to help extracting, and we don't all bother doing all of hem if we're happy with what we're already producing. Some only tamp the coffe coming out of the tamper with no shaking or puck raking etc.

I have not yet wanted to add more extra steps like the hog (many needles insterted straight into the puck) but dropping a filter in my portafilter is not a hassle to me. Let's see what it takes to keep the metal mesh clean and how long it will last. It's said to have additional effect on puck compared to filter as it also physically compress the puck a little.

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#6: Post by BruceWayne »

I had a question about adjusting the dose for the puck screen. I'm assuming I don't want to have the puck screen rubbing against the screen in the machine when inserting my portafilter, so should the dose be slightly less to allow for more room? Is that what others are doing? Is it safe to just slap the screen on because it's thinner than a nickel (assuming I've adjusted my tamp using the nickel test).

Edit: Compared to a nickel, my screen is about the same thickness, so back to the question, how much adjustment to the dose or tamping have you been making when using a screen?


#7: Post by Eiern »

I went from 18g in 18g VST basket with paper filter to 18g in 20g VST basket with Flair screen.

As I have a Pullman tamper with the TampSure system it's easy to see if I can get the same depth from rim of basket to puck.


#8: Post by PeetsFan »

I was just thinking that my espresso-making routine isn't complicated enough, and I need to add more steps.


#9: Post by blutch »

My shots have improved dramatically since using the Bplus. I got a new tamper (bravo) at about the same time, but was still experiencing some channeling. With the screen, that has gone away almost completely. It's a pain to deal with, but I have it in my routine fine by now. I lightly tap it out into my knockbox and then on the other side of the bar I tap the puck out. Works out so I don't have to touch it when it is so hot.

It was a good investment for me.


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#10: Post by Sprobuzz »

Jeff wrote: What I can say, from personal experience, that it does is that it keeps the group head a lot cleaner and the pucks come out of the basket more cleanly.
I just received my screen and it solved my long-standing issues with channeling, so not only do I appreciate the clean basket but also the lack of geysers on the bottom of my portafilter making a mess on the counter! I must admit that flavor issues I had in the cup before using the screen still remain so I need to continue to improve my puck prep (RDT, WDT, leveler tool, leveling tamp).