Uneven extraction on bottomless portafilter [SOLVED] - Page 2

Need help with equipment usage or want to share your latest discovery?
Bret
Posts: 611
Joined: 8 years ago

#11: Post by Bret »

Also, since you first noticed this with a ridged basket over the last week, have you returned to the prior basket to confirm whether or not it still occurs? I assume you have, but I didn't notice it in your description. Maybe there is something off about your ridged basket. Long-shot, but it seems we are in long-shot territory now.

JayBeck (original poster)
Posts: 1216
Joined: 7 years ago

#12: Post by JayBeck (original poster) replying to Bret »

It's not the basket. I'm going to try a few things and will update the post later.

r7
Posts: 231
Joined: 8 years ago

#13: Post by r7 »

You might check the levelness at the bottom of your portafilter in both front/rear and side/side axis.

Charlene
Posts: 494
Joined: 7 years ago

#14: Post by Charlene »

The problem sounds like there is uneven resistance to water flow across the group screen.

Have you tried rotating the group shower screen 180 degrees?

Also, just for information, what is the pressure gauge showing as you pull a shot?

JayBeck (original poster)
Posts: 1216
Joined: 7 years ago

#15: Post by JayBeck (original poster) »

r7 wrote:You might check the levelness at the bottom of your portafilter in both front/rear and side/side axis.
It's level.

JayBeck (original poster)
Posts: 1216
Joined: 7 years ago

#16: Post by JayBeck (original poster) »

Charlene wrote:The problem sounds like there is uneven resistance to water flow across the group screen.

Have you tried rotating the group shower screen 180 degrees?

Also, just for information, what is the pressure gauge showing as you pull a shot?
I may try to rotate the screen. I'm not 100% certain how to though as they go in at such strange angles and I've been trying different screens / gaskets lately so variables are all over the place.

Pressure is perfect 9 bar every time.

JayBeck (original poster)
Posts: 1216
Joined: 7 years ago

#17: Post by JayBeck (original poster) »

Here's an update:

I pulled around 10 shots last night playing with different variables. A few things I noticed.

1. I tried the 'Nickel Test' for the first time ever (had to go to the store to get an actual nickel; I have no change in my house at all). I'm not sure exactly how you tell. Often times, I felt like me trying to pick up the nickel disturbed the puck moreso than anything else. A neutral dose perhaps was a little snug (again, maybe) so I did 17g in an 18g VST.

2. I tried two filter holders: By beloved La Marzocco Bottomless and an ECM Bottomless. It appears that the ECM provides slightly more head space (maybe 0.5mm) over E61 designs. Not sure if it's worth trying to sand off the excess lip or just drop dose 0.5-1.0g so I can use it.

3. Because I only had 3 shots left of my Olympia Natural Ethopia that I've been using, I saved it and used a Cimarron Decaf Blend that I had a lot of. I also removed the spring and dosed 17g into an 18g VST. Ironically, the pours were all pretty good with the decaf blend. They began beading on the out ring but immediately hit the center and formed into a center pour. No intense striping but I wasn't expecting it with a decaf. Here's the odd thing: The coffee and basket stuck to the shower screen so I had to sort of 'knock' it off each time. What's more, even though the pour was near perfect looking, when I did knock out the puck it appears to be sort of slanted still.

So here's my theory: My IMS show screen may be crooked perhaps?!?!? By taking the spring out of my filter holder and the puck/basket sticking to it after the shot, I know for sure the puck is taking the shape of the IMS screen. When i inspect it out of the machine it looks 'normal' but maybe these things when crooked are more subtle to observe. I'm going to use the stock screen for a while and see how things progress. And maybe it's just getting inserted at a slight angle causing half the puck to be closer than the other half which causes channeling and uneven distribution.

How do you all insert the E61 shower screen and is it even possible for it to get uneven unless bent? I have tried the method posted by Seatle Coffee Gear and recently started using the method posted by ECM (both via Youtube). This whole variable I've never even thought of makes me wish it had a screw like the Pro 300 / LMLM / BDB.

samuellaw178
Supporter ♡
Posts: 2483
Joined: 13 years ago

#18: Post by samuellaw178 »

Jayson,

A while ago, someone posted about solving a persisting channeling issue by down-dosing of about 2g from the VST basket rating, who was also switching up the stock portafilter and La Marzocco's portafilter. I couldn't find the post now. (so this thread felt very deja vu-ish :? ). Was that you by any chance?

I think it's quite unlikely a crooked screen will do that. Is the water dispersed evenly without the portafilter?


p/s: To remove the nickel, you can try inverting the portafilter instead of digging it out. The coffee puck should stay adhered to the basket (assuming it's been tamped). You can also do a dual-nickel test to check the 'crookedness' of the screen/portafilter. :P

BaristaBob
Posts: 1866
Joined: 6 years ago

#19: Post by BaristaBob »

samuellaw178 wrote:

p/s: To remove the nickel, you can try inverting the portafilter instead of digging it out. The coffee puck should stay adhered to the basket (assuming it's been tamped). You can also do a dual-nickel test to check the 'crookedness' of the screen/portafilter. :P
Sam...you state the obvious about removing the nickel, but I never thought of that! :oops: Perhaps it's because I mostly use just the distribution tool to prep my puck and once I inverted it for some reason and it fell right out into the sink. :cry:

About the double nickel to check levelness, maybe Jayson could fill the pf extra high, lock it in the group head, remove before pulling a shot, then check the whole surface to see if the grounds have been unevenly disturbed. Worth a look I guess.
Bob "hello darkness my old friend..I've come to drink you once again"

samuellaw178
Supporter ♡
Posts: 2483
Joined: 13 years ago

#20: Post by samuellaw178 »

BaristaBob wrote:Perhaps it's because I mostly use just the distribution tool to prep my puck and once I inverted it for some reason and it fell right out into the sink.
That 'tamped' disclaimer was added for exactly this reason! :lol: