Extraction favors near side of portafilter

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smuseby

Extraction favors near side of portafilter

Post by smuseby »

I am unable to get an even extraction: the flow is always concentrated at the side of the portafilter nearest the handle with much slower and very dark coffee coming from the far side; after removing the puck, the far side of the basket is always stained dark brown. I'm using 18g of coffee, medium roasted, fresh beans in a Mazzer mini; extraction time is about 30 seconds for 40ml, at 93C. I weigh the portafilter (tolerance +/- 0.5g) before leveling with my finger, and tamp until there is no more give. I have tried nutation, level tamps, tilted tamps both toward and away from the handle. I have tried 16g shots. I clean the portafilter to insure that none of the holes are blocked. Always the same result. Espressos taste good, but I bet I could do better.
Any suggestion as to what else I can try?
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chas
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Re: Extraction favors near side of portafilter

Post by chas »

It sounds like you are doing all the right things though 99.9% of the time this problem is due to grind, level, tamp issues. Just to be sure, you may want to individually lay your basket and also your PF upside down on a table top to ensure that both are perfectly level across their tops.

If that is OK then it seems you are back to your PF loading and packing technique. If you always do your process with the PF handle oriented in the same way relative to your body, you should try rotating it 90 or even 180 degrees. If you do that and it is your process, one would think that the problem area would also rotate to a new location when pulling a shot.
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
smuseby

Re: Extraction favors near side of portafilter

Post by smuseby »

Chris - thanks for the reply. If you have a moment, I would appreciate a couple of clarifications:
1) turning the PF and basket upside down to ensure that they are level? Not clear what that means; and
2) Changing the orientation of the PF handle: as best I can tell, it is only possible to insert the PF in one position - about 9 o'clock from a bird's point of view, and seat it by turning it to about 6 o'clock.
I didn't mention in my original post that I do a 5 second pre-infusion, which is included in the 30 second total time for the shot.
You did inspire some new thinking however, and while it's premature to declare victory after one good shot, I rotated the basket 180 degrees within the PF, and it worked. - once. While all this mystery at some level is part of the fun, this one bugs me.
MDL
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Re: Extraction favors near side of portafilter

Post by MDL »

I think that Chas was
1. suggesting that you check to see if the top lip of the basket is flat.
2. suggesting that you check for uneven tamping or other basket loading effects by turning the portafilter before you tamp (effectively doing what you did by rotating the basket).

Good luck
smuseby

Re: Extraction favors near side of portafilter

Post by smuseby »

Actually, I rotated the basket in the PF, then loaded it with coffee and tamped. Assuming that is the only thing that changed (the basket position with respect to the PF), AND assuming that it continues to extract evenly, what I will have discovered is that both the basket and the distribution of water are not symmetrical. Hard to believe.
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chas
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Re: Extraction favors near side of portafilter

Post by chas »

Here are some additional things you can look at to see if it is a machine issue:

1) Take off the shower screens and run a shot with the PF and screens off. Look up into the group while the water is running and check the water flow coming through the holes in the dispersion disk.
If the flow doesn't look even try loosening and rotating the dispersion disk to see if the flow changes.
2) Put the shower screens back on and repeat the test to see if the flow of water is even through the shower screens. You might even try rotating the two screens relative to each other. The two screens can be aligned so that the holes in the metal disks are mostly aligned with each other or they can be completely offset from each other. Try it both ways to see if it makes a difference. I actually did some of these tests when I had a V2. I thought I would see a noticeable difference but I really didn't. However, your mileage may vary.

These days you can buy aftermarket laser cut shower screens and PF baskets. If all else fails to resolve your problem and you have some extra money burning a hole in your pocket. you might want to consider those options.
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
smuseby

Re: Extraction favors near side of portafilter

Post by smuseby »

The laser cut screen just arrived in my mail box. I'm skeptical, but ready to try anything. Aligning the two screens sounds like a possible culprit.
More later.
smuseby

Re: Extraction favors near side of portafilter

Post by smuseby »

Update: with the laser cut screen and the addition of the 3 shot basket, I'm doing better. While the near side still has more flow than the backside, it no longer leaves the dark brown stain on the far side on the basket.
Logically, it seems as though it must be my tamping technique, but I don't know what I can do that might improve it. It's a mystery. So much for my prospects as a barista.
jfrescki
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Re: Extraction favors near side of portafilter

Post by jfrescki »

You could try to grind a bit finer and do a light tamp using only your fingers on the tamper. It's very easy to tell if you're level with your fingertips. I've just adopted this method very recently because I feel like I'm getting better flow and shot clarity. I either grind finer / increase my dose a bit.

Just playing around with my technique, I also took the spring out of the portafilter so I could prepare the basket separately. I'm not still doing that, but it is what led me to try the lighter finger tamp/finer grind.

EDIT: I left out that I also feel it's necessary to WDT. I dose 15g - 16g, WDT, shake to level, then tamp.
John

Mini Vivaldi, EPC-8, SJ, Steel Burr Vario
Behmor, Modded Poppery
Coffee Stuff
smuseby

Re: Extraction favors near side of portafilter

Post by smuseby »

WDT - ?
Update #2: If I tamp with most of the coffee adjacent to the handle, I am able to get even flow during the extraction. The variance - slope in the basket - is not subtle. This suggests to me that the problem is not my tamping technique, but I have no idea what else might explain this. But the shots are good. No complaint there - I just don't like the way I get them.
I haven't tried no tamping - next on my list. Although with the triple shot basket, my pucks are now very wet and no longer resemble pucks the way they were with the double shot basket.
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chas
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Re: Extraction favors near side of portafilter

Post by chas »

Soupy pucks are pretty normal with the S1 and have no bearing on flavor. The job of the 3-way valve is to equalize the pressure in the PF before you remove it, not to remove all the water. Something about the geometry of the S1's group and PF seems to lend itself to soupy pucks. The alternative is to load so much coffee in to the PF that there is no room for excess water on top of the pick, but then that causes other shot inconsistencies.
Chas
LM GS/3 & LaSpaziale Dream v 1.25 (US 120V)
Mazzer Kony E, Customized Rocky
Hottop P/B
jfrescki
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Re: Extraction favors near side of portafilter

Post by jfrescki »

smuseby wrote:WDT - ?
Weiss Distribution Technique - essentially stirring the grounds with a very thin implement (ie wire or unbent paperclip) to evenly distribute the grounds.
John

Mini Vivaldi, EPC-8, SJ, Steel Burr Vario
Behmor, Modded Poppery
Coffee Stuff
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