WDT - what causes uneven distribution in the first place?

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coffee_plXR

#1: Post by coffee_plXR »

Hello guys,
I'm using Fiorenzato F83E in my coffee shop.

Back a few week, I was squeezing my head to troubleshot some cumbersome extraction issue.
Every time I pull the shots, shots were only half-extracted. Half of the coffee puck was wet while the other side wasn't. :(

While searching for any wisdom, I was so glad to find out topics on what I was curious about.
The Weiss Distribution Technique!

What do you think is the cause of uneven distribution of coffee particles?

My theoretical assumption goes like this:
Especially for burr grinder; the distance between two facing burr is identical in every direction. It's so natural the grind size varies within error.

It sounds so weird the entire particles act completely the opposite just by stirring well..
I didn't even know that stirring makes that much difference.
(Since then I started using this remedy every time I make coffee, because the extraction never goes well without it. My wrist hurts so much!)

If it's just owing to poor particle distribution then why does it have to do with the grinding process?
Some argue about burr misalignment, I've done that with aluminum foil and made for nothing. Now I strongly doubt the shape of the burr.

Last but not least, I wonder if any shape of the flat burr affects particle evenness.
If you guys have any posts or research paper about this topic, please help me share that idea together!

If it's just owing to the grinder itself, the last call that remains is to upgrade my grinder.
Upgrade version of mine costs almost double. That means I should be very cautious :)

Thanks

mikelipino

#2: Post by mikelipino »

Hi Phillip, do you grind directly into the portafilter? Your grinder may be throwing grinds to one side making it more compacted even if you level afterwards. WDT will make the puck more homogenous, which I think you're seeing. Another way to approach would be to grind into a dosing cup, put the portafilter on top, shake, and flip.

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cafeIKE
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#3: Post by cafeIKE »

Better off to put the cup in the PF, then shake to distribute.

A leveler may help if you can't do it by hand.

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Jeff
Team HB

#4: Post by Jeff »

Especially for classic designs (pretty much everything from the well-recognized names), they've got moderate to long passages from the grind chamber to the outlet. Many end up extruding the coffee down the passage, sometimes with a static-control or de-clumper device in the path. You've got clumps being generated after the burrs. Then, if you're not completely even in how you fill the basket, there is more unevenness. Depending on how obsessed you are with prep, something as simple as flipping over a dosing cup can lead to unacceptable bias in the density of the grinds in the basket.

coffee_plXR (original poster)

#5: Post by coffee_plXR (original poster) »

Mike, That's the point.
I have no way to prove "the grinder throws out different sizes of particles in specific direction", which was only my assumption by far.

So let's say if this is a sheer grinder issue and mine is bad, how about upgrading to another one? No one knows.
I didn't want myself to stay stuck on experiences, rather find out a proper reason for this, and barely I could find scientific data.

But I can say that WDT is the only solution to this.

coffee_plXR (original poster)

#6: Post by coffee_plXR (original poster) »

Jeff wrote:Especially for classic designs (pretty much everything from the well-recognized names), they've got moderate to long passages from the grind chamber to the outlet. Many end up extruding the coffee down the passage, sometimes with a static-control or de-clumper device in the path. You've got clumps being generated after the burrs. Then, if you're not completely even in how you fill the basket, there is more unevenness. Depending on how obsessed you are with prep, something as simple as flipping over a dosing cup can lead to unacceptable bias in the density of the grinds in the basket.
I do WDT for every single shot which is very exhausting. My wrist already started to give me a bad signal I wish I could have a small automated mixing tool :(

Jeff, can you toss me any links or research data if you have one?
In my opinion, what happens while grinding, and the burr itself actually matters.
In order for 'what happens inside the passage' to be an issue, let's say the passage has an issue that it intentionally sorts out the specific particles by any reason, the usage of WDT would still lead to random and uneven extraction for every shot because the particle sizes have already been distorted. But it wasn't.

I'm using triangular whisk for WDT.
Moving it parallel mitigates extraction problem and just up-and-downward motion brings no change at all.

longpvo

#7: Post by longpvo »

coffee_plXR wrote:I do WDT for every single shot which is very exhausting. My wrist already started to give me a bad signal I wish I could have a small automated mixing tool :(
Nurri VDT - yet to be proven

Duomo The Eight - repeatability, works good if your grinder allows dosing directly without major clumpings in the first place

Nate42

#8: Post by Nate42 »

coffee_plXR wrote:I do WDT for every single shot which is very exhausting. My wrist already started to give me a bad signal I wish I could have a small automated mixing tool :(
If you are injuring yourself doing WDT you are probably way over doing it. Buy/make a levercraft style multi pronged tool. You should be able to do a quick WDT in about a second with minimal effort. In the meantime, just slow down, and stop sooner. It shouldn't take much.

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HB
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#9: Post by HB »

coffee_plXR wrote:I'm using Fiorenzato F83E in my coffee shop.
For reference, here's a link: https://www.fiorenzato.com/en/coffee-gr ... and/f83-e/
coffee_plXR wrote:I have no way to prove "the grinder throws out different sizes of particles in specific direction", which was only my assumption by far... But I can say that WDT is the only solution to this.
You have a timer-based on-demand grinder. For better timed accuracy, they usually have a flapper/gate to help meter out coffee more slowly than simply letting the grounds fly out of the burrs. This compression helps with timed accuracy, but may cause clumping. The WDT is a "clump buster". If you had a doser and thwack thwack thwacked the doser handle, you probably wouldn't need to WDT.

If you post a photo of an undisturbed dose, it'd be easier to confirm clumping is the main cause or just a "bad landing". That can happen when the grinder tends to hit the same spot. If that's the case, rotating the portafilter handle while the grinder fills the basket can compensate. If you post a video of your routine, we can offer more specifics.
Dan Kehn

coffee_plXR (original poster)

#10: Post by coffee_plXR (original poster) »

Thanks Dan:)
I still didn't get used to post picture properly, I just uploaded that big original ones It might get you a bit hard to go
(I have no idea for downsizing it.)

So here's the grinder




1. Without WDT

I use 1) distribution tool, 2) PUQ tamper only, and then go straight to espresso.


You see the extraction coming from the left? It happens everyday when I'm not using WDT
In my opinion, It at least shows that the density of the coffee grinds on one side is heavier than the other. But why this happens is a tough question.
In my case, the extraction occurs mostly on the left side(the right side is mostly clogged). I think it occurs randomly if it should happen because clumping doesn't tell any left or right side.

2. With WDT

On top of the previous prep, I added triangular whisk to stir coffee grinds.


Here's the change.


Witnessing the difference, I definitely couldn't miss the advantage of WDT, even though it's tough for me to repeat this on every single shot.

By the way, can you recommend me any doserless grinder in the light of this?
I think I'm going to buy Mazzer Major VP, but not sure if it can handle this problem.