Espresso Distribution Tool Debate Update #1

Hey everyone,

Here we go with our first post for the Great Distribution Tool Debate!

First of all, a big thanks to everyone who contributed funds, and shared the project around the industry. We’re off to a great start.

Here’s a video with our initial thoughts and an intro. Dissent and criticism welcome!

Remember: only contributors can comment in here. If you’re reading this and would like to throw your hat in the ring or help us along, you can contribute here.

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Agree, simple test to see if the “vanes” on the tools distribute evenly in a single plane. For my mind it would be worth repeating this test for various dry doses, a quick way to see if their may be an optimum bed depth where the distribution is most uniform for each tool.

Quick thought on the use of refractometers for further study (if there is time/funds). It seems that a lot of the claims from the manufacturers are focussed on the consistency of extrations, and whilst this has been done before, some blind testing of this woukd be interesting to both check their claims but also see how it matches up with the data from the first test.

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Regarding the subjective tasting, would it be possible to get in contact with local baristas and look at getting volunteers in for it?

So excited to see how this will go.

I’d be interested in seeing difference in consistency from humans new to coffee vs. experienced baristas using both distribution tools and tapping method.

Probably a different study altogether but I imagine many trainers consider ease of learning plays a big role when teaching distribution. Distributing tool seems to eliminate the risk of burning the hand associated with practising the tapping method, often a discouraging factor for new baristas.

Might be easy to simply use razorblades for the bottom of the tool! Especially if you have access to a 3d printer.

Also. You might be able to do the same type of test to find out the distribution from the center to the edge.
It could be that every “pizza slice” is more dense on the tip of each slice, making all of them the same weight.
You could measure the total surface area, divide that into equal surfaceparts where only the inner part is a circle and the others are rings and weigh those.

I agree on not testing on brewing, but keeping it on the actual distribution of grounds. Otherwise too many unnecessary variables will be involved.
Great start!

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This is very cool! I completely agree with this approach and will be eagerly awaiting the results!
I’m curious about the weight resolution you will aim for with each “puck slice”.
For example: using a 20g dose, each slice should be 3.33333g, but at what point is a distribution tool not doing it’s job effectively? If one slice is 3.334g and another is 3.332 is it bunk?
This is rad Matt, thanks for taking this on! I’m stoked to see what happens.

Definitely want to get into extraction testing. But I think it’s an immediate fail if there’s obvious problems with this test. Nobody can argue even extraction if there’s obvious problems with density.

@nico I’m truly more sceptical of large groups for subjective tasting than I am with a small focused and calibrated group. Subjective testing has big problems.

@TumiFerrer Any method that has room for human error will have human error. This test feels a bit redundant if we’re hunting for a method that’s consistent no matter what.

@Rob We’re on the same page with razors. Only problem is they’re small, and it’d be difficult to mount themn on something that wouldn’t disturb the grinds as it was pushed in. I’m trying to find something that’s thin enough to create minimal disturbance but also robust enough to have a consistent cross section as deep as the puck. Looking like 1mm or 0.5mm SS sheet laser cut and sharpened will be the go.

@ThreePines We have no idea about required precision. It could be 1g. It could be 0.01g. We’ll have to test and see. If they’re all so close that it could be considered noise, then we’ll have to investigate other methods. If the sections are obviously different then we have a winner.

Thanks everyone! I’m working on the test unit and will get back to you once we have made some progress. :slight_smile:


Hey there, good job so far!
One thing I didn’t get: To find out, whether or not dozers work, you have to compare it to other techniques. What will they be?
If you tamp directly, without any touching of the grounds beforehand, the result will depend on the grinder and the shape of the little “powdermountain” in the basket. If it is concentric and even, and the tamp is perfectly even, then the puck will probably be of even density as well. If the grounds in the basket are all over the place, then probably not. But that’s to find out!
So I think you can’t just isolate the dozer, you need to include the whole grinding/ tamping thing as well.
BTW: Gilberto has a dozer that is adjustable in depth, would be great to include it in the tests.
Hopefully I am allowed to post this Video:


Mate! That’s a pretty sweet dosing tool!

Where can we get one of those? The auto-weight, reverse spin, and the non-centered cuts all intrigue me!

We’re going to compare it to nothing (control) and also tapping, which previous quick tests have revealed to create the highest and most consistent extraction.

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Hey Matt! Glad you like it. Gilberto has a very small Company in Brasil. Just drop him a line at He speaks english.
He also makes excellent handgrinders. And dynanometric tampers. His craft is exceptional!
Click this:

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Will the type of coffee (blend/single origin) have an effect upon final weighing of the segments?

Technically, you probably don’t even need to use coffee. Something with a consistent grain size would create a better control test, no?

I emailed Gilberto about his distribution tool, he said he has a second batch in the works to correct an issue he found in the first batch.

I currently use a V2 OCD but have also used a V1 OCD. I used to use a paperclip… lol

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I also thought that you can consider using another material. What do you reckon? @MattPerger

Why would you use a different material? How would you verify whether the results are transferable?

Yes it might have an effect, but we’ll use a well sorted, tightly screened, single origin/variety coffee.

Re another material, it only adds variables. I see absolutely no reason to substitute coffee with another material except for show. @danielcroft

Has anyone seen this gadget, SIFDIS:

They claim that no tapping of the basket is necessary. They argue it will separate the contact from portafilter body. Simply sieve then tamp.
I can understand that the sieving will eliminate absolutely all clumping (like sieving flour in baking) and the water should have an even pathway after tamping. Whereas a clump may not break up after a tamp and not allow the water to distribute through the bed? Is this part of the thinking for WDT?

Another thought regarding distribution - vibration excites the particles and potentially splits them up. When the vibration stops, the particles settle in an evenly distributed fashion. Industry uses this technique for all sorts of things.

That’s my 2 ideas. Feel free to tear these limb from limb.

I’ve been thinking for a while that distribution would best be done before the coffee was in the basket. That is a rather neat solution, although a painfully slow workflow.

I’d be inclined to try grinding straight into it whilst rotating the “gear”.

you could model it empirically in Matlab. I was bad in that subject. You’ve got your granulometry results from grinding tests. There’s probably some data on dissolvability on coffee solids. You have the data on basket shape, holes and wall design.

… This computer model may be just used as a bench mark if anything… like, if a modelled distribution is xyz, then extraction is going to be xyz… and from this result you may deduce that it’s not going to make much of a difference anyway.

Also, get an opinion from a mathematical/statistics person because remember, your only going to be as accurate as your least accurate measuring equipment. Like, if you measure with centremeters, you can only accurate to +/- 0.5cm. Depending on the outcome, if you want to keep this scientific, then it may not even be worth all this work.

Im also guessing there would be some movement in grinds as they settle and let water pass through them. So do the grinds actually settle and become equally distributed even if they aren’t perfectly distributed?

Good luck!!!

PS IMS and VST probably already have their respective CAE models that hold for perfect distribution.

Big tuning fork and touch the portafilter!!!:rofl:

Would add a new level of “experience” to making espresso.

A vibrating sift would speed things up. The Sifdis required hand spinning to he the siding action. Plus the shape of the sift needed a “V” to attempt to even out the flow into the group and not have too much around the edge or middle. A vibrating one may keep the height into the group even? After that I think a tamp is enough as suggested by the Sifdis guys as no clumps will be left.