Help to diagnose channeling before i get discouraged - Page 4

Beginner and pro baristas share tips and tricks.

#31: Post by lamarzoccofan92 »

Jeff wrote:The tool for WDT or WDT-like actions matters immensely. Too large and it can cause more channeling than it prevents. I've found a toothpick too large. A 1 mm cake tester or 0.8 mm paperclip didn't harm, but didn't help much with my grinder. 0.3-0.4 mm acupuncture needles are my current choice. In my experience with a grinder that is generally un-lumpy, most of the wire out there is too wide to be effective. Loops or bends at the end seem to work against you as well.
Interesting. I have been recommended the Londinium Tool which has a loop at the end at based on the popularity i would expect it to be the most effective out there. May i know where did you get your information from? Also when you use acupuncture needles, do the needles scratch the bottom of your filter basket? do you stick a couple of needles into a cork and use it like a londinium tool or just by itself? I am currently using a toothpick and it has been working as far as i know.

Also shipping the londinium tool to AUS is unbelievably expensive. I'm looking for an alternative.


#32: Post by pcrussell50 »

More than one person has made a "poor man's Londinium" by using one of these: ... 059&sr=8-5

The small kind. 5 or 6 inches long total length.

In my "lab grade" prep, I only use dissecting needles for leveling the pile before going to the grooming tool. The actual mixing is done with a Londinium or cocktail whisk type tool. I dull the tip of my dissecting needle, though when only used for leveling the pile, I rarely need to touch the bottom of the basket anyway.

LMWDP #553


#33: Post by Jeff »

There are several commercial variants of fine-needle tools, including ... hine-bplus ... tool-black

The needles I use are sold online as "3D printer nozzle cleaning kit" or the like, around US$10. I drilled 1/16" (~1.5 mm) holes into a cork and stuck the handles into the holes, getting the tips aligned in length. My tool looks a lot like the DE rake.

I tried dulling the tips, but they are so flexible, I don't know if I accomplished anything. I haven't seen any evidence of scratching of the basket, though I don't spend time dragging the tool over the bottom of the basket.

My decision on wire size was based on videoing shot after shot and examining measured flow/pressure during the extraction. I haven't tried any smaller than 0.3 mm. Some people are trying 0.2 mm. Completely unsupported hypothesis of mine is that if the particles are on the order of 200 µm (0.2 mm), things on the order of 1 mm or more look more like a plow or bulldozer, leaving furrows.

I tried a looped-end tool (Etsy-sourced, visually similar to the Londinium tool) and found that there was "random" channeling associated with my use of them, that I did not see with tools of comparable wire size and count.


#34: Post by mgwolf »

Interesting. I have been recommended the Londinium Tool which has a loop at the end at based on the popularity i would expect it to be the most effective out there. May i know where did you get your information from?

Please look at the link I posted on the previous page. It will answer your question about cheap alternatives. And yes, acupuncture (or other needles) WILL scratch your PF basket.


#35: Post by jevenator »

mgwolf wrote: And yes, acupuncture (or other needles) WILL scratch your PF basket.
I just looked very carefully at my 18g DE basket. There are some very surface level scratches. It's not going to affect your espresso extraction. I never "babied" it with my Londinium nor 3D printed acupuncture needle tool (4 needles)

LMWDP #643


#36: Post by Jeff »

I try to keep things in perspective. I haven't seen evidence in my baskets that the needles have done any damage or that, if they did, the damage was anything more than cosmetic. Baskets in a commercial setting are wear items.

That perspective is shaped by the cost of coffee. Some of the beans I enjoy are running $20/225 g or more. That's around $2 a shot or more. Blow 15 shots from weaker puck prep and you've paid for a new basket, not to mention skipping the frustration and disappointment of bad shots.


#37: Post by pcrussell50 »

Gonna have to go with Jeff and Jev here. While I do the bulk of my really aggressive mixing in a glass jar before depositing into the portafilter, I did dull the tip of my dissecting needle that I use to stir/level the pile once in the portafilter. And still there are so scratches on the order of Jevs. I never thought twice about it. And I think going forward, I'm still not going too.

LMWDP #553


#38: Post by lamarzoccofan92 »

Amazing discussions going on here. I have been able to play around with WDT and have been able to draw my own, albeit rudimentary, conclusion.

First of all, I experimented with a single 30g needle (with a diameter of approximately 0.3mm, so similar to an acupuncture needle I suppose) and also a piece of toy rubber toy, with 3 sewing needles sharp side into the toy (meaning the blunt rounded side stirring the coffee grounds).

First of all, both methods resulted in very very very very very little instances of channeling, virtually zero, so I am super happy I adopted the WDT in my puck preparation technique!! Obviously, the 3 needle design, also with slightly thicker needles, took less effort to stir the grounds around, the one needle (thinner) took a little bit more effort, but honestly I don't even think that's even an issue as a home barista, we talking about like 10 seconds extra. I used a toothpick before I got the needles and I noticed it caused channeling at the point where I removed the toothpick, so I would say toothpicks are definitely not an ideal tool for WDT. I'm going to move forward with the 3 needle design and I find that it works good enough, and I cannot justify paying 100AUD for the londinium tool shipped to Australia.

I definitely noticed superficial scratches on the bottom of my basket but that is not a worry at all. As with all of you, I highly doubt that would affect the functional structure of the basket at all. They feel very well made and are built to last!

One surprising thing I realised was the use of a distribution tool, the chisel designed ones by pullman, was actually counter productive, and I have noticed fair instances of channeling after "grooming" with the tool compared to just tamping it after WDT. I cannot seem to figure out why this is the case but regardless I'm just gonna retire the tool after this, since I'm producing good coffee without it anyway. It might be my technique, depth or whatever the reason and results might vary with other people, this is just what I noticed on my shots.

Again, amazing bunch amazing discussion!


#39: Post by Tzuyu »

Here is a distribution tool, y'all might consider, consistency every time. ... 3f38E3erto