Euro or US curved tamper base to fix donut channeling?

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boren

#1: Post by boren »

My main tamper is has a 58.35mm flat bottom base. It works well and I really like its self-leveling mechanism but I still sometimes get donut channeling. I normally make single shots, not sure if this would be an issue with double shot baskets, as I hardly use them (nor want to). I borrowed a curved base tamper from a friend and it seems to solve this issue, I assume because it pushes some of the coffee to the sides, blocking possible channels. I'm not sure what is the diameter of this tamper, but I think it uses US curve. Here's a picture of the base:



The basket I'm using is a Quick Mill AC0970FI1, like this one.

I need to return this tamper and am thinking of replacing my tamper's bottom with one that's 58.5mm with Euro curve. Any thoughts?

Update: I can confirm that the curved tamper base solved the problem. No more side channeling.

ojt

#2: Post by ojt »

I'm no expert and/but I use the OEM plastic tamper with my Pavoni (*) and I do not get almost any donut effect. The curve of the tamper is pretty much the same as the curve of the bottom of the baskets I have. I do not know if this just a coincidence and there is something else in my prep routine that mitigates the "issue" (is it an issue?). So I guess I'm saying there could be something to this but someone more experienced should chime in.

* Since as a minority group member I have to explain my use of the plastic tamper here's the long story short: I have found no reason to upgrade since I modified the tamper to fit perfectly in the baskets. I am intending to hold off upgrading until I find the the perfect tamper and the right time to buy it. Reg Barber would be a good example of something worthy IMO.
Osku

boren (original poster)

#3: Post by boren (original poster) »

If you don't encounter any issues there's really no need to upgrade. Just keep what works.

In my case the self-leveling tamper was an upgrade because I don't need to worry about leveling, but I'm not quite there yet if (donut) channeling still occasionally happens. That's why I'm thinking of replacing its base.

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cafeIKE
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#4: Post by cafeIKE »

I like this for singles or doubles. It's double ended and no longer available at Espresso Care.



You need a lot of coffee to use a 58mm tamper in a single basket, more like a short double that an actual single.
What do you mean by 'donut channeling'? If you get a ring around the edge which quickly fills to the center, that's normal.

boren (original poster)

#5: Post by boren (original poster) »

I'm using 11.7 gram per shot, so it's a common single for E61 machines, not so much the traditional 7 gram standard.

By donut channeling I mean either ring shaped channeling, or more commonly, small holes on the very edge of the basket.

emradguy

#6: Post by emradguy »

The fact that you only pull donuts "sometimes", indicates the problem is your distribution, not your tamper. You'll need to work harder on getting consistent spread of coffee throughout the basket. In a flat bottomed basket, circumferentially edge-to-edge even distribution is the goal but, of course, with the basket you're using it's not as simple as that. Sorry I can't help more than that, but I've never pulled a single shot in all of my 18.5 years at this craft. However, I would suggest that if you're not using WDT, it's time to start doing so. Others with experience on single shot puck building should be able to help you, and I'm sure there are threads here dedicated to that.

Ah, here's a thread on it, right on page one of this subsection...

7 gram single shot?? Mission impossible!
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cafeIKE
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#7: Post by cafeIKE »

boren wrote:By donut channeling I mean either ring shaped channeling, or more commonly, small holes on the very edge of the basket.
I may be thick, but channeling results in an excess flow in an area causing an off center cone in a BPF or a dancing flow in a spouted. If you have a ring of drops appear around perforated periphery which quickly fill to the center and the cone flow remains centered OR a few holes on the perforated periphery don't flow, it's fine.

This 41mm tamper might be better suited for singles. It also comes in an oak handle. Personally, I prefer a 38mm curved base, but there don't seem to be many single tamper makers left any more.

Reg Barber [martha@regbarber.com] might be able to spin up one up. Or most any metal shop could turn down a 58mm

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baldheadracing
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#8: Post by baldheadracing »

That kind of single basket shape can be a PITA to use. You have to adjust the dose to get sufficient bed depth at the edges - otherwise holes at the edges of the puck are pretty much going to happen. In addition, pucks made from darker roasts seem to have more integrity; lighter roasts seem to channel much more often (given that shape of basket).

I've used convex tampers and also Reg Barber's C-Flat and, while the incidence of channeling may have been slightly reduced, I still had to fine-tune the dose with every single @#$&+! bag of coffee.

While the IMS "The Single" and LM "Precision" single basket designs work better than what you have, I eventually switched to the LM Strada/VST straight-walled single basket design and Tidaka 41mm funnel and tamper. Now I never have channeling, even with 6g doses.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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Jeff
Team HB

#9: Post by Jeff »

In addition to the linked thread on "Mission Impossible", you might also want to keep your eye on the thread Jim just started, Making Single and Double Espressos that Taste the Same

boren (original poster)

#10: Post by boren (original poster) »

Thanks everyone for the helpful feedback!
emradguy wrote:The fact that you only pull donuts "sometimes", indicates the problem is your distribution, not your tamper. You'll need to work harder on getting consistent spread of coffee throughout the basket.
I don't often get channeling and I like to keep my routine simple. This means I don't do WDT nor see the reason to. All I do is spin a leveler tool twice, then tamp with a self-leveling tamper. Depending on how the coffee mound looks, I sometime start with a tap or two on the side of the portafilter. It normally works very well and my shot times are consistent. Sometimes though there are holes on the sides of the basket, and these increase the flow and reduce the quality of espresso. I believe that a curved tamper would keep my routine as simple as it is, but would practically remove the occasional side channeling. The question is which curve would work better with my Quick Mill basket - US or Euro?

I have a 7 gram basket and a 41mm tamper. They work ok, but I prefer a larger amount of coffee. 12 gram in the basket and 24 gram in the cup is what I normally want. No more, no less.
baldheadracing wrote:That kind of single basket shape can be a PITA to use. You have to adjust the dose to get sufficient bed depth at the edges - otherwise holes at the edges of the puck are pretty much going to happen. In addition, pucks made from darker roasts seem to have more integrity; lighter roasts seem to channel much more often (given that shape of basket).
Interesting. Maybe I should set my 270Wi grinder for different doses depending on the type of beans. It's normally set to 11.7 gram and I don't think there's a lot of room for more. A dose of 12 gram usually doesn't touch the shower screen when I attach the portafilter, but I like to have some space left to not have the screen "break" the puck.
cafeIKE wrote:I may be thick, but channeling results in an excess flow in an area causing an off center cone in a BPF or a dancing flow in a spouted. If you have a ring of drops appear around perforated periphery which quickly fill to the center and the cone flow remains centered OR a few holes on the perforated periphery don't flow, it's fine.
The flow is centered and usually is not accompanied by any significant spurts, but when it's quicker then normal I normally find a hole or two close to the edge of the basket. This is what I'm trying to solve.
This 41mm tamper might be better suited for singles. It also comes in an oak handle. Personally, I prefer a 38mm curved base, but there don't seem to be many single tamper makers left any more.
As I mentioned, I already have a very similar basket and tamper, but I normally prefer a larger amount of coffee.