Bad cracks and donut + channeling with Elektra Microcasa a Leva - Page 2

Beginner and pro baristas share tips and tricks.
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StefanoB (original poster)

#11: Post by StefanoB (original poster) »

Thanks you for the tip. Yes, I have already tried also to tamp harder, and also increase a bit the dose. This improved the "craking" issue, but dounuts are still here...

Thanks for the suggestion for tampers. I've had a look, they look great :-) Do you think a 49.1mm base would be enough to best seal the puck against the sides in a 49.8mm basket? I was even considering trying a 49.7mm tamper base in desperation...

I could also do both: I have read in another forum someone managed to solve a dounuting issue by tamping twice: first with a convex tamper, second with a flat. I could first tamp moderate with the 49.1mm convex, then hard with a 49.7mm flat one. But we shouldn't have to do that...
Stefano

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StefanoB (original poster)

#12: Post by StefanoB (original poster) »

baldheadracing wrote:Coincidentally, I just ordered new piston seals, shower, group gasket, etc., from espressocare.com and decided to go with the IMS shower. I'll post when I try it.
It seems you've been right on the target:

https://medium.com/@rmckeon/espresso-ma ... d7e602468d

Changing the shower screen for an IMS precision one is less expensive than a new high-end convex tamper, so I'll try that first and report :wink:
Stefano

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baldheadracing
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#13: Post by baldheadracing »

StefanoB wrote:Thanks you for the tip. Yes, I have already tried also to tamp harder, and also increase a bit the dose. This improved the "craking" issue, but dounuts are still here...

Thanks for the suggestion for tampers. I've had a look, they look great :-) Do you think a 49.1mm base would be enough to best seal the puck against the sides in a 49.8mm basket? I was even considering trying a 49.7mm tamper base in desperation...

I could also do both: I have read in another forum someone managed to solve a dounuting issue by tamping twice: first with a convex tamper, second with a flat. I could first tamp moderate with the 49.1mm convex, then hard with a 49.7mm flat one. But we shouldn't have to do that...
I've never noticed any relation between donuts happening and which tamper I was using. However, I haven't looked for a relationship, either. When I get donuts, they usually happen because my coffee has past its peak for espresso - and my solution in those cases is to add milk to mask any taste changes. However, my donuts otherwise are rare, so whatever is causing you donuts most of the time isn't the same (unless you are always using old coffee!)
StefanoB wrote:It seems you've been right on the target:

https://medium.com/@rmckeon/espresso-ma ... d7e602468d

Changing the shower screen for an IMS precision one is less expensive than a new high-end convex tamper, so I'll try that first and report :wink:
I'm not sure that I agree with everything in that article, but that's for a different day.

You can visually compare the shower of water that your machine produces to the video that I previously posted. I can almost guarantee you that if your flow looks like the video, then the shower screen is probably not the problem. (If the flow looks good but is just too fast, then lower the boiler pressure.) On the other hand, I do hope that the new shower will help you - after all, I also have the same shower screen coming from Stefano at espressocare.com 8)
What I'm interested in is my worst espresso being fantastic - James Hoffmann

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StefanoB (original poster)

#14: Post by StefanoB (original poster) »

So you are not optimistic... Anyway I have ordered the IMS shower screen that was not money-draining, so I'll see.

From a simple look, the water flow looks normal, but as it goes fast it is not easy to tell. I should do a movie but I don't have the proper equipment.

I have let the PSTAT to the factory setting, because it is a good compromise between what is needed for a good coffee and for a powerful steam. Like you my first drink in the morning is a cap, and this machine is fantastic for making milk drinks :P So I don't want to spoil that. But then, my second (and third) drinks are espressi...

What I already do: before locking the portafilter, I push down the lever right before the point where the water starts flowing. Then I lock the portafilter, and I move down the lever for just a tiny bit, so that the water flow is gentle (you can ear that). Then after a few second I move the lever all the way down, and I can ear the flow becomes faster. And this didn't solve my issues.

Anyway, a test I could do tomorrow: heat up the machine, then switch off the power button, and wait until the pressure has fallen into the 0.8 bar range to lock the portafilter and extract. This would confirm the issue does not come from a too fast water flow.

Another test I can try tomorrow for my subsequent coffee: use one of the paper filter provided with the Cafelat Robot, cut it to the correct size for the Elektra's basket, and put it on the top of the puck. If doing so I get rid of these dounuts, that would imply that the issue is certainly coming from water distribution from the shower screen.

I'll report on these tests.

Thanks for helping and for your suggestions. :D
Stefano

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StefanoB (original poster)

#15: Post by StefanoB (original poster) »

Test carried out this morning.

I have put one of the aeropress-type paper filters supplied with the Cafelat Robot (slightly cut on the edges so that it fits) above my grind cake in the filter.

Second modification of my routine: as I realized that I had forgotten to wet the paper filter (without wetting it cannot properly settle on the coffee cake), I poured 2 small teaspoons of hot water on it, which allowed the filter to stick well on the cake, but also led to wetting the cake itself and thus to a first long passive pre-infusion of the cake.

Rest of the puck preparation unchanged.

On arrival: the "dounuting" appeared but only very briefly, a clear progress! :D

At the end, under the paper filter, the cake is absolutely nickel: a nice smooth and uniform cake (I'll take a picture next time). Never had such a nice looking cake so far.

Conclusion: it would seem that the problem indeed comes from the shower screen after all (or water distribution in any case)! I can't wait to see if the IMS precision shower screen I have just ordered would fix my issues.

However, some additional tests await me: the flow of coffee out was faster (due to the long passive pre-infusion I imagine), so I will take another coffee later today by adjusting to a 1/2 click finer my C40 grinder (with Redclix).

And tomorrow, I will try to simply wet the paper filter (necessary to position it correctly) but without wetting the cake this time, see how things goes.

Let me know if you have some remarks / other suggestions.

Even if the IMS shower screen does not solve all the issues by itself, now I anyway have a solution at hand with this paper filter stuff. :)
Stefano

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StefanoB (original poster)

#16: Post by StefanoB (original poster) »

I think I got excited too quickly ...

I made another coffee by tightening the grinder, it goes more slowly (adequate flow with the tiny mouse-tail), and now my usual donut resurfaces ... Sniff ... :(

Earlier the donut went quickly because the flow was too fast...

So a priori it is not the handshower that is in question ...

Below is an image of the cake removed less than 2' after extraction (extraction done with the filter paper and wet bed, filter paper removed for the photo): it is pretty, but I have the impression that it is not sealed well at the ends, is it?


Stefano

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StefanoB (original poster)

#17: Post by StefanoB (original poster) »

After yesterday's tests I have ordered a 49.7mm base size tamper (for 49.8mm filter) with a "double flat" base (eazytamp 5 stars pro). I think the "double flat" base should help even better than a convex tamper to push some grinds on the sides of the basket and seal the grind cake well. I might combine that with a second tamp using my current flat base tamper, to finally achieve a fully flat base. I'll try single and double tamps and see how it goes.

In the mean time,I have tested nutation this morning and it seems to have improved things a bit. Still my donut at the beginning of extraction, but it stays for a shorter time. Two coffees this morning without the paper filter, the coffee puck looks nice (not like in the photos I have posted in the beginning of this thread), result in the cup tasted good (not anymore this unpleasant "channeling" aftertaste). So I will continue in this way training my nutation technique, see how it goes.

I also expect to receive IMS precision handshower next Monday a priori, when tested I'll then report on that.
Stefano

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baldheadracing
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#18: Post by baldheadracing »

baldheadracing wrote:Coincidentally, I just ordered new piston seals, shower, group gasket, etc., from espressocare.com and decided to go with the IMS shower. I'll post when I try it. (I'm not expecting anything over a good version of the stock shower screen.)
...
Just to follow up, I tried the IMS shower screen - it is actually for a La Pavoni - and it shows an improvement in evenness of unrestricted flow over my old shower screens. Unfortunately, the force of the flow blasts a huge crater in the middle of the puck with some coffees.
StefanoB wrote:... (I prepare the puck directly on the basket, the pf is on the group head heating in the meantime) ...
Please try leaving the basket in the portafilter for the whole process.
What I'm interested in is my worst espresso being fantastic - James Hoffmann

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StefanoB (original poster)

#19: Post by StefanoB (original poster) »

I have also seen marked improvements when moving to IMS shower screen. I have not any issue any more.

About the force of the flow: I had the same issue as you. So now I use the following strategy: before engaging the puck I move the lever down just to the point before the water starts to flow, I engage, and then just move the lever slightly down so that the flow starts but remains moderate, let it flow for a few seconds, and then I move the lever completely down slowly.
Stefano