Longer pre-infusion for less channeling? - Page 2

Beginner and pro baristas share tips and tricks for making espresso.
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lassepavoni (original poster)
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#11: Post by lassepavoni (original poster) »

baldheadracing wrote:To me, Europiccola implies puck screen if one wants to be consistent.
A puck screen is a thing that I have yet to try, and at the same time tried to avoid, since it is one more thing to keep clean, as I think it may easily spoil the first shot if it is not perfectly clean. Then again, I would probably clean it anyway while I hot-flush the group head to bring it up to temperature. Might as well just order one along with a new WDT tool.
baldheadracing wrote:I was going to do a "100 pulls - 100 graphs" post :lol:.
Yes, please :D
baldheadracing wrote:For pre-infusion in a Europiccola - assuming that you are using the stock pressurestat setting of 0.7bar-0.8bar, pre-infuse until first drips start, and then pull down. Pre-infusion should take less than ten seconds, and closer to five seconds.
Yes, stock pressurestat setting, but no gauge to check the actual value. I did not use a timer while pre-infusing, but I'm probably more in the range of 15 to 20 seconds before I get nervous and start to pull, but at the current grind level there a no drips at all prior to pulling the lever down.
Kaffee Bitte wrote:Getting the grinds evenly distributed prior to tamp is the most important part and the hardest to know when you got it.
Yes, that's pretty much along the line of what I think is the actual problem here. Looks like my current tool is not up to the task and pre-infusion alone cannot fix that.
Regards, Lasse
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Jeff
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#12: Post by Jeff »

I didn't expect to be saying this, but

> People have been pulling classic espresso from classic roasts without WDT or fancy tools for more than half a century.

Try less -- dose, tap or finger/knife swipe to level, tamp, go

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lassepavoni (original poster)
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#13: Post by lassepavoni (original poster) »

Been there, done that. Those couple of times that I expressly tried to not-WDT or simply tried to achieve some leveling by tapping the portafilter were all failures and not very good shots, concluding that a bad WDT is still better than no WDT at all.
After all I was surprised to learn that even some "blond gushers" (produced with WDT, that is) can actually taste pretty good. But not all do.
Regards, Lasse
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bullet08
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#14: Post by bullet08 »

WDT, distribution, and good tamping all matter, at least to me. Tamping was the big part. Used level tamper at first. But with inconsistency due to number of things like little or more dose, water volume being used by machine, pressure of the extraction.. Level tamp wasn't giving what I wanted. Just a regular manual tamper gave better shot consistently. Took some time to tamp properly, but it was worth the time spent. I'm sure with much better machine, level tamp would be great.

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mrgnomer
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#15: Post by mrgnomer »

I've just started using a puckscreen with my Europiccola. It helps to keep the puck down, I think. I lock in when the lever is up and just before water starts flowing. For dark roast a preinfusion hold and one Fellini move or so works well.

I found my Europiccola unforgiving. It needed a good puck prep for an even extraction which took me a while to get. I do think if you can pull good shots on a Europiccola you can pull good shots on anything.
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baldheadracing
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#16: Post by baldheadracing »

lassepavoni wrote:Yes, stock pressurestat setting, but no gauge to check the actual value. I did not use a timer while pre-infusing, but I'm probably more in the range of 15 to 20 seconds before I get nervous and start to pull, but at the current grind level there a no drips at all prior to pulling the lever down.
If I were you, then I'd grind probably grind coarser. If you leave the lever up for pre-infusion and start a timer, how long will it take for drops to appear? Even for lighter roasts, thirty seconds is about as long as I'd want. I believe that you said dark roasts? Dark roasts on a Europiccola I would want drops out like I said, between 5 to 10 seconds, and closer to five. If you have a bottomless portafilter, then I would want to see the whole basket surface covered at five seconds. These numbers are for a 14g dose (and weigh the dose). The point is to get a consistent result first, and then you can play.

I would also not go with a hot machine. A rule of thumb is the lighter the roast, the longer the pre-infusion (at stock pressurestat setting), and the lighter the roast, the hotter the group should be. While rules are made to be broken, again, the point is to get a consistent result first, and then you can play.

That being said, one technique for Pavoni's and dark roasts is to grind super-fine to pre-infuse for a very long time, well over a minute. Again, do not pull down the lever until drops appear.

(... and I'd advise no Fellini for the type of shots that you want to achieve.)

Good luck!
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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lassepavoni (original poster)
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#17: Post by lassepavoni (original poster) »

I have tried a lot of things already, and figured that the faster running shots, using a coarser grind, or a cold machine produce shots that are too sour for my liking. When I started out venturing into coffee territory (which is only about two years ago), I used a french press and pretty soon did all my brews with boiling water directly off the kettle :shock: . Didn't manage to produce a single brew that I would have described bitter or burnt tasting. In this regard my taste is probably a little unusual, but I know that I can produce tasty shots on the Pavoni, since that happens occasionally. And if you want to know another quirk of my coffee career: I haven't had a single espresso at a café for all my life, so I don't even know what's supposed to taste good or not :roll:

As far as technique is concerned, I am mostly with Kirk in that I also lift the lever up as far as it goes before the water starts flowing, and only then lock in the portafilter. I've done so right from the beginning when I got my Europiccola. Never tried a Fellini move though. I do weigh the beans before I put them into the grinder (on a 50g/1mg accurate scale), but not afterwards, so the final grounds in the basket only vary by the retention of the grinder and by how much I spill during puck prep. 14g is my baseline, too, but currently I am testing out 16g, which is as high as I can go without touching the shower screen.
For the next few shots I will set up a timer and let the puck soak until the first drops appear. I don't have a bottomless portafilter, but I ordered one together with a proper WDT tool and 0.2mm puck screen.
Regards, Lasse
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lassepavoni (original poster)
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#18: Post by lassepavoni (original poster) »

Science can be hard and unrelenting at times :| . Pulled four shots this morning, and not a single one was tasty.

I did everything like I do normally, except for the pre-infusion times. Used the same beans for every shot, 100% robusta about 7 weeks past roast, 16g weighed into the grinder. I set up a camera to film the shots and derived the PI time and pull time afterwards. PI time is measured from the time that the lever is fully up and water audibly rushes into the group, until the first drop lands in the cup. Mind you that I am using the standard portafilter and not a naked one, so my time might be a couple of seconds longer than the time until the first drips can be seen underneath the basket. Pull time then is the time it takes from the first drop in the cup until I stop pushing on the lever, usually as soon as the stream of coffee ceases into single drops.

Here are all the times and grind setting for all the four shots:
Shot	PI	Pull	Grind
1	114s	22s	normal
2	108s	17s	normal
3	105s	9s	coarser
4	7s	33s	normal
The first two shots were about as equal and consistent as I could do them. The PI took almost two minutes until the first drop. The pull afterwards ran much too fast, there wasn't a lot of crema, the result in the cup was pretty runny and did taste much too sour accordingly.
For the third shot I set the grinder 2/3 clicks coarser to see how that would work out. PI time wasn't much shorter (am I grinding much too fine?), but the pull afterwards literally ran through in no time. That would make me think that grinding any coarser is not the best way to go.
For the fourth shot I re-set the grinder to the finer setting that I used for the first two shots. This time I skipped the PI as much as possible, and the 7s is basically just the time that it took me to put the cup under the spout and pull the lever down to full pressure. A couple more seconds passed until the first drop landed in the cup, and the resulting pull time was much more like I am used to. Still, the last shot showed some signs of channeling again, as the stream got too blonde about halfway through and the result wasn't all that tasty.

To sum up, I would say that my puck prep still sucks, and a pre-infusion time approaching two minutes is not the panacea I am looking for.
Regards, Lasse
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PIXIllate
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#19: Post by PIXIllate »

As I said in my earlier post, if you don't get the dry grounds evenly and uniformly distributed in the basket pre tamp then you are working with a bed of coffee that has areas of greater and lesser density to begin with. No amount of PI induced swelling is going to overcome this.

I don't think PI times beyond 10-20 seconds with your setup will be helpful. And even then only with lighter roast coffees. With 100% robusta I'd use the least amount of PI time possible to avoid the inherent bitter nature of the varietal.
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baldheadracing
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#20: Post by baldheadracing »

Do you have temp strips or a grouphead temp sensor on your machine?

I would say that you are grinding way too fine, and as a result pulling down with too much force - I suspect anyone would get channeling in such a situation.

I would also suggest dropping the dose to 14g, or maybe even 12g.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada