18. Trapped Air, Spongy Pulls, Low Shot Volume, Spongy Pulls, and The La Pavoni Sneeze.
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- čas přidán 16. 06. 2022
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An exploration of the OnShape CAD model of the La Pavoni Espresso Machines to understand the cause and effect of trapped air in the group head.
More here:
• La Pavoni Lever Espres...
Flash Vaporization Spreadsheet:
docs.google.com/spreadsheets/... - Jak na to + styl
Still improving with my Gen 3 vs Gen 2 thanks to your videos. Findings last few days:
- As stated in video one can heat up GH with pulling up and down without letting water out. Water cycles groupneckboiler. Quite effective at heating and more controllable than Gen 2 with Steam.
- I had good results with putting the PF into GH without locking and letting water in for 2 seconds and then locking all the way. Air has easy way to get out. Improved my output from 24g to 31g, which is my aim. Before I also had all this bubbly coffee at the end of shot and couldn't understand the reason (trapped air following water through coffee). Thought GH was too hot and it was the steam.
- Putting paper filter on the puck prevents the degradation and puck comes out with flat surface. Tastes better too. Only solution for Gen 2 since no 49mm puck screens in the market.
- I have 1 more solution in mind to trapped air. Unscrew the spout, lock in PF, hold the hole with finger to prevent air getting in. Needs to be tested, since currently using bottomless.
Thanks for your explanation here. It was really clear and helpful.
Really useful and helpful - thank you very much. I took mine apart for a fiddle and found nothing wrong, then after watching this realised I was probably just not allowing enough time to heat sink the head plus not pausing enough at the toop of the stroke to allow the water to fill the head. Have also tried the slight up and down movement which seems to help.
Hell yea!!! You don't post often, but when you do it's prime grade A quality! Delivering the content people need but don't deserve.
Thanks
Great explanation. It took me quite a while before I was able to consistently have no spongy pulls while achieving the temperature profile that I wanted for a particular coffee. The catch is I can only pull two shots before the extraction temperature is too high (unless I do some active cooling), but one or two shots is all I want from my Europiccola :-).
Two lattes every morning for me and my wife on ours starts our day perfectly.
Thanks for the video!
You're welcome!
Thank you for the videos :)
The ultimate solution for spongy pulls is the "Airbuster" by CoffeeSensor. I installed this on mine LP and.. no more spongy pulls with any group temperature. The leaver feels hard to push from the very high position, even with 0.8 bar boiler pressure.
Yes, the air buster works very well.
coffee-sensor.com/product/airbuster-release-valve-and-chamber-for-la-pavoni-lever-group-heads/
Wasn’t there a solution in user manual? It is recommended to release air when machine heats up via steamer…
Very informative with the cross section shown. Are these CAD drawings available to the public (probably not as I know the kind of effort that goes into it)?
Thanks. Yes it took a while to model this in CAD from scratch. The models are free for everyone to use. If you publish anything, I'd love to be credited. Here is a link to the CAD models of the history of the La Pavoni lever machines. bit.ly/LaPavoni
I am trying to understand the way the sneeze is described here. It seem so scary, dangerous, messy, something “you want to avoid” as you put it. Isn’t it intuitive to just stay on the lever and make sure everything is purged out air and water through the puck? Take out the cup when yield is reached and keep the lever down. Or isn’t it common sense to just raise the piston a bit to relieve the built pressure before removing the portafilter? I am asking because i am really curious if more people are really fallIng into these scary sneeze accidents. Also it is a manual lever machine, what is the rush to remove the pf just to make another coffee for the guests? I mean it is a manual, pour over to refill , cool down the bell kinda machine... what is another couple of seconds to wait for the pf to depressurize either by lift or by patience?
Not sure if you’ve done a video on it, but I’m having trouble in the opposite way, in that the lever wants to pull down not letting me put any pressure on it to extract the coffee. It’s like a vacuum effect. Any ideas?
Brad, check out czcams.com/video/W3_8EnN1APo/video.html
My guess is the piston has come unscrewed a bit from the shaft. I suspect this problem has slowly gotten worse as it unscrewed a bit each time.
For really good support, check out this Facebook group:
facebook.com/groups/lapavonienthusiastsgroup/?ref=share
@@JohnMichaelHauck thanks' I’ll check it out
I am having the opposite problem, my la pavoni lever is suctioning down with force? If I let go of the lever it just falls down....any idea?
Dillon, my understanding of your problem is that it occurs when you have the portafilter attached with finely ground fresh coffee grounds tamped firmly in it. You raise the lever all the way and the lever just wants to go back down. I also suspect that if you hold the lever up for a while (maybe 20 seconds), the lever will stay up and you can pull your shot just fine. If so, this indeed is a problem, and it liley that the piston has unscrewed itself a bit from the piston rod. This can be confirmed by raising the lever all the way (with no portafilter) and observing something less than a forcefull dispensing of scalding hot water. You will have noticed the time it takes for the lever to stay up has been increasing over the weeks or months. I'll call this a low water flow problem, and video 21 talks about this a bit more. czcams.com/video/W3_8EnN1APo/video.html
If on the other hand you are explaining what happens with no coffee beans (or the portafilter not attached), then what you are describing is normal. With no fresh finley ground coffee in the portafilter, the lever will always* want to force itself down. *Well, unless the machine is turned off and cooling and the anti-vacuum valve is not fitted or stuck closed, then the lever embarassingly goes up by itself.
Let me know how it goes. There could be many other issues too. I would suggest joining this Facebook group to connect with a bunch of knowledgable and helpful folks who will be more thoughtful and responsive than I can be: facebook.com/groups/lapavonienthusiastsgroup
I have a problem with coffee dripping before I pull the lever. It is a Gen 3 machine. I have an Ok grinder(silenzio) and don't have this problem on my Gen 2 Pavoni.
Coffee dripping before you pull the lever is usually a result of beans that are too old, grinding the beans too coarse, not enough ground beans in the portafilter, and (arguably) tamping too light.
The portafilter diameter on a gen 3 is slightly larger than the gen 2, so it takes a few more grams of beans to offer the same resistance. Maybe that is the difference between your two machines that you are noticing.
Another possibility could be the boiler pressure in your gen 3 is higher than your gen 2. It is the boiler pressure that is forcing the coffee extraction that starts when you raise the lever completely, but before you start pressing it down.
So, I would treat each machine separately. Start with locally roasted beans roasted less than a month ago, grind fine with a good quality grinder, use 14-16g of coffee in your portafilter, and tamp with at least a moderate amount of pressure. As for tamping, make sure the bed of coffee is level in the portafilter and that there are no air pockets.
I hope this helps.
@@JohnMichaelHauck Thanks for the reply. Enjoyed your group head explanation videos a lot. Every Pavoni user has to know this.
Does the steam return channel in the v2 group head mean spongy pulls ought not happen?
Richard, Spongey pulls happen with the v2 group head too. The steam channel in the v2 group head is positioned very high in the group head which means there is no opportunity for air trapped under the piston to be exposed to that channel. See this video: czcams.com/video/ViNrag4lYJg/video.html
Side note: The steam heating of the v2 group head means the group head runs hotter than other models - and hotter group heads result in less spongey pulls because of flash vaporization.
Side side note: Hotter group heads means more extraction of bitter flavors from the ground coffee.
@@JohnMichaelHauck thanks John, and a massive thank you for your dedication and passion for creating this project.
@@richardedwards4997 Thanks for the thanks. Don't forget, all the CAD models are freely available at bit.ly/LaPavoni
Example of the La Pavoni sneeze
images.app.goo.gl/PQ3sfHtMeubhiPUw5
images.app.goo.gl/x1h7Sv3g7SduagAp9
What about the air above the piston? Surely there's air trapped above it
There sure is, but it gets pushed back into the boiler when the piston is up. Some say you should bleed this off with the steam wand or it will cause "false pressure". I'll address it in more detail someday.
Awesome, I assumed so.
Perhaps a good preparation would be to lift the lever, and bleed with the steam wand before locking in the portafilter.
This would heat up the group and bleed the pressure in two motions.
Regardless, thanks for the reply.