10: Bong's Isolator - A Modification to Keep Group Heads Cooler - La Pavoni Espresso Machine
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- čas přidán 28. 08. 2024
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An exploration of the OnShape CAD model of the La Pavoni Espresso Machine to see how Bong's Isolator works to keep the group head cooler in machines built since about 1975.
More here:
• La Pavoni Lever Espres...
You had me at "Bong"
Hi, in my case i have a Elektra with that problem to much temperature in the brew group and i find on the internet one seal similiar of this to Pavoni and it´s result good! yes
With respect to needing a new siphon tube, I did not communicate the issue clearly in the video. The isolator will work with any existing unmodified siphon tube. It does not replace the siphon tube. The concern I tried to raise in the video is for people who cut a notch in their siphon tubes (for a different kind of modification). Those people will need to get a new siphon tube to use the isolator. I hope this clears up the confusion I caused.
Nice video, fun and informative, superbly done
I think, if the room behind the isolator is flushed, then there always are air in there, so the pressure from out coming water is not the same as if the siphon is direct connected to the group, and its more steamy. With the traditional tempMod with a hole in the siphon a bit more water comes out and more important the water behind the isolator is not totally changed with new hot water, so the temperature is more stable... or what you guys think?
Btw. The direct metal contact group head and boiler is for the temperature stability not so relevant, I just tested with Teflon gaskets, maybe 5% less agile temperature behavior
Why isn't there something like this for the Olympia Cremina? It would be great if someone would invent temperature stability for the Cemina's grouphead.
on the gen 2, does the isolator eliminate the need to purge the air build up above the piston? the "false pressure" problem so to speak.
i have learnt so much about my la pav from your videos, they are so informative. thank you so much for the work you've put in.
David,
Most of the discussions I have seen where the term "false pressure" is discussed is at www.home-barista.com/levers/ There the concern is for air trapped in the BOILER. Any air in the boiler can contribute to the temperature of the water being too cold in the boiler. Opening up the steam tap for a second or two should clear this out. The latest generation of pressure release valves actually does this automatically. You can hear it click closed after the boiler starts generating steam and most of the air is out. Still, it does not hurt to open the steam valve once the boiler is up to pressure. Then let the boiler rebuild pressure before proceeding. The BongIsolator has very little impact on this.
The BongIsolator on the generation 2 machines makes them behave much more like a generation 3 group head. I believe that in this configuration air can be trapped in the group head and the only way to purge that is to raise the lever all the way for a brief period. This trapped air is not so much of an issue on an unmodified generation 2 group head. However, this trapped air is not usually what is meant when we speak of false pressure. Instead, this trapped air often is covered under the topic of "short shots" and "spongy pulls".
To collaborate with people that have these and alternative views, I would suggest plugging in to this friendly group: facebook.com/groups/lapavonienthusiastsgroup
@@JohnMichaelHauck
Yeah, so i'd been reading up in these spongy shots. Like you say steam wand open and lift the lever, absolutely amazing the difference it makes. Thanks so much for the feedback. Really informative. Hopefully I'll learn more tricks as time goes on.
Hi, in Bong's video, I noticed his portafilter basket handle had small metal retaining bracket to keep the portafilter in when he banged out the used puck. Any idea where I could get one? Also, can you explain why he is spritzing the group head between shots? Is he cooling it down? Excellent video whcih explains the function and design of the thermal insulator.
@@JohnMichaelHauck Ah, that makes sense, though I am too much of a primitive to do that myself. I will and yes, he seems like a nice person. Thank you for the advice.
Where do I get my hands on one of these isolators?
coffee-sensor.com/product/bong-isolator-and-water-heated-grouphead-mod-for-la-pavoni/
seriously, do you have ant temp numbers before and after the mod?
Hi, I have a generation 2 Europiccola (year 2000). I only every brew light roasted bean. I am experiencing issues with my grouphead overheating very soon after the first shot. I try to brew around 93C and wanted to ask whether Bong's Isolator would enable me to still heat the Groupheat to 93C and then optain continues shot at this temperature without the need to switch the machine off to cool. I ask this as most comments online suggest that Bong's isolator enables them to keep the group at 83C and I need it to be 93C. Thanks so much for any advise Jim
Jim, sorry for the delay. I do not know the answer to your question. You can ask Bong directly though. You can find him here:
facebook.com/groups/lapavonienthusiastsgroup
I will leave my comment here for a faster search later.
Can you help me identify mine? It has the larger copper tank, gold plated base, green turn on switch, pressure gauge, wooden knob, handle and cap. It says professional under base but I don't know what year it was made.
For questions like these, I would like to refer you to this excellent source:
www.francescoceccarelli.eu/lapavoni_pr_eng.htm
Whats your opinion On patina? Keep or polish her? I have a little rust spot in my drip tray, how can I fix that, or is it possible to get a new base? Is there anyone who can refurbish to make it look brand new?
For questions like these, I would like to refer you to three excellent sources:
www.francescoceccarelli.eu/lapavoni_schemi_eng.htm
www.home-barista.com/levers/
I am confused, I thought the head had to be hot to get the best performance? That's why we get a temperature strip to be able to check.
Akaroa, well, the group head should not be too cold and not too hot.
If the group head is too cold: You may have overly acidic coffee, weak coffee (low extraction), low shot volume, spongy feeling pull, and danger of a la Pavoni sneeze if you remove the portafilter too soon.
If the group head is too hot: You may have overly bitter coffee, strong coffee (high extraction), and a lot of resistance to the pull.
It is fun to experiment with different temperatures of the group head and compare the taste to see what you enjoy.
@@JohnMichaelHauck Cheers John.
This might be a silly question but do you end up with a load of stagnant water between the isolator and group head with the isolator? Also I wonder does the isolator remove the issue of air in the group head which is a problem on generation 2?
Alex,
These are difficult questions to be sure.
>> do you end up with a load of stagnant water between the isolator and group head with the isolator?
The neck (between the boiler and group head) is filled with hot water (and likely a bit of air). This water cools slightly as it is somewhat insulated from the boiler. When a shot is pulled, this cooler water mixes with the hotter incoming boiler water to provide a cooler shot. A cooler shot extracts less off-flavors from the coffee grounds, which is good. Because of the mixing, I would not call this water stagnant. You can see this in the 13th video where I modeled the water flow in a computer simulator: czcams.com/video/eQuEZDY6Awo/video.html
>> Also I wonder does the isolator remove the issue of air in the group head which is a problem on generation 2
Air can be trapped in three places in the generation 2 group head with the Bong isolator:
1) In the neck
2) Above the piston
3) Below the piston
I think the first two can be purged by raising the lever with an empty portafilter (or no portafilter). The violent steam and hot water should push the air out.
The third comes when you raise the piston to pull a shot - air enters under the piston through the coffee grounds to fill the vacuum created. There is a hole in the cylinder, near the top that lets water in. When you raise the piston above that hole, water rushes into the area under the piston. A lot of air gets pushed back out through the coffee grounds, but not all of it. This remaining air then is compressible and makes your shot feel spongy. That is, if you let go of the lever halfway through pulling the shot, the lever will go back up a bit - like a spring. The spongier the feel, the more air there is, and the less water there is, which is less volume in your cup, which is not the most pleasant flavor.
OK, so how do you get rid of that air?
If the first few drops of water entering the area under the piston are hot enough, they will flash vaporize into steam. This violent steam then pushes the air out more effectively than just water. This is why I ensure the group head is hot enough before pulling a shot. The steam condenses back to water so then there is just water.
The Bong Isolator does an effective job of keeping the shot water temperature cool enough to avoid extracting off-flavors. This, however, comes at the expense of water that may not be hot enough to create flash steam to avoid a spongy shot with a low volume extraction and the resulting unpleasant flavor.
I hope this helps.
I think it would be good to hear the thoughts of others at these more lively communities:
facebook.com/groups/lapavonienthusiastsgroup
www.home-barista.com/levers/
@@JohnMichaelHauck a really detailed and interesting reply, thank you. I had not really considered the role of the air under the piston in creating a spongy pull.
@@JohnMichaelHauck that's the clerset explanation of the problem and its relation to the isolator I've read to date. So how do you avoid spongy shots with the isolator?
@@jonathansahar2772 I think by and large you will have to put up with spongy shots with the isolator. It's not a horrible problem to have if the isolator cools the brew water to the point that you have great tasting espresso (according to your taste buds).
Yet, you can "throw money" at the problem and get the "air buster" (which requires the "pressure profiling kit"). This will for sure solve the problem. In fact, the air buster was designed in direct response to the more spongy pull "created" by the isolator.
Of course, now it is starting to sound like I am recommending all these product ad-ons for your La Pavoni. I am not recommending anything, I am simply trying to educate. Just so everyone is clear, I do not profit from the sale of these products.
I hope that helps.
@@JohnMichaelHauck thank you! I think I've thrown enough money at the problem for now 😅
I've just seen another video of yours, and that made me realize that it's not actually a solvable problem (barring more modifications) - cooling down the grouphead in order not to over-exract the coffee actually entails a spongier pull due to less flash steam being created. So I guess I'll have to live with the sponginess.. do you do a Fellini to compensate for the lower volume?
After I did this mod I started getting "short shots" what happened?
It could be that the cooler group head is now retaining more air under the piston.
This video is my attempt at explaining it: czcams.com/video/w2pORowl7r4/video.html
For more perspectives, reach out to a hoard of helpful folks (including Tudor and Bong) here: facebook.com/groups/lapavonienthusiastsgroup
@John Michael Hauck that makes sense thank you John
And make sure the siphon tube is not cracked or leaking where is screws in.
And make sure the piston rod is screwed all the way into the piston.
@John Michael Hauck I just found out about dry pumping so you were right that solved the issue. I'm only 2 weeks in with this pre millennium so I'm still learning.
@@DQridesbikes The learning never ends! Enjoy the trip.