Mod for taming the 1st gen Europiccola
-
- Posts: 376
- Joined: 9 years ago
This was originally posted in the Ultimate Europiccola thread. Initiated by drgary's suggestion, it is moved here, since it is of relevance also beyond the Ultimate EP.
Original post starts below.
------------------------------------------------------------------------------------------------------
So I meant to wait even a bit longer with this post, but as I have already mentioned I would write it, I don't feel like postponing...
I admit that this post is more about presenting the idea/concept than providing evidence for that it works.
TL;DR: Group gets hot. Plug the bridge between boiler and group to reduce heat transfer. Groups is (seems to be) less hot.
Since this post has a focus on group temperature, I will first make a small (turns out it became long...) remark on how I measure:
I have an IR thermometer with adjustable IR-emissivity setting. I measure on Scotch tape which I think someone mentioned has emissivity of 0.95. This is the level I have used for calibration of my second thermometer, but even with readings for 1.00 emissivity (which gives me a true lower bound for the real temperature) indicate overheating. I measure with the IR thermometer on the front part of the group, above the piston when not operated.
I have also attached a disassembled digital kitchen thermometer like in the enormous Europiccola thermometer thread. I have positioned the point of measurement so that it as much as possible coincides with the value of the IR thermometer in/around brewing range. A bit fuzzy explanation, but the goal was just to be able to rely on this thermometer only, since it's simpler than using the "IR pistol".
Finally, I'd like to point out that the kitchen thermometer gives (relative to the IR) reliable readings up to somewhere around 94-95°C. Beyond that it soon starts being wrong by several degrees. I can not recall ever seeing it display 99 (or even 98?), even when the IR thermometer (on the front side, which should be colder) has displayed above 100°C with 1.00 emissivity.
Temperature issues
My first and foremost goal when starting the Ultimate Eurpiccola project was to be able to turn on the machine and go for a shower in the morning. I was also hoping to make my girlfriend the milk drinks (with art) that she so much likes...
It turns out I can't do both.
I currently have my p-stat set to somewhere around 0.6 bar. Already at this level, the group heats up very fast. Too fast, at least for shaving. However, lowering the pressure would further reduce the success frequency of my latte art. The final nail in the coffin is that I have found myself operating the machine as if it were a 2-switch model, turning it on and off just to make that second shot. Disregarding convenience, I would rather have a real 2-switch version.
Similar issues were also described by the buyer of Francesco's 1st gen p-stat machine. The buyer had also bought a normal 1st gen and found it performed much better (my guess: due to temperature)
Simple mod
So, after observing that my 3rd gen seems more stable (And yes, drgary, I still remember having promised you a data-supported comparison between the "unmodded" 1st gen and the 3rd.) and after briefly trying DanoM's mod for the 2nd gen and seeing it perform even better (although compared with another thermometer unit), I wanted to know what was different to the 1st gen. My hypothesis was that there are two types of heat transfer from the boiler to the group: through condensation inside the bridge, on the back of the group as well as heat transfer through the metal in the bridge. One I could stop, the other not
By plugging the cylinder boiler-group-bridge with a heat resistant, $1 silicone plug (with a hole for the dipper tube), I'm suggesting that the exchange of steam between the two then separated volumes is decreased. (I'm guessing that shielding the group from condensation contributes to making the 3rd gen so efficient.)
The plug also has a radial cut, allowing it to be installed around the dipper tube from above (use a finger as a wedge to keep it open and, using the same finger, guide it down to the dipper tube)
This is a photo from the top of the boiler. This plug is quite long and sticks out a bit into the boiler.
When I installed it last Sunday, I left the machine on. After 30 min, I could read temperatures around 93°C (kitchen thermometer). I am quite certain this heat-up is slower than before, which suggests lower rates of heat transfer to the group. Since last Sunday, I have made my coffee directly out of the shower (+shaving) every morning.
The next morning I have time, I'll try increasing the boiler pressure.
How about a real comparison?
I'm aware I'm lacking a real comparison. Although the plug is not too difficult to put into place, a real comparison will have to wait for the next version plug.
In the current iteration, the hole for the dipper tube is anything but regular. As a result, the plug doesn't fit well and is just partially obstructing the hole, rather than plugging it. I hope that a better fitting plug would do an even better job, but unfortunately I don't know how/do not have the tools to make a good hole for the dipper tube.
The mod is simple, but I'm not sure how well I described it.
Since it's both cheap and fully reversible, I invite you all to try.
------------------------------------------------------------------------------------------------------
End of original post.
Update: This morning, I woke up early and had time to adjust the p-stat. It is not shutting off at 0.75 bar. After 15 min the group was at ~85°C.
Original post starts below.
------------------------------------------------------------------------------------------------------
So I meant to wait even a bit longer with this post, but as I have already mentioned I would write it, I don't feel like postponing...
I admit that this post is more about presenting the idea/concept than providing evidence for that it works.
TL;DR: Group gets hot. Plug the bridge between boiler and group to reduce heat transfer. Groups is (seems to be) less hot.
Since this post has a focus on group temperature, I will first make a small (turns out it became long...) remark on how I measure:
I have an IR thermometer with adjustable IR-emissivity setting. I measure on Scotch tape which I think someone mentioned has emissivity of 0.95. This is the level I have used for calibration of my second thermometer, but even with readings for 1.00 emissivity (which gives me a true lower bound for the real temperature) indicate overheating. I measure with the IR thermometer on the front part of the group, above the piston when not operated.
I have also attached a disassembled digital kitchen thermometer like in the enormous Europiccola thermometer thread. I have positioned the point of measurement so that it as much as possible coincides with the value of the IR thermometer in/around brewing range. A bit fuzzy explanation, but the goal was just to be able to rely on this thermometer only, since it's simpler than using the "IR pistol".
Finally, I'd like to point out that the kitchen thermometer gives (relative to the IR) reliable readings up to somewhere around 94-95°C. Beyond that it soon starts being wrong by several degrees. I can not recall ever seeing it display 99 (or even 98?), even when the IR thermometer (on the front side, which should be colder) has displayed above 100°C with 1.00 emissivity.
Temperature issues
My first and foremost goal when starting the Ultimate Eurpiccola project was to be able to turn on the machine and go for a shower in the morning. I was also hoping to make my girlfriend the milk drinks (with art) that she so much likes...
It turns out I can't do both.
I currently have my p-stat set to somewhere around 0.6 bar. Already at this level, the group heats up very fast. Too fast, at least for shaving. However, lowering the pressure would further reduce the success frequency of my latte art. The final nail in the coffin is that I have found myself operating the machine as if it were a 2-switch model, turning it on and off just to make that second shot. Disregarding convenience, I would rather have a real 2-switch version.
Similar issues were also described by the buyer of Francesco's 1st gen p-stat machine. The buyer had also bought a normal 1st gen and found it performed much better (my guess: due to temperature)
Simple mod
So, after observing that my 3rd gen seems more stable (And yes, drgary, I still remember having promised you a data-supported comparison between the "unmodded" 1st gen and the 3rd.) and after briefly trying DanoM's mod for the 2nd gen and seeing it perform even better (although compared with another thermometer unit), I wanted to know what was different to the 1st gen. My hypothesis was that there are two types of heat transfer from the boiler to the group: through condensation inside the bridge, on the back of the group as well as heat transfer through the metal in the bridge. One I could stop, the other not
By plugging the cylinder boiler-group-bridge with a heat resistant, $1 silicone plug (with a hole for the dipper tube), I'm suggesting that the exchange of steam between the two then separated volumes is decreased. (I'm guessing that shielding the group from condensation contributes to making the 3rd gen so efficient.)
The plug also has a radial cut, allowing it to be installed around the dipper tube from above (use a finger as a wedge to keep it open and, using the same finger, guide it down to the dipper tube)
This is a photo from the top of the boiler. This plug is quite long and sticks out a bit into the boiler.
When I installed it last Sunday, I left the machine on. After 30 min, I could read temperatures around 93°C (kitchen thermometer). I am quite certain this heat-up is slower than before, which suggests lower rates of heat transfer to the group. Since last Sunday, I have made my coffee directly out of the shower (+shaving) every morning.
The next morning I have time, I'll try increasing the boiler pressure.
How about a real comparison?
I'm aware I'm lacking a real comparison. Although the plug is not too difficult to put into place, a real comparison will have to wait for the next version plug.
In the current iteration, the hole for the dipper tube is anything but regular. As a result, the plug doesn't fit well and is just partially obstructing the hole, rather than plugging it. I hope that a better fitting plug would do an even better job, but unfortunately I don't know how/do not have the tools to make a good hole for the dipper tube.
The mod is simple, but I'm not sure how well I described it.
Since it's both cheap and fully reversible, I invite you all to try.
------------------------------------------------------------------------------------------------------
End of original post.
Update: This morning, I woke up early and had time to adjust the p-stat. It is not shutting off at 0.75 bar. After 15 min the group was at ~85°C.
- rpavlis
- Posts: 1799
- Joined: 12 years ago
I think the title was meant to be 2nd gen Europiccola? There really is no problem with 1st gen.
The second gen ones are heated mostly by STEAM transfer to the space above the piston. This heating is, however, required, without it the machine would take half an hour or more to heat. There have been a few threads in the past, if I recall correctly, about running a tube from the small hole at the top of the cylinder parallel to the dip tube, so that the space above the piston is filled with water like it is in the Cremina. Then one can control temperature by pumping the group handle bringing fresh hot water into the space with each upward movement of the piston and expelling back into the boiler with each downward one. I once considered doing this, but eventually I decided to keep a ramekin at the side of the machine and using it when it became necessary to cool it. (Simply draw the water in one filled about 3/4 of the way to the top into the group by putting it under the group and raising the handle part way.)
The second gen ones are heated mostly by STEAM transfer to the space above the piston. This heating is, however, required, without it the machine would take half an hour or more to heat. There have been a few threads in the past, if I recall correctly, about running a tube from the small hole at the top of the cylinder parallel to the dip tube, so that the space above the piston is filled with water like it is in the Cremina. Then one can control temperature by pumping the group handle bringing fresh hot water into the space with each upward movement of the piston and expelling back into the boiler with each downward one. I once considered doing this, but eventually I decided to keep a ramekin at the side of the machine and using it when it became necessary to cool it. (Simply draw the water in one filled about 3/4 of the way to the top into the group by putting it under the group and raising the handle part way.)
-
- Posts: 376
- Joined: 9 years ago
No to the first, and disagreement to the second.rpavlis wrote:I think the title was meant to be 2nd gen Europiccola? There really is no problem with 1st gen.
To me, the concept sounds more like a first gen EP than a Cremina (the difference in this context being the separation between the group and the boiler steam)rpavlis wrote:The second gen ones are heated mostly by STEAM transfer to the space above the piston. This heating is, however, required, without it the machine would take half an hour or more to heat. There have been a few threads in the past, if I recall correctly, about running a tube from the small hole at the top of the cylinder parallel to the dip tube, so that the space above the piston is filled with water like it is in the Cremina. Then one can control temperature by pumping the group handle bringing fresh hot water into the space with each upward movement of the piston and expelling back into the boiler with each downward one. I once considered doing this, but eventually I decided to keep a ramekin at the side of the machine and using it when it became necessary to cool it. (Simply draw the water in one filled about 3/4 of the way to the top into the group by putting it under the group and raising the handle part way.)
A tried and very successful alternative is described in the thread I linked in the original post.
On the one machine I tried it on, the result was a machine stabilizing at somewhere around 92°C (back of the group) at 0.8 bar boiler pressure. Both my first gens reach 100°C (front of the group) at lower pressure.
You say there is no problem.
I say there is a difference and the former is more desirable.
The main difference I see is the separation of the group and the steam. My next step is already in the post above.
- rpavlis
- Posts: 1799
- Joined: 12 years ago
For the first generation the problem of overheating from having the space above the piston constantly at boiler temperature does not apply. Indeed the heat transfer occurs from hot water being brought into the space AROUND the piston, not steam on top. I suspect one could reduce the heat transfer by filling the space between the piston walls and the group walls with something so that less hot water is in this area. That would seem difficult to do.
I have to admit that I never have any problem with my 1964 in either direction. It does not have a pressurestat, so it is always used immediately. For this one can pump the group handle up and down as soon as it is up to pressure until the temperature is right. I almost never make more than two cups. Also, the 1964 tends not to have spongy pull problems.
The 1999 is another story. Temperature needs constant attention. Care is also required to avoid spongy pulls. Still it can be mastered very well.
I have to admit that I never have any problem with my 1964 in either direction. It does not have a pressurestat, so it is always used immediately. For this one can pump the group handle up and down as soon as it is up to pressure until the temperature is right. I almost never make more than two cups. Also, the 1964 tends not to have spongy pull problems.
The 1999 is another story. Temperature needs constant attention. Care is also required to avoid spongy pulls. Still it can be mastered very well.
- drgary
- Team HB
- Posts: 14370
- Joined: 14 years ago
This first part is written about 1st gen machines that have the original heating system of a high/low element that is always on. A simple way to adjust the 1st gen machines so they don't overheat is to adjust the tension of the spring in the overpressure valve. The springs tend to get weak, so I shim them. If the spring is too strong, you could compress it or change it out. This reduces the boiler temperature and allows the machine to naturally sink heat. I like these machines to cruise at about 0.9 bar and test that with a manometer, either attached at the top of the sightglass, or where there is no sightglass access at the top in some versions, temporarily attaching a manometer to the steam wand.
When retrofitting a 1st gen machine with a pressure switch and a single element, it may still need some venting or may overheat. I like the idea proprosed above by Max and look forward to comparative measurements.
All that said, I don't think there's a single way to manage heat in a La Pavoni manual lever. Many methods are posted. The ability to increase or decrease temperature on the fly is an asset when adjusting to different coffees, sometimes in the same session.
When retrofitting a 1st gen machine with a pressure switch and a single element, it may still need some venting or may overheat. I like the idea proprosed above by Max and look forward to comparative measurements.
All that said, I don't think there's a single way to manage heat in a La Pavoni manual lever. Many methods are posted. The ability to increase or decrease temperature on the fly is an asset when adjusting to different coffees, sometimes in the same session.
Gary
LMWDP#308
What I WOULD do for a good cup of coffee!
LMWDP#308
What I WOULD do for a good cup of coffee!
-
- Posts: 376
- Joined: 9 years ago
Since the displacement of water by the piston would not change by filling that gap, I don't see how filling it would change anything.rpavlis wrote:For the first generation the problem of overheating from having the space above the piston constantly at boiler temperature does not apply. Indeed the heat transfer occurs from hot water being brought into the space AROUND the piston, not steam on top. I suspect one could reduce the heat transfer by filling the space between the piston walls and the group walls with something so that less hot water is in this area. That would seem difficult to do.
I have to admit that I never have any problem with my 1964 in either direction. It does not have a pressurestat, so it is always used immediately. For this one can pump the group handle up and down as soon as it is up to pressure until the temperature is right. I almost never make more than two cups. Also, the 1964 tends not to have spongy pull problems.
The 1999 is another story. Temperature needs constant attention. Care is also required to avoid spongy pulls. Still it can be mastered very well.
Moreover, the group eventually overheats even without touching the lever.
Therefore, what I'm suggesting is to limit the steam/condensation at the back of the group by separating the boiler volume from the inside of the "bridge".
I agree with you that next to a 2nd gen, I would never question the 1st gen. For one-off pulls it's also not of highest priority. However, from my perspective there is still room for improvement, and I have the same feeling on the machine without p-stat. This sentiment is echoed by two friends here, both comparing with their Creminas.
I am also looking forward to them, as well as the next plug version with the more regular hole.drgary wrote:I like the idea proprosed above by Max and look forward to comparative measurements.
All that said, I don't think there's a single way to manage heat in a La Pavoni manual lever. Many methods are posted. The ability to increase or decrease temperature on the fly is an asset when adjusting to different coffees, sometimes in the same session.
The two main suggestions I have received so far are to use some special "plug drill" found in chemistry workshops, or to first cool it down with liquid nitrogen and then drill with drill bit for wood. Unlike rpavlis, I don't have access to either of these, but I'm working on it
I agree that there are many methods to control temperature. Since raising it is easy with half pumps, my goal is to find an equilibrium group temperature which is lower than my lowest brewing temp. This way, I could increase it when desired, and, after each shot, it would (at least slowly) return to the good level. A positive side effect is that the machine won't overheat when being left on.
- drgary
- Team HB
- Posts: 14370
- Joined: 14 years ago
One of the easy methods if brewing a roast that needs a low temperature is toggling off. Measuring at the group, as you're doing, allows you to make adjustments. I was able to manage a 2nd gen perfectly well with multiple shots by measuring and toggling on/off. I advise against using wood as a plug inside the machine as it's a great medium for growing mold and who knows what else. It will also eventually break down and could impart nasty flavors.
Reaching the Zen Zone with a Two Switch La Pavoni
Reaching the Zen Zone with a Two Switch La Pavoni
Gary
LMWDP#308
What I WOULD do for a good cup of coffee!
LMWDP#308
What I WOULD do for a good cup of coffee!
-
- Posts: 376
- Joined: 9 years ago
I seek the convenience of not needing to toggle off, which is what I am currently doing for additional shots (the beans themselves seldom need low temps).
And I would never use wood; silicone is still the plan. What was suggested to me was to cool it down with liquid nitrogen and the use a drill bit for wood to make the appropriate hole. The other alternative was using a special drill bit for this purpose, generally found in chemistry workshops.
And I would never use wood; silicone is still the plan. What was suggested to me was to cool it down with liquid nitrogen and the use a drill bit for wood to make the appropriate hole. The other alternative was using a special drill bit for this purpose, generally found in chemistry workshops.
- drgary
- Team HB
- Posts: 14370
- Joined: 14 years ago
Ah, good idea. Sorry I didn't understand.max wrote:And I would never use wood; silicone is still the plan. What was suggested to me was to cool it down with liquid nitrogen and the use a drill bit for wood to make the appropriate hole. The other alternative was using a special drill bit for this purpose, generally found in chemistry workshops.
Gary
LMWDP#308
What I WOULD do for a good cup of coffee!
LMWDP#308
What I WOULD do for a good cup of coffee!
- crazy4espresso
- Posts: 677
- Joined: 14 years ago
I found the OPs post a bit confusing as he's mixing different generations of LPs even though the title mentions "1st gen". The early machines do NOT experience the overheating issues of the 2nd generation, unless maybe you intend to pull 8 shots in a row? I've never pulled more than 3, and really I don't believe they were meant to pull much more than that. Still if you want to leave it on while you are showering, as you say, leave it on the low element. I don't brew with the high element so I don't see the need to mess with the safety valve. The low element will not push it much past half a BAR, though I've never left it on for long periods of time, but even still the steel ball will allow some steam to escape well below the rated 1 BAR spring. I think these machines work very well in stock form, for their intended purpose, but if you're pushing limits then I suppose you could "improve" them.
"I would rather suffer with coffee than be senseless." — Napoleon Bonaparte
LMWDP #427
LMWDP #427