Hi John, just discovered your channel and will be watching all your La Pavoni content! This is a gold mine of information for a Europiccola owner like me. Thank you for putting the time and effort in to share this.
John, while I was watching, I was struck by how important grouphead mass is for tempering boiler water as it enters the area around the GH sleeve. This might explain why "dry pumping" will raise GH temp, but that we need to let the dry pumping take effect and also to not overshoot the target GH temp of 85-90°C (per Bong in our FB group). Your explanation here shows how much of this tempered water is mixed with boiler water (also tempered slightly by GH mass as it makes its way to the lower chamber) to achieve the desired brew temp of 91-92°C (or at least how I imagine it in my head). It's remarkable that we get any decent shots at all. It shows why there is as much "art" in pulling a shot on a LP as there is "science." Thanks again, John.
the 2/3 ratio is why you should raise & lower the lever (less than full range) to fill complely fill the grouphead with hot water. A temp gauge (thermoplastic) will show the impact. btw, I learned this on youtube.
This is incredibly helpful. I'm trying to jerry-rig a homemade lever espresso system and this gives a lot of insight on how I could potentially do that. Thank you!
I guess you should be able to generate a model for the brew water temperature based on the boiler set-point (and hysteresis) + the real time grouphead temperature - I assume the water in the grouphead will more or less match the temperature of the grouphead (which is climbing over time).
Great video. So interesting. Presumably this does not happen with the gen 2 unless you have the isolator. Also, if you flush before a shot I guess you are replacing that cool water with boiler temp water?
> Presumably this does not happen with the gen 2 unless you have the isolator. Correct. There is no liquid water retention in the unmodified generation 2 group head. In fact, with the piston down, even the liquid water in the siphon tube drains back into the boiler. Steam then fills the upper part of the group head, the neck, the upper part of the siphon tube and the upper part of the boiler. > if you flush before a shot I guess you are replacing that cool water with boiler temp water? Exactly. Well, technically it mixes, so there is a bit of chaos going on. The practical result is that the average water temperature in the group head is to some "degree", hotter.
This is really helpful indeed! Thank you for providing all the information! I was wondering if read the model correctly in that only about 1/3rd of the double shot basket can or should be filled with coffee (post tamping)?
Personally, I find 13.5g to 14g of coffee works well on my gen3 and gen4 machines using a single lever motion. The thickness of that depends on the beans and roast level. I would guess about 12mm of height for light roasts. I hope that helps.
Hello. I love so much your vids. They are very interesting for me. Can you tell me how to avoid air in the group head? Sometimes I can extract a lot a coffee Like 40g in the cup for 20g coffee in the basket. I can feel directly the pressure on the lever. Sometimes not. I feel the pressure very low. Can you help me? Thanks a lot
Mathieu, A quick answer is that I think 20g is too much for a La Pavoni Lever Machine to brew. Consider a fine grind (on a quality grinder right before pulling the shot), of freshly roasted (~2 weeks old) 14g in the double (larger) basket, lightly tamped. Raise the lever all the way to let the water rush in. Wait about 5 seconds and then start your pull. There is a much better place to diagnose your brewing. I'd like to refer you to a very helpful group of La Pavoni owners. facebook.com/groups/lapavonienthusiastsgroup I think it is worth the trouble creating a Facebook account just for this resource.
i do not understand how you get 53 ml of water available for the shot . in my experience 10 ml stays in puck after the shot and 35 gr is max i heard of including the coffee soluble matter so it gives about total 45 ml total if you calculate the sleeve above the piston and hole volume you get 46 ml up to coffee pack. if 53 ml were available you could get more than 40 gram per shot this is not the case.
Guy, Thanks for the comment. I actually think we are in agreement that not all 53 ml goes into the cup. I just rewatched the video and found these relevant points: 3:04 - I state the portafilter holds about 10 ml of water 3:11 - I state that this plus the water below the piston gives us about 53 ml 3:25 - I state that when you pump, it is just the volume under the piston (43 ml) that gets displaced. (into the cup). This then is in line with your experience of 40g per shot. I hope you also think we agree on this now. If not, I probably am not understanding your concern and an open to more of your thoughts. The reason I spend time even talking about the 53 ml is in trying to explain that every time we pull a shot, we draw 53 ml of water from the boiler. Some of that water is mixed with the cooler water already in the group head, which makes the temperature of the water used to extract the coffee a bit cooler.
@@JohnMichaelHauck the difference in my experience with 14 grams of ground coffee after brew you get 30 grams of coffee and added 10 grams to the coffee pack so in total you have 40 grams of available water for coffee not 53 . Sure if you wait longer with lever up you can get as much as you want but brewed coffee will be something else . if i lower lever as soon as first drop falls i get 30 grams of coffee . i think in reality coffee pack is closer to shower screen . i do not think there is room for 10 ml there . it does not coincide with my findings
Guy, I just pulled a shot, with a single stroke of the lever, (no pumping), and a very tight grind (no dripping before a 9-bar pull). I removed the cup while the last few bitter drops were still falling from the portafilter (I wanted to drink it). Here is the result: IN (Ground Coffee): 15.0g OUT (Espresso): 39.3g RETAINED (Weight added to ground coffee by water): 9.9g TOTAL WATER (less bitter drips after pull): 49.2g This experiment result of 49.2g did not get to my calculations of 53g. Yet if I would have kept the last drips it would have been closer. Raw data (boring): Metal Basket Empty: 22.6g Metal Basket w/ Dry Ground Coffee: 37.6g Cup Empty: 112.9g Cup w/Espresso: 152.2g Metal Basket w/ Wet Ground Coffee: 47.5g
As for temperatures, see my reply to you in video #5 "Generation 2 Steam Heated Group Head" czcams.com/video/qQaqW0SAJjs/video.html As for volumes, the amount of water that consists of the shot should be nearly identical in all four generations of group heads. See this for comparison: #2 "Four Generations of Group Heads" czcams.com/video/ViNrag4lYJg/video.html
@@JohnMichaelHauck I loved that video and have studied it religiously, but I don't think it necessarily answers the shot volume question. To clarify, I don't just mean the shear volume of water, I mean the relative volumes of waters of different temperatures, and which flow first into the puck. Or I might just not have understood it which is entirely possible since I'm an idiot. Thanks again!
So, I guess to be clear, there is no other water in the generation 2 group head like there is in the generation 3 group head. The generation 2 is brewed directly with boiler water (say 120C) and the generation 3 is brewed with slight cooler water since it mixes with cooler water outside the sleeve before entering the brew water chamber. Please, don't stop asking - because I am suspecting I am missing a part of your question. Also, there is a lot about how these machines work that I simply don't understand - and what I do understand is likely off or oversimplified in my mind.
@@JohnMichaelHauck That actually explains it really well, I can't believe I didn't realize that. But is the water that comes into the outer sleeve area constantly recirculating or is it static until the next shot is pulled? It would also help to know the internal surface area of the outer sleeve area compared to the surface area of the inner brew chamber, because on the gen2 the brew chamber walls have a direct connection to the outside of the grouphead, thus making that surface a heatsink, whereas on the gen 3 the brewchamber walls can no longer act as a heat sink since they are also surrounded by water (I think, I'm not sure, that might depend on if that water is ever purged completely). Would the water surrounding the brew chamber walls in the gen 3 be capable of absorbing more thermal energy than the brass wall of the grouphead brewchamber in gen2? Thanks for being so patient with me, I really appreciate it!
Hi John, just discovered your channel and will be watching all your La Pavoni content! This is a gold mine of information for a Europiccola owner like me. Thank you for putting the time and effort in to share this.
John, while I was watching, I was struck by how important grouphead mass is for tempering boiler water as it enters the area around the GH sleeve. This might explain why "dry pumping" will raise GH temp, but that we need to let the dry pumping take effect and also to not overshoot the target GH temp of 85-90°C (per Bong in our FB group). Your explanation here shows how much of this tempered water is mixed with boiler water (also tempered slightly by GH mass as it makes its way to the lower chamber) to achieve the desired brew temp of 91-92°C (or at least how I imagine it in my head).
It's remarkable that we get any decent shots at all. It shows why there is as much "art" in pulling a shot on a LP as there is "science."
Thanks again, John.
the 2/3 ratio is why you should raise & lower the lever (less than full range) to fill complely fill the grouphead with hot water. A temp gauge (thermoplastic) will show the impact.
btw, I learned this on youtube.
This is incredibly helpful. I'm trying to jerry-rig a homemade lever espresso system and this gives a lot of insight on how I could potentially do that. Thank you!
Awesome!
great videos thx for your work
I guess you should be able to generate a model for the brew water temperature based on the boiler set-point (and hysteresis) + the real time grouphead temperature - I assume the water in the grouphead will more or less match the temperature of the grouphead (which is climbing over time).
Check out video #13
czcams.com/video/eQuEZDY6Awo/video.html
Here is the full list
czcams.com/play/PLPX9KWMNFMwNk_aBK7plrFBF1VJx0OMVw.html
Great video. So interesting. Presumably this does not happen with the gen 2 unless you have the isolator. Also, if you flush before a shot I guess you are replacing that cool water with boiler temp water?
> Presumably this does not happen with the gen 2 unless you have the isolator.
Correct. There is no liquid water retention in the unmodified generation 2 group head. In fact, with the piston down, even the liquid water in the siphon tube drains back into the boiler. Steam then fills the upper part of the group head, the neck, the upper part of the siphon tube and the upper part of the boiler.
> if you flush before a shot I guess you are replacing that cool water with boiler temp water?
Exactly. Well, technically it mixes, so there is a bit of chaos going on. The practical result is that the average water temperature in the group head is to some "degree", hotter.
This is really helpful indeed! Thank you for providing all the information! I was wondering if read the model correctly in that only about 1/3rd of the double shot basket can or should be filled with coffee (post tamping)?
Personally, I find 13.5g to 14g of coffee works well on my gen3 and gen4 machines using a single lever motion. The thickness of that depends on the beans and roast level. I would guess about 12mm of height for light roasts. I hope that helps.
Hello. I love so much your vids.
They are very interesting for me.
Can you tell me how to avoid air in the group head?
Sometimes I can extract a lot a coffee
Like 40g in the cup for 20g coffee in the basket. I can feel directly the pressure on the lever.
Sometimes not. I feel the pressure very low.
Can you help me? Thanks a lot
Mathieu,
A quick answer is that I think 20g is too much for a La Pavoni Lever Machine to brew. Consider a fine grind (on a quality grinder right before pulling the shot), of freshly roasted (~2 weeks old) 14g in the double (larger) basket, lightly tamped. Raise the lever all the way to let the water rush in. Wait about 5 seconds and then start your pull.
There is a much better place to diagnose your brewing. I'd like to refer you to a very helpful group of La Pavoni owners. facebook.com/groups/lapavonienthusiastsgroup
I think it is worth the trouble creating a Facebook account just for this resource.
Thanks John, amazing. Do similar principles apply with the Gen 2 -- just in different volumes?
Oh great. I see you have a model of the gen 2 also and vid, I'm checking that out.
Adam,
I put together a play list here czcams.com/play/PLPX9KWMNFMwNk_aBK7plrFBF1VJx0OMVw.html
i do not understand how you get 53 ml of water available for the shot . in my experience 10 ml stays in puck after the shot and 35 gr is max i heard of including the coffee soluble matter so it gives about total 45 ml total if you calculate the sleeve above the piston and hole volume you get 46 ml up to coffee pack. if 53 ml were available you could get more than 40 gram per shot this is not the case.
Guy,
Thanks for the comment.
I actually think we are in agreement that not all 53 ml goes into the cup. I just rewatched the video and found these relevant points:
3:04 - I state the portafilter holds about 10 ml
of water
3:11 - I state that this plus the water below the piston gives us about 53 ml
3:25 - I state that when you pump, it is just the volume under the piston (43 ml) that gets displaced. (into the cup).
This then is in line with your experience of 40g per shot.
I hope you also think we agree on this now.
If not, I probably am not understanding your concern and an open to more of your thoughts.
The reason I spend time even talking about the 53 ml is in trying to explain that every time we pull a shot, we draw 53 ml of water from the boiler. Some of that water is mixed with the cooler water already in the group head, which makes the temperature of the water used to extract the coffee a bit cooler.
@@JohnMichaelHauck the difference in my experience with 14 grams of ground coffee after brew you get 30 grams of coffee and added 10 grams to the coffee pack so in total you have 40 grams of available water for coffee not 53 . Sure if you wait longer with lever up you can get as much as you want but brewed coffee will be something else . if i lower lever as soon as first drop falls i get 30 grams of coffee . i think in reality coffee pack is closer to shower screen . i do not think there is room for 10 ml there . it does not coincide with my findings
Guy,
I just pulled a shot, with a single stroke of the lever, (no pumping), and a very tight grind (no dripping before a 9-bar pull). I removed the cup while the last few bitter drops were still falling from the portafilter (I wanted to drink it).
Here is the result:
IN (Ground Coffee): 15.0g
OUT (Espresso): 39.3g
RETAINED (Weight added to ground coffee by water): 9.9g
TOTAL WATER (less bitter drips after pull): 49.2g
This experiment result of 49.2g did not get to my calculations of 53g.
Yet if I would have kept the last drips it would have been closer.
Raw data (boring):
Metal Basket Empty: 22.6g
Metal Basket w/ Dry Ground Coffee: 37.6g
Cup Empty: 112.9g
Cup w/Espresso: 152.2g
Metal Basket w/ Wet Ground Coffee: 47.5g
How does this compare to the gen 2 in terms of volumes and temps?
As for temperatures, see my reply to you in video #5 "Generation 2 Steam Heated Group Head" czcams.com/video/qQaqW0SAJjs/video.html
As for volumes, the amount of water that consists of the shot should be nearly identical in all four generations of group heads. See this for comparison: #2 "Four Generations of Group Heads" czcams.com/video/ViNrag4lYJg/video.html
@@JohnMichaelHauck I loved that video and have studied it religiously, but I don't think it necessarily answers the shot volume question. To clarify, I don't just mean the shear volume of water, I mean the relative volumes of waters of different temperatures, and which flow first into the puck.
Or I might just not have understood it which is entirely possible since I'm an idiot.
Thanks again!
So, I guess to be clear, there is no other water in the generation 2 group head like there is in the generation 3 group head. The generation 2 is brewed directly with boiler water (say 120C) and the generation 3 is brewed with slight cooler water since it mixes with cooler water outside the sleeve before entering the brew water chamber.
Please, don't stop asking - because I am suspecting I am missing a part of your question. Also, there is a lot about how these machines work that I simply don't understand - and what I do understand is likely off or oversimplified in my mind.
@@JohnMichaelHauck That actually explains it really well, I can't believe I didn't realize that.
But is the water that comes into the outer sleeve area constantly recirculating or is it static until the next shot is pulled?
It would also help to know the internal surface area of the outer sleeve area compared to the surface area of the inner brew chamber, because on the gen2 the brew chamber walls have a direct connection to the outside of the grouphead, thus making that surface a heatsink, whereas on the gen 3 the brewchamber walls can no longer act as a heat sink since they are also surrounded by water (I think, I'm not sure, that might depend on if that water is ever purged completely). Would the water surrounding the brew chamber walls in the gen 3 be capable of absorbing more thermal energy than the brass wall of the grouphead brewchamber in gen2?
Thanks for being so patient with me, I really appreciate it!