New victim for measuring piston pressure: the BOSCO group - Page 2

A haven dedicated to manual espresso machine aficionados.
User avatar
naked-portafilter (original poster)
Posts: 698
Joined: 10 years ago

#11: Post by naked-portafilter (original poster) »

mivanitsky wrote: I assume that this proposed version would work on the Londinium R as well... Am I correct?
I think so. But I'll check that with [anonymized] if we have our first proto type.

User avatar
JohnB.
Supporter ♡
Posts: 6579
Joined: 16 years ago

#12: Post by JohnB. »

naked-portfilter wrote:Don't be that sensitive, pls! I think these kind of discussions can reveal a lot for less experienced users.



Of course I know. If you sometimes (all the times) hold back the lever of your Bosco, which means you manipulate the pressure, you do sg similar as with a manual lever.
A) After a couple of pulls with a MANUAL LEVER you know exactly what's going on and the piston pressure kits are "about as usefull as tits on a bull".
B) this kit could be just as useful for spring lever as for manual levers.

But I vote for option

C) It's all about personal preferences/taste.

It's optional and any time reversible.

I'd be happy to read more of your comments, John.
Ok, since I disagree with several of your points I'll jump back in. :lol:

When you manipulate a manual lever you control the applied pressure completely unlike a spring lever where you are only able to lightly tweak the pressure profile set by the spring rate. It's quite easy to apply way too much pressure or not nearly enough with a manual lever especially if you aren't using it everyday. The spring lever is pretty much foolproof but it's helps to sometimes assist the spring if your grind was a little too fine.

The only time I hold back the lever on my Bosco is when I want to preinfuse at higher then boiler pressure. This is done by holding the lever right at the point of spring engagement. The previously mentioned tests with my pressure rig showed a 2.5-3 bar pressure everytime so I don't need to see it with each shot as it isn't going to change.

Your gauge kit on my Cremina allows me to mimic the spring lever profile or try others if I chose. The profile of the spring lever is set by boiler pressure/line pressure & the spring rate. In the case of my Sorrento I consider it pretty much perfection so I don't mess with it often. With your dual spring set up I can understand why you'd be regularly trying to change (improve?) the profile.

I do agree that it is all about personal taste & preferences. I'm sure that if you come up with a kit you won't have trouble finding customers.
LMWDP 267

User avatar
naked-portafilter (original poster)
Posts: 698
Joined: 10 years ago

#13: Post by naked-portafilter (original poster) »

JohnB. wrote:Ok, since I disagree with several of your points I'll jump back in. :lol:
Great :-)
JohnB. wrote: If you manipulate a manual lever you control the applied pressure completely unlike a spring lever where you are only able to lightly tweak the pressure profile set by the spring rate.
Lightly? I'm able completely change the spring profile (even one handed). And I bet you are able too.
JohnB. wrote:The spring lever is pretty much foolproof but it's helps to sometimes assist the spring if your grind was a little too fine.
sono d'accordo
JohnB. wrote: only time I hold back the lever on my Bosco is when I want to preinfuse at higher then boiler pressure. This is done by holding the lever right at the point of spring engagement.
I do the same.
JohnB. wrote:Your gauge kit on my Cremina allows me to mimic the spring lever profile or try others if I chose. The profile of the spring lever is set by boiler pressure/line pressure & the spring rate. In the case of my Sorrento I consider it pretty much perfection so I don't mess with it often.
JohnB. wrote:With your dual spring set up I can understand why you'd be regularly trying to change (improve?) the profile.
:-). The Pro800 is in the roastery. Is way too big for our kitchen. On daily basis I use the Cremina and recently the CT1
JohnB. wrote: do agree that it is all about personal taste & preferences. I'm sure that if you come up with a kit you won't have trouble finding customers.
John, it's not about "finding costumers". It' about the challenge. If it was all about finding customers I wouldn't have wasted any time with the Strietman and let wait the orders for the Cremina and Pavoni versions months long. I don't see an interesting market potential for this kit in the Bosco group segment. Making a proto type is easy. To make it work as an easy to install product is hell lot of work.

Ellejaycafe
Posts: 644
Joined: 9 years ago

#14: Post by Ellejaycafe »

For someone like me who is using these groups commercially, back to back, knowing exactly what pressure my second stage preinfusion is for lighter roast would take the guess work out and let me focus on customers. Just knowing exactly what's going on every single shot would give me peace of mind, and would make things A LOT easier for my business partner, my wife, to pull shots on the lever. She isn't as "obsessed" as me so having a gauge would let her know she's doing things right. Plus I think it would look cool as hell!
LMWDP #544

desmodici
Posts: 256
Joined: 11 years ago

#15: Post by desmodici »

JohnB. wrote:Best thing you could do for that 800 is toss the inner spring in a drawer & put it back together. Of course that's just my opinion.
John, could you tell me more about your recommendation to remove the inner spring? I know the Strega and 800 have double springs, my LR has a single spring. What's your experience on double vs single?

Thanks in advance

User avatar
Almico
Posts: 3612
Joined: 10 years ago

#16: Post by Almico »

I'm with William on this. I'm about to start a coffee bar using a 3gr Victoria Arduino Athena. I love making coffee, just not sure I'll love it as much doing it non-stop for 10 hours a day! Any extra data I can collect can only help me train employees much quicker. I'm in for 3. Wait...1 more for the Londinium at home.

User avatar
JohnB.
Supporter ♡
Posts: 6579
Joined: 16 years ago

#17: Post by JohnB. »

naked-portfilter wrote: I don't see an interesting market potential for this kit in the Bosco group segment. Making a proto type is easy. To make it work as an easy to install product is hell lot of work.
Your time might be better spent developing a kit for the Strega models that fill the group via pump. Those guys have been dreaming about a group pressure gauge ever since the Strega came out. I know as I used to be one of them. You can fill the Strega group anywhere between 2-11 bar with the pump but it's all guess work. A gauge would be useful on that spring lever.
LMWDP 267

User avatar
JohnB.
Supporter ♡
Posts: 6579
Joined: 16 years ago

#18: Post by JohnB. »

desmodici wrote:John, could you tell me more about your recommendation to remove the inner spring? I know the Strega and 800 have double springs, my LR has a single spring. What's your experience on double vs single?

Thanks in advance
My only direct experience with the dual spring set up was with my Strega. Even with the mods I did to allow the group to fill at pressure as low as 2 bar I always found the flavors sharper/harsher then I was happy with. From reading the posts from Salvatore & Pro 800 owners it would seem that the large group dual spring set up can yield peak pressures up around 11+ bar. That's just too damn high. I don't run my pump machine over 8.5-8.75 bar anymore as the shots just taste better then they do at higher settings (imo).

The single spring that Bosco uses gives a peak pressure of just over 8 bar dropping slowly to 6 bar by the time the shot is cut. This is a classic spring lever profile for a good reason. It produces delicious shots. Roberta Bosco told me that they had experimented with using an inner spring a few years ago. It was lighter gauge then the inner spring that comes in the standard group but they switched back after less then 2 months as they felt that the shots were just not as good.
LMWDP 267

randyh
Posts: 267
Joined: 8 years ago

#19: Post by randyh »

Here's a vid showing the pressure profile of the Pro 800 using what looks like the Scace 2 device:

http://www.youtube.com/watch?v=QB-6DgldRnM

1 bar preinfusion (boiler pressure), then Utilizing the "hold back the lever" technique to get that 2-4 bar second stage pre-infusion. Looks like the pressure peaks at just over 9 bar for a second, then slowly drops. Not sure how much of a difference in the cup there is between 8 bar and 9 bar peak.

mathof
Posts: 1474
Joined: 13 years ago

#20: Post by mathof »

JohnB. wrote:My only direct experience with the dual spring set up was with my Strega. Even with the mods I did to allow the group to fill at pressure as low as 2 bar I always found the flavors sharper/harsher then I was happy with. From reading the posts from Salvatore & Pro 800 owners it would seem that the large group dual spring set up can yield peak pressures up around 11+ bar. That's just too damn high. I don't run my pump machine over 8.5-8.75 bar anymore as the shots just taste better then they do at higher settings (imo).

The single spring that Bosco uses gives a peak pressure of just over 8 bar dropping slowly to 6 bar by the time the shot is cut. This is a classic spring lever profile for a good reason. It produces delicious shots. Roberta Bosco told me that they had experimented with using an inner spring a few years ago. It was lighter gauge then the inner spring that comes in the standard group but they switched back after less then 2 months as they felt that the shots were just not as good.
During the development phase of the Londinium, Reiss experimented with double-spring setups. He reached the same conclusion as you and Bosco.

Matt