Olympia Cremina Temperature Study, Part 1 - Page 2
- michaelbenis
- Posts: 1517
- Joined: 15 years ago
Reiss of Londinium is absolutely right there in my experience. Flushing water through the Cremina is much less effective when you want to get the grouphead up to temperature either first thing or after the machine has been left idle for a while, especially in cold weather. The mechanics of this are explained nicely with a diagram here Olympia Cremina 2002: The evolution of design in Steve Robinson's excellent write up of the 2002 millenium and its predecessor.
Nice work, Dennis, in particular to have some figures confirming the Cremina really is an all-day-on machine.
Nice work, Dennis, in particular to have some figures confirming the Cremina really is an all-day-on machine.
LMWDP No. 237
- orphanespresso
- Sponsor
- Posts: 1843
- Joined: 16 years ago
Dennis...KUDOS on your work here. I do appreciate that you have asked specific questions oriented to your own user experience and gone about answering them. Very clearly presented and documented. Thank you very much!
As for the design differences of the new and older machines...perhaps covered elsewhere, but the reworking of the group to boiler seal is one main change and perhaps one that can be adapted to the older machines as well. The new group uses a full flange thick seal between the group and the boiler, much like the gasket on a commercial machine. This part could possibly be die cut from teflon sheet. The Olympia OEM part here is an open cell type white foam material rather than teflon but a thermal break here could bring the older machines more into line with the results you are getting....particularly the walk up and pull result...which is most interesting.
You did not mention that you broke your Mater pstat during this experiment....hope the new one gets things back in service so you can keep working on these temp experiments....why Olympia would go to the trouble of removing the pstat set screw and adding thread lock is beyond me!
Brilliant work.
As for the design differences of the new and older machines...perhaps covered elsewhere, but the reworking of the group to boiler seal is one main change and perhaps one that can be adapted to the older machines as well. The new group uses a full flange thick seal between the group and the boiler, much like the gasket on a commercial machine. This part could possibly be die cut from teflon sheet. The Olympia OEM part here is an open cell type white foam material rather than teflon but a thermal break here could bring the older machines more into line with the results you are getting....particularly the walk up and pull result...which is most interesting.
You did not mention that you broke your Mater pstat during this experiment....hope the new one gets things back in service so you can keep working on these temp experiments....why Olympia would go to the trouble of removing the pstat set screw and adding thread lock is beyond me!
Brilliant work.
Doug Garrott
www.orphanespresso.com
www.orphanespresso.com
- erics
- Supporter ★
- Posts: 6302
- Joined: 19 years ago
Sure, no charge , especially for all the work you did in creating this study - http://www.omega.com/ppt/pptsc.asp?ref= ... Nav=temf01If anyone knows where to get such strip please let me know.
The part number for your desired range would be RLC-50-60/90-10 .
- peacecup
- Posts: 3649
- Joined: 19 years ago
Leaving the machine on all day is not the problem - the group can dissipate the small amount of heat tranferred from the boiler when not in use. The tests demonstrate that the Cremina, like other home levers, overheats when multiple shots are pulled in succession. Overheating, and general temperature management when pulling multiple shots is THE major issue with any pressurized home levers.
They also show that by the time the group gets to 90C when the temp strip lights up, its more or less too hot to brew with. I have the same issue with the Sama. In fact, the group never gets hot enough to even show 90C. But since I like to brew at 90C, its obvious that the group needs to be be much cooler than that to act as a heat sink for the boiler water.
These tests are done with a relatively low p-stat setting - how is the milk steaming with the Cremina at this setting?
PC
They also show that by the time the group gets to 90C when the temp strip lights up, its more or less too hot to brew with. I have the same issue with the Sama. In fact, the group never gets hot enough to even show 90C. But since I like to brew at 90C, its obvious that the group needs to be be much cooler than that to act as a heat sink for the boiler water.
These tests are done with a relatively low p-stat setting - how is the milk steaming with the Cremina at this setting?
PC
LMWDP #049
Hand-ground, hand-pulled: "hands down.."
Hand-ground, hand-pulled: "hands down.."
- tekomino (original poster)
- Posts: 1105
- Joined: 14 years ago
Yes, indeed. As long as I manage temperature so I hoover around 199°F +/- 2-3°F its good. But here is kicker really that has be surprised, for some coffee which were lightly roasted I had some killer shots when first bar was in blue so they were brewed way too hot at about 208°F. They did not taste burnt at all. That little nugget has me stumped.farmroast wrote: ps. were the best shots in the basket temp. range you expected?
- tekomino (original poster)
- Posts: 1105
- Joined: 14 years ago
Its 2011.summer wrote: Just for reference Dennis, is your Cremina a 2011?
- tekomino (original poster)
- Posts: 1105
- Joined: 14 years ago
Thank you Doug. You and Barb rock and I'll have something for you guys in the mailorphanespresso wrote: You did not mention that you broke your Mater pstat during this experiment....hope the new one gets things back in service so you can keep working on these temp experiments....why Olympia would go to the trouble of removing the pstat set screw and adding thread lock is beyond me!
- tekomino (original poster)
- Posts: 1105
- Joined: 14 years ago
Wow, Eric comes to save the day. Thank you so much Eric. You are THE master of Omega site. Not in million years would I have found that. Ordered!erics wrote:Sure, no charge , especially for all the work you did in creating this study - http://www.omega.com/ppt/pptsc.asp?ref= ... Nav=temf01
The part number for your desired range would be RLC-50-60/90-10 .
Now I am excited to do another round of tests with these new strips so I can devise good method that we can use to pull shots at right temp range. Thanks again Eric.
- tekomino (original poster)
- Posts: 1105
- Joined: 14 years ago
I observed exactly same with PVL I had. I think PVL and Sama work little differently. The group might be more massive?peacecup wrote: They also show that by the time the group gets to 90C when the temp strip lights up, its more or less too hot to brew with. I have the same issue with the Sama. In fact, the group never gets hot enough to even show 90C. But since I like to brew at 90C, its obvious that the group needs to be be much cooler than that to act as a heat sink for the boiler water.
So mine hovers at 0.75-0.9 bars. Steams fantastic.peacecup wrote: These tests are done with a relatively low p-stat setting - how is the milk steaming with the Cremina at this setting?
- peacecup
- Posts: 3649
- Joined: 19 years ago
The 60-90 strips indeed look very promising. I'm going to need some of those also.
PC
PC
LMWDP #049
Hand-ground, hand-pulled: "hands down.."
Hand-ground, hand-pulled: "hands down.."