Endo Senior Member Joined: 26 Jun 2008 Posts: 804 Location: , location, location. Expertise: I love coffee
Espresso: machine is < important than... Grinder: !
Posted Sun Nov 13, 2011, 5:53pm Subject: 67/11 Cremina Mods
Added the OE gasket rebuild kit, new 2011 vac cap, 2011 steam wand and 2011 portafilter (cut bottomess). Pretty much everything I can add and still be able to revert back to stock '77 if ever needed.
Now on to the toughest part....temperature management.
The OE temp strip turned out to be useless, since it starts at only 194FC (too high). Ideally, someone will make a sweet little stainless remote grouphead thermometer (with a removable "spring band" type attachment to the grouphead)... but until then, my yellow monster will have to do. (Note the equilibrium idle grouphead temp of 192F).
Not exactly what I'm looking for...but has anyone tried attaching a Icelsius to their machine?
Posted Sun Nov 13, 2011, 9:22pm Subject: Re: 67/11 Cremina Mods
As mentioned by Dennis in the thread, a temp strip with lower range was suggested at 60-90C range. That's because around 70c was shown to give the best brewing temp.
I am looking forward Dennis' result before deciding to get one since he already had one order in. And with Cremina, precise temperature ain't that crucial so I could still survive without one. Having one though probably would make my life more perfect. :P I hope it worked out.
The 60-90C would work only for the warm-up and first shot, after that, it would be too low a range. Although adding both the 60-90 and 90-120 would work.
Still, these strips are not precise enough for my liking as I've been trying to estimate the shot temp differential between the grouphead thermocouple shown (T1) and a DIY Cremina Scace (T2) at different warm-up times (a little like what Dennis was doing).
Not true in my experiments. I did detailed studies with espresso temperature measurements that you can read about in that thread and 90C is top of top of the range. You'd be brewing at about 205°F-210°F...
I'm using a modified Scace basket for my shot temps so I'm pretty sure of my accuracy.
My grouphead is currently stabilizing at 89C at a spot 1" up from the bottom of the grouphead and will overshoot this quite a bit during the shot itself.
If using the strips, I'd use both strips and splice them togther to get the full range.
But I've decided the large 5C increments and awkward color indication make it a very poor indicator. I'm not interested in a mood ring.
There is no huge diference where you place your strip on group head straight part above the bottom bell. Certainly there is no difference that would require getting the group up to 90C to pull shot. Not in any of my tests and I did lot of them. Unless that is, you are running your Cremina below 0.7 bars at the top of the pstat!
You need to test your brew temperatures instead. See how I did it in my thread on HB. Then and only then you could come up with conclusions regarding the group-head temperature as it relates to shot temperature. Without that its all guessing and there is no value in it...
"Ideal strip for Cremina should start at 65°C/149°F and go up to 100°C."
So which is it? 90C or 100C?
As I said, I have both group head thermocouple AND a Scace and can form my own conclusions. Personally I find the 90C +/- 5C grouphead range very useful so if I ever go back to a strip (which is unlikely), I'd splice ranges.
I know you have Scace. Did you use it to measure actual brew temperature. Not group-head temperature, but espresso brew temperature? Unless you have done that you do not know how group head temperature relates to brew temperature and I don't know what are you basing your claims on. I'd love to see your data that show how group head temperature and boiler pressure relates to brew temperature. Looking forward to it.
By design, a Scace is a brew measurement device. I also have a second thermocouple attached to the grouphead. I sometimes have access to a datalogger but unfortunately it's at work right now and I only have my cheap Chinese E-bay meter at home (with no logging capability). It does have both a T1 and T2 input as well as T1-T2 function so I was toggling between both thermocouples and lookng at differences using the T1-T2.
I have been holding off buying a dedicated datalogger since I think these things will soon become obsolete as there seem to be more and more USB thermocouple devices available with free datalogging apps I can run off my laptop. I've been looking at the Icelsius for $37 and I may try to build that into my current DIY Scace. When I do I'll post the results.
Sorry, I'd post these comments on H-B to add to the discussion, but 1st admendment rights seem to have been suspended over at H-B, at least for certain jokers like me. LOL. So I'll just post the graphs on my blog (or here) if you are interested.
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