Sunbeam Cafe Series baskets - are they compatible with professional machines?
Are the Sunbeam Cafe Series (EM6900/6910/7000 etc) baskets compatible with any high end machines? I mean just the basket by itself - not the group handle. The reason I ask is that I have an idea of how to do a rough calibration of the pressure gauge in my EM6910 - I would measure the flow rates through the single shot DOUBLE WALL filter basket, when used with a professional machine that has an accurate pressure gauge and that also allows the brew pressure to be varied. I would do the test with the basket unloaded, so that the resistance would be a constant. (the single shot dual wall basket seems to build up a reasonable pressure even without any grinds, which is a very useful thing for this test. I assume the double shot one would too but I haven't tried it yet)
This would at least allow me to figure out roughly where the magic 9 bar pressure is on my gauge. I think it would be an easier and cheaper way to do the test, rather than actually hooking up portafilter that has been modified to accept a pressure gauge, unless anyone knows of someone in Sydney that has that kind of equipment?
If it is compatible with any high end machines, the next step is to get someone to help me do the test.
The baskets I have for the 6910 fit the alex duetto and the synesso cyncra - pretty sure they'd fit any 58 mm machine.
When I used the 6910, I spent quite a bit of time worrying about what pressure it might be producing and how that might affect the shot. After lots of stuffing around (at one point experimenting with fitting an opv - not my idea, but following the lead of another snob - have forgotten his name). The upshot was, the pressure of the two 6910s I played with were in the ballpark, and changing the pressure had almost no affect on the shot that I could detect. (In fact, the only affect was that one set-up produced sour shots because of the way the opv was fitted and the increased flow rate meant that the thermo-block couldn't keep up and the shot temp dropped.)
Although pressure does have an affect on the shot (I can detect it using the duetto), many other variables have much greater influence and these outweigh anything due to pressure in a machine like the 6910.
I don't mean any of this to stifle your experimental enthusiasm - I fully understand the desire to know as much about your machine as possible and how much fun it can be! But if you want to improve your espresso, time is better spent experimenting with dose and grind and learning how they affect flavor and pretty much ignoring the pressure gauge. Plus, you get to taste more coffee!!!
I'd have to concur with Pete.
IF (and that is a big if) you managed to determine what point on the gauge relates to 9barg, what would you do with that information to improve your coffee?
MrJack: What I would do is improve my understanding. At the moment I'm a bit puzzled, because in order to produce a 25 second shot for the double (single wall) basket), the pressure gauge has to be a fair bit higher than the centre of the recommended range. I have not yet carefully compared the taste from a fast (under 20 second) shot with the needle in the centre, to a slower shot with the needle higher, though.
I'm happy with the results I'm getting though, and I'm only using decaf at the moment too.
Anyway, knowing that the baskets are standard (that's great), I'll see if I can find someone now to do my test. Btw, thinking about it, it will probably be easier for me to determine what pressure my gauge happens to read when using the dual-wall basket(s), rather than determining the 9 bar point. If the two unloaded dual-wall baskets produce appreciably different pressures/flow-rates, I should test both on the pro machine, because having two pressure points on my gauge will be a bit better than only one.
I have successfully used the sunbeam double in a cimbali / Faema and Bezzera Galatea. Looks to be a decently made basket, should fit all 58mm groups I would say. It is a smidge smaller in capacity than my synesso double.
Or, you could dig out the pump curve, and estimate the pressure from the flowrate, which is quite easy to measure.
Originally Posted by Skip
I still don't see what action you could take to alter how you make your coffee. Without an OPV, the pour flowrate and pump pressure are strongly interdependent.
That's pressure at the pump, though, so you can't account for losses in the system between the pump and the pressure gauge.
Originally Posted by MrJack
In terms of changes to coffee... isn't the answer to make the changes you can make (dose, tamp, grind) and taste the difference? The only other thing you can do is buy a machine with an OPV.
Artman (or Pete, or anyone else): If you can, I would greatly appreciate it if you could do the following test:
1. Fit any Cafe Series DUAL-WALL(pressurised) basket to a machine that can vary the brew pressure accurately. Do not put any grinds in the basket at all.
2. Start a shot, and wait for the pressure to stabilise.
3. Once the pressure has stabilised, put a container under the portafilter and start collecting the pour, and at the same time, start a timer on a stopwatch.
4. Time how long it takes to gather 60mL.
5. If it is 16 seconds, report the brew pressure. (end of test)
6. If the time is longer than 16 seconds, empty the container, increase the brew pressure, and go to step 2.
7. If the time is shorter than 16 seconds, empty the container, reduce the brew pressure, and go to step 2.
p.s Both the single-shot and double-shot dual-wall basket produce exactly the same pressure reading on my machine.
Last edited by Skip; 2nd May 2014 at 01:00 AM.
Sorry but don't have any dual wall baskets.
I have dual wall baskets, but they're 51mm so no good for my proper machine.
What are you trying to achieve?
(also, is the flow rate of the empty single and double shot basket the same?)
Hildy: I'm trying to do a poor man's calibration of my EM6910 pressure gauge. The aforementioned test should at least give me ONE pressure value on my dial, which is better than nothing at all. (assuming the basket used on the machine used for measuring the pressure behaves the same as my basket, of course - it would be more accurate to actually give the tester my basket)
Since the pressure achieved with the empty single is the same as the double, the flow rate must also be the same, because the EM6910 does not have an over pressure valve. (I could measure it just to prove this, but I am sure what the result will be)
As a matter of courtesy, note that I have posted a request for help to do the test over here: http://coffeesnobs.com.au/brewing-eq...ure-gauge.html
Given potential hydraulic variations between machines, baskets and even the potential variation in position of the gauge connection, I can't see how this could give a more useful result than extrapolation from the pump curve (and even the value of that is questionable).
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