Have both an Expobar Brewtus and a Scace device? May I interest you in a simple experiment?
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cgfan
- Posts: 38
- Joined: 17 years ago
From time to time, particularly when trying to dial in some beans that seems to be happier with higher brew temps, I seem to run into a problem whereby any attempts to increase the brew boiler temps after a certain point does not give me any perceptible changes in the cup. This, even though I am very used to easily tasting cup differences with a 1 degree C change (the smallest change my Brewtus 1 can do) and always have wished that I can make 1 degree F changes...
So it occurred to me that if the water were at any point in the brewpath to lose pressure, then the water would instantly lose its heat and any setting which relied on getting the brew boiler temps above 100 degrees C may indeed be wasted. Note that the brew boiler temps should reach a target of the front panel temp + any programmed offset (C0) in the Brewtus controller.
In brief, I conducted a series of tests at the 5 mm bolt in the brewhead where from a set front panel temp of 96 degrees and a varying programmed offset (C0) of -1 to -9 degrees (i.e. target brew boiler temps from 97 to 105 degrees C) that any offsets from -4 to -9 failed to make any difference in the measured water temperatures.
If I could there'd be one thing that I'd change with how I ran the experiment, and that is with the 5 mm bolt in place and all efforts done to ensure that it simulates as much as possible a loaded puck in the portafilter as well, with all temperature measurements taken right at the puck itself.
This is something that one can easily do with a Scace device, and if I had one I wouldn't be making this request.
So if you're at all interested, all I ask is for a series of measurements as follows:
BTW here are the results of my original tests:
So it occurred to me that if the water were at any point in the brewpath to lose pressure, then the water would instantly lose its heat and any setting which relied on getting the brew boiler temps above 100 degrees C may indeed be wasted. Note that the brew boiler temps should reach a target of the front panel temp + any programmed offset (C0) in the Brewtus controller.
In brief, I conducted a series of tests at the 5 mm bolt in the brewhead where from a set front panel temp of 96 degrees and a varying programmed offset (C0) of -1 to -9 degrees (i.e. target brew boiler temps from 97 to 105 degrees C) that any offsets from -4 to -9 failed to make any difference in the measured water temperatures.
If I could there'd be one thing that I'd change with how I ran the experiment, and that is with the 5 mm bolt in place and all efforts done to ensure that it simulates as much as possible a loaded puck in the portafilter as well, with all temperature measurements taken right at the puck itself.
This is something that one can easily do with a Scace device, and if I had one I wouldn't be making this request.
So if you're at all interested, all I ask is for a series of measurements as follows:
- With the front panel temperature fixed at 96 degrees C, measure the brew water at the portafilter with a Scace device under varying values (-1 to -9) of Brewtus' offset (C0) parameter
- For consistency start each measurement by waiting for the brew power light to go on then go off
- As soon as the brew light goes off, start the pump and make the measurement, or at least before an espresso's worth of water has been drawn
BTW here are the results of my original tests:
Expected Estimated
Boiler Temp at Temp at
Setpoint Offset Temp G/H bolt P/F
96.00 -9.00 105.00 99.00 96.78
96.00 -8.00 104.00 99.00 96.78
96.00 -7.00 103.00 99.00 96.78
96.00 -6.00 102.00 99.00 96.78
96.00 -5.00 101.00 99.00 96.78
96.00 -4.00 100.00 99.00 96.78
96.00 -3.00 99.00 97.39 95.17
96.00 -2.00 98.00 96.78 94.56
96.00 -1.00 97.00 94.17 91.94
