jonr Senior Member Joined: 25 Jun 2013 Posts: 314 Location: Americas Expertise: I love coffee
Posted Sun Sep 8, 2013, 2:39pm Subject: Re: Home made Scace device (kinda)
I find that real coffee causes flow to increase as the shot progresses. So when looking at exact temperature profiles, a coffee simulator doesn't do a good job of matching coffee. Even if you could adjust a valve accurately as the shot progresses to simulate this, the initial absorption of water by the coffee is probably hard to account for.
An alternative is computer control of flow profiles. Then you don't need a coffee simulator or even coffee to get the right flow over time.
Apparently many thermocouple thermometers have horribly slow response time. You might want to check that it can rise from room temp to 212.0F in less than a second.
DeanOK Senior Member Joined: 24 Sep 2012 Posts: 720 Location: OK Expertise: I like coffee
Espresso: QM Vetrano 2B Grinder: Vario W
Posted Wed Sep 18, 2013, 1:39pm Subject: Re: Home made Scace device (kinda)
Ok.... I am feeling pretty good about the accuracy of my little scace type temperature device. I am considering ordering an data logger that will log the temperature profile and make a nice graph but the one I am considering ordering will not log any faster than every 1 second. I know I can get a logger that will log faster, but I am also ordering the logger for work and I can't really justify paying more for a logger than will log faster than every one second. I know I don't need a logger for my brew water temp, but I just think it would be fun to be able to log and check my machine and possibly others.
What I ended up doing is lining the bottom of my blind basket with black high temperature RTV silicone. The silicone is a bit ugly but provides the thermal resistance needed (from the blind basket) to get an accurate brew head water temperature. Calibrated for temperature, its within a couple of degrees of my V2B which was supposedly scaced by the distributor to provide an accurate brew head water temperature. My gut feeling is that my little device is extremely accurate, but I just can't prove it. By extremely I mean within 1 degree F or so. Close enough I think.
One thing that became glaring apparent was how far off the brew head temperature was on my CC1. I ended up playing with the CC1, adjusting the P9 offset, and learning how to do a warming flush and was able to get it reasonably close to the display brew temperature.
The next obvious question is "how much did it improve the taste of the CC1 shots?" Well, I don't know... I have the new V2b and I just haven't had the desire to play with the CC1 enough to find out. Hopefully I will find out soon though.
That should be close enough for home use. You might have to step up if competing with Scace :) The thermofilter confirms that you are close, then a degree or so one way or the other by the cup. Taste counts more than the readout as you know. That said, the data logger will be fun to use and document what you see.
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