Good flavour development for espresso.
First crack should be at about 7:40 and the default level 3.0 will stop the roast at 20% DTR at 9:35. Extending the development to 25% takes the roast to 10:00 at level 3.5. Darker roasts will have larger DTR, up to level 5.9 which will end at 15:20 at 240 deg C.
Created by Rob Hoos at Firestarter workshop, Melbourne, 5 Feb 2019, with subsequent tweaks by Chris Hilder to some profile settings.
Each profile contains a setting called roast_required_power. In the Firestarter profile this is set comparatively high at 1350W. In calculating the required voltage the roaster measures the supply voltage and uses Ohm's law to calculate the power that voltage will deliver. It also adjusts the required power by a factor based on ambient temperature. At 20 degrees C and 1350W required, it will require sqrt(1350*40.4) = 233.5V. Should your supply measure 229V that equates to 229*229/40.4 = 1298W, which is 96% of the required power of 1350 W. At ambient temperatures below 20 deg C the required power is increased by about 0.5% per degree below 20. So my guess is your ambient temperature was around 16 deg, and the machine was reading 229V. If I am wrong there is something else going on that I have not accounted for.
The short answer is that the roast_required_power setting in the Firestarter profile is probably too high, and a value of 1300 or 1250 is most likely more reasonable. You could either customise your copy of the profile using the 'Profile settings' tab of Profile Management Studio, or just ignore the power warnings unless they are below 90%.
So my guess is your ambient temperature was around 16 deg, and the machine was reading 229V. If I am wrong there is something else going on that I have not accounted for.
It was definitely saying 239V; I double-checked the picture I took of it to be sure. I should have a log of that roast if it would help.
I'm currently roasting my second batch of Firestarter, and it said 240V is 95% recommended when I last looked at it; just after starting it going I'm pretty sure it claimed 231V was 98% recommended.
It looks like the ambient temperature adjustment is the culprit here. The roaster has detected an ambient temperature of 13.5 deg C. However, it seems to be over-correcting for temperature. I will carry out further investigations here, meanwhile I would ignore any warnings so long as it claims over 90%.
"Created by Rob Hoos at Firestarter workshop, Melbourne, 5 Feb 2019"
Intrigued....Chris could you give us a little more info on how this came about?
Did Mr Hoos spend much time with the Nano...was this his first profile with it?
Rob Hoos had about an hour with the Nano 7. After completing one roast he made a series of changes to the profile changing both temperature and fan. The result I have published as the Firestarter profile with his permission. Although he had only a short space of time with the roaster, he has a wealth of experience with air roasting at similar batch size and was able to immediately see the direction he wanted to take the profile in.
kaffelogic wrote: ↑Sat 30 Nov, 2019 5:26 pm
Rob Hoos .... made ... changes to the profile changing ....[the] fan.
This is fascinating.
Looking at the area under the Firestarter fan curve compared to the standard fan there is (my estimate) perhaps 20% more air in the system. The received wisdom from your writings, Chris, is that the air flow keeps the beans at the glass/fluid interface and the air needs to be reduced as the beans loose mass. Clearly Rob Hoos has thrown that received wisdom away and supplanted his own.
Should we increase the fan à la Rob Hoos for the other profiles too? if not, why?
Firestarter.kpro
