Steve's Ultimate Profiles 100g - Constantly Declining Fan Profile (Fan Cal 0.91)

[Steve]

I reckon that is about the right med - dark roasts and probably sit on that for some time.

Hi Steve

I’m wonder how your MD4 is after a few days now for espresso/with milk. And if you have used other beans with the profile with success?

Also to anyone else reading this that have tried Steve’s MD4 profile and feedback please.

Cheers

I think that most of these 1200 to 1300W start profiles a probably overdoing it.

This thread was my response to how the PID handles power (heater) throughout a roast.
Try and "charge" the roast with a heap of heat so that it stabilises things and the PID will not make too many adjustments, I thought it kind of worked...BUT I continue to experience / gather evidence that any reduction in power (heater) throughout the roast by the PID is creating roast defects. Where and how many times this happens during the roast determines what kind of defects will be most prominent or just a muddled baked mess.

Since your questions on power profiling I was inspired to go back and have another serious crack at it, so this is what I have been doing in between my probe crapping out twice. Last night I managed to cobble together a new probe similar in length to stock thermocouple sheath, using the old stock thermocouple and an old instant read thermometer tip and its working quite well.

This is where I am at....with the caveat that this is for ONE particular green coffee, 2020 washed Caturra from Costa Rica, 1400 - 1700 MASL. Any hope of getting this approach to work with other coffees will likely require several test roasts with careful observation of how they play out then with an understanding of how and why power profiles work make careful adjustments to the calculations to get the best possible result.

These settings will not be directly transferable to anyone else's roaster or location environment even using the same green coffee but likely a good starting point.


Starting power / pre heat power = 1000W
I want to hit colour change around 2:45 - 3:00 at 1200W

Zone 1
Start: 0:00
End: 3:10
Boost: 25 (boost is 25% on 1000W should be 1250W, BUT the calculations used on the power profile zones do not like large numbers, the larger the number the more the gap grows. But its usually around 5 to 6% loss of programmed increase boost %, so 25% boost allows for this giving me close to 1200W by 3:00)

I want roughly around the same time to FCS 2:45 - 3:00

Zone 2
Start: 3:00 (this needs to be 10 sec before the end of zone 1 otherwise there will be a blip where PID comes back online)
End: 8:00
Boost: 4.16

I have not been able to use a Zone 3 successfully without power interruptions from PID?

The Zone 2 end point time combined with Boost % will determine ROR going into and through first crack, which requires some trial and error depending on whether you want a dark or light roast. Darker roasts need to be going faster through first crack to hit higher end temps with a constantly increasing power profile.
Something like 3:00 / 3:00 / 2:30 to 3:00 to the start of 2nd crack is great starting point for most Arabica.

The following are from the Costa Rica Caturra previoulsy mentioned.
Both are 13.4% weight loss
Both look very similar whole bean and ground, that is where the similarities end.
The POWER profile is cupping very clean and focused, sweet and aromatic with no off tastes.

Once I was happy with the POWER profile I made it into a normal PID profile to see what would happen. It tastes as bad as it looks, I figure the way power is all over the place at the start (big increase and decrease like my previous profiles in this thread) is causing underdevelopment this is followed by a big increase in heat /power up to and through colour change then a dramatic drop around the start of browning which will be BAKING the hell out of it. This results in a strong roasted vegetable character, thin, not sweet, no acidity and a persistent rough bitterness aftertaste. These 2 nearly identical roast could not be further apart in taste....

CostaPOWER.JPG (84.73 KiB) Viewed 7330 times

CostaPIDpower.JPG (88.17 KiB) Viewed 7330 times

FanProfilePOWER.JPG (70.18 KiB) Viewed 7330 times

Power.kpro

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[Geronimo]

Good stuff Steve

I see you’ve gone back to a decreasing RoR. Interesting fan profile. Any particular reasoning for the shape, rather than using your constant declining option?

Interesting zone 3 doesn’t work, and that was zone I tried and failed, when I should have used zone 2. I wonder if there is something different with the zone 3 coding, and should have worked for me?

Anyway, thanks for your efforts again. I was going to try another power profile yesterday, but luckily held off, and glad, as Ive been able to gleam some more knowledge which is helpful.

Cheers

[Steve]

Good stuff Steve

I see you’ve gone back to a decreasing RoR. Interesting fan profile. Any particular reasoning for the shape, rather than using your constant declining option?

Interesting zone 3 doesn’t work, and that was zone I tried and failed, when I should have used zone 2. I wonder if there is something different with the zone 3 coding, and should have worked for me?

Anyway, thanks for your efforts again. I was going to try another power profile yesterday, but luckily held off, and glad, as Ive been able to gleam some more knowledge which is helpful.

Cheers

The declining ROR happened by accident seems it is the natural consequence of a well executed roast?
Which will make many people happy im sure.....

The fan profile is still constantly declining, just less and less as the roast progresses.
The shape is what I came up with after A LOT of trial and error. If i swap out the fan profie for the diagonal line from CDFP the roast takes off like a rocket into and through first crack. It will hit like 225C before finishing first crack and then flys straight into 2nd crack.

Zone 3 issues i have no idea, the programs are above my pay grade...im just trying to get the best out of it

[Geronimo]

The fan profile is still constantly declining, just less and less as the roast progresses.
The shape is what I came up with after A LOT of trial and error. If i swap out the fan profie for the diagonal line from CDFP the roast takes off like a rocket into and through first crack. It will hit like 225C before finishing first crack and then flys straight into 2nd crack.

Zone 3 issues i have no idea, the programs are above my pay grade...im just trying to get the best out of it

Hi Steve

I understand now on the fan profile, makes sense.

Cheers

[fnq]

Hi Steve

I am trying to get my head around the bean difference between power and pid jpegs.
Quite thought provoking.

I haven't been able to keep up with your inventiveness ( my caffeine intake is already excessive) but i do appreciate your experimenting and sharing Darryl

[Steve]

None of this was invented by me im just following / paraphrasing what others much smarter than me worked out long ago about basic roasting principles.

It is the environment ( think oven, hooded BBQ) that the green coffee is exposed to which does the roasting. Simple logic says we better control that environment as best we can and others have established that this ideally is 240 - 270C, likely 235 - 250 for air roaster.

If the environment is a big heavy steel drum, that will require pre heating like you would an oven or BBQ. The KL is basically roasting in a beer can using a constant stream of hot air which also is responsible for agitation, so no pre heating required.

Once you have started applying heat to the seeds, ideally the environment which is doing the roasting will steadily rise all the way to the very end getting slower and slower in that rise (ROR) but never suddenly stopping or dramatic changes up / down.

Conversely, when baking bread I want to heat up my steel mass / plate much hotter than I would to roast something. So that once the bread has steamed for 10 - 15 mins i will have a constantly declining oven temp.

The only way to have a solid chance of producing a good roasting environment with the KL, is if the power profile which is the heater element is constantly slowly / steadily increasing in power which results in the hot air stream that is our roasting environment (hopefully) always steadily increasing until we hit cool.

Going back to ovens and BBQs, you can roast or slow cook a chunk of meat. It can be very useful to have a probe inserted into the center of the meat linked to an external thermometer to help measure when its done. But if one was to rely solely on this measurements rate of rise to roast or slow cook, you will have no idea what to do with the burner settings. Instead, we usually have another environment probe in the BBQ and a thermostat in an oven calibrated to an external temperature control dial.

With coffee roasting we can not measure the inside of each individual seed so best we have is a "pile temp" which is a very chaotic and noisy mixture of air, seeds and radiant heat from the roasting vessel = not very consistent data.

Best thing we can do is to find a consistent way of measuring the environment that does the roasting. I tried various locations just outside the roast chamber inside the KL and the variation of different locations makes this not possible. The variation is likely the consequence of how fast the air is moving through the roaster.

Which leaves us with the power profile or heating element profile never being allowed to stop rising.
Balance this with the appropriate fan profile and roast time for a particular seed size / moisture release at first crack and we have a roast profile and in this case with a ROR that also looks pretty good as an artifact of everything else.

Hence focusing only on Bean Pile Temp ROR-ology is putting the cart before the horse.

Hope that helps explain things better and why ive gone to such great lengths.

[fnq]

Great explanation.

[Mark]

Below is a screenshot of Steve's "Power" at 4.9 (Colombian Volcan Galeras Supremo).
At first glance - whoa overshoot ... but it did a good job of following the profile ... just well above the line.
But the original was set at 1.4 ... not 4.9 as this is ... so is it meant to be above the line?

Cheers Mark

[mr. bean]

I had similar experience. Tried POWER with Colombian Excelsor.
Roasted to 2.3 for about 21% DEV

I tried another batch with the fan calibration down to 0.91 (from 0.94), and up from 100g to 110g, just to see if that helped, but the take off was even greater!

log0402 (POWER with Excelsor).png (86.8 KiB) Viewed 7217 times

[Matt S]

Mark and Mr Bean, notwithstanding the overshoot, do you have any feedback on aroma/taste? I’ll be interested to hear how you find it.