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Using a Fixed Profile Bob Books
allenb
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Posted on 11/01/2023 10:01 AM

Quote

So DRUMTC posted a link to this Scott Rao chart for roasting times. I have not tried to verify this.
https://www.bobbo...

Note that I find myself in the middle of those min-max times when I roast.


I'm reposting Harrydogs post citing Bob Books good article on using a profile that can work for most coffees.

I've come to the same conclusion over the last couple of years of experimentation with lots of coffees. With my 1/4 lb drum, it's a fairly fast 3 1/2 to 4 minute ramp to yellow, cruise through Maillard in 3 minutes and 1:30 development for a nice light roast.

For my 1 lb drum, 6 minutes to yellow, 5 for Maillard, 1:30 development for light roast. My standard for both drum roasters is a 10 F/min RoR for development. The only thing I find I'm altering depending on greens, is the development time.

I can't stress the importance of experimenting with different development times with any new coffee. For an example, I recently bought some Kenya Njawato and did several roasts in the 1/4 lb drum using anywhere from 1:40 to 2:10 development with a 10 F or so per minute rate. All of them lacked that Kenya sparkle and winey acidity. I concluded that it was a so-so Kenya. Then a few days later I did another roast and decided to try a shorter development which ended up being 1:20. Did a french press the next morning and it was an entirely different experience. Full body, classic winey Kenya acidity and various spice notes. During one more experiment with the same coffee I tried the same roast but using 8F/min development instead of 10. While it was a good cup of coffee, it lacked complexity and sparkle.

I think Bob's major point is to find a profile for your particular roaster that gives the best overall results and with any new coffee, only play around with development RoR and development time which will keep the variables down to as few as possible otherwise, you will be chasing after the wind.
Edited by allenb on 11/01/2023 11:30 AM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
HarryDog
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Posted on 11/11/2023 8:48 AM
What matters in the Yellowing Phase?

What I hear or read is pour the heat to the beans as much as possible without causing roast defects. I also hear that this has Zero effect on the taste of the coffee?

I'm looking at this phase as my last round of tests are just so different from each of the other roasts that I want to find a good Yellowing ROR that would set up the rest of the roast for success.

My best roast so far was dropped at 230F, TP=189.6 with a yellowing ROR=33F/min After watching this video was thinking about how narrow the window for the yellowing stage might be?



Two pics from the video and one on a Resting coffee study.
HarryDog attached the following images:
resting.jpg roast-info.jpg roast-changes.jpg
 
renatoa
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Posted on 11/11/2023 1:30 PM
Conclusions based on Dry phase RoR should be taken with some salt, because this number is a convention, not a real thing.
That's because it is computed from TP, not from the start of roast... the TP being also a convention... in no way is it possible to have 90 C degrees beans temp at minute 1, don't you think ? Would scorch as hell...

The RoR displayed by Artisan is computed from TP, not from the roast start, so the values are artificially lower... it's easy to have 33F(18C) degrees average RoR during dry, if computed as 150C (dry end temperature) - 90C (at TP), divided by time from TP to DE... thus 60C degrees, divided by 3:20 minutes.

Instead, the real dry phase RoR average should be 150C (dry end temperature) - 25C (beans temperature at charge), divided by dry end time, counted from the start = 4:20
This gives us a whooping 29C = 52F average RoR during dry.
One more reason to not trust Artisan values.
 
HarryDog
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Posted on 11/11/2023 2:19 PM
I agree with that, I'm just looking at the data in the video as they use the same reference points and my results look to follow much of the same pattern.

I don't think my TP will be the same but based on that video I want to try a roast at a lower Charge/TP to see if I can improve the cup or not?

So far just going hotter and lowering FC has not improved the cup like I expected. I have enough beans for one more test.
 
allenb
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Posted on 11/12/2023 10:54 AM
Nicki's test results are of value to people using similar sized drum roasters with similar thermometry as their so called turning point will be in the range of her roaster and subsequently, RoR average will track closer to hers. Otherwise, the takeaway is that the curve shape of the drying phase can affect the end product.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
HarryDog
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Posted on 11/12/2023 1:55 PM
Hey allenb, what is your yellowing ROR when you hit 10F/min development?

So far looking at my data if yellowing ROR is around 31.5F/min = 12F/min development, at 35.5F = 8.5F/min development.

Now I'm sure each bean is going to be a little different but in my data it look's like around 33-34F/min yellowing is easier or more natural to end around 10F/min development for me and my roast style.

I should add that this is looking at the faster/hotter lighter roasts I have been trying lately.
Edited by HarryDog on 11/12/2023 2:07 PM
 
renatoa
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Posted on 11/12/2023 2:33 PM
Did you tried to find such answers using the Artisan Designer?
Just draw a profile and check on screen the RoR in various stages...
Unfortunately, Artisan don't give a hint about the effect of changes on the final taste...
 
allenb
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Posted on 11/12/2023 4:51 PM

Quote

HarryDog wrote:

Hey allenb, what is your yellowing ROR when you hit 10F/min development?

So far looking at my data if yellowing ROR is around 31.5F/min = 12F/min development, at 35.5F = 8.5F/min development.

Now I'm sure each bean is going to be a little different but in my data it look's like around 33-34F/min yellowing is easier or more natural to end around 10F/min development for me and my roast style.

I should add that this is looking at the faster/hotter lighter roasts I have been trying lately.


Since the drying phase includes the steepest slope area of the roast (at the start), there's really no area within this phase that has a constant rate of rise. My typical roast now is hitting a RoR in the upper 40's F just after TP (165F) then for the majority of this phase it's tapering down from upper 30's F down to 25 F/min by the time BT hits 320F (yellow). By 340 F BT, it's typically down to 20F/min.
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
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