Coffee Roasting     Up for a little crowd sourced coffee science?

2023-11-24 11:42

Up for a little crowd sourced coffee science?

If you are up for a bit of coffee science, I've got a request.

We've been thinking a lot about how mid-phase development time affects post first crack development.

It might seem obvious, but a lot of Roasteers -not a typo- ...seem to overlook the fact that coffee heats from the outside to the inside. The entire idea behind development time ratios is to allow the time necessary for heat to penetrate into the interior of the seed for more complete development.

We'll be doing a sequence of roasts next week with the same green/yellow transition, first crack, development time and finish temp while extending the mid-phase by 1 minute.

That's something like first crack at 8:00, 9:00, 10:00. and 11:00 with 1:40 development to 10 degrees Fahrenheit beyond first crack.

I'm asking you to roast at least 3 iterations, measure whole bean and ground roast color, cup each one and finally report your findings and share your roast profiles in this forum.

If you don't have a Lightells CM100 or CM200, mail me 200 gram samples and we'll measure for you.

If this pans out, we should be able to come up with a super cool and super useful predictive model for post first crack development.

If you have any questions, comments or suggestions, let me know here or call me at 612-886-2089








2023-12-02 02:23

Not seeing any responses here, but this looks like an interesting experiment. Are you suggesting a specific green? Also, I can easily hit those targets on my PID controlled 3e. My MCR 3kg will still not be up and running next week. I don't have Lightells, but I do have a KN201. Given other roasters tests even the same brand meters can be off quite bit when measuring the same coffee.



2023-12-02 03:38

Any green on any roaster you can connect RoastPATH to.

Give it a shot and mail samples for color analysis.

Repeat the process with your 3kg when its running.



2023-12-05 19:20

I really like the idea of this. I gave it a couple of tries but couldn't nail it. I'll have to try it again down the road when I've got a better mastery of this machine. I'm excited to see the results of this!



2023-12-14 20:38

...With that being said, is there some sort of mathematical function (I'm assuming calculus?) that allows one to calculate "Temperature Guide Posts" for a given time range?

My logic says that if I have the following information...

  • Green to Yellow data (Time, Temp, ROR)
  • Desired Mid Phase data (Time delta, Temp delta)
  • Development Phase data (Time delta, Temp delta, Average ROR)

...that there's a some sort of mathematical function (probably calculus, possibly integrals involved?) that would allow me to generate "Guide Post Temperatures" with a ROR to sit nicely between the RORs from the other phases.

Am I crazy? Am I overthinking this?






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