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How to control Behmor Rate of Rise?

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  • How to control Behmor Rate of Rise?

    After FC I want to reduce the ROR but not so much as to stall it. I did some trial runs, without beans, so I could understand the ROR for P2, P3 and P4.

    ROR for P2, P3 and P4 were approx 3C/min, 9C/min and 14C/min respectively (ambient 26C). In practice this would vary depending on the volume of beans.

    What is puzzling is when you drop a power level, eg P4 to P3, rather than going from 14C/min to 9C/min ROR, it plateaued and went to 0C/min (top line). And when going from P3 to P2 it stalls and ROR is actually negative (middle line). So it seems reducing ROR but not stalling is not possible, not at least without flicking a higher power level on and off which surely can't the be way to operate this thing???

    Advice? Essentially I want my profile to look like this.
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  • #2
    The RoR will vary dramatically with beans vs no beans in the roaster. The RoR with no beans in the roaster is in no way equivalent to what you'll see when actually roasting with beans. The key is to think ahead of the roast and reduce the heat input before the RoR gets out of control. Approaching first crack coffee beans are endothermic, i.e. they are absorbing heat. When they hit first crack they go exothermic, i.e. they release heat. How much and when your reduce the heat will be determined by the beans you are roasting, the mass of the beans, and the heat input approaching first crack. The beauty of the Behmor Plus is that you have full control over how much heat is applied when. Forget trying to use a 'set and forget' approach. Using the manual settings will lead to far better results.

    Take a look at the profiles others have used, learn from them, and then apply what you've learned to your own roasting.

    Java "Experimenting is fun!" phile
    Toys! I must have new toys!!!


    • #3
      The RoR at the exhaust / wall (or in the space above the bean mass) is not the same as the RoR in temperature of the bean mass. I'd really advise concentrating on roasting great tasting beans first, and then stuffing around with noisy and/or biased measurements of the target variable. You risk driving yourself crazy coming up with a psuedo-solution to a non-problem. I have no problem avoiding a real stall with a 400g load that reduces from 100% to 75% to 50% (and even then 25%)....for most beans anyway.

      I suspect this issue might best be moved to one of the other active Behmor roasting threads.


      • #4
        Indeed Barry, this is a good thread for further discussion:

        Java "Thread closed" phile
        Toys! I must have new toys!!!