Hi everyone, I’ve been doing some experimenting with my roast profiles lately to see what kind of effect they have on the final cup and roast trajectory in general and what I’ve been seeing has been surprising so I’d love to hear your thoughts!
My recipes are typically 775g with preheats between 275/280*C as a baseline. Previously I had beeb charging the roast at P8 then P9 then working my way down with some P + F adjustments but leaving D9 the whole roast.
I’ve now tried on about 6 different beans to charge the beans at P2 for about a minute before jumping to P9 and making adjustments from there to P + F. Drum remains D9 throughout. What’s been surprising to me is that the roasts with a soak carry more heat/momentum into FC than without a soak. Without a soak I rarely/if ever need to get to F4/5 and usually maintain P7 into/through development unless I need to drop to P6. With these roasts utilizing a soak period I actively need to hit F4/P6 around ~190* in order to avoid blowing through FC with RoR around 11/12*
I supposed my shock is that less power early on and that soak time would have stunted my roasts but instead it appears it has accelerated them to some degree. What are your experiences w/ or w/out soak?
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Interesting finding. Did you notice any different in flavor?
During a soak, the beans are heated gently by contact with the hot drum, so heat moves slowly into the bean core without creating much early RoR. At the same time, moisture inside the bean redistributes and leaves earlier and more evenly. Because of this, less moisture remains later in the roast to absorb heat and slow things down.
When you then apply high power, energy keeps stacking in beans that are already warm throughout. Around 180–190 °C, the stored internal heat is released quickly, RoR rises sharply, and the roast gains strong momentum into first crack. That is why you have to reduce power and increase airflow earlier to stay in control. Without a soak, more moisture remains to provide natural braking, so momentum into first crack is lower and the roast is easier to manage.
Starting with high heat drives energy quickly into the bean surface, creating an early RoR spike and flashing off surface moisture, while much of the core stays cooler. That remaining internal moisture provides natural evaporative cooling later, so there is less stored core energy and less momentum into first crack compared to a soak.
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Such a phenomenal explanation and insight! THANKS @secuspec
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Yeah, some mellowing in nice ways that highlight sweetness and softer notes that I love in light roasted beans. I can definitely tell though in one of the roasts that got away from me bc I wasn’t expecting the momentum @secuspec described and my RoR was hotter than I would like throughout development time which resulted in some harshness in the cup until it really cooled down.
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I’m curious how your FC times compare in these two roasts?
Ironically they were pretty consistent and similar. However DT* and DV % read different because the RoR were inconsistent between them.
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