Why RoR is a bad reference for ... [webinar] - Page 5

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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Team HB

#41: Post by another_jim »

Marcelnl wrote:it's basically this part above and the fact that need for power input decreases that brought me to my current 'system' of keeping air flow constant, gas power input steady for x seconds (3'20 or thereabout) from charge (no soak) to then decrease by Y Kpa per Z seconds (0.5KPa per 30 sec). The specific heat of my roaster is constant, that of the beans is not. It seems to work in a perf drum Huky doing 400g batches pretty nicely.
My guess is that this is the way most competent drum roasters approach the roast. The question is what kinds of temperature monitoring are needed to decide the timing of when to decrease power, and at what rate. I use BT = 190C as my trigger to start turning down the heat (the Quest is not a very heavy or high momentum roaster); and I use keeping the ET constant to regulate the rate I decrease the power.

If your charge weights and roasting environment are very constant, pure timing will probably work just as well. If things are more wonky and variable, maybe looking at the rate of rise helps as well. But this very specific use of RoR (for timing the decrease of heat going into the first crack) is very far from all omens of flicks and crashes that are being decried in the video.
Jim Schulman