For many years there has been a fashion for good-looking, straight, steadily declining RoR profile curves. Either your curve looks like a half of a perfectly shaped mountainside or something’s wrong. Whether only just this one RoR shape is right is a topic for another day and today let’s focus on another matter – its value.
You can have the best looking RoR curve ever with no flicks, bumps and crashes, but your coffee’s gonna taste flat and lifeless when the temperature rise over time is insufficient. It’s tricky to create a reliable rule of thumb here due to differences in size, location and type of probes.
Also different coffees need different speeds of roasting. But from my experience, from various drum roasters hitting the crack with the RoR lower than 8°C/min will most likely end up with some baked flavors and coffee lacking intensity and articulation. The lower you go with the value, the most evident it becomes. Regardless of the curve shape.
Try to find your optimal RoR window before, during and after crack. It might be a matter of speeding up the roast in its last phase in order to bring more brightness, saturation and character out of given coffee.
Our Roasting Tips are brought to you by Piotr Jeżewski (88 Graines Q Grader & Sourcing Director)