Regarding RoR (Rate of Rise)
RoR (Rate of Rise) is a numerical value that represents how quickly the temperature of coffee beans is rising.
Simply put, it's an indicator of
"how intensely the beans are currently being heated."
RoR = Green Line
■ Understanding through an image
For example,
- Temperature rising slowly → Low RoR
- Temperature rising rapidly → High RoR
That's the basic idea.
■ Why is RoR important?
RoR is a crucial indicator that greatly influences the outcome of roasting.
- Too high → Easily scorched, likely to result in unstable roasting
- Too low → Roasting doesn't progress as desired, taste tends to be bland
Therefore, it's important to increase the bean temperature smoothly while monitoring the RoR.
■ Key points for Kaffelogic
With Kaffelogic, if the RoR gets too high, the roasting may stop as a safety feature. This is not a malfunction; it's the machine's safety device stopping the roast because a sudden rise in temperature can cause heat to build up inside the unit.
■ For first-time roasters (Basic concept for profile creation)
Example of KL-Classic
There's no need to overthink it at first.
Kaffelogic's default profiles are designed for a smooth, gradual decrease in RoR values.
Therefore, it's important to have the image of gradually lowering the RoR and slowly increasing the roasting temperature over time, as shown in the picture below.
In KL-Classic, the RoR is designed to gradually become gentler as roasting time progresses from the start.
For example,
- Immediately after roasting starts: Approx. 1 minute to raise +80℃
- After 1 minute: Approx. 2 and a half minutes to raise +80℃
By designing the temperature increase to gradually slow down in this way, it's possible to prevent the occurrence of thermal runaway.
【❌ Examples of profiles prone to thermal runaway】
Example ①: Rapid increase in ROR
Ideally, the ROR should gradually decrease as roasting progresses. However, in this profile example, the ROR exceeded 100℃/min and increased after about 3 minutes from the start of roasting. The heating amount became excessive, and the safety device activated at 3:30, stopping the roast and resulting in a thermal runaway error.
Example ②: ROR re-increase
Ideally, the ROR should gradually decrease with roasting time, but in this profile, the ROR re-increased around the 3-minute mark. The actual temperature also increased by about 50℃ in one minute from 3:00 to 4:00, and at 4:20, it was judged as thermal runaway, and the safety device activated.