Rate of Rise, or RoR, measures how quickly bean temperature climbs during a roast, expressed in degrees per minute. For roasteries working with green coffee from Intercontinental Coffee Trading, reading and adjusting RoR is the difference between a flat, baked cup and one that expresses the origin clearly. A declining RoR curve from turning point through first crack is the standard target, but the rate of that decline, and how it moves through development, changes what ends up in the cup. Roasters who monitor RoR in real time can catch crashes, flicks, and stalls before they lock in defects that no blending or brewing adjustment can undo later.
This guide walks through what RoR actually tells you, when to intervene with gas or airflow, and how to read the curve across different origins and bean densities.
What Rate of Rise Actually Measures
RoR is the first derivative of the bean temperature curve. If your bean probe reads 300°F at one minute and 320°F the next, your RoR at that point is 20°F per minute. Most roasting software calculates this on a rolling basis, smoothing the data to avoid noise from probe lag or fluctuations.
The number itself matters less than its trajectory. A high RoR early in the roast is normal and expected as the drum transfers heat into cold green beans. As the beans absorb energy and approach first crack, RoR should gradually decrease, showing that the roast is developing evenly rather than accelerating into a scorched finish.
Why a Declining Curve Matters
A steadily declining RoR curve indicates controlled energy transfer. When the curve declines too fast, beans can bake, producing flat, cardboard-like flavors. When it declines too slowly or climbs again, you risk tipping, scorching, and bitter roasted notes masking origin character.
The Ideal Shape
Most specialty roasters target a curve that drops from around 30°F per minute at turning point to between 5°F and 10°F per minute by first crack, then continues declining through development. The exact numbers depend on batch size, drum material, and roaster design, but the shape should remain consistent batch to batch for any given coffee.
Reading Crashes and Flicks
Two RoR patterns cause the most problems in specialty roasting: crashes and flicks. A crash happens when RoR drops sharply right before or during first crack, often because gas was cut too aggressively. The result is under-developed coffee with sour, grassy, or hay-like notes.
A flick is the opposite problem. RoR declines normally, then spikes back upward during development, usually from residual drum heat or late gas adjustments. Flicks produce harsh, ashy, or burnt flavors that overpower the sweetness you worked to build earlier in the roast.
Catching Problems Early
Watching RoR in the 30 to 60 seconds before first crack gives you a window to adjust before either pattern locks in. Small gas reductions of five to ten percent can smooth a curve that is declining too slowly, while holding gas steady through first crack can prevent the crash that follows an aggressive late cut.
When to Adjust Gas
Gas adjustments move RoR more than any other variable. The timing of those adjustments determines whether you shape the curve or chase it. Early-roast gas changes, made in the drying phase, influence the overall slope of the curve. Mid-roast changes, made during Maillard reactions, affect how the curve transitions into first crack. Late-roast changes shape development and finish.
A common mistake is reacting to RoR spikes with large gas cuts. The drum and beans have significant thermal mass, so a gas change made at 7:30 into the roast may not fully register on the RoR reading until 30 to 45 seconds later. Making small, anticipatory adjustments produces smoother curves than large, reactive ones.
When to Adjust Airflow
Airflow affects RoR by changing convective heat transfer and evacuating chaff and moisture. Increasing airflow mid-roast can flatten a curve that is declining too slowly by pulling heat away from the bean surface. Decreasing airflow has the opposite effect, concentrating heat but risking smoke retention and tipping on lighter beans.
For dense, high-grown coffees from origins like Ethiopia, Kenya, and Colombia available through Intercontinental Coffee Trading, airflow becomes a finishing tool. These beans hold onto moisture longer and benefit from slightly increased airflow in the final two minutes of the roast to prevent RoR flicks and evacuate volatiles that can muddy the cup. Contact Intercontinental Coffee Trading to source green coffee that gives you the quality foundation your roast profile needs.
How Bean Density Changes the Math
Dense beans from high-altitude origins absorb energy differently than softer, lower-grown coffees. A RoR profile that works beautifully for a washed Brazil at 1,100 meters will often crash a washed Ethiopian at 2,000 meters because the denser bean needs more sustained heat to reach first crack without stalling.
Roasters working with diverse origins should expect to recalibrate RoR targets for each coffee rather than forcing every bean through the same curve. Tracking turning point temperature, time to first crack, and development ratio alongside RoR gives you the full picture needed to dial in each lot.
Building a Repeatable Profile
Once a roast produces the cup you want, the RoR curve from that batch becomes your reference. Recording the curve, along with environmental conditions, charge temperature, and gas settings, lets you reproduce results across seasons and batch sizes.
Software like Cropster, Artisan, and RoastLog stores these profiles and overlays live roasts against them, making deviations visible in real time. Consistency here protects wholesale accounts and subscription customers who expect the same coffee to taste the same every week.
Common Adjustments for Common Problems
Certain RoR patterns call for specific responses, and recognizing them speeds up your decision-making during live roasts:
- RoR climbing instead of declining in the drying phase usually means charge temperature was too high or gas is set too aggressively
- A stall near 300°F often indicates insufficient gas during the endothermic stretch before Maillard reactions begin
- Crashes approaching first crack typically trace back to gas cuts made too early or too sharply
- Flicks after first crack point to residual drum heat or late gas changes that took effect after the crack started
Reading these patterns across dozens of roasts builds the intuition needed to move from reacting to RoR data to actively shaping it. The roasters who consistently produce clean, expressive cups are the ones who have internalized what their specific machine does with their specific coffees, and who source green beans good enough to reward that attention.