Roast Curve Simulator
Drag the five points to shape a roast. Watch the rate of rise, and we'll call out scorching or baking if the curve produces it.
Batch size changes how the curve should behave: a smaller batch has less thermal mass, so it charges cooler, turns faster, and moves through the roast quicker than a shop-scale batch.
Rate of rise — how fast the beans are heating, in °F per minute. This is what actually decides scorching or baking, so watch it as you drag: it should climb right after the turning point, then fall smoothly the rest of the way. The shaded band is where a roast starts to bake.
The rate of rise climbed back up after it had already started falling. That usually means too much heat too early — the surface of the bean is browning faster than the inside can catch up. Try lowering the charge temperature or pulling back heat sooner after the turning point.
The rate of rise dropped and stayed too low for too long. The beans are still gaining heat, but too slowly to develop flavor — this flattens the roast and mutes acidity and sweetness. Try shortening that flat stretch or adding a touch more heat through the middle of the roast.
