Log a roast, score it on an SCA-style cupping sheet, and work out your brew ratio — all linked to the same batch, so you can actually see which roasting choices produced the best cup.
Enter your times and weights — weight loss and development time ratio are calculated automatically.
DTR is the percentage of your total roast time spent between first crack and drop — (drop time − first crack time) ÷ total roast time × 100. A commonly-cited target for specialty roasting is 20–25%, though the cup itself is always the final judge, not the number.
The real SCA protocol assesses five identical cups of the same coffee, which is how uniformity, clean cup and sweetness get properly tested. At home you're almost always tasting one cup, so those three categories are simplified to a straightforward yes/no here rather than requiring five servings — everything else follows the same 6–10 scoring and 80-point specialty threshold professionals actually use.
A roast log on its own tells you what you did. A cupping score on its own tells you how it tasted. Neither tells you much alone — the value is in seeing them together over enough batches to notice a real pattern, like "my highest scores keep coming from a slightly higher DTR on washed coffees."
The reference ranges reflect common specialty-coffee practice, but roast level, grind, and personal taste all shift the right ratio for a given coffee. Use the calculator to get in the right neighbourhood, then adjust from there.