Development time ratio

Definition

Development time ratio (DTR) is (time after first crack) / total roast time. A common starting band is 20–25%. Shorter DTR keeps more acidity and can taste grassy if underdeveloped; longer DTR pushes sweetness then roastiness. DTR is a clock ratio, not a colour meter — two roasts with the same DTR can still miss if rate of rise collapsed after crack.

Calculators that use this

• Coffee roasting

  Roast Development Time Ratio Calculator

  Compute development minutes and DTR percent from time to first crack and total roast time. A clock ratio, not a colour meter.

• Coffee roasting

  Roasting Weight Loss Calculator

  Turn green and roasted mass into percent weight loss and yield. A crude roast level proxy: more loss usually means a darker roast.