Artisan Coffee Roasting & Data Analytics

RoastDTR Pro

Calculate roast Development Time Ratio (DTR %), moisture weight loss %, and roast phase percentages for Aillio Bullet, Gene Cafe, and commercial drum roasters.

☕ Batch Timing & Weights
e.g. 454g (1 lb)
e.g. 392g
⏱️ Roast Milestone Timestamps
📊 Roast Profile Diagnostics
17.1%
Optimal Specialty DTR (Sweet & Balanced)
13.66%
Moisture Weight Loss
1:45
Development Time (FC→Drop)
10:15
Total Roast Time
City / Light-Med
Estimated Roast Level
Three-Phase Roast Proportion Drying: 46% | Maillard: 37% | Dev: 17%
■ Drying (Yellow) ■ Maillard (Orange) ■ Development (Purple)
💡 Flavor Prediction: 17.1% DTR with 13.7% loss provides a clean, vibrant cup with pronounced origin fruit notes and chocolate caramelization.
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The Science of Coffee Roast Development & Weight Loss

In specialty coffee roasting, raw green seeds undergo complex exothermic and endothermic chemical transformations. Two primary metrics define roast consistency across batches: Weight Loss Percentage and Development Time Ratio (DTR).

The DTR Formula Explained

Development Time = Drop Time - First Crack Start Time
DTR % = (Development Time / Total Roast Time) × 100%
Weight Loss % = ((Green Weight - Roasted Weight) / Green Weight) × 100%

Pioneered by coffee consultant Scott Rao, keeping DTR within the 15% to 20% golden window ensures the bean core is thoroughly roasted without baking out the organic acids (citric, malic, phosphoric) that give high-elevation Arabica coffees their prized complexity.

Frequently Asked Questions

What happens if DTR is below 14%?
A very low DTR often leaves the bean core under-caramelized. This results in grassy, hay-like, astringent, or sharp sour flavors with a peanutty aftertaste.
What happens if DTR exceeds 22%?
Excessive development time creates a "baked" profile where heat has degraded the origin fruit acids, leaving a hollow, bread-crust, flat cup lacking fragrance.