Dialling In — DTR, Rate of Rise & the Roaster’s Craft

June 12, 2026

Coffee Education · Part 3 of 3 · Final

We have explored what roasting does to a bean, and how origin and processing shape flavour before a bean even arrives in our roastery. Now we go inside the roast itself. This is where craft lives. What separates a memorable cup from a forgettable one is not usually the equipment — it is the precision of the roaster's decisions in a six-to-eight-minute window.

What Is a Roast Profile?

A roast profile is a complete record of a roast — a map of time against temperature showing exactly how the bean was heated from loading to drop. It captures the charge temperature, the turning point (when bean surface temperature begins rising), the progression through each stage, and the drop point. Experienced roasters develop profiles over dozens of test roasts, then lock them in. Consistency is the signature of mastery.

Rate of Rise — Managing the Momentum

Rate of Rise (ROR) is the speed at which bean temperature is increasing, measured in degrees per minute (°C/min). The ideal ROR for a specialty light roast is consistently declining throughout the roast — highest in the early drying phase (12–15°C/min) and slowing steadily toward first crack (5–8°C/min). A smoothly declining ROR is associated with clean, well-developed cups.

Three ROR Problems to Avoid

The Crash — ROR drops to near-zero. Bean stalls. Result: baked, flat, lifeless. The enemy of specialty roasting.
The Flick — ROR rises after declining. Causes scorching or uneven development.
The Smooth Decline ✓ — Consistent, gradual reduction throughout. This is what we target every batch on the Typhoon.

"In roasting, as in life, a steady declining rate of rise — not a crash, not a sudden flick — produces the clearest and most developed result."

Development Time Ratio (DTR) — The Master Metric

DTR is the single most important metric in specialty roasting. It measures how long the bean spent developing after first crack, as a percentage of the total roast time.

DTR (%) = Time from First Crack to Drop ÷ Total Roast Time × 100

Example: First crack at 5m 30s, total roast 7 min → DTR = (1.5 ÷ 7) × 100 = 21.4%

DTR Range	Outcome	Sensory Result	Best Suited For
<14%	Under-developed	Flat, bread-like, raw sour note	Avoid entirely
14–18% ✓	Light, clean, bright	Floral, citrus, tea-like, high clarity	Washed Ethiopian · Gesha · TCE light roasts
18–22% ✓	Balanced development	Caramel, chocolate, clean sweetness	Medium roast · natural-process single origins
22–25%	Extended development	Bittersweet, body-forward, rich	Medium-dark · traditional espresso
>25%	Over-developed	Ashy, monotone, no origin complexity	Dark roast only

TCE targets 15–20% DTR across all its light roasts on the Typhoon — single origins and both house blends alike, none exceeding 202°C.

Degassing — Why Fresh Coffee Needs to Rest

Roasting produces enormous amounts of CO₂ trapped within the bean's cell structure. Brewing too soon means CO₂ repels water and prevents proper extraction. Rest is not optional; it is part of the roasting process.

Brew Method	Recommended Rest	Why
Espresso	5–14 days post-roast	High pressure extraction needs more CO₂ purging; longer rest produces more stable shots
Filter / Pour-Over	2–7 days post-roast	3–4 days is the sweet spot; more CO₂ bloom means more even extraction
Cold Brew	3–5 days post-roast	Minimum rest before cold-brew steeping to allow CO₂ dissipation

Roast Defects — What to Avoid

Defect	Cause	Sensory Impact	Prevention
Baked	Stalled ROR / excess time at low heat	Flat, bread-like, hollow, no brightness	Maintain declining ROR; avoid long plateaus
Scorched	Excess initial contact temperature	Harsh, acrid on front palate	Air roasting minimises risk significantly
Underdeveloped	DTR too short — dropped before first crack	Grassy, astringent, raw sourness	Always develop past first crack; monitor DTR
Tipped	Excess conductive heat on bean tips	Smoky, papery notes	Convective roasting eliminates tip scorching
Quaker	Immature / unripe green bean (sourcing issue)	Peanutty, sour, harsh note	Detected in cupping; removed before release
Overdark	Extended past second crack	Carbon, ash, no origin character	Drop before second crack for specialty coffees

Every Roast Is an Act of Intention

When we load green beans into the Typhoon and begin a roast, we are not simply executing a process. We are making a statement of intent — that we will pay attention, manage the heat with care, and give this bean the best opportunity to become everything it was grown to be.

At The Caffeine Experience, we believe the same about every person we work with. Our beneficiaries — men and women restarting their lives — are not problems to be managed. They are people of extraordinary potential, waiting for the right conditions: a steady environment, someone paying careful attention, and the space to develop at the right pace. Roasting teaches us this every single day.

"For we are God's handiwork, created in Christ Jesus to do good works, which God prepared in advance for us to do."

Ephesians 2:10 — Every person, like every bean, is prepared with purpose.

Coffees From Our Roastery

Coffee	Origin	Tasting Notes	Price
Cornerstone Blend	Brazil Cerrado + PNG Mt Otto	Chocolate · Banana	SGD 13/100g
Crossroads Blend	Brazil Cerrado + Ethiopian Sidamo	Dark Choc · Wild Berry · Floral	SGD 13/100g
Halo Berity Yirgacheffe G1	Ethiopia · Washed · G1	Peach · Jasmine · Oolong	SGD 14/100g
Ethiopian Sidamo	Ethiopia · Washed	Floral · Citrus · Berry	SGD 14/100g
Colombia Gesha Estate	Colombia · Washed · Gesha	Pomegranate · Ribena	SGD 16/100g

Coffee Education Series — Roasting ✔ Complete

Part 1 — 29 May ✓
From Green to Gold
Roasting basics, Typhoon & roast levels.

Part 2 — 5 Jun ✓
The World in Your Cup
Origins, terroir & processing.

Part 3 — Now Reading
Dialling In
DTR, Rate of Rise & defects.

References
Rao, S. (2014) The Coffee Roaster's Companion. Scott Rao Publications. | SCA (2024) Roasting Foundations. sca.coffee. | ASEAN Coffee Institute (ACI) (2025) Barista Certification Level 2 — Roasting Module. aseancoffeeinstitute.org. | Barista Hustle (2025) 'Understanding Development Time Ratio'. baristahustle.com. | Schenker, S. et al. (2002) 'Impact of roasting conditions on the formation of aroma compounds in coffee beans', Journal of Food Science, 67(1), pp. 60–66.

Soli Deo Gloria — To God alone be the glory. | The Caffeine Experience | theofficialtce.com